city.c

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/***********************************************************************
 Freeciv - Copyright (C) 1996 - A Kjeldberg, L Gregersen, P Unold
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.
 
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
***********************************************************************/
 
#ifdef HAVE_CONFIG_H
#include <fc_config.h>
#endif
 
#include <stdlib.h>
#include <string.h>
#include <math.h> /* pow, sqrt, exp */
 
/* utility */
#include "distribute.h"
#include "fcintl.h"
#include "log.h"
#include "mem.h"
#include "support.h"
 
/* common */
#include "ai.h"
#include "citizens.h"
#include "effects.h"
#include "game.h"
#include "government.h"
#include "improvement.h"
#include "map.h"
#include "movement.h"
#include "packets.h"
#include "specialist.h"
#include "traderoutes.h"
#include "unit.h"
 
/* aicore */
#include "cm.h"
 
#include "city.h"
 
/* Define this to add in extra (very slow) assertions for the city code. */
#undef CITY_DEBUGGING
 
static char *citylog_map_line(int y, int city_radius_sq, int *city_map_data);
#ifdef FREECIV_DEBUG
/* only used for debugging */
static void citylog_map_index(enum log_level level);
static void citylog_map_radius_sq(enum log_level level);
#endif /* FREECIV_DEBUG */
 
/* Get city tile informations using the city tile index. */
static struct iter_index *city_map_index = NULL;
/* Get city tile informations using the city tile coordinates. This is an
 * [x][y] array of integer values corresponding to city_map_index. The
 * coordinates x and y are in the range [0, CITY_MAP_MAX_SIZE] */
static int city_map_xy[CITY_MAP_MAX_SIZE][CITY_MAP_MAX_SIZE];
 
/* number of tiles of a city; depends on the squared city radius */
static int city_map_numtiles[CITY_MAP_MAX_RADIUS_SQ + 1];
 
/* definitions and functions for the tile_cache */
struct tile_cache {
  int output[O_LAST];
};
 
static inline void city_tile_cache_update(const struct civ_map *nmap,
                                          struct city *pcity);
static inline int city_tile_cache_get_output(const struct city *pcity,
                                             int city_tile_index,
                                             enum output_type_id o);
 
struct citystyle *city_styles = NULL;
 
/* One day these values may be read in from the ruleset.  In the meantime
 * they're just an easy way to access information about each output type. */
struct output_type output_types[O_LAST] = {
  {O_FOOD, N_("Food"), "food", TRUE, UNHAPPY_PENALTY_SURPLUS},
  {O_SHIELD, N_("Shield"), "shield", TRUE, UNHAPPY_PENALTY_SURPLUS},
  {O_TRADE, N_("Trade"), "trade", TRUE, UNHAPPY_PENALTY_NONE},
  {O_GOLD, N_("Gold"), "gold", FALSE, UNHAPPY_PENALTY_ALL_PRODUCTION},
  {O_LUXURY, N_("Luxury"), "luxury", FALSE, UNHAPPY_PENALTY_NONE},
  {O_SCIENCE, N_("Science"), "science", FALSE, UNHAPPY_PENALTY_ALL_PRODUCTION}
};
 
/**********************************************************************/
bool city_tile_index_to_xy(int *city_map_x, int *city_map_y,
                           int city_tile_index, int city_radius_sq)
{
  fc_assert_ret_val(city_radius_sq >= CITY_MAP_MIN_RADIUS_SQ, FALSE);
  fc_assert_ret_val(city_radius_sq <= CITY_MAP_MAX_RADIUS_SQ, FALSE);
 
  /* tile indices are sorted from smallest to largest city radius */
  if (city_tile_index < 0
      || city_tile_index >= city_map_tiles(city_radius_sq)) {
    return FALSE;
  }
 
  *city_map_x = CITY_REL2ABS(city_map_index[city_tile_index].dx);
  *city_map_y = CITY_REL2ABS(city_map_index[city_tile_index].dy);
 
  return TRUE;
}
 
/**********************************************************************/
int city_tile_xy_to_index(int city_map_x, int city_map_y,
                          int city_radius_sq)
{
  fc_assert_ret_val(city_radius_sq >= CITY_MAP_MIN_RADIUS_SQ, 0);
  fc_assert_ret_val(city_radius_sq <= CITY_MAP_MAX_RADIUS_SQ, 0);
  fc_assert_ret_val(is_valid_city_coords(city_radius_sq, city_map_x,
                                         city_map_y), 0);
 
  return city_map_xy[city_map_x][city_map_y];
}
 
/**********************************************************************/
int city_map_radius_sq_get(const struct city *pcity)
{
  /* a save return value is only the minimal squared radius */
  fc_assert_ret_val(pcity != NULL, CITY_MAP_MIN_RADIUS_SQ);
 
  return pcity->city_radius_sq;
}
 
/**********************************************************************/
void city_map_radius_sq_set(struct city *pcity, int radius_sq)
{
  fc_assert_ret(radius_sq >= CITY_MAP_MIN_RADIUS_SQ);
  fc_assert_ret(radius_sq <= CITY_MAP_MAX_RADIUS_SQ);
 
  pcity->city_radius_sq = radius_sq;
}
 
/**********************************************************************/
int rs_max_city_radius_sq(void)
{
  int max_rad = game.info.init_city_radius_sq
    + effect_cumulative_max(EFT_CITY_RADIUS_SQ, NULL, 0);
 
  return MIN(max_rad, CITY_MAP_MAX_RADIUS_SQ);
}
 
/**********************************************************************/
int city_map_tiles(int city_radius_sq)
{
  if (city_radius_sq == CITY_MAP_CENTER_RADIUS_SQ) {
    /* special case: city center; first tile of the city map */
    return 0;
  }
 
  fc_assert_ret_val(city_radius_sq >= CITY_MAP_MIN_RADIUS_SQ, -1);
  fc_assert_ret_val(city_radius_sq <= CITY_MAP_MAX_RADIUS_SQ, -1);
 
  return city_map_numtiles[city_radius_sq];
}
 
/**********************************************************************/
bool is_valid_city_coords(const int city_radius_sq, const int city_map_x,
                          const int city_map_y)
{
  /* The city's valid positions are in a circle around the city center.
   * Depending on the value for the squared city radius the circle will be:
   *
   *  - rectangular (max radius = 5; max squared radius = 26)
   *
   *        0    1    2    3    4    5    6    7    8    9   10
   *
   *  0                        26   25   26                       -5
   *  1              25   20   17   16   17   20   25             -4
   *  2         25   18   13   10    9   10   13   18   25        -3
   *  3         20   13    8    5    4    5    8   13   20        -2
   *  4    26   17   10    5    2    1    2    5   10   17   26   -1
   *  5    25   16    9    4    1    0    1    4    9   16   25   +0
   *  6    26   17   10    5    2    1    2    5   10   17   26   +1
   *  7         20   13    8    5    4    5    8   13   20        +2
   *  8         25   18   13   10    9   10   13   18   25        +3
   *  9              25   20   17   16   17   20   25             +4
   * 10                        26   25   26                       +5
   *
   *       -5   -4   -3   -2   -1   +0   +1   +2   +3   +4   +5
   *
   * - hexagonal (max radius = 5; max squared radius = 26)
   *
   *        0    1    2    3    4    5    6    7    8    9   10
   *
   *  0                             25   25   25   25   25   25   -5
   *  1                        25   16   16   16   16   16   25   -4
   *  2                   25   16    9    9    9    9   16   25   -3
   *  3              25   16    9    4    4    4    9   16   25   -2
   *  4         25   16    9    4    1    1    4    9   16   25   -1
   *  5    25   16    9    4    1    0    1    4    9   16   25   +0
   *  6    25   16    9    4    1    1    4    9   16   25        +1
   *  7    25   16    9    4    4    4    9   16   25             +2
   *  8    25   16    9    9    9    9   16   25                  +3
   *  9    25   16   16   16   16   16   25                       +4
   * 10    25   25   25   25   25   25                            +5
   *
   *       -5   -4   -3   -2   -1   +0   +1   +2   +3   +4   +5
   *
   * The following tables show the tiles per city radii / squared city radii.
   * '-' indicates no change compared to the previous value
   *
   * radius            |  0 |  1 |    |    |  2 |    |    |    |    |  3
   * radius_sq         |  1 |  2 |  3 |  4 |  5 |  6 |  7 |  8 |  9 | 10
   * ------------------+----+----+----+----+----+----+----+----+----+----
   * tiles rectangular |  5 |  9 |  - | 13 | 21 |  - |  - | 25 | 29 | 37
   * tiles hexagonal   |  7 |  - |  - | 19 |  - |  - |  - |  - | 37 |  -
   *
   * radius            |    |    |    |    |    |    |  4 |    |    |
   * radius_sq         | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20
   * ------------------+----+----+----+----+----+----+----+----+----+----
   * tiles rectangular |  - |  - | 45 |  - |  - | 49 | 57 | 61 |  - | 69
   * tiles hexagonal   |  - |  - |  - |  - |  - | 61 |  - |  - |  - |  -
   *
   * radius            |    |    |    |    |    |  5
   * radius_sq         | 21 | 22 | 23 | 24 | 25 | 26
   * ------------------+----+----+----+----+----+----
   * tiles rectangular |  - |  - |  - |  - | 81 | 89
   * tiles hexagonal   |  - |  - |  - |  - | 91 |  -
   *
   * So radius_sq == 5 (radius == 2) corresponds to the "traditional"
   * used city map.
   */
  int dist = map_vector_to_sq_distance(CITY_ABS2REL(city_map_x),
                                       CITY_ABS2REL(city_map_y));
 
  return dist <= city_radius_sq;
}
 
/**********************************************************************/
bool city_tile_to_city_map(int *city_map_x, int *city_map_y,
                           const int city_radius_sq,
                           const struct tile *city_center,
                           const struct tile *map_tile)
{
  map_distance_vector(city_map_x, city_map_y, city_center, map_tile);
 
  *city_map_x += CITY_MAP_MAX_RADIUS;
  *city_map_y += CITY_MAP_MAX_RADIUS;
 
  return is_valid_city_coords(city_radius_sq, *city_map_x, *city_map_y);
}
 
/**********************************************************************/
bool city_base_to_city_map(int *city_map_x, int *city_map_y,
                           const struct city *const pcity,
                           const struct tile *map_tile)
{
  return city_tile_to_city_map(city_map_x, city_map_y,
                               city_map_radius_sq_get(pcity), pcity->tile,
                               map_tile);
}
 
/**********************************************************************/
bool city_map_includes_tile(const struct city *const pcity,
                            const struct tile *map_tile)
{
  int tmp_x, tmp_y;
 
  return city_base_to_city_map(&tmp_x, &tmp_y, pcity, map_tile);
}
 
/**********************************************************************/
struct tile *city_map_to_tile(const struct civ_map *nmap,
                              const struct tile *city_center,
                              int city_radius_sq, int city_map_x,
                              int city_map_y)
{
  int tile_x, tile_y;
 
  fc_assert_ret_val(is_valid_city_coords(city_radius_sq, city_map_x,
                                         city_map_y), NULL);
 
  index_to_map_pos(&tile_x, &tile_y, tile_index(city_center));
  tile_x += CITY_ABS2REL(city_map_x);
  tile_y += CITY_ABS2REL(city_map_y);
 
  return map_pos_to_tile(nmap, tile_x, tile_y);
}
 
/**********************************************************************/
static int cmp(int v1, int v2)
{
  if (v1 == v2) {
    return 0;
  } else if (v1 > v2) {
    return 1;
  } else {
    return -1;
  }
}
 
/**********************************************************************/
int compare_iter_index(const void *a, const void *b)
{
  const struct iter_index *index1 = a, *index2 = b;
  int value;
 
  value = cmp(index1->dist, index2->dist);
  if (value != 0) {
    return value;
  }
 
  value = cmp(index1->dx, index2->dx);
  if (value != 0) {
    return value;
  }
 
  value = cmp(index1->dy, index2->dy);
  fc_assert(0 != value);
  return value;
}
 
/**********************************************************************/
#define CITYLOG_MAX_VAL 9999 /* maximal value displayed in the citylog */
static char *citylog_map_line(int y, int city_radius_sq, int *city_map_data)
{
  int x, mindex;
  static char citylog[128], tmp[8];
 
  fc_assert_ret_val(city_map_data != NULL, NULL);
 
  /* print y coordinates (absolut) */
  fc_snprintf(citylog, sizeof(citylog), "%2d ", y);
 
  /* print values */
  for (x = 0; x < CITY_MAP_MAX_SIZE; x++) {
    if (is_valid_city_coords(city_radius_sq, x, y)) {
      mindex = city_tile_xy_to_index(x, y, city_radius_sq);
      /* show values between -10000 and +10000 */
      if (city_map_data[mindex] >= -CITYLOG_MAX_VAL
          && city_map_data[mindex] <= CITYLOG_MAX_VAL) {
        fc_snprintf(tmp, sizeof(tmp), "%5d", city_map_data[mindex]);
        sz_strlcat(citylog, tmp);
      } else {
        fc_snprintf(tmp, sizeof(tmp), " ####");
        sz_strlcat(citylog, tmp);
      }
    } else {
      fc_snprintf(tmp, sizeof(tmp), "     ");
      sz_strlcat(citylog, tmp);
    }
  }
 
  /* print y coordinates (relativ) */
  fc_snprintf(tmp, sizeof(tmp), " %+4d", CITY_ABS2REL(y));
  sz_strlcat(citylog, tmp);
 
  return citylog;
}
#undef CITYLOG_MAX_VAL
 
/**********************************************************************/
void citylog_map_data(enum log_level level, int radius_sq, int *map_data)
{
  int x, y;
  char line[128], tmp[8];
 
  if (!log_do_output_for_level(level)) {
    return;
  }
 
  log_base(level, "(max squared city radius = %d)", CITY_MAP_MAX_RADIUS_SQ);
 
  /* print x coordinates (absolut) */
  fc_snprintf(line, sizeof(line), "   ");
  for (x = 0; x < CITY_MAP_MAX_SIZE; x++) {
    fc_snprintf(tmp, sizeof(tmp), "%+5d", x);
    sz_strlcat(line, tmp);
  }
  log_base(level, "%s", line);
 
  for (y = 0; y < CITY_MAP_MAX_SIZE; y++) {
    log_base(level, "%s", citylog_map_line(y, radius_sq, map_data));
  }
 
  /* print x coordinates (relativ) */
  fc_snprintf(line, sizeof(line), "   ");
  for (x = 0; x < CITY_MAP_MAX_SIZE; x++) {
    fc_snprintf(tmp, sizeof(tmp), "%+5d", CITY_ABS2REL(x));
    sz_strlcat(line, tmp);
  }
  log_base(level, "%s", line);
}
 
/**********************************************************************/
void citylog_map_workers(enum log_level level, struct city *pcity)
{
  int *city_map_data = NULL;
  const struct civ_map *nmap = &(wld.map);
 
  fc_assert_ret(pcity != NULL);
 
  if (!log_do_output_for_level(level)) {
    return;
  }
 
  city_map_data = fc_calloc(city_map_tiles(city_map_radius_sq_get(pcity)),
                            sizeof(*city_map_data));
 
  city_map_iterate(city_map_radius_sq_get(pcity), cindex, x, y) {
    struct tile *ptile = city_map_to_tile(nmap,
                                          city_tile(pcity),
                                          city_map_radius_sq_get(pcity),
                                          x, y);
    city_map_data[cindex] = (ptile && tile_worked(ptile) == pcity)
                            ? (is_free_worked_index(cindex) ? 2 : 1) : 0;
  } city_map_iterate_end;
 
  log_base(level, "[%s (%d)] workers map:", city_name_get(pcity), pcity->id);
  citylog_map_data(level, city_map_radius_sq_get(pcity), city_map_data);
  FC_FREE(city_map_data);
}
 
#ifdef FREECIV_DEBUG
/**********************************************************************/
static void citylog_map_index(enum log_level level)
{
  int *city_map_data = NULL;
 
  if (!log_do_output_for_level(level)) {
    return;
  }
 
  city_map_data = fc_calloc(city_map_tiles(CITY_MAP_MAX_RADIUS_SQ),
                            sizeof(*city_map_data));
 
  city_map_iterate(CITY_MAP_MAX_RADIUS_SQ, cindex, x, y) {
    city_map_data[cindex] = cindex;
  } city_map_iterate_end;
 
  log_debug("city map index:");
  citylog_map_data(level, CITY_MAP_MAX_RADIUS_SQ, city_map_data);
  FC_FREE(city_map_data);
}
 
/**********************************************************************/
static void citylog_map_radius_sq(enum log_level level)
{
  int *city_map_data = NULL;
 
  if (!log_do_output_for_level(level)) {
    return;
  }
 
  city_map_data = fc_calloc(city_map_tiles(CITY_MAP_MAX_RADIUS_SQ),
                            sizeof(*city_map_data));
 
  city_map_iterate(CITY_MAP_MAX_RADIUS_SQ, cindex, x, y) {
    city_map_data[cindex] = map_vector_to_sq_distance(CITY_ABS2REL(x),
                                                      CITY_ABS2REL(y));
  } city_map_iterate_end;
 
  log_debug("city map squared radius:");
  citylog_map_data(level, CITY_MAP_MAX_RADIUS_SQ, city_map_data);
  FC_FREE(city_map_data);
}
#endif /* FREECIV_DEBUG */
 
/**********************************************************************/
void generate_city_map_indices(void)
{
  int i, dx, dy, city_x, city_y, dist, city_count_tiles = 0;
  struct iter_index city_map_index_tmp[CITY_MAP_MAX_SIZE
                                       * CITY_MAP_MAX_SIZE];
 
  /* initialise map information for each city radii */
  for (i = 0; i <= CITY_MAP_MAX_RADIUS_SQ; i++) {
     city_map_numtiles[i] = 0; /* will be set below */
  }
 
  /* We don't use city-map iterators in this function because they may
   * rely on the indices that have not yet been generated. Furthermore,
   * we don't know the number of tiles within the city radius, so we need
   * an temporary city_map_index array. Its content will be copied into
   * the real array below. */
  for (dx = -CITY_MAP_MAX_RADIUS; dx <= CITY_MAP_MAX_RADIUS; dx++) {
    for (dy = -CITY_MAP_MAX_RADIUS; dy <= CITY_MAP_MAX_RADIUS; dy++) {
      dist = map_vector_to_sq_distance(dx, dy);
 
      if (dist <= CITY_MAP_MAX_RADIUS_SQ) {
        city_map_index_tmp[city_count_tiles].dx = dx;
        city_map_index_tmp[city_count_tiles].dy = dy;
        city_map_index_tmp[city_count_tiles].dist = dist;
 
        for (i = CITY_MAP_MAX_RADIUS_SQ; i >= 0; i--) {
          if (dist <= i) {
            /* increase number of tiles within this squared city radius */
            city_map_numtiles[i]++;
          }
        }
 
        city_count_tiles++;
      }
 
      /* Initialise city_map_xy. -1 defines a invalid city map positions. */
      city_map_xy[CITY_REL2ABS(dx)][CITY_REL2ABS(dy)] = -1;
    }
  }
 
  fc_assert(NULL == city_map_index);
  city_map_index = fc_malloc(city_count_tiles * sizeof(*city_map_index));
 
  /* copy the index numbers from city_map_index_tmp into city_map_index */
  for (i = 0; i < city_count_tiles; i++) {
    city_map_index[i] = city_map_index_tmp[i];
  }
 
  qsort(city_map_index, city_count_tiles, sizeof(*city_map_index),
        compare_iter_index);
 
  /* set the static variable city_map_xy */
  for (i = 0; i < city_count_tiles; i++) {
    city_x = CITY_REL2ABS(city_map_index[i].dx);
    city_y = CITY_REL2ABS(city_map_index[i].dy);
    city_map_xy[city_x][city_y] = i;
  }
 
#ifdef FREECIV_DEBUG
  citylog_map_radius_sq(LOG_DEBUG);
  citylog_map_index(LOG_DEBUG);
 
  for (i = CITY_MAP_MIN_RADIUS_SQ; i <= CITY_MAP_MAX_RADIUS_SQ; i++) {
    log_debug("radius_sq = %2d, tiles = %2d", i, city_map_tiles(i));
  }
 
  for (i = 0; i < city_count_tiles; i++) {
    city_x = CITY_REL2ABS(city_map_index[i].dx);
    city_y = CITY_REL2ABS(city_map_index[i].dy);
    log_debug("[%2d]: (dx,dy) = (%+2d,%+2d), (x,y) = (%2d,%2d), "
              "dist = %2d, check = %2d", i,
              city_map_index[i].dx, city_map_index[i].dy, city_x, city_y,
              city_map_index[i].dist, city_map_xy[city_x][city_y]);
  }
#endif /* FREECIV_DEBUG */
 
  cm_init_citymap();
}
 
/**********************************************************************/
void free_city_map_index(void)
{
  FC_FREE(city_map_index);
}
 
/**********************************************************************/
const char *get_output_identifier(Output_type_id output)
{
  fc_assert_ret_val(output >= 0 && output < O_LAST, NULL);
  return output_types[output].id;
}
 
/**********************************************************************/
const char *get_output_name(Output_type_id output)
{
  fc_assert_ret_val(output >= 0 && output < O_LAST, NULL);
  return _(output_types[output].name);
}
 
/**********************************************************************/
struct output_type *get_output_type(Output_type_id output)
{
  fc_assert_ret_val(output >= 0 && output < O_LAST, NULL);
  return &output_types[output];
}
 
/**********************************************************************/
Output_type_id output_type_by_identifier(const char *id)
{
  Output_type_id o;
 
  for (o = 0; o < O_LAST; o++) {
    if (fc_strcasecmp(output_types[o].id, id) == 0) {
      return o;
    }
  }
 
  return O_LAST;
}
 
/**********************************************************************/
const char *city_improvement_name_translation(const struct city *pcity,
                                              const struct impr_type *pimprove)
{
  static char buffer[256];
  const char *state = NULL;
 
  if (is_great_wonder(pimprove)) {
    if (great_wonder_is_available(pimprove)) {
      state = Q_("?wonder:W");
    } else if (great_wonder_is_destroyed(pimprove)) {
      state = Q_("?destroyed:D");
    } else {
      state = Q_("?built:B");
    }
  }
  if (pcity) {
    struct player *pplayer = city_owner(pcity);
 
    if (improvement_obsolete(pplayer, pimprove, pcity)) {
      state = Q_("?obsolete:O");
    } else if (is_improvement_redundant(pcity, pimprove)) {
      state = Q_("?redundant:*");
    }
  }
 
  if (state) {
    fc_snprintf(buffer, sizeof(buffer), "%s(%s)",
                improvement_name_translation(pimprove), state); 
    return buffer;
  } else {
    return improvement_name_translation(pimprove);
  }
}
 
/**********************************************************************/
const char *city_production_name_translation(const struct city *pcity)
{
  static char buffer[256];
 
  switch (pcity->production.kind) {
  case VUT_IMPROVEMENT:
    return city_improvement_name_translation(pcity, pcity->production.value.building);
  default:
    /* fallthru */
    break;
  };
  return universal_name_translation(&pcity->production, buffer, sizeof(buffer));
}
 
/**********************************************************************/
bool city_production_has_flag(const struct city *pcity,
                              enum impr_flag_id flag)
{
  return VUT_IMPROVEMENT == pcity->production.kind
      && improvement_has_flag(pcity->production.value.building, flag);
}
 
/**********************************************************************/
int city_production_build_shield_cost(const struct city *pcity)
{
  return universal_build_shield_cost(pcity, &pcity->production);
}
 
/**********************************************************************/
bool city_production_build_units(const struct city *pcity,
                                 bool add_production, int *num_units)
{
  const struct unit_type *utype;
  struct universal target;
  int build_slots = city_build_slots(pcity);
  int shields_left = pcity->shield_stock;
  int unit_shield_cost, i;
 
  fc_assert_ret_val(num_units != NULL, FALSE);
  (*num_units) = 0;
 
  if (pcity->production.kind != VUT_UTYPE) {
    /* not a unit as the current production */
    return FALSE;
  }
 
  utype = pcity->production.value.utype;
  if (utype_pop_value(utype, pcity) != 0 || utype_has_flag(utype, UTYF_UNIQUE)) {
    /* unit with population cost or unique unit means that only one unit can
     * be build */
    (*num_units)++;
    return FALSE;
  }
 
  if (add_production) {
    shields_left += pcity->prod[O_SHIELD];
  }
 
  unit_shield_cost = utype_build_shield_cost(pcity, NULL, utype);
 
  for (i = 0; i < build_slots; i++) {
    if (shields_left < unit_shield_cost) {
      /* not enough shields */
      break;
    }
 
    (*num_units)++;
    shields_left -= unit_shield_cost;
 
    if (worklist_length(&pcity->worklist) > i) {
      (void) worklist_peek_ith(&pcity->worklist, &target, i);
      if (target.kind != VUT_UTYPE
          || utype_index(target.value.utype) != utype_index(utype)) {
        /* stop if there is a build target in the worklist not equal to the
         * unit we build */
        break;
      }
    }
  }
 
  return TRUE;
}
 
/************************************************************************/
int city_production_unit_veteran_level(struct city *pcity,
                                       const struct unit_type *punittype)
{
  int levels = get_unittype_bonus(city_owner(pcity), pcity->tile, punittype,
                                  NULL, EFT_VETERAN_BUILD);
  int max_levels = utype_veteran_levels(punittype) - 1;
 
  levels = CLIP(0, levels, max_levels);
 
  return levels;
}
 
/**********************************************************************/
int city_production_turns_to_build(const struct city *pcity,
                                   bool include_shield_stock)
{
  return city_turns_to_build(pcity, &pcity->production, include_shield_stock);
}
 
/**********************************************************************/
bool can_city_build_improvement_direct(const struct city *pcity,
                                       const struct impr_type *pimprove)
{
  if (!can_player_build_improvement_direct(city_owner(pcity), pimprove)) {
    return FALSE;
  }
 
  if (city_has_building(pcity, pimprove)) {
    return FALSE;
  }
 
  return are_reqs_active(&(const struct req_context) {
                           .player = city_owner(pcity),
                           .city = pcity,
                           .tile = pcity->tile,
                         },
                         NULL,
                         &(pimprove->reqs), RPT_CERTAIN);
}
 
/**********************************************************************/
bool can_city_build_improvement_now(const struct city *pcity,
                                    const struct impr_type *pimprove)
{  
  if (!can_city_build_improvement_direct(pcity, pimprove)) {
    return FALSE;
  }
  if (improvement_obsolete(city_owner(pcity), pimprove, pcity)) {
    return FALSE;
  }
 
  return TRUE;
}
 
/**********************************************************************/
bool can_city_build_improvement_later(const struct city *pcity,
                                      const struct impr_type *pimprove)
{
  const struct req_context city_ctxt = {
    .player = city_owner(pcity),
    .city = pcity,
    .tile = city_tile(pcity),
  };
 
  /* Can the _player_ ever build this improvement? */
  /* NOTE: It checks for obsoletion player-level. What aboult checking
   * for it city-level? That may unlist from a worklist some things
   * we'll be able to switch to after e.g. selling something else */
  if (!can_player_build_improvement_later(city_owner(pcity), pimprove)) {
    return FALSE;
  }
 
  /* Check for requirements that aren't met and that are unchanging (so
   * they can never be met). */
  requirement_vector_iterate(&pimprove->reqs, preq) {
    if (is_req_preventing(&city_ctxt, NULL, preq, RPT_POSSIBLE)) {
      return FALSE;
    }
  } requirement_vector_iterate_end;
 
  return TRUE;
}
 
/**********************************************************************/
bool can_city_build_unit_direct(const struct city *pcity,
                                const struct unit_type *punittype)
{
  const struct civ_map *nmap = &(wld.map);
 
  if (!can_player_build_unit_direct(city_owner(pcity), punittype)) {
    return FALSE;
  }
 
  /* Check unit build requirements. */
  if (!are_reqs_active(&(const struct req_context) {
                         .player = city_owner(pcity),
                         .city = pcity,
                         .tile = city_tile(pcity),
                         .unittype = punittype,
                       },
                       NULL,
                       &punittype->build_reqs, RPT_CERTAIN)) {
    return FALSE;
  }
 
  /* You can't build naval units inland. */
  if (!uclass_has_flag(utype_class(punittype), UCF_BUILD_ANYWHERE)
      && !is_native_near_tile(nmap, utype_class(punittype),
                              pcity->tile)) {
    return FALSE;
  }
 
  if (punittype->city_slots > 0
      && city_unit_slots_available(pcity) < punittype->city_slots) {
    return FALSE;
  }
 
  return TRUE;
}
 
/**********************************************************************/
bool can_city_build_unit_now(const struct city *pcity,
                             const struct unit_type *punittype)
{  
  if (!can_city_build_unit_direct(pcity, punittype)) {
    return FALSE;
  }
  while ((punittype = punittype->obsoleted_by) != U_NOT_OBSOLETED) {
    if (can_player_build_unit_direct(city_owner(pcity), punittype)) {
      return FALSE;
    }
  }
  return TRUE;
}
 
/**********************************************************************/
bool can_city_build_unit_later(const struct city *pcity,
                               const struct unit_type *punittype)
{
  const struct civ_map *nmap = &(wld.map);
 
  /* Can the _player_ ever build this unit? */
  if (!can_player_build_unit_later(city_owner(pcity), punittype)) {
    return FALSE;
  }
 
  /* Some units can be built only in certain cities -- for instance,
     ships may be built only in cities adjacent to ocean. */
  if (!uclass_has_flag(utype_class(punittype), UCF_BUILD_ANYWHERE)
      && !is_native_near_tile(nmap, utype_class(punittype),
                              pcity->tile)) {
    return FALSE;
  }
 
  return TRUE;
}
 
/**********************************************************************/
bool can_city_build_direct(const struct city *pcity,
                           const struct universal *target)
{
  switch (target->kind) {
  case VUT_UTYPE:
    return can_city_build_unit_direct(pcity, target->value.utype);
  case VUT_IMPROVEMENT:
    return can_city_build_improvement_direct(pcity, target->value.building);
  default:
    break;
  };
  return FALSE;
}
 
/**********************************************************************/
bool can_city_build_now(const struct city *pcity,
                        const struct universal *target)
{
  switch (target->kind) {
  case VUT_UTYPE:
    return can_city_build_unit_now(pcity, target->value.utype);
  case VUT_IMPROVEMENT:
    return can_city_build_improvement_now(pcity, target->value.building);
  default:
    break;
  };
  return FALSE;
}
 
/**********************************************************************/
bool can_city_build_later(const struct city *pcity,
                          const struct universal *target)
{
  switch (target->kind) {
  case VUT_UTYPE:
    return can_city_build_unit_later(pcity, target->value.utype);
  case VUT_IMPROVEMENT:
    return can_city_build_improvement_later(pcity, target->value.building);
  default:
    break;
  };
  return FALSE;
}
 
/**********************************************************************/
int city_unit_slots_available(const struct city *pcity)
{
  int max = get_city_bonus(pcity, EFT_UNIT_SLOTS);
  int current;
 
  current = 0;
  unit_list_iterate(pcity->units_supported, punit) {
    current += unit_type_get(punit)->city_slots;
  } unit_list_iterate_end;
 
  return max - current;
}
 
/**********************************************************************/
bool city_can_use_specialist(const struct city *pcity,
                             Specialist_type_id type)
{
  return are_reqs_active(&(const struct req_context) {
                           .player = city_owner(pcity),
                           .city = pcity,
                         },
                         NULL,
                         &specialist_by_number(type)->reqs, RPT_POSSIBLE);
}
 
/**********************************************************************/
bool city_can_change_build(const struct city *pcity)
{
  return !pcity->did_buy || pcity->shield_stock <= 0;
}
 
/**********************************************************************/
void city_choose_build_default(struct city *pcity)
{
  if (NULL == city_tile(pcity)) {
    /* When a "dummy" city is created with no tile, then choosing a build 
     * target could fail.  This currently might happen during map editing.
     * FIXME: assumes the first unit is always "valid", so check for
     * obsolete units elsewhere. */
    pcity->production.kind = VUT_UTYPE;
    pcity->production.value.utype = utype_by_number(0);
  } else {
    struct unit_type *u = best_role_unit(pcity, L_FIRSTBUILD);
 
    if (u) {
      pcity->production.kind = VUT_UTYPE;
      pcity->production.value.utype = u;
    } else {
      bool found = FALSE;
 
      /* Just pick the first available item. */
      improvement_iterate(pimprove) {
        if (can_city_build_improvement_direct(pcity, pimprove)) {
          found = TRUE;
          pcity->production.kind = VUT_IMPROVEMENT;
          pcity->production.value.building = pimprove;
          break;
        }
      } improvement_iterate_end;
 
      if (!found) {
        unit_type_iterate(punittype) {
          if (can_city_build_unit_direct(pcity, punittype)) {
#ifndef FREECIV_NDEBUG
            /* Later than this, 'found' is only needed in an fc_assert() */
            found = TRUE;
#endif /* FREECIV_NDEBUG */
            pcity->production.kind = VUT_UTYPE;
            pcity->production.value.utype = punittype;
          }
        } unit_type_iterate_end;
      }
 
      fc_assert_msg(found, "No production found for city %s!",
                    city_name_get(pcity));
    }
  }
}
 
/**********************************************************************/
const char *city_name_get(const struct city *pcity)
{
  return (pcity->name != NULL) ? pcity->name : "City missing a name";
}
 
/**********************************************************************/
void city_name_set(struct city *pcity, const char *new_name)
{
  if (pcity->name != NULL) {
    free(pcity->name);
  }
 
  if (strlen(new_name) < MAX_LEN_CITYNAME) {
    pcity->name = fc_strdup(new_name);
  } else {
    log_warn(_("City name \"%s\" too long"), new_name);
    pcity->name = fc_malloc(MAX_LEN_CITYNAME);
    sz_strlcpy(pcity->name, new_name);
  }
}
 
/**********************************************************************/
void city_size_add(struct city *pcity, int add)
{
  citizens size = city_size_get(pcity);
 
  fc_assert_ret(pcity != NULL);
  fc_assert_ret(MAX_CITY_SIZE - size >= add);
 
  /* Client sets size to zero to start stacking citizens in */
  fc_assert_ret(size >= -add);
 
  city_size_set(pcity, size + add);
}
 
/**********************************************************************/
void city_size_set(struct city *pcity, citizens size)
{
  fc_assert_ret(pcity != NULL);
 
  /* Set city size. */
  pcity->size = size;
}
 
/**********************************************************************/
int city_population(const struct city *pcity)
{
  /*  Sum_{i=1}^{n} i  ==  n*(n+1)/2  */
  return city_size_get(pcity) * (city_size_get(pcity) + 1) * 5;
}
 
/**********************************************************************/
int city_total_impr_gold_upkeep(const struct city *pcity)
{
  int gold_needed = 0;
 
  if (pcity == NULL) {
    return 0;
  }
 
  city_built_iterate(pcity, pimprove) {
    gold_needed += city_improvement_upkeep(pcity, pimprove);
  } city_built_iterate_end;
 
  return gold_needed;
}
 
/**********************************************************************/
int city_total_unit_gold_upkeep(const struct city *pcity)
{
  int gold_needed = 0;
 
  if (pcity == NULL || pcity->units_supported == NULL) {
    return 0;
  }
 
  unit_list_iterate(pcity->units_supported, punit) {
    gold_needed += punit->upkeep[O_GOLD];
  } unit_list_iterate_end;
 
  return gold_needed;
}
 
/**********************************************************************/
bool city_has_building(const struct city *pcity,
                       const struct impr_type *pimprove)
{
  if (NULL == pimprove) {
    /* Callers should ensure that any external data is tested with 
     * valid_improvement_by_number() */
    return FALSE;
  }
  return (pcity->built[improvement_index(pimprove)].turn > I_NEVER);
}
 
/**********************************************************************/
int city_improvement_upkeep(const struct city *pcity,
                            const struct impr_type *b)
{
  int upkeep;
 
  if (NULL == b) {
    return 0;
  }
  if (is_wonder(b)) {
    return 0;
  }
 
  upkeep = b->upkeep;
  if (upkeep <= get_building_bonus(pcity, b, EFT_UPKEEP_FREE)) {
    return 0;
  }
 
  return upkeep;
}
 
/**********************************************************************/
int city_tile_output(const struct city *pcity, const struct tile *ptile,
                     bool is_celebrating, Output_type_id otype)
{
  int prod;
  const struct req_context city_ctxt = {
    .player = pcity ? city_owner(pcity) : NULL,
    .city = pcity,
    .tile = ptile,
  };
  struct terrain *pterrain = tile_terrain(ptile);
  const struct output_type *output = &output_types[otype];
 
  fc_assert_ret_val(otype >= 0 && otype < O_LAST, 0);
 
  if (T_UNKNOWN == pterrain) {
    /* Special case for the client.  The server doesn't allow unknown tiles
     * to be worked but we don't necessarily know what player is involved. */
    return 0;
  }
 
  prod = pterrain->output[otype];
  if (tile_resource_is_valid(ptile)) {
    prod += tile_resource(ptile)->data.resource->output[otype];
  }
 
  switch (otype) {
  case O_SHIELD:
    if (pterrain->mining_shield_incr != 0) {
      prod += pterrain->mining_shield_incr
        * get_target_bonus_effects(NULL, &city_ctxt, NULL, EFT_MINING_PCT)
        / 100;
    }
    break;
  case O_FOOD:
    if (pterrain->irrigation_food_incr != 0) {
      prod += pterrain->irrigation_food_incr
        * get_target_bonus_effects(NULL, &city_ctxt, NULL,
                                   EFT_IRRIGATION_PCT) / 100;
    }
    break;
  case O_TRADE:
  case O_GOLD:
  case O_SCIENCE:
  case O_LUXURY:
  case O_LAST:
    break;
  }
 
  prod += tile_roads_output_incr(ptile, otype);
  prod += (prod * tile_roads_output_bonus(ptile, otype) / 100);
 
  prod += get_tile_output_bonus(pcity, ptile, output, EFT_OUTPUT_ADD_TILE);
  if (prod > 0) {
    int penalty_limit = get_tile_output_bonus(pcity, ptile, output,
                                              EFT_OUTPUT_PENALTY_TILE);
 
    if (prod >= game.info.granularity) {
      prod += get_tile_output_bonus(pcity, ptile, output,
                                    EFT_OUTPUT_INC_TILE);
 
      if (is_celebrating) {
        prod += get_tile_output_bonus(pcity, ptile, output,
                                      EFT_OUTPUT_INC_TILE_CELEBRATE);
      }
    }
 
    prod += (prod 
             * get_tile_output_bonus(pcity, ptile, output,
                                     EFT_OUTPUT_PER_TILE)) 
            / 100;
    if (!is_celebrating && penalty_limit > 0 && prod > penalty_limit) {
      if (prod <= game.info.granularity) {
        prod = 0;
      } else {
        prod -= game.info.granularity;
      }
    }
  }
 
  prod -= (prod
           * get_tile_output_bonus(pcity, ptile, output,
                                   EFT_OUTPUT_TILE_PUNISH_PCT))
           / 100;
 
  if (NULL != pcity && is_city_center(pcity, ptile)) {
    prod = MAX(prod, game.info.min_city_center_output[otype]);
  }
 
  return prod;
}
 
/**********************************************************************/
int city_tile_output_now(const struct city *pcity, const struct tile *ptile,
                         Output_type_id otype)
{
  return city_tile_output(pcity, ptile, city_celebrating(pcity), otype);
}
 
/**********************************************************************/
bool base_city_can_work_tile(const struct player *restriction,
                             const struct city *pcity,
                             const struct tile *ptile)
{
  struct player *powner = city_owner(pcity);
  int city_map_x, city_map_y;
 
  if (NULL == ptile) {
    return FALSE;
  }
 
  if (!city_base_to_city_map(&city_map_x, &city_map_y, pcity, ptile)) {
    return FALSE;
  }
 
  if (NULL != restriction
      && TILE_UNKNOWN == tile_get_known(ptile, restriction)) {
    return FALSE;
  }
 
  if (NULL != tile_owner(ptile) && tile_owner(ptile) != powner) {
    return FALSE;
  }
  /* TODO: civ3-like option for borders */
 
  if (NULL != tile_worked(ptile) && tile_worked(ptile) != pcity) {
    return FALSE;
  }
 
  if (powner == restriction
      && TILE_KNOWN_SEEN != tile_get_known(ptile, powner)) {
    return FALSE;
  }
 
  if (!is_free_worked(pcity, ptile)
      && NULL != unit_occupies_tile(ptile, powner)) {
    return FALSE;
  }
 
  if (get_city_tile_output_bonus(pcity, ptile, NULL, EFT_TILE_WORKABLE) <= 0) {
    return FALSE;
  }
 
  return TRUE;
}
 
/**********************************************************************/
bool city_can_work_tile(const struct city *pcity, const struct tile *ptile)
{
  return base_city_can_work_tile(city_owner(pcity), pcity, ptile);
}
 
/**********************************************************************/
bool citymindist_prevents_city_on_tile(const struct civ_map *nmap,
                                       const struct tile *ptile)
{
  /* citymindist minimum is 1, meaning adjacent is okay */
  int citymindist = game.info.citymindist;
 
  square_iterate(nmap, ptile, citymindist - 1, ptile1) {
    if (tile_city(ptile1)) {
      return TRUE;
    }
  } square_iterate_end;
 
  return FALSE;
}
 
/**********************************************************************/
bool city_can_be_built_here(const struct civ_map *nmap,
                            const struct tile *ptile,
                            const struct unit *punit,
                            bool hut_test)
{
  if (!city_can_be_built_tile_only(nmap, ptile)) {
    return FALSE;
  }
 
  if (punit == NULL) {
    /* The remaining checks tests if punit can found a city here */
    return TRUE;
  }
 
  if (hut_test) {
    struct player *towner;
 
    /* Huts can be found only from native tiles, owned by the unit owner.
     * Unlike actual city building, this behavior is not affected
     * by the ruleset. */
    if (!can_unit_exist_at_tile(nmap, punit, ptile)) {
      return FALSE;
    }
 
    towner = tile_owner(ptile);
 
    if (towner == NULL || towner == unit_owner(punit)) {
      return TRUE;
    }
 
    return FALSE;
  }
 
  action_by_result_iterate(paction, ACTRES_FOUND_CITY) {
    if (!utype_can_do_action(unit_type_get(punit), paction->id)) {
      /* This action can't be done by this unit type at all. */
      continue;
    }
 
    /* Non native tile detection */
    if (!can_unit_exist_at_tile(nmap, punit, ptile)
        /* The ruleset may allow founding cities on non native terrain. */
        && !utype_can_do_act_when_ustate(unit_type_get(punit), paction->id,
                                         USP_LIVABLE_TILE, FALSE)) {
      /* Many rulesets allow land units to build land cities and sea units
       * to build ocean cities. Air units can build cities anywhere. */
      continue;
    }
 
    /* Foreign tile detection. */
    if (tile_owner(ptile) && tile_owner(ptile) != unit_owner(punit)
        /* The ruleset may allow founding cities on foreign terrain. */
        && !can_utype_do_act_if_tgt_diplrel(unit_type_get(punit),
                                            paction->id,
                                            DRO_FOREIGN, TRUE)) {
      /* Cannot steal borders by settling. This has to be settled by
       * force of arms. */
      continue;
    }
 
    return TRUE;
  } action_by_result_iterate_end;
 
  return FALSE;
}
 
/**********************************************************************/
bool city_can_be_built_tile_only(const struct civ_map *nmap,
                                 const struct tile *ptile)
{
  if (terrain_has_flag(tile_terrain(ptile), TER_NO_CITIES)) {
    /* No cities on this terrain. */
    return FALSE;
  }
 
  if (citymindist_prevents_city_on_tile(nmap, ptile)) {
    return FALSE;
  }
 
  return TRUE;
}
 
/**********************************************************************/
bool is_capital(const struct city *pcity)
{
  return pcity->capital != CAPITAL_NOT;
}
 
/**********************************************************************/
bool is_gov_center(const struct city *pcity)
{
  return (get_city_bonus(pcity, EFT_GOV_CENTER) > 0);
}
 
/**********************************************************************/
bool city_got_defense_effect(const struct city *pcity,
                             const struct unit_type *attacker)
{
  if (!attacker) {
    /* Any defense building will do */
    return get_city_bonus(pcity, EFT_DEFEND_BONUS) > 0;
  }
 
  return get_unittype_bonus(city_owner(pcity), pcity->tile, attacker,
                            NULL, EFT_DEFEND_BONUS) > 0;
}
 
/**********************************************************************/
bool city_happy(const struct city *pcity)
{
  return (city_size_get(pcity) >= game.info.celebratesize
          && pcity->feel[CITIZEN_ANGRY][FEELING_FINAL] == 0
          && pcity->feel[CITIZEN_UNHAPPY][FEELING_FINAL] == 0
          && pcity->feel[CITIZEN_HAPPY][FEELING_FINAL] >= (city_size_get(pcity) + 1) / 2);
}
 
/**********************************************************************/
bool city_unhappy(const struct city *pcity)
{
  return (pcity->feel[CITIZEN_HAPPY][FEELING_FINAL]
        < pcity->feel[CITIZEN_UNHAPPY][FEELING_FINAL]
          + 2 * pcity->feel[CITIZEN_ANGRY][FEELING_FINAL]);
}
 
/**********************************************************************/
bool base_city_celebrating(const struct city *pcity)
{
  return (city_size_get(pcity) >= game.info.celebratesize && pcity->was_happy);
}
 
/**********************************************************************/
bool city_celebrating(const struct city *pcity)
{
  return base_city_celebrating(pcity) && city_happy(pcity);
}
 
/**********************************************************************/
bool city_rapture_grow(const struct city *pcity)
{
  /* .rapture is checked instead of city_celebrating() because this
     function is called after .was_happy was updated. */
  return (pcity->rapture > 0 && pcity->surplus[O_FOOD] > 0
          && (pcity->rapture % game.info.rapturedelay) == 0
          && get_city_bonus(pcity, EFT_RAPTURE_GROW) > 0);
}
 
/**********************************************************************/
bool city_is_occupied(const struct city *pcity)
{
  if (is_server()) {
    /* The server sees the units inside the city. */
    return (unit_list_size(city_tile(pcity)->units) > 0);
  } else {
    /* The client gets the occupied property from the server. */
    return pcity->client.occupied;
  }
}
 
/**********************************************************************/
struct city *city_list_find_number(struct city_list *This, int id)
{
  if (id != 0) {
    city_list_iterate(This, pcity) {
      if (pcity->id == id) {
        return pcity;
      }
    } city_list_iterate_end;
  }
 
  return NULL;
}
 
/**********************************************************************/
struct city *city_list_find_name(struct city_list *This, const char *name)
{
  city_list_iterate(This, pcity) {
    if (fc_strcasecmp(name, pcity->name) == 0) {
      return pcity;
    }
  } city_list_iterate_end;
 
  return NULL;
}
 
/**********************************************************************/
int city_name_compare(const void *p1, const void *p2)
{
  return fc_strcasecmp((*(const struct city **) p1)->name,
                       (*(const struct city **) p2)->name);
}
 
/**********************************************************************/
int city_style_by_translated_name(const char *s)
{
  int i;
 
  for (i = 0; i < game.control.styles_count; i++) {
    if (0 == strcmp(city_style_name_translation(i), s)) {
      return i;
    }
  }
 
  return -1;
}
 
/**********************************************************************/
int city_style_by_rule_name(const char *s)
{
  const char *qs = Qn_(s);
  int i;
 
  for (i = 0; i < game.control.styles_count; i++) {
    if (0 == fc_strcasecmp(city_style_rule_name(i), qs)) {
      return i;
    }
  }
 
  return -1;
}
 
/**********************************************************************/
const char *city_style_name_translation(const int style)
{
  return name_translation_get(&city_styles[style].name);
}
 
/**********************************************************************/
const char *city_style_rule_name(const int style)
{
   return rule_name_get(&city_styles[style].name);
}
 
/* Cache of what city production caravan shields are allowed to help. */
static bv_imprs caravan_helped_impr;
static bv_unit_types caravan_helped_utype;
 
/**********************************************************************/
void city_production_caravan_shields_init(void)
{
  struct requirement prod_as_req;
 
#define log_ca_s_init log_debug
 
  /* Remove old data. */
  BV_CLR_ALL(caravan_helped_impr);
  BV_CLR_ALL(caravan_helped_utype);
 
  /* Common for all production kinds. */
  prod_as_req.range = REQ_RANGE_LOCAL;
  prod_as_req.survives = FALSE;
  prod_as_req.present = TRUE;
 
  /* Check improvements */
  prod_as_req.source.kind = VUT_IMPROVEMENT;
 
  improvement_iterate(itype) {
    /* Check this improvement. */
    prod_as_req.source.value.building = itype;
 
    action_enabler_list_iterate(action_enablers_for_action(
                                  ACTION_HELP_WONDER),
                                enabler) {
      if (!does_req_contradicts_reqs(&prod_as_req,
                                     &(enabler->target_reqs))
          && !req_vec_wants_type(&(enabler->target_reqs), VUT_UTYPE)
          && !req_vec_wants_type(&(enabler->target_reqs), VUT_UCLASS)
          && !req_vec_wants_type(&(enabler->target_reqs), VUT_UTFLAG)
          && !req_vec_wants_type(&(enabler->target_reqs), VUT_UCFLAG)) {
        /* This improvement kind can receive caravan shields. */
 
        BV_SET(caravan_helped_impr, improvement_index(itype));
 
        /* Move on to the next improvement */
        break;
      }
    } action_enabler_list_iterate_end;
 
    log_ca_s_init("Help Wonder: %s for %s",
                  (BV_ISSET(caravan_helped_impr, improvement_index(itype))
                   ? "possible" : "impossible"),
                  improvement_rule_name(itype));
  } improvement_iterate_end;
 
  /* Check units. */
  prod_as_req.source.kind = VUT_UTYPE;
 
  unit_type_iterate(putype) {
    /* Check this utype. */
    prod_as_req.source.value.utype = putype;
 
    action_enabler_list_iterate(action_enablers_for_action(
                                  ACTION_HELP_WONDER),
                                enabler) {
      if (!does_req_contradicts_reqs(&prod_as_req,
                                     &(enabler->target_reqs))
          && !req_vec_wants_type(&(enabler->target_reqs), VUT_IMPROVEMENT)
          && !req_vec_wants_type(&(enabler->target_reqs), VUT_IMPR_GENUS)) {
        /* This unit type kind can receive caravan shields. */
 
        BV_SET(caravan_helped_utype, utype_index(putype));
 
        /* Move on to the next unit type */
        break;
      }
    } action_enabler_list_iterate_end;
 
    log_ca_s_init("Help Wonder: %s for %s",
                  (BV_ISSET(caravan_helped_utype, utype_index(putype))
                   ? "possible" : "impossible"),
                  utype_rule_name(putype));
  } unit_type_iterate_end;
 
#undef log_ca_s_init
}
 
/**********************************************************************/
bool city_production_gets_caravan_shields(const struct universal *tgt)
{
  switch (tgt->kind) {
  case VUT_IMPROVEMENT:
    return BV_ISSET(caravan_helped_impr,
                    improvement_index(tgt->value.building));
  case VUT_UTYPE:
    return BV_ISSET(caravan_helped_utype,
                    utype_index(tgt->value.utype));
  default:
    fc_assert(FALSE);
    return FALSE;
  };
}
 
/**********************************************************************/
int city_change_production_penalty(const struct city *pcity,
                                   const struct universal *target)
{
  int shield_stock_after_adjustment;
  enum production_class_type orig_class;
  enum production_class_type new_class;
  int unpenalized_shields = 0, penalized_shields = 0;
 
  switch (pcity->changed_from.kind) {
  case VUT_IMPROVEMENT:
    if (is_wonder(pcity->changed_from.value.building)) {
      orig_class = PCT_WONDER;
    } else {
      orig_class = PCT_NORMAL_IMPROVEMENT;
    }
    break;
  case VUT_UTYPE:
    orig_class = PCT_UNIT;
    break;
  default:
    orig_class = PCT_LAST;
    break;
  };
 
  switch (target->kind) {
  case VUT_IMPROVEMENT:
    if (is_wonder(target->value.building)) {
      new_class = PCT_WONDER;
    } else {
      new_class = PCT_NORMAL_IMPROVEMENT;
    }
    break;
  case VUT_UTYPE:
    new_class = PCT_UNIT;
    break;
  default:
    new_class = PCT_LAST;
    break;
  };
 
  /* Changing production is penalized under certain circumstances. */
  if (orig_class == new_class
      || orig_class == PCT_LAST) {
    /* There's never a penalty for building something of the same class. */
    unpenalized_shields = pcity->before_change_shields;
  } else if (city_built_last_turn(pcity)) {
    /* Surplus shields from the previous production won't be penalized if
     * you change production on the very next turn.  But you can only use
     * up to the city's surplus amount of shields in this way. */
    unpenalized_shields = MIN(pcity->last_turns_shield_surplus,
                              pcity->before_change_shields);
    penalized_shields = pcity->before_change_shields - unpenalized_shields;
  } else {
    /* Penalize 50% of the production. */
    penalized_shields = pcity->before_change_shields;
  }
 
  /* Do not put penalty on these. It shouldn't matter whether you disband unit
     before or after changing production...*/
  unpenalized_shields += pcity->disbanded_shields;
 
  /* Caravan shields are penalized (just as if you disbanded the caravan)
   * if you're not building a wonder. */
  if (city_production_gets_caravan_shields(target)) {
    unpenalized_shields += pcity->caravan_shields;
  } else {
    penalized_shields += pcity->caravan_shields;
  }
 
  shield_stock_after_adjustment =
    unpenalized_shields + penalized_shields / 2;
 
  return shield_stock_after_adjustment;
}
 
/**********************************************************************/
int city_turns_to_build(const struct city *pcity,
                        const struct universal *target,
                        bool include_shield_stock)
{
  int city_shield_surplus = pcity->surplus[O_SHIELD];
  int city_shield_stock = include_shield_stock ?
      city_change_production_penalty(pcity, target) : 0;
  int cost = universal_build_shield_cost(pcity, target);
 
  if (target->kind == VUT_IMPROVEMENT
      && is_great_wonder(target->value.building)
      && !great_wonder_is_available(target->value.building)) {
    return FC_INFINITY;
  }
 
  if (include_shield_stock && (city_shield_stock >= cost)) {
    return 1;
  } else if (city_shield_surplus > 0) {
    return (cost - city_shield_stock - 1) / city_shield_surplus + 1;
  } else {
    return FC_INFINITY;
  }
}
 
/**********************************************************************/
int city_turns_to_grow(const struct city *pcity)
{
  if (pcity->surplus[O_FOOD] > 0) {
    return (city_granary_size(city_size_get(pcity)) - pcity->food_stock +
            pcity->surplus[O_FOOD] - 1) / pcity->surplus[O_FOOD];
  } else if (pcity->surplus[O_FOOD] < 0) {
    /* turns before famine loss */
    return -1 + (pcity->food_stock / pcity->surplus[O_FOOD]);
  } else {
    return FC_INFINITY;
  }
}
 
/**********************************************************************/
bool city_can_grow_to(const struct city *pcity, int pop_size)
{
  return (get_city_bonus(pcity, EFT_SIZE_UNLIMIT) > 0
          || pop_size <= get_city_bonus(pcity, EFT_SIZE_ADJ));
}
 
/**********************************************************************/
struct city *tile_enemy_city(const struct tile *ptile,
                             const struct player *pplayer)
{
  struct city *pcity = tile_city(ptile);
 
  if (pcity != NULL && pplayers_at_war(pplayer, city_owner(pcity))) {
    return pcity;
  }
 
  return NULL;
}
 
/**********************************************************************/
struct city *tile_allied_city(const struct tile *ptile,
                              const struct player *pplayer)
{
  struct city *pcity = tile_city(ptile);
 
  if (pcity != NULL && pplayers_allied(pplayer, city_owner(pcity))) {
    return pcity;
  }
 
  return NULL;
}
 
/**********************************************************************/
struct city *tile_non_attack_city(const struct tile *ptile,
                                  const struct player *pplayer)
{
  struct city *pcity = tile_city(ptile);
 
  if (pcity != NULL && pplayers_non_attack(pplayer, city_owner(pcity))) {
    return pcity;
  }
 
  return NULL;
}
 
/**********************************************************************/
struct city *tile_non_allied_city(const struct tile *ptile,
                                  const struct player *pplayer)
{
  struct city *pcity = tile_city(ptile);
 
  if (pcity != NULL && !pplayers_allied(pplayer, city_owner(pcity))) {
    return pcity;
  }
 
  return NULL;
}
 
/**********************************************************************/
bool is_unit_near_a_friendly_city(const struct civ_map *nmap,
                                  const struct unit *punit)
{
  return is_friendly_city_near(nmap, unit_owner(punit), unit_tile(punit));
}
 
/**********************************************************************/
bool is_friendly_city_near(const struct civ_map *nmap,
                           const struct player *owner,
                           const struct tile *ptile)
{
  square_iterate(nmap, ptile, 3, ptile1) {
    struct city *pcity = tile_city(ptile1);
 
    if (pcity && pplayers_allied(owner, city_owner(pcity))) {
      return TRUE;
    }
  } square_iterate_end;
 
  return FALSE;
}
 
/**********************************************************************/
bool city_exists_within_max_city_map(const struct tile *ptile,
                                     bool may_be_on_center)
{
  const struct civ_map *nmap = &(wld.map);
 
  city_tile_iterate(nmap, CITY_MAP_MAX_RADIUS_SQ, ptile, ptile1) {
    if (may_be_on_center || !same_pos(ptile, ptile1)) {
      if (tile_city(ptile1)) {
        return TRUE;
      }
    }
  } city_tile_iterate_end;
 
  return FALSE;
}
 
/**********************************************************************/
int city_granary_size(int city_size)
{
  int food_inis = game.info.granary_num_inis;
  int food_inc = game.info.granary_food_inc;
  int base_value;
 
  /* If the city has no citizens, there is no granary. */
  if (city_size == 0) {
    return 0;
  }
 
  /* Granary sizes for the first food_inis citizens are given directly.
   * After that we increase the granary size by food_inc per citizen. */
  if (city_size > food_inis) {
    base_value = game.info.granary_food_ini[food_inis - 1];
    base_value += food_inc * (city_size - food_inis);
  } else {
    base_value = game.info.granary_food_ini[city_size - 1];
  }
 
  return MAX(base_value * game.info.foodbox / 100, 1);
}
 
/**********************************************************************/
static int player_base_citizen_happiness(const struct player *pplayer)
{
  int cities = city_list_size(pplayer->cities);
  int content = get_player_bonus(pplayer, EFT_CITY_UNHAPPY_SIZE);
  int basis = get_player_bonus(pplayer, EFT_EMPIRE_SIZE_BASE);
  int step = get_player_bonus(pplayer, EFT_EMPIRE_SIZE_STEP);
 
  if (basis + step <= 0) {
    /* Value of zero means effect is inactive */
    return content;
  }
 
  if (cities > basis) {
    content--;
    if (step != 0) {
      /* the first penalty is at (basis + 1) cities;
         the next is at (basis + step + 1), _not_ (basis + step) */
      content -= (cities - basis - 1) / step;
    }
  }
  return content;
}
 
/**********************************************************************/
citizens player_content_citizens(const struct player *pplayer)
{
  int content = player_base_citizen_happiness(pplayer);
 
  return CLIP(0, content, MAX_CITY_SIZE);
}
 
/**********************************************************************/
citizens player_angry_citizens(const struct player *pplayer)
{
  if (!game.info.angrycitizen) {
    return 0;
  } else {
    /* Create angry citizens only if we have a negative number of possible
     * content citizens. This can happen when empires grow really big. */
    int content = player_base_citizen_happiness(pplayer);
 
    return CLIP(0, -content, MAX_CITY_SIZE);
  }
}
 
/**********************************************************************/
int get_final_city_output_bonus(const struct city *pcity, Output_type_id otype)
{
  struct output_type *output = &output_types[otype];
  int bonus1 = 100 + get_city_tile_output_bonus(pcity, NULL, output,
                                                EFT_OUTPUT_BONUS);
  int bonus2 = 100 + get_city_tile_output_bonus(pcity, NULL, output,
                                                EFT_OUTPUT_BONUS_2);
 
  return MAX(bonus1 * bonus2 / 100, 0);
}
 
/**********************************************************************/
int get_city_tithes_bonus(const struct city *pcity)
{
  int tithes_bonus = 0;
 
  if (get_city_bonus(pcity, EFT_HAPPINESS_TO_GOLD) <= 0) {
    return 0;
  }
 
  tithes_bonus += get_city_bonus(pcity, EFT_MAKE_CONTENT);
  tithes_bonus += get_city_bonus(pcity, EFT_FORCE_CONTENT);
 
  return tithes_bonus;
}
 
/**********************************************************************/
void add_tax_income(const struct player *pplayer, int trade, int *output)
{
  const int SCIENCE = 0, TAX = 1, LUXURY = 2;
  unsigned rates[3];
  int result[3];
 
  if (game.info.changable_tax) {
    rates[SCIENCE] = pplayer->economic.science;
    rates[LUXURY] = pplayer->economic.luxury;
    rates[TAX] = 100 - rates[SCIENCE] - rates[LUXURY];
  } else {
    rates[SCIENCE] = game.info.forced_science;
    rates[LUXURY] = game.info.forced_luxury;
    rates[TAX] = game.info.forced_gold;
  }
 
  /* ANARCHY */
  if (government_of_player(pplayer) == game.government_during_revolution) {
    rates[SCIENCE] = 0;
    rates[LUXURY] = 100;
    rates[TAX] = 0;
  }
 
  distribute(trade, 3, rates, result);
 
  output[O_SCIENCE] += result[SCIENCE];
  output[O_GOLD] += result[TAX];
  output[O_LUXURY] += result[LUXURY];
}
 
/**********************************************************************/
bool city_built_last_turn(const struct city *pcity)
{
  return pcity->turn_last_built + 1 >= game.info.turn;
}
 
/**********************************************************************/
static inline void get_worked_tile_output(const struct city *pcity,
                                          int *output, bool *workers_map)
{
  bool is_worked;
#ifdef CITY_DEBUGGING
  bool is_celebrating = base_city_celebrating(pcity);
#endif
  struct tile *pcenter = city_tile(pcity);
  const struct civ_map *nmap = &(wld.map);
 
  memset(output, 0, O_LAST * sizeof(*output));
 
  city_tile_iterate_index(nmap, city_map_radius_sq_get(pcity), pcenter, ptile,
                          city_tile_index) {
    if (workers_map == NULL) {
      struct city *pwork = tile_worked(ptile);
 
      is_worked = (NULL != pwork && pwork == pcity);
    } else {
      is_worked = workers_map[city_tile_index];
    }
 
    if (is_worked) {
      output_type_iterate(o) {
#ifdef CITY_DEBUGGING
        /* This assertion never fails, but it's so slow that we disable
         * it by default. */
        fc_assert(city_tile_cache_get_output(pcity, city_tile_index, o)
                  == city_tile_output(pcity, ptile, is_celebrating, o));
#endif /* CITY_DEBUGGING */
        output[o] += city_tile_cache_get_output(pcity, city_tile_index, o);
      } output_type_iterate_end;
    }
  } city_tile_iterate_index_end;
}
 
/**********************************************************************/
void add_specialist_output(const struct city *pcity, int *output)
{
  specialist_type_iterate(sp) {
    int count = pcity->specialists[sp];
 
    output_type_iterate(stat_index) {
      int amount = get_specialist_output(pcity, sp, stat_index);
 
      output[stat_index] += count * amount;
    } output_type_iterate_end;
  } specialist_type_iterate_end;
}
 
/**********************************************************************/
static inline void set_city_bonuses(struct city *pcity)
{
  output_type_iterate(o) {
    pcity->bonus[o] = get_final_city_output_bonus(pcity, o);
  } output_type_iterate_end;
}
 
/**********************************************************************/
static inline void city_tile_cache_update(const struct civ_map *nmap,
                                          struct city *pcity)
{
  bool is_celebrating = base_city_celebrating(pcity);
  int radius_sq = city_map_radius_sq_get(pcity);
 
  /* Initialize tile_cache if needed */
  if (pcity->tile_cache == NULL || pcity->tile_cache_radius_sq == -1
      || pcity->tile_cache_radius_sq != radius_sq) {
    pcity->tile_cache = fc_realloc(pcity->tile_cache,
                                   city_map_tiles(radius_sq)
                                   * sizeof(*(pcity->tile_cache)));
    pcity->tile_cache_radius_sq = radius_sq;
  }
 
  /* Any unreal tiles are skipped - these values should have been memset
   * to 0 when the city was created. */
  city_tile_iterate_index(nmap, radius_sq, pcity->tile, ptile, city_tile_index) {
    output_type_iterate(o) {
      (pcity->tile_cache[city_tile_index]).output[o]
        = city_tile_output(pcity, ptile, is_celebrating, o);
    } output_type_iterate_end;
  } city_tile_iterate_index_end;
}
 
/**********************************************************************/
static inline int city_tile_cache_get_output(const struct city *pcity,
                                             int city_tile_index,
                                             enum output_type_id o)
{
  fc_assert_ret_val(pcity->tile_cache_radius_sq
                    == city_map_radius_sq_get(pcity), 0);
  fc_assert_ret_val(city_tile_index < city_map_tiles_from_city(pcity), 0);
 
  return (pcity->tile_cache[city_tile_index]).output[o];
}
 
/**********************************************************************/
static void set_surpluses(struct city *pcity)
{
  output_type_iterate(o) {
    pcity->surplus[o] = pcity->prod[o] - pcity->usage[o];
  } output_type_iterate_end;
}
 
/**********************************************************************/
static void happy_copy(struct city *pcity, enum citizen_feeling i)
{
  int c = 0;
 
  for (; c < CITIZEN_LAST; c++) {
    pcity->feel[c][i] = pcity->feel[c][i - 1];
  }
}
 
/**********************************************************************/
static void citizen_base_mood(struct city *pcity)
{
  struct player *pplayer = city_owner(pcity);
  citizens *happy = &pcity->feel[CITIZEN_HAPPY][FEELING_BASE];
  citizens *content = &pcity->feel[CITIZEN_CONTENT][FEELING_BASE];
  citizens *unhappy = &pcity->feel[CITIZEN_UNHAPPY][FEELING_BASE];
  citizens *angry = &pcity->feel[CITIZEN_ANGRY][FEELING_BASE];
  citizens size = city_size_get(pcity);
  citizens spes = city_specialists(pcity);
 
  /* This is the number of citizens that may start out content, depending
   * on empire size and game's city unhappysize. This may be bigger than
   * the size of the city, since this is a potential. */
  citizens base_content = player_content_citizens(pplayer);
  /* Similarly, this is the potential number of angry citizens. */
  citizens base_angry = player_angry_citizens(pplayer);
 
  /* Create content citizens. Take specialists from their ranks. */
  *content = MAX(0, MIN(size, base_content) - spes);
 
  /* Create angry citizens. Specialists never become angry. */
  fc_assert_action(base_content == 0 || base_angry == 0, *content = 0);
  *angry = MIN(base_angry, size - spes);
 
  /* Create unhappy citizens. In the beginning, all who are not content,
   * specialists or angry are unhappy. This is changed by luxuries and 
   * buildings later. */
  *unhappy = (size - spes - *content - *angry);
 
  /* No one is born happy. */
  *happy = 0;
}
 
/**********************************************************************/
static inline void citizen_luxury_happy(struct city *pcity, int *luxuries)
{
  citizens *happy = &pcity->feel[CITIZEN_HAPPY][FEELING_LUXURY];
  citizens *content = &pcity->feel[CITIZEN_CONTENT][FEELING_LUXURY];
  citizens *unhappy = &pcity->feel[CITIZEN_UNHAPPY][FEELING_LUXURY];
  citizens *angry = &pcity->feel[CITIZEN_ANGRY][FEELING_LUXURY];
 
  while (*luxuries >= game.info.happy_cost && *angry > 0) {
    /* Upgrade angry to unhappy: costs HAPPY_COST each. */
    (*angry)--;
    (*unhappy)++;
    *luxuries -= game.info.happy_cost;
  }
  while (*luxuries >= game.info.happy_cost && *content > 0) {
    /* Upgrade content to happy: costs HAPPY_COST each. */
    (*content)--;
    (*happy)++;
    *luxuries -= game.info.happy_cost;
  }
  while (*luxuries >= 2 * game.info.happy_cost && *unhappy > 0) {
    /* Upgrade unhappy to happy.  Note this is a 2-level upgrade with
     * double the cost. */
    (*unhappy)--;
    (*happy)++;
    *luxuries -= 2 * game.info.happy_cost;
  }
  if (*luxuries >= game.info.happy_cost && *unhappy > 0) {
    /* Upgrade unhappy to content: costs HAPPY_COST each. */
    (*unhappy)--;
    (*content)++;
    *luxuries -= game.info.happy_cost;
  }
}
 
/**********************************************************************/
static inline void citizen_happy_luxury(struct city *pcity)
{
  int x = pcity->prod[O_LUXURY];
 
  citizen_luxury_happy(pcity, &x);
}
 
/**********************************************************************/
static inline void citizen_content_buildings(struct city *pcity)
{
  citizens *content = &pcity->feel[CITIZEN_CONTENT][FEELING_EFFECT];
  citizens *unhappy = &pcity->feel[CITIZEN_UNHAPPY][FEELING_EFFECT];
  citizens *angry = &pcity->feel[CITIZEN_ANGRY][FEELING_EFFECT];
  int faces = get_city_bonus(pcity, EFT_MAKE_CONTENT);
 
  /* make people content (but not happy):
     get rid of angry first, then make unhappy content. */
  while (faces > 0 && *angry > 0) {
    (*angry)--;
    (*unhappy)++;
    faces--;
  }
  while (faces > 0 && *unhappy > 0) {
    (*unhappy)--;
    (*content)++;
    faces--;
  }
}
 
/**********************************************************************/
static inline void citizen_happiness_nationality(struct city *pcity)
{
  citizens *happy = &pcity->feel[CITIZEN_HAPPY][FEELING_NATIONALITY];
  citizens *content = &pcity->feel[CITIZEN_CONTENT][FEELING_NATIONALITY];
  citizens *unhappy = &pcity->feel[CITIZEN_UNHAPPY][FEELING_NATIONALITY];
 
  if (game.info.citizen_nationality) {
    int pct = get_city_bonus(pcity, EFT_ENEMY_CITIZEN_UNHAPPY_PCT);
 
    if (pct > 0) {
      int enemies = 0;
      int unhappy_inc;
      struct player *owner = city_owner(pcity);
 
      citizens_foreign_iterate(pcity, pslot, nationality) {
        if (pplayers_at_war(owner, player_slot_get_player(pslot))) {
          enemies += nationality;
        }
      } citizens_foreign_iterate_end;
 
      unhappy_inc = enemies * pct / 100;
 
      /* First make content => unhappy, then happy => unhappy,
       * then happy => content. No-one becomes angry. */
      while (unhappy_inc > 0 && *content > 0) {
        (*content)--;
        (*unhappy)++;
        unhappy_inc--;
      }
      while (unhappy_inc > 1 && *happy > 0) {
        (*happy)--;
        (*unhappy)++;
        unhappy_inc -= 2;
      }
      while (unhappy_inc > 0 && *happy > 0) {
        (*happy)--;
        (*content)++;
        unhappy_inc--;
      }
    }
  }
}
 
/**********************************************************************/
static inline void citizen_happy_units(struct city *pcity)
{
  citizens *happy = &pcity->feel[CITIZEN_HAPPY][FEELING_MARTIAL];
  citizens *content = &pcity->feel[CITIZEN_CONTENT][FEELING_MARTIAL];
  citizens *unhappy = &pcity->feel[CITIZEN_UNHAPPY][FEELING_MARTIAL];
  citizens *angry = &pcity->feel[CITIZEN_ANGRY][FEELING_MARTIAL];
  citizens  amt = pcity->martial_law;
 
  /* Pacify discontent citizens through martial law.  First convert
   * angry => unhappy, then unhappy => content. */
  while (amt > 0 && *angry > 0) {
    (*angry)--;
    (*unhappy)++;
    amt--;
  }
  while (amt > 0 && *unhappy > 0) {
    (*unhappy)--;
    (*content)++;
    amt--;
  }
 
  /* Now make citizens unhappier because of military units away from home.
   * First make content => unhappy, then happy => unhappy,
   * then happy => content. */
  amt = pcity->unit_happy_upkeep;
  while (amt > 0 && *content > 0) {
    (*content)--;
    (*unhappy)++;
    amt--;
  }
  while (amt > 1 && *happy > 0) {
    (*happy)--;
    (*unhappy)++;
    amt -= 2;
  }
  while (amt > 0 && *happy > 0) {
    (*happy)--;
    (*content)++;
    amt--;
  }
  /* Any remaining unhappiness is lost since angry citizens aren't created
   * here. */
  /* FIXME: Why not? - Per */
}
 
/**********************************************************************/
static inline void citizen_happy_wonders(struct city *pcity)
{
  citizens *happy = &pcity->feel[CITIZEN_HAPPY][FEELING_FINAL];
  citizens *content = &pcity->feel[CITIZEN_CONTENT][FEELING_FINAL];
  citizens *unhappy = &pcity->feel[CITIZEN_UNHAPPY][FEELING_FINAL];
  citizens *angry = &pcity->feel[CITIZEN_ANGRY][FEELING_FINAL];
  int bonus = get_city_bonus(pcity, EFT_MAKE_HAPPY);
 
  /* First create happy citizens from content, then from unhappy
   * citizens; we cannot help angry citizens here. */
  while (bonus > 0 && *content > 0) {
    (*content)--;
    (*happy)++;
    bonus--;
  }
  while (bonus > 1 && *unhappy > 0) {
    (*unhappy)--;
    (*happy)++;
    bonus -= 2;
  }
  /* The rest falls through and lets unhappy people become content. */
 
  if (get_city_bonus(pcity, EFT_NO_UNHAPPY) > 0) {
    *content += *unhappy + *angry;
    *unhappy = 0;
    *angry = 0;
    return;
  }
 
  bonus += get_city_bonus(pcity, EFT_FORCE_CONTENT);
 
  /* get rid of angry first, then make unhappy content */
  while (bonus > 0 && *angry > 0) {
    (*angry)--;
    (*unhappy)++;
    bonus--;
  }
  while (bonus > 0 && *unhappy > 0) {
    (*unhappy)--;
    (*content)++;
    bonus--;
  }
}
 
/**********************************************************************/
static inline void unhappy_city_check(struct city *pcity)
{
  if (city_unhappy(pcity)) {
    output_type_iterate(o) {
      switch (output_types[o].unhappy_penalty) {
      case UNHAPPY_PENALTY_NONE:
        pcity->unhappy_penalty[o] = 0;
        break;
      case UNHAPPY_PENALTY_SURPLUS:
        pcity->unhappy_penalty[o] = MAX(pcity->prod[o] - pcity->usage[o], 0);
        break;
      case UNHAPPY_PENALTY_ALL_PRODUCTION:
        pcity->unhappy_penalty[o] = pcity->prod[o];
        break;
      }
 
      pcity->prod[o] -= pcity->unhappy_penalty[o];
    } output_type_iterate_end;
  } else {
    memset(pcity->unhappy_penalty, 0,
           O_LAST * sizeof(*pcity->unhappy_penalty));
  }
}
 
/**********************************************************************/
int city_pollution_types(const struct city *pcity, int shield_total,
                         int *pollu_prod, int *pollu_pop, int *pollu_mod)
{
  int prod, pop, mod;
 
  /* Add one one pollution per shield, multipled by the bonus. */
  prod = 100 + get_city_bonus(pcity, EFT_POLLU_PROD_PCT);
  prod = shield_total * MAX(prod, 0) / 100;
 
  /* Add one pollution per citizen for baseline combined bonus (100%). */
  pop = (100 + get_city_bonus(pcity, EFT_POLLU_POP_PCT))
      * (100 + get_city_bonus(pcity, EFT_POLLU_POP_PCT_2))
      / 100;
  pop = (city_size_get(pcity) * MAX(pop, 0)) / 100;
 
  /* Then there is base pollution (usually a negative number). */
  mod = game.info.base_pollution;
 
  if (pollu_prod) {
    *pollu_prod = prod;
  }
  if (pollu_pop) {
    *pollu_pop = pop;
  }
  if (pollu_mod) {
    *pollu_mod = mod;
  }
  return MAX(prod + pop + mod, 0);
}
 
/**********************************************************************/
int city_pollution(const struct city *pcity, int shield_total)
{
  return city_pollution_types(pcity, shield_total, NULL, NULL, NULL);
}
 
/**********************************************************************/
static int get_trade_illness(const struct city *pcity)
{
  float illness_trade = 0.0;
 
  trade_partners_iterate(pcity, trade_city) {
    if (trade_city->turn_plague != -1
        && game.info.turn - trade_city->turn_plague < 5) {
      illness_trade += (float)game.info.illness_trade_infection
                       * sqrt(1.0 * city_size_get(pcity)
                              * city_size_get(trade_city)) / 100.0;
    }
  } trade_partners_iterate_end;
 
  return (int)illness_trade;
}
 
/**********************************************************************/
static int get_city_health(const struct city *pcity)
{
  return get_city_bonus(pcity, EFT_HEALTH_PCT);
}
 
/**********************************************************************/
int city_illness_calc(const struct city *pcity, int *ill_base,
                      int *ill_size, int *ill_trade, int *ill_pollution)
{
  int illness_size = 0, illness_trade = 0, illness_pollution = 0;
  int illness_base, illness_percent;
 
  if (game.info.illness_on
      && city_size_get(pcity) > game.info.illness_min_size) {
    /* offset the city size by game.info.illness_min_size */
    int use_size = city_size_get(pcity) - game.info.illness_min_size;
 
    illness_size = (int)((1.0 - exp(- (float)use_size / 10.0))
                         * 10.0 * game.info.illness_base_factor);
    if (is_server()) {
      /* on the server we recalculate the illness due to trade as we have
       * all informations */
      illness_trade = get_trade_illness(pcity);
    } else {
      /* on the client we have to rely on the value saved within the city
       * struct */
      illness_trade = pcity->illness_trade;
    }
 
    illness_pollution = pcity->pollution
                        * game.info.illness_pollution_factor / 100;
  }
 
  illness_base = illness_size + illness_trade + illness_pollution;
  illness_percent = 100 - get_city_health(pcity);
 
  /* returning other data */
  if (ill_size) {
    *ill_size = illness_size;
  }
 
  if (ill_trade) {
    *ill_trade = illness_trade;
  }
 
  if (ill_pollution) {
    *ill_pollution = illness_pollution;
  }
 
  if (ill_base) {
    *ill_base = illness_base;
  }
 
  return CLIP(0, illness_base * illness_percent / 100 , 999);
}
 
/**********************************************************************/
bool city_had_recent_plague(const struct city *pcity)
{
  /* Correctly handles special case turn_plague == -1 (never) */
  return (pcity->turn_plague == game.info.turn);
}
 
/**********************************************************************/
int city_build_slots(const struct city *pcity)
{
  return get_city_bonus(pcity, EFT_CITY_BUILD_SLOTS);
}
 
/**********************************************************************/
int city_airlift_max(const struct city *pcity)
{
  return get_city_bonus(pcity, EFT_AIRLIFT);
}
 
/**********************************************************************/
inline void set_city_production(struct city *pcity)
{
  /* Calculate city production!
   *
   * This is a rather complicated process if we allow rules to become
   * more generalized.  We can assume that there are no recursive dependency
   * loops, but there are some dependencies that do not follow strict
   * ordering.  For instance corruption must be calculated before 
   * trade taxes can be counted up, which must occur before the science bonus
   * is added on.  But the calculation of corruption must include the
   * trade bonus.  To do this without excessive special casing means that in
   * this case the bonuses are multiplied on twice (but only saved the second
   * time).
   */
 
  output_type_iterate(o) {
    pcity->prod[o] = pcity->citizen_base[o];
  } output_type_iterate_end;
 
  /* Add on special extra incomes: trade routes and tithes. */
  trade_routes_iterate(pcity, proute) {
    struct city *tcity = game_city_by_number(proute->partner);
    bool can_trade;
 
    /* Partner city may have not yet been sent to the client, or
     * there's just a placeholder city with a placeholder owner
     * created for some tile->worked. */
    if (!is_server()
        && (tcity == NULL
            || city_owner(tcity)->slot == NULL)) {
      continue;
    }
 
    fc_assert_action(tcity != NULL, continue);
 
    can_trade = can_cities_trade(pcity, tcity);
 
    if (!can_trade) {
      enum trade_route_type type = cities_trade_route_type(pcity, tcity);
      struct trade_route_settings *settings = trade_route_settings_by_type(type);
 
      if (settings->cancelling == TRI_ACTIVE) {
        can_trade = TRUE;
      }
    } 
 
    if (can_trade) {
      int value;
 
      value =
        trade_base_between_cities(pcity, game_city_by_number(proute->partner));
      proute->value = trade_from_route(pcity, proute, value);
      pcity->prod[O_TRADE] += proute->value
        * (100 + get_city_bonus(pcity, EFT_TRADE_ROUTE_PCT)) / 100;
    } else {
      proute->value = 0;
    }
  } trade_routes_iterate_end;
  pcity->prod[O_GOLD] += get_city_tithes_bonus(pcity);
 
  /* Account for waste.  Note that waste is calculated before tax income is
   * calculated, so if you had "science waste" it would not include taxed
   * science.  However waste is calculated after the bonuses are multiplied
   * on, so shield waste will include shield bonuses. */
  output_type_iterate(o) {
    pcity->waste[o] = city_waste(pcity, o,
                                 pcity->prod[o] * pcity->bonus[o] / 100,
                                 NULL);
  } output_type_iterate_end;
 
  /* Convert trade into science/luxury/gold, and add this on to whatever
   * science/luxury/gold is already there. */
  add_tax_income(city_owner(pcity),
                 pcity->prod[O_TRADE] * pcity->bonus[O_TRADE] / 100
                 - pcity->waste[O_TRADE] - pcity->usage[O_TRADE],
                 pcity->prod);
 
  /* Add on effect bonuses and waste.  Note that the waste calculation
   * (above) already includes the bonus multiplier. */
  output_type_iterate(o) {
    pcity->prod[o] = pcity->prod[o] * pcity->bonus[o] / 100;
    pcity->prod[o] -= pcity->waste[o];
  } output_type_iterate_end;
}
 
/**********************************************************************/
int city_unit_unhappiness(struct unit *punit, int *free_unhappy)
{
  struct city *pcity;
  const struct unit_type *ut;
  struct player *plr;
  int happy_cost;
 
  if (!punit || !free_unhappy) {
    return 0;
  }
 
  pcity = game_city_by_number(punit->homecity);
  if (pcity == NULL) {
    return 0;
  }
 
  ut = unit_type_get(punit);
  plr = unit_owner(punit);
  happy_cost = utype_happy_cost(ut, plr);
 
  if (happy_cost <= 0) {
    return 0;
  }
 
  fc_assert_ret_val(0 <= *free_unhappy, 0);
 
  if (!unit_being_aggressive(punit) && !is_field_unit(punit)) {
    return 0;
  }
 
  happy_cost -= get_city_bonus(pcity, EFT_MAKE_CONTENT_MIL_PER);
  if (happy_cost <= 0) {
    return 0;
  }
 
  if (*free_unhappy >= happy_cost) {
    *free_unhappy -= happy_cost;
    return 0;
  } else {
    happy_cost -= *free_unhappy;
    *free_unhappy = 0;
  }
 
  return happy_cost;
}
 
/**********************************************************************/
static inline void city_support(struct city *pcity)
{
  int free_unhappy, martial_law_each;
 
  /* Clear all usage values. */
  memset(pcity->usage, 0, O_LAST * sizeof(*pcity->usage));
  pcity->martial_law = 0;
  pcity->unit_happy_upkeep = 0;
 
  /* Building and unit gold upkeep depends on the setting
   * 'game.info.gold_upkeep_style':
   * GOLD_UPKEEP_CITY: The upkeep for buildings and units is paid by the
   *                   city.
   * GOLD_UPKEEP_MIXED: The upkeep for buildings is paid by the city.
   *                    The upkeep for units is paid by the nation.
   * GOLD_UPKEEP_NATION: The upkeep for buildings and units is paid by the
   *                     nation. */
  fc_assert_msg(gold_upkeep_style_is_valid(game.info.gold_upkeep_style),
                "Invalid gold_upkeep_style %d", game.info.gold_upkeep_style);
  switch (game.info.gold_upkeep_style) {
  case GOLD_UPKEEP_CITY:
    pcity->usage[O_GOLD] += city_total_unit_gold_upkeep(pcity);
    fc__fallthrough; /* No break */
  case GOLD_UPKEEP_MIXED:
    pcity->usage[O_GOLD] += city_total_impr_gold_upkeep(pcity);
    break;
  case GOLD_UPKEEP_NATION:
    /* nothing */
    break;
  }
  /* Food consumption by citizens. */
  pcity->usage[O_FOOD] += game.info.food_cost * city_size_get(pcity);
 
  /* military units in this city (need _not_ be home city) can make
   * unhappy citizens content */
  martial_law_each = get_city_bonus(pcity, EFT_MARTIAL_LAW_EACH);
  if (martial_law_each > 0) {
    int count = 0;
    int martial_law_max = get_city_bonus(pcity, EFT_MARTIAL_LAW_MAX);
 
    unit_list_iterate(pcity->tile->units, punit) {
      if ((count < martial_law_max || martial_law_max == 0)
          && is_military_unit(punit)
          && unit_owner(punit) == city_owner(pcity)) {
        count++;
      }
    } unit_list_iterate_end;
 
    pcity->martial_law = CLIP(0, count * martial_law_each, MAX_CITY_SIZE);
  }
 
  free_unhappy = get_city_bonus(pcity, EFT_MAKE_CONTENT_MIL);
  unit_list_iterate(pcity->units_supported, punit) {
    pcity->unit_happy_upkeep += city_unit_unhappiness(punit, &free_unhappy);
    output_type_iterate(o) {
      if (O_GOLD != o) {
        /* O_GOLD is handled with "game.info.gold_upkeep_style", see over. */
        pcity->usage[o] += punit->upkeep[o];
      }
    } output_type_iterate_end;
  } unit_list_iterate_end;
}
 
/**********************************************************************/
void city_refresh_from_main_map(struct city *pcity, bool *workers_map)
{
  const struct civ_map *nmap = &(wld.map);
 
  if (workers_map == NULL) {
    /* do a full refresh */
 
    /* Calculate the bonus[] array values. */
    set_city_bonuses(pcity);
    /* Calculate the tile_cache[] values. */
    city_tile_cache_update(nmap, pcity);
    /* manage settlers, and units */
    city_support(pcity);
  }
 
  /* Calculate output from citizens (uses city_tile_cache_get_output()). */
  get_worked_tile_output(pcity, pcity->citizen_base, workers_map);
  add_specialist_output(pcity, pcity->citizen_base);
 
  set_city_production(pcity);
  citizen_base_mood(pcity);
  /* Note that pollution is calculated before unhappy_city_check() makes
   * deductions for disorder; so a city in disorder still causes pollution */
  pcity->pollution = city_pollution(pcity, pcity->prod[O_SHIELD]);
 
  happy_copy(pcity, FEELING_LUXURY);
  citizen_happy_luxury(pcity);  /* with our new found luxuries */
 
  happy_copy(pcity, FEELING_EFFECT);
  citizen_content_buildings(pcity);
 
  happy_copy(pcity, FEELING_NATIONALITY);
  citizen_happiness_nationality(pcity);
 
  /* Martial law & unrest from units */
  happy_copy(pcity, FEELING_MARTIAL);
  citizen_happy_units(pcity);
 
  /* Building (including wonder) happiness effects */
  happy_copy(pcity, FEELING_FINAL);
  citizen_happy_wonders(pcity);
 
  unhappy_city_check(pcity);
  set_surpluses(pcity);
}
 
/**********************************************************************/
int city_waste(const struct city *pcity, Output_type_id otype, int total,
               int *breakdown)
{
  int penalty_waste = 0;
  int penalty_size = 0;  /* separate notradesize/fulltradesize from normal
                          * corruption */
  int total_eft = total; /* normal corruption calculated on total reduced by
                          * possible size penalty */
  int waste_level = get_city_output_bonus(pcity, get_output_type(otype),
                                          EFT_OUTPUT_WASTE);
  bool waste_all = FALSE;
 
  if (otype == O_TRADE) {
    /* FIXME: special case for trade: it is affected by notradesize and
     * fulltradesize server settings.
     *
     * If notradesize and fulltradesize are equal then the city gets no
     * trade at that size. */
    int notradesize = MIN(game.info.notradesize, game.info.fulltradesize);
    int fulltradesize = MAX(game.info.notradesize, game.info.fulltradesize);
 
    if (city_size_get(pcity) <= notradesize) {
      penalty_size = total_eft; /* Then no trade income. */
    } else if (city_size_get(pcity) >= fulltradesize) {
      penalty_size = 0;
     } else {
      penalty_size = total_eft * (fulltradesize - city_size_get(pcity))
                     / (fulltradesize - notradesize);
    }
  }
 
  /* Apply corruption only to anything left after tradesize */
  total_eft -= penalty_size;
 
  /* Distance-based waste.
   * Don't bother calculating if there's nothing left to lose. */
  if (total_eft > 0) {
    int waste_by_dist = get_city_output_bonus(pcity, get_output_type(otype),
                                              EFT_OUTPUT_WASTE_BY_DISTANCE);
    int waste_by_rel_dist = get_city_output_bonus(pcity, get_output_type(otype),
                                                  EFT_OUTPUT_WASTE_BY_REL_DISTANCE);
    if (waste_by_dist > 0 || waste_by_rel_dist > 0) {
      const struct city *gov_center = NULL;
      int min_dist = FC_INFINITY;
 
      /* Check the special case that city itself is gov center
       * before expensive iteration through all cities. */
      if (is_gov_center(pcity)) {
        gov_center = pcity;
        min_dist = 0;
      } else {
        city_list_iterate(city_owner(pcity)->cities, gc) {
          /* Do not recheck current city */
          if (gc != pcity && is_gov_center(gc)) {
            int dist = real_map_distance(gc->tile, pcity->tile);
 
            if (dist < min_dist) {
              gov_center = gc;
              min_dist = dist;
            }
          }
        } city_list_iterate_end;
      }
 
      if (gov_center == NULL) {
        waste_all = TRUE; /* no gov center - no income */
      } else {
        waste_level += waste_by_dist * min_dist / 100;
        if (waste_by_rel_dist > 0) {
          /* Multiply by 50 as an "standard size" for which EFT_OUTPUT_WASTE_BY_DISTANCE
           * and EFT_OUTPUT_WASTE_BY_REL_DISTANCE would give same result. */
          waste_level += waste_by_rel_dist * 50 * min_dist / 100
            / MAX(wld.map.xsize, wld.map.ysize);
        }
      }
    }
  }
 
  if (waste_all) {
    penalty_waste = total_eft;
  } else {
    int waste_pct = get_city_output_bonus(pcity, get_output_type(otype),
                                          EFT_OUTPUT_WASTE_PCT);
 
    /* corruption/waste calculated only for the actually produced amount */
    if (waste_level > 0) {
      penalty_waste = total_eft * waste_level / 100;
    }
 
    /* bonus calculated only for the actually produced amount */
    penalty_waste -= penalty_waste * waste_pct / 100;
 
    /* Clip */
    penalty_waste = MIN(MAX(penalty_waste, 0), total_eft);
  }
 
  if (breakdown) {
    breakdown[OLOSS_WASTE] = penalty_waste;
    breakdown[OLOSS_SIZE]  = penalty_size;
  }
 
  /* add up total penalty */
  return penalty_waste + penalty_size;
}
 
/**********************************************************************/
citizens city_specialists(const struct city *pcity)
{
  citizens count = 0;
 
  specialist_type_iterate(sp) {
    fc_assert_ret_val(MAX_CITY_SIZE - count > pcity->specialists[sp], 0);
    count += pcity->specialists[sp];
  } specialist_type_iterate_end;
 
  return count;
}
 
/**********************************************************************/
Specialist_type_id best_specialist(Output_type_id otype,
                                   const struct city *pcity)
{
  int best = DEFAULT_SPECIALIST;
  int val = get_specialist_output(pcity, best, otype);
 
  specialist_type_iterate(i) {
    if (!pcity || city_can_use_specialist(pcity, i)) {
      int val2 = get_specialist_output(pcity, i, otype);
 
      if (val2 > val) {
        best = i;
        val = val2;
      }
    }
  } specialist_type_iterate_end;
 
  return best;
}
 
/**********************************************************************/
void city_add_improvement(struct city *pcity,
                          const struct impr_type *pimprove)
{
  pcity->built[improvement_index(pimprove)].turn = game.info.turn; /*I_ACTIVE*/
 
  if (is_server() && is_wonder(pimprove)) {
    /* Client just read the info from the packets. */
    wonder_built(pcity, pimprove);
  }
}
 
/**********************************************************************/
void city_remove_improvement(struct city *pcity,
                             const struct impr_type *pimprove)
{
  log_debug("Improvement %s removed from city %s",
            improvement_rule_name(pimprove), pcity->name);
  
  pcity->built[improvement_index(pimprove)].turn = I_DESTROYED;
 
  if (is_server() && is_wonder(pimprove)) {
    /* Client just read the info from the packets. */
    wonder_destroyed(pcity, pimprove);
  }
}
 
/**********************************************************************/
bool is_city_option_set(const struct city *pcity, enum city_options option)
{
  return BV_ISSET(pcity->city_options, option);
}
 
/**********************************************************************/
void city_styles_alloc(int num)
{
  int i;
 
  city_styles = fc_calloc(num, sizeof(*city_styles));
  game.control.styles_count = num;
 
  for (i = 0; i < game.control.styles_count; i++) {
    requirement_vector_init(&city_styles[i].reqs);
  }
}
 
/**********************************************************************/
void city_styles_free(void)
{
  int i;
 
  for (i = 0; i < game.control.styles_count; i++) {
    requirement_vector_free(&city_styles[i].reqs);
  }
 
  free(city_styles);
  city_styles = NULL;
  game.control.styles_count = 0;
}
 
/**********************************************************************/
struct city *create_city_virtual(struct player *pplayer,
                                 struct tile *ptile, const char *name)
{
  int i;
 
  /* Make sure that contents of city structure are correctly initialized,
   * if you ever allocate it by some other mean than fc_calloc() */
  struct city *pcity = fc_calloc(1, sizeof(*pcity));
 
  fc_assert_ret_val(NULL != name, NULL);        /* No unnamed cities! */
 
  /* Do this early, so any logging later will have the city name */
  city_name_set(pcity, name);
 
  pcity->tile = ptile;
  fc_assert_ret_val(NULL != pplayer, NULL);     /* No unowned cities! */
  pcity->owner = pplayer;
 
  if (is_server()) {
    pcity->original = pplayer;
  }
 
  /* City structure was allocated with fc_calloc(), so contents are initially
   * zero. There is no need to initialize it a second time. */
 
  /* Now set some useful default values. */
  pcity->capital = CAPITAL_NOT;
  city_size_set(pcity, 1);
  pcity->specialists[DEFAULT_SPECIALIST] = 1;
 
  output_type_iterate(o) {
    pcity->bonus[o] = 100;
  } output_type_iterate_end;
 
  pcity->turn_plague = -1; /* -1 = never */
  pcity->did_buy = FALSE;
  pcity->city_radius_sq = game.info.init_city_radius_sq;
  pcity->turn_founded = game.info.turn;
  pcity->turn_last_built = game.info.turn;
 
  pcity->tile_cache_radius_sq = -1; /* -1 = tile_cache must be initialised */
 
  /* pcity->ai.act_cache: worker activities on the city map */
 
  /* Initialise improvements list */
  for (i = 0; i < ARRAY_SIZE(pcity->built); i++) {
    pcity->built[i].turn = I_NEVER;
  }
 
  /* Set up the worklist */
  worklist_init(&pcity->worklist);
 
  pcity->units_supported = unit_list_new();
  pcity->routes = trade_route_list_new();
  pcity->task_reqs = worker_task_list_new();
 
  if (is_server()) {
    pcity->server.mgr_score_calc_turn = -1; /* -1 = never */
 
    CALL_FUNC_EACH_AI(city_alloc, pcity);
  } else {
    pcity->client.info_units_supported =
        unit_list_new_full(unit_virtual_destroy);
    pcity->client.info_units_present =
        unit_list_new_full(unit_virtual_destroy);
    /* collecting_info_units_supported set by fc_calloc().
     * collecting_info_units_present set by fc_calloc(). */
  }
 
  return pcity;
}
 
/**********************************************************************/
void destroy_city_virtual(struct city *pcity)
{
  CALL_FUNC_EACH_AI(city_free, pcity);
 
  citizens_free(pcity);
 
  /* Free worker tasks */
  while (worker_task_list_size(pcity->task_reqs) > 0) {
    struct worker_task *ptask = worker_task_list_get(pcity->task_reqs, 0);
 
    worker_task_list_remove(pcity->task_reqs, ptask);
 
    free(ptask);
  }
  worker_task_list_destroy(pcity->task_reqs);
 
  /* Free rally points */
  city_rally_point_clear(pcity);
 
  unit_list_destroy(pcity->units_supported);
  trade_route_list_destroy(pcity->routes);
  if (pcity->tile_cache != NULL) {
    free(pcity->tile_cache);
  }
 
  if (pcity->cm_parameter) {
    free(pcity->cm_parameter);
  }
 
  if (!is_server()) {
    unit_list_destroy(pcity->client.info_units_supported);
    unit_list_destroy(pcity->client.info_units_present);
    /* Handle a rare case where the game is freed in the middle of a
     * spy/diplomat investigate cycle. */
    if (pcity->client.collecting_info_units_supported != NULL) {
      unit_list_destroy(pcity->client.collecting_info_units_supported);
    }
    if (pcity->client.collecting_info_units_present != NULL) {
      unit_list_destroy(pcity->client.collecting_info_units_present);
    }
  }
 
  free(pcity->name);
 
  memset(pcity, 0, sizeof(*pcity)); /* ensure no pointers remain */
  free(pcity);
}
 
/**********************************************************************/
bool city_exist(int id)
{
  /* Check if city exist in game */
  if (game_city_by_number(id)) {
    return TRUE;
  }
 
  return FALSE;
}
 
/**********************************************************************/
bool city_is_virtual(const struct city *pcity)
{
  if (!pcity) {
    return FALSE;
  }
 
  return pcity != game_city_by_number(pcity->id);
}
 
/**********************************************************************/
bool is_free_worked(const struct city *pcity, const struct tile *ptile)
{
  return is_city_center(pcity, ptile);
}
 
/**********************************************************************/
void *city_ai_data(const struct city *pcity, const struct ai_type *ai)
{
  return pcity->server.ais[ai_type_number(ai)];
}
 
/**********************************************************************/
void city_set_ai_data(struct city *pcity, const struct ai_type *ai,
                      void *data)
{
  pcity->server.ais[ai_type_number(ai)] = data;
}
 
/**********************************************************************/
void city_rally_point_clear(struct city *pcity)
{
  /* Free rally points */
  if (pcity->rally_point.length > 0) {
    pcity->rally_point.length = 0;
    pcity->rally_point.persistent = FALSE;
    pcity->rally_point.vigilant = FALSE;
    free(pcity->rally_point.orders);
    pcity->rally_point.orders = NULL;
  }
}
 
/**********************************************************************/
void city_rally_point_receive(const struct packet_city_rally_point *packet,
                              struct city *pcity)
{
  struct unit_order *checked_orders;
  const struct civ_map *nmap = &(wld.map);
 
  if (pcity == NULL) {
    /* Probably lost. */
    log_verbose("handle_city_rally_point() bad city number %d.",
                packet->city_id32);
    return;
  }
 
  if (0 > packet->length || MAX_LEN_ROUTE < packet->length) {
    /* Shouldn't happen */
    log_error("city_rally_point_receive() invalid packet length %d (max %d)",
              packet->length, MAX_LEN_ROUTE);
    return;
  }
 
  pcity->rally_point.length = packet->length;
 
  if (packet->length == 0) {
    pcity->rally_point.vigilant = FALSE;
    pcity->rally_point.persistent = FALSE;
    if (pcity->rally_point.orders) {
      free(pcity->rally_point.orders);
      pcity->rally_point.orders = NULL;
    }
  } else {
    checked_orders = create_unit_orders(nmap, packet->length,
                                        packet->orders);
    if (!checked_orders) {
      pcity->rally_point.length = 0;
      log_error("invalid rally point orders for city number %d.",
                packet->city_id32);
      return;
    }
 
    pcity->rally_point.persistent = packet->persistent;
    pcity->rally_point.vigilant = packet->vigilant;
    pcity->rally_point.orders = checked_orders;
  }
}