source/libs/lua52/lua52-src/src/ltablib.c

   1 /*
   2 ** $Id: ltablib.c,v 1.65.1.2 2014/05/07 16:32:55 roberto Exp $
   3 ** Library for Table Manipulation
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <limits.h>
   9 #include <stddef.h>
  10
  11 #define ltablib_c
  12 #define LUA_LIB
  13
  14 #include "lua.h"
  15
  16 #include "lauxlib.h"
  17 #include "lualib.h"
  18
  19
  20 #define aux_getn(L,n)   (luaL_checktype(L, n, LUA_TTABLE), luaL_len(L, n))
  21
  22
  23
  24 #if defined(LUA_COMPAT_MAXN)
  25 static int maxn (lua_State *L) {
  26   lua_Number max = 0;
  27   luaL_checktype(L, 1, LUA_TTABLE);
  28   lua_pushnil(L);  /* first key */
  29   while (lua_next(L, 1)) {
  30     lua_pop(L, 1);  /* remove value */
  31     if (lua_type(L, -1) == LUA_TNUMBER) {
  32       lua_Number v = lua_tonumber(L, -1);
  33       if (v > max) max = v;
  34     }
  35   }
  36   lua_pushnumber(L, max);
  37   return 1;
  38 }
  39 #endif
  40
  41
  42 static int tinsert (lua_State *L) {
  43   int e = aux_getn(L, 1) + 1;  /* first empty element */
  44   int pos;  /* where to insert new element */
  45   switch (lua_gettop(L)) {
  46     case 2: {  /* called with only 2 arguments */
  47       pos = e;  /* insert new element at the end */
  48       break;
  49     }
  50     case 3: {
  51       int i;
  52       pos = luaL_checkint(L, 2);  /* 2nd argument is the position */
  53       luaL_argcheck(L, 1 <= pos && pos <= e, 2, "position out of bounds");
  54       for (i = e; i > pos; i--) {  /* move up elements */
  55         lua_rawgeti(L, 1, i-1);
  56         lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */
  57       }
  58       break;
  59     }
  60     default: {
  61       return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
  62     }
  63   }
  64   lua_rawseti(L, 1, pos);  /* t[pos] = v */
  65   return 0;
  66 }
  67
  68
  69 static int tremove (lua_State *L) {
  70   int size = aux_getn(L, 1);
  71   int pos = luaL_optint(L, 2, size);
  72   if (pos != size)  /* validate 'pos' if given */
  73     luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, "position out of bounds");
  74   lua_rawgeti(L, 1, pos);  /* result = t[pos] */
  75   for ( ; pos < size; pos++) {
  76     lua_rawgeti(L, 1, pos+1);
  77     lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
  78   }
  79   lua_pushnil(L);
  80   lua_rawseti(L, 1, pos);  /* t[pos] = nil */
  81   return 1;
  82 }
  83
  84
  85 static void addfield (lua_State *L, luaL_Buffer *b, int i) {
  86   lua_rawgeti(L, 1, i);
  87   if (!lua_isstring(L, -1))
  88     luaL_error(L, "invalid value (%s) at index %d in table for "
  89                   LUA_QL("concat"), luaL_typename(L, -1), i);
  90   luaL_addvalue(b);
  91 }
  92
  93
  94 static int tconcat (lua_State *L) {
  95   luaL_Buffer b;
  96   size_t lsep;
  97   int i, last;
  98   const char *sep = luaL_optlstring(L, 2, "", &lsep);
  99   luaL_checktype(L, 1, LUA_TTABLE);
 100   i = luaL_optint(L, 3, 1);
 101   last = luaL_opt(L, luaL_checkint, 4, luaL_len(L, 1));
 102   luaL_buffinit(L, &b);
 103   for (; i < last; i++) {
 104     addfield(L, &b, i);
 105     luaL_addlstring(&b, sep, lsep);
 106   }
 107   if (i == last)  /* add last value (if interval was not empty) */
 108     addfield(L, &b, i);
 109   luaL_pushresult(&b);
 110   return 1;
 111 }
 112
 113
 114 /*
 115 ** {======================================================
 116 ** Pack/unpack
 117 ** =======================================================
 118 */
 119
 120 static int pack (lua_State *L) {
 121   int n = lua_gettop(L);  /* number of elements to pack */
 122   lua_createtable(L, n, 1);  /* create result table */
 123   lua_pushinteger(L, n);
 124   lua_setfield(L, -2, "n");  /* t.n = number of elements */
 125   if (n > 0) {  /* at least one element? */
 126     int i;
 127     lua_pushvalue(L, 1);
 128     lua_rawseti(L, -2, 1);  /* insert first element */
 129     lua_replace(L, 1);  /* move table into index 1 */
 130     for (i = n; i >= 2; i--)  /* assign other elements */
 131       lua_rawseti(L, 1, i);
 132   }
 133   return 1;  /* return table */
 134 }
 135
 136
 137 static int unpack (lua_State *L) {
 138   int i, e;
 139   unsigned int n;
 140   luaL_checktype(L, 1, LUA_TTABLE);
 141   i = luaL_optint(L, 2, 1);
 142   e = luaL_opt(L, luaL_checkint, 3, luaL_len(L, 1));
 143   if (i > e) return 0;  /* empty range */
 144   n = (unsigned int)e - (unsigned int)i;  /* number of elements minus 1 */
 145   if (n > (INT_MAX - 10) || !lua_checkstack(L, ++n))
 146     return luaL_error(L, "too many results to unpack");
 147   lua_rawgeti(L, 1, i);  /* push arg[i] (avoiding overflow problems) */
 148   while (i++ < e)  /* push arg[i + 1...e] */
 149     lua_rawgeti(L, 1, i);
 150   return n;
 151 }
 152
 153 /* }====================================================== */
 154
 155
 156
 157 /*
 158 ** {======================================================
 159 ** Quicksort
 160 ** (based on `Algorithms in MODULA-3', Robert Sedgewick;
 161 **  Addison-Wesley, 1993.)
 162 ** =======================================================
 163 */
 164
 165
 166 static void set2 (lua_State *L, int i, int j) {
 167   lua_rawseti(L, 1, i);
 168   lua_rawseti(L, 1, j);
 169 }
 170
 171 static int sort_comp (lua_State *L, int a, int b) {
 172   if (!lua_isnil(L, 2)) {  /* function? */
 173     int res;
 174     lua_pushvalue(L, 2);
 175     lua_pushvalue(L, a-1);  /* -1 to compensate function */
 176     lua_pushvalue(L, b-2);  /* -2 to compensate function and `a' */
 177     lua_call(L, 2, 1);
 178     res = lua_toboolean(L, -1);
 179     lua_pop(L, 1);
 180     return res;
 181   }
 182   else  /* a < b? */
 183     return lua_compare(L, a, b, LUA_OPLT);
 184 }
 185
 186 static void auxsort (lua_State *L, int l, int u) {
 187   while (l < u) {  /* for tail recursion */
 188     int i, j;
 189     /* sort elements a[l], a[(l+u)/2] and a[u] */
 190     lua_rawgeti(L, 1, l);
 191     lua_rawgeti(L, 1, u);
 192     if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
 193       set2(L, l, u);  /* swap a[l] - a[u] */
 194     else
 195       lua_pop(L, 2);
 196     if (u-l == 1) break;  /* only 2 elements */
 197     i = (l+u)/2;
 198     lua_rawgeti(L, 1, i);
 199     lua_rawgeti(L, 1, l);
 200     if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
 201       set2(L, i, l);
 202     else {
 203       lua_pop(L, 1);  /* remove a[l] */
 204       lua_rawgeti(L, 1, u);
 205       if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
 206         set2(L, i, u);
 207       else
 208         lua_pop(L, 2);
 209     }
 210     if (u-l == 2) break;  /* only 3 elements */
 211     lua_rawgeti(L, 1, i);  /* Pivot */
 212     lua_pushvalue(L, -1);
 213     lua_rawgeti(L, 1, u-1);
 214     set2(L, i, u-1);
 215     /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
 216     i = l; j = u-1;
 217     for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
 218       /* repeat ++i until a[i] >= P */
 219       while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
 220         if (i>=u) luaL_error(L, "invalid order function for sorting");
 221         lua_pop(L, 1);  /* remove a[i] */
 222       }
 223       /* repeat --j until a[j] <= P */
 224       while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
 225         if (j<=l) luaL_error(L, "invalid order function for sorting");
 226         lua_pop(L, 1);  /* remove a[j] */
 227       }
 228       if (j<i) {
 229         lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
 230         break;
 231       }
 232       set2(L, i, j);
 233     }
 234     lua_rawgeti(L, 1, u-1);
 235     lua_rawgeti(L, 1, i);
 236     set2(L, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
 237     /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
 238     /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
 239     if (i-l < u-i) {
 240       j=l; i=i-1; l=i+2;
 241     }
 242     else {
 243       j=i+1; i=u; u=j-2;
 244     }
 245     auxsort(L, j, i);  /* call recursively the smaller one */
 246   }  /* repeat the routine for the larger one */
 247 }
 248
 249 static int sort (lua_State *L) {
 250   int n = aux_getn(L, 1);
 251   luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
 252   if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
 253     luaL_checktype(L, 2, LUA_TFUNCTION);
 254   lua_settop(L, 2);  /* make sure there is two arguments */
 255   auxsort(L, 1, n);
 256   return 0;
 257 }
 258
 259 /* }====================================================== */
 260
 261
 262 static const luaL_Reg tab_funcs[] = {
 263   {"concat", tconcat},
 264 #if defined(LUA_COMPAT_MAXN)
 265   {"maxn", maxn},
 266 #endif
 267   {"insert", tinsert},
 268   {"pack", pack},
 269   {"unpack", unpack},
 270   {"remove", tremove},
 271   {"sort", sort},
 272   {NULL, NULL}
 273 };
 274
 275
 276 LUAMOD_API int luaopen_table (lua_State *L) {
 277   luaL_newlib(L, tab_funcs);
 278 #if defined(LUA_COMPAT_UNPACK)
 279   /* _G.unpack = table.unpack */
 280   lua_getfield(L, -1, "unpack");
 281   lua_setglobal(L, "unpack");
 282 #endif
 283   return 1;
 284 }
 285