external/mit/lua/dist/src/ltablib.c

   1 /*      $NetBSD: ltablib.c,v 1.1.1.2 2012/03/15 00:08:07 alnsn Exp $    */
   2
   3 /*
   4 ** $Id: ltablib.c,v 1.1.1.2 2012/03/15 00:08:07 alnsn Exp $
   5 ** Library for Table Manipulation
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9
  10 #include <stddef.h>
  11
  12 #define ltablib_c
  13 #define LUA_LIB
  14
  15 #include "lua.h"
  16
  17 #include "lauxlib.h"
  18 #include "lualib.h"
  19
  20
  21 #define aux_getn(L,n)   (luaL_checktype(L, n, LUA_TTABLE), luaL_getn(L, n))
  22
  23
  24 static int foreachi (lua_State *L) {
  25   int i;
  26   int n = aux_getn(L, 1);
  27   luaL_checktype(L, 2, LUA_TFUNCTION);
  28   for (i=1; i <= n; i++) {
  29     lua_pushvalue(L, 2);  /* function */
  30     lua_pushinteger(L, i);  /* 1st argument */
  31     lua_rawgeti(L, 1, i);  /* 2nd argument */
  32     lua_call(L, 2, 1);
  33     if (!lua_isnil(L, -1))
  34       return 1;
  35     lua_pop(L, 1);  /* remove nil result */
  36   }
  37   return 0;
  38 }
  39
  40
  41 static int foreach (lua_State *L) {
  42   luaL_checktype(L, 1, LUA_TTABLE);
  43   luaL_checktype(L, 2, LUA_TFUNCTION);
  44   lua_pushnil(L);  /* first key */
  45   while (lua_next(L, 1)) {
  46     lua_pushvalue(L, 2);  /* function */
  47     lua_pushvalue(L, -3);  /* key */
  48     lua_pushvalue(L, -3);  /* value */
  49     lua_call(L, 2, 1);
  50     if (!lua_isnil(L, -1))
  51       return 1;
  52     lua_pop(L, 2);  /* remove value and result */
  53   }
  54   return 0;
  55 }
  56
  57
  58 static int maxn (lua_State *L) {
  59   lua_Number max = 0;
  60   luaL_checktype(L, 1, LUA_TTABLE);
  61   lua_pushnil(L);  /* first key */
  62   while (lua_next(L, 1)) {
  63     lua_pop(L, 1);  /* remove value */
  64     if (lua_type(L, -1) == LUA_TNUMBER) {
  65       lua_Number v = lua_tonumber(L, -1);
  66       if (v > max) max = v;
  67     }
  68   }
  69   lua_pushnumber(L, max);
  70   return 1;
  71 }
  72
  73
  74 static int getn (lua_State *L) {
  75   lua_pushinteger(L, aux_getn(L, 1));
  76   return 1;
  77 }
  78
  79
  80 static int setn (lua_State *L) {
  81   luaL_checktype(L, 1, LUA_TTABLE);
  82 #ifndef luaL_setn
  83   luaL_setn(L, 1, luaL_checkint(L, 2));
  84 #else
  85   luaL_error(L, LUA_QL("setn") " is obsolete");
  86 #endif
  87   lua_pushvalue(L, 1);
  88   return 1;
  89 }
  90
  91
  92 static int tinsert (lua_State *L) {
  93   int e = aux_getn(L, 1) + 1;  /* first empty element */
  94   int pos;  /* where to insert new element */
  95   switch (lua_gettop(L)) {
  96     case 2: {  /* called with only 2 arguments */
  97       pos = e;  /* insert new element at the end */
  98       break;
  99     }
 100     case 3: {
 101       int i;
 102       pos = luaL_checkint(L, 2);  /* 2nd argument is the position */
 103       if (pos > e) e = pos;  /* `grow' array if necessary */
 104       for (i = e; i > pos; i--) {  /* move up elements */
 105         lua_rawgeti(L, 1, i-1);
 106         lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */
 107       }
 108       break;
 109     }
 110     default: {
 111       return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
 112     }
 113   }
 114   luaL_setn(L, 1, e);  /* new size */
 115   lua_rawseti(L, 1, pos);  /* t[pos] = v */
 116   return 0;
 117 }
 118
 119
 120 static int tremove (lua_State *L) {
 121   int e = aux_getn(L, 1);
 122   int pos = luaL_optint(L, 2, e);
 123   if (!(1 <= pos && pos <= e))  /* position is outside bounds? */
 124    return 0;  /* nothing to remove */
 125   luaL_setn(L, 1, e - 1);  /* t.n = n-1 */
 126   lua_rawgeti(L, 1, pos);  /* result = t[pos] */
 127   for ( ;pos<e; pos++) {
 128     lua_rawgeti(L, 1, pos+1);
 129     lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
 130   }
 131   lua_pushnil(L);
 132   lua_rawseti(L, 1, e);  /* t[e] = nil */
 133   return 1;
 134 }
 135
 136
 137 static void addfield (lua_State *L, luaL_Buffer *b, int i) {
 138   lua_rawgeti(L, 1, i);
 139   if (!lua_isstring(L, -1))
 140     luaL_error(L, "invalid value (%s) at index %d in table for "
 141                   LUA_QL("concat"), luaL_typename(L, -1), i);
 142     luaL_addvalue(b);
 143 }
 144
 145
 146 static int tconcat (lua_State *L) {
 147   luaL_Buffer b;
 148   size_t lsep;
 149   int i, last;
 150   const char *sep = luaL_optlstring(L, 2, "", &lsep);
 151   luaL_checktype(L, 1, LUA_TTABLE);
 152   i = luaL_optint(L, 3, 1);
 153   last = luaL_opt(L, luaL_checkint, 4, luaL_getn(L, 1));
 154   luaL_buffinit(L, &b);
 155   for (; i < last; i++) {
 156     addfield(L, &b, i);
 157     luaL_addlstring(&b, sep, lsep);
 158   }
 159   if (i == last)  /* add last value (if interval was not empty) */
 160     addfield(L, &b, i);
 161   luaL_pushresult(&b);
 162   return 1;
 163 }
 164
 165
 166
 167 /*
 168 ** {======================================================
 169 ** Quicksort
 170 ** (based on `Algorithms in MODULA-3', Robert Sedgewick;
 171 **  Addison-Wesley, 1993.)
 172 */
 173
 174
 175 static void set2 (lua_State *L, int i, int j) {
 176   lua_rawseti(L, 1, i);
 177   lua_rawseti(L, 1, j);
 178 }
 179
 180 static int sort_comp (lua_State *L, int a, int b) {
 181   if (!lua_isnil(L, 2)) {  /* function? */
 182     int res;
 183     lua_pushvalue(L, 2);
 184     lua_pushvalue(L, a-1);  /* -1 to compensate function */
 185     lua_pushvalue(L, b-2);  /* -2 to compensate function and `a' */
 186     lua_call(L, 2, 1);
 187     res = lua_toboolean(L, -1);
 188     lua_pop(L, 1);
 189     return res;
 190   }
 191   else  /* a < b? */
 192     return lua_lessthan(L, a, b);
 193 }
 194
 195 static void auxsort (lua_State *L, int l, int u) {
 196   while (l < u) {  /* for tail recursion */
 197     int i, j;
 198     /* sort elements a[l], a[(l+u)/2] and a[u] */
 199     lua_rawgeti(L, 1, l);
 200     lua_rawgeti(L, 1, u);
 201     if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
 202       set2(L, l, u);  /* swap a[l] - a[u] */
 203     else
 204       lua_pop(L, 2);
 205     if (u-l == 1) break;  /* only 2 elements */
 206     i = (l+u)/2;
 207     lua_rawgeti(L, 1, i);
 208     lua_rawgeti(L, 1, l);
 209     if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
 210       set2(L, i, l);
 211     else {
 212       lua_pop(L, 1);  /* remove a[l] */
 213       lua_rawgeti(L, 1, u);
 214       if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
 215         set2(L, i, u);
 216       else
 217         lua_pop(L, 2);
 218     }
 219     if (u-l == 2) break;  /* only 3 elements */
 220     lua_rawgeti(L, 1, i);  /* Pivot */
 221     lua_pushvalue(L, -1);
 222     lua_rawgeti(L, 1, u-1);
 223     set2(L, i, u-1);
 224     /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
 225     i = l; j = u-1;
 226     for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
 227       /* repeat ++i until a[i] >= P */
 228       while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
 229         if (i>u) luaL_error(L, "invalid order function for sorting");
 230         lua_pop(L, 1);  /* remove a[i] */
 231       }
 232       /* repeat --j until a[j] <= P */
 233       while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
 234         if (j<l) luaL_error(L, "invalid order function for sorting");
 235         lua_pop(L, 1);  /* remove a[j] */
 236       }
 237       if (j<i) {
 238         lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
 239         break;
 240       }
 241       set2(L, i, j);
 242     }
 243     lua_rawgeti(L, 1, u-1);
 244     lua_rawgeti(L, 1, i);
 245     set2(L, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
 246     /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
 247     /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
 248     if (i-l < u-i) {
 249       j=l; i=i-1; l=i+2;
 250     }
 251     else {
 252       j=i+1; i=u; u=j-2;
 253     }
 254     auxsort(L, j, i);  /* call recursively the smaller one */
 255   }  /* repeat the routine for the larger one */
 256 }
 257
 258 static int sort (lua_State *L) {
 259   int n = aux_getn(L, 1);
 260   luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
 261   if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
 262     luaL_checktype(L, 2, LUA_TFUNCTION);
 263   lua_settop(L, 2);  /* make sure there is two arguments */
 264   auxsort(L, 1, n);
 265   return 0;
 266 }
 267
 268 /* }====================================================== */
 269
 270
 271 static const luaL_Reg tab_funcs[] = {
 272   {"concat", tconcat},
 273   {"foreach", foreach},
 274   {"foreachi", foreachi},
 275   {"getn", getn},
 276   {"maxn", maxn},
 277   {"insert", tinsert},
 278   {"remove", tremove},
 279   {"setn", setn},
 280   {"sort", sort},
 281   {NULL, NULL}
 282 };
 283
 284
 285 LUALIB_API int luaopen_table (lua_State *L) {
 286   luaL_register(L, LUA_TABLIBNAME, tab_funcs);
 287   return 1;
 288 }
 289