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  1. /*
  2. ** $Id: ltablib.c,v 1.38.1.3 2008/02/14 16:46:58 roberto Exp $
  3. ** Library for Table Manipulation
  4. ** See Copyright Notice in lua.h
  5. */
  6.  
  7.  
  8. #include <stddef.h>
  9.  
  10. #define ltablib_c
  11. #define LUA_LIB
  12.  
  13. #include "lua.h"
  14.  
  15. #include "lauxlib.h"
  16. #include "lualib.h"
  17.  
  18.  
  19. #define aux_getn(L,n)   (luaL_checktype(L, n, LUA_TTABLE), luaL_getn(L, n))
  20.  
  21.  
  22. static int foreachi (lua_State *L) {
  23.   int i;
  24.   int n = aux_getn(L, 1);
  25.   luaL_checktype(L, 2, LUA_TFUNCTION);
  26.   for (i=1; i <= n; i++) {
  27.     lua_pushvalue(L, 2);  /* function */
  28.     lua_pushinteger(L, i);  /* 1st argument */
  29.     lua_rawgeti(L, 1, i);  /* 2nd argument */
  30.     lua_call(L, 2, 1);
  31.     if (!lua_isnil(L, -1))
  32.       return 1;
  33.     lua_pop(L, 1);  /* remove nil result */
  34.   }
  35.   return 0;
  36. }
  37.  
  38.  
  39. static int foreach (lua_State *L) {
  40.   luaL_checktype(L, 1, LUA_TTABLE);
  41.   luaL_checktype(L, 2, LUA_TFUNCTION);
  42.   lua_pushnil(L);  /* first key */
  43.   while (lua_next(L, 1)) {
  44.     lua_pushvalue(L, 2);  /* function */
  45.     lua_pushvalue(L, -3);  /* key */
  46.     lua_pushvalue(L, -3);  /* value */
  47.     lua_call(L, 2, 1);
  48.     if (!lua_isnil(L, -1))
  49.       return 1;
  50.     lua_pop(L, 2);  /* remove value and result */
  51.   }
  52.   return 0;
  53. }
  54.  
  55.  
  56. static int maxn (lua_State *L) {
  57.   lua_Number max = 0;
  58.   luaL_checktype(L, 1, LUA_TTABLE);
  59.   lua_pushnil(L);  /* first key */
  60.   while (lua_next(L, 1)) {
  61.     lua_pop(L, 1);  /* remove value */
  62.     if (lua_type(L, -1) == LUA_TNUMBER) {
  63.       lua_Number v = lua_tonumber(L, -1);
  64.       if (v > max) max = v;
  65.     }
  66.   }
  67.   lua_pushnumber(L, max);
  68.   return 1;
  69. }
  70.  
  71.  
  72. static int getn (lua_State *L) {
  73.   lua_pushinteger(L, aux_getn(L, 1));
  74.   return 1;
  75. }
  76.  
  77.  
  78. static int setn (lua_State *L) {
  79.   luaL_checktype(L, 1, LUA_TTABLE);
  80. #ifndef luaL_setn
  81.   luaL_setn(L, 1, luaL_checkint(L, 2));
  82. #else
  83.   luaL_error(L, LUA_QL("setn") " is obsolete");
  84. #endif
  85.   lua_pushvalue(L, 1);
  86.   return 1;
  87. }
  88.  
  89.  
  90. static int tinsert (lua_State *L) {
  91.   int e = aux_getn(L, 1) + 1;  /* first empty element */
  92.   int pos;  /* where to insert new element */
  93.   switch (lua_gettop(L)) {
  94.     case 2: {  /* called with only 2 arguments */
  95.       pos = e;  /* insert new element at the end */
  96.       break;
  97.     }
  98.     case 3: {
  99.       int i;
  100.       pos = luaL_checkint(L, 2);  /* 2nd argument is the position */
  101.       if (pos > e) e = pos;  /* `grow' array if necessary */
  102.       for (i = e; i > pos; i--) {  /* move up elements */
  103.         lua_rawgeti(L, 1, i-1);
  104.         lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */
  105.       }
  106.       break;
  107.     }
  108.     default: {
  109.       return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
  110.     }
  111.   }
  112.   luaL_setn(L, 1, e);  /* new size */
  113.   lua_rawseti(L, 1, pos);  /* t[pos] = v */
  114.   return 0;
  115. }
  116.  
  117.  
  118. static int tremove (lua_State *L) {
  119.   int e = aux_getn(L, 1);
  120.   int pos = luaL_optint(L, 2, e);
  121.   if (!(1 <= pos && pos <= e))  /* position is outside bounds? */
  122.    return 0;  /* nothing to remove */
  123.   luaL_setn(L, 1, e - 1);  /* t.n = n-1 */
  124.   lua_rawgeti(L, 1, pos);  /* result = t[pos] */
  125.   for ( ;pos<e; pos++) {
  126.     lua_rawgeti(L, 1, pos+1);
  127.     lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
  128.   }
  129.   lua_pushnil(L);
  130.   lua_rawseti(L, 1, e);  /* t[e] = nil */
  131.   return 1;
  132. }
  133.  
  134.  
  135. static void addfield (lua_State *L, luaL_Buffer *b, int i) {
  136.   lua_rawgeti(L, 1, i);
  137.   if (!lua_isstring(L, -1))
  138.     luaL_error(L, "invalid value (%s) at index %d in table for "
  139.                   LUA_QL("concat"), luaL_typename(L, -1), i);
  140.     luaL_addvalue(b);
  141. }
  142.  
  143.  
  144. static int tconcat (lua_State *L) {
  145.   luaL_Buffer b;
  146.   size_t lsep;
  147.   int i, last;
  148.   const char *sep = luaL_optlstring(L, 2, "", &lsep);
  149.   luaL_checktype(L, 1, LUA_TTABLE);
  150.   i = luaL_optint(L, 3, 1);
  151.   last = luaL_opt(L, luaL_checkint, 4, luaL_getn(L, 1));
  152.   luaL_buffinit(L, &b);
  153.   for (; i < last; i++) {
  154.     addfield(L, &b, i);
  155.     luaL_addlstring(&b, sep, lsep);
  156.   }
  157.   if (i == last)  /* add last value (if interval was not empty) */
  158.     addfield(L, &b, i);
  159.   luaL_pushresult(&b);
  160.   return 1;
  161. }
  162.  
  163.  
  164.  
  165. /*
  166. ** {======================================================
  167. ** Quicksort
  168. ** (based on `Algorithms in MODULA-3', Robert Sedgewick;
  169. **  Addison-Wesley, 1993.)
  170. */
  171.  
  172.  
  173. static void set2 (lua_State *L, int i, int j) {
  174.   lua_rawseti(L, 1, i);
  175.   lua_rawseti(L, 1, j);
  176. }
  177.  
  178. static int sort_comp (lua_State *L, int a, int b) {
  179.   if (!lua_isnil(L, 2)) {  /* function? */
  180.     int res;
  181.     lua_pushvalue(L, 2);
  182.     lua_pushvalue(L, a-1);  /* -1 to compensate function */
  183.     lua_pushvalue(L, b-2);  /* -2 to compensate function and `a' */
  184.     lua_call(L, 2, 1);
  185.     res = lua_toboolean(L, -1);
  186.     lua_pop(L, 1);
  187.     return res;
  188.   }
  189.   else  /* a < b? */
  190.     return lua_lessthan(L, a, b);
  191. }
  192.  
  193. static void auxsort (lua_State *L, int l, int u) {
  194.   while (l < u) {  /* for tail recursion */
  195.     int i, j;
  196.     /* sort elements a[l], a[(l+u)/2] and a[u] */
  197.     lua_rawgeti(L, 1, l);
  198.     lua_rawgeti(L, 1, u);
  199.     if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
  200.       set2(L, l, u);  /* swap a[l] - a[u] */
  201.     else
  202.       lua_pop(L, 2);
  203.     if (u-l == 1) break;  /* only 2 elements */
  204.     i = (l+u)/2;
  205.     lua_rawgeti(L, 1, i);
  206.     lua_rawgeti(L, 1, l);
  207.     if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
  208.       set2(L, i, l);
  209.     else {
  210.       lua_pop(L, 1);  /* remove a[l] */
  211.       lua_rawgeti(L, 1, u);
  212.       if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
  213.         set2(L, i, u);
  214.       else
  215.         lua_pop(L, 2);
  216.     }
  217.     if (u-l == 2) break;  /* only 3 elements */
  218.     lua_rawgeti(L, 1, i);  /* Pivot */
  219.     lua_pushvalue(L, -1);
  220.     lua_rawgeti(L, 1, u-1);
  221.     set2(L, i, u-1);
  222.     /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
  223.     i = l; j = u-1;
  224.     for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
  225.       /* repeat ++i until a[i] >= P */
  226.       while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
  227.         if (i>u) luaL_error(L, "invalid order function for sorting");
  228.         lua_pop(L, 1);  /* remove a[i] */
  229.       }
  230.       /* repeat --j until a[j] <= P */
  231.       while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
  232.         if (j<l) luaL_error(L, "invalid order function for sorting");
  233.         lua_pop(L, 1);  /* remove a[j] */
  234.       }
  235.       if (j<i) {
  236.         lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
  237.         break;
  238.       }
  239.       set2(L, i, j);
  240.     }
  241.     lua_rawgeti(L, 1, u-1);
  242.     lua_rawgeti(L, 1, i);
  243.     set2(L, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
  244.     /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
  245.     /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
  246.     if (i-l < u-i) {
  247.       j=l; i=i-1; l=i+2;
  248.     }
  249.     else {
  250.       j=i+1; i=u; u=j-2;
  251.     }
  252.     auxsort(L, j, i);  /* call recursively the smaller one */
  253.   }  /* repeat the routine for the larger one */
  254. }
  255.  
  256. static int sort (lua_State *L) {
  257.   int n = aux_getn(L, 1);
  258.   luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
  259.   if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
  260.     luaL_checktype(L, 2, LUA_TFUNCTION);
  261.   lua_settop(L, 2);  /* make sure there is two arguments */
  262.   auxsort(L, 1, n);
  263.   return 0;
  264. }
  265.  
  266. /* }====================================================== */
  267.  
  268.  
  269. static const luaL_Reg tab_funcs[] = {
  270.   {"concat", tconcat},
  271.   {"foreach", foreach},
  272.   {"foreachi", foreachi},
  273.   {"getn", getn},
  274.   {"maxn", maxn},
  275.   {"insert", tinsert},
  276.   {"remove", tremove},
  277.   {"setn", setn},
  278.   {"sort", sort},
  279.   {NULL, NULL}
  280. };
  281.  
  282.  
  283. LUALIB_API int luaopen_table (lua_State *L) {
  284.   luaL_register(L, LUA_TABLIBNAME, tab_funcs);
  285.   return 1;
  286. }
  287.  
  288.