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

   1 /*      $NetBSD: ltablib.c,v 1.4 2015/10/08 13:21:00 mbalmer Exp $      */
   2
   3 /*
   4 ** Id: ltablib.c,v 1.80 2015/01/13 16:27:29 roberto Exp
   5 ** Library for Table Manipulation
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9 #define ltablib_c
  10 #define LUA_LIB
  11
  12 #include "lprefix.h"
  13
  14
  15 #ifndef _KERNEL
  16 #include <limits.h>
  17 #include <stddef.h>
  18 #endif
  19
  20 #include "lua.h"
  21
  22 #include "lauxlib.h"
  23 #include "lualib.h"
  24
  25
  26
  27 /*
  28 ** Structure with table-access functions
  29 */
  30 typedef struct {
  31   int (*geti) (lua_State *L, int idx, lua_Integer n);
  32   void (*seti) (lua_State *L, int idx, lua_Integer n);
  33 } TabA;
  34
  35
  36 /*
  37 ** Check that 'arg' has a table and set access functions in 'ta' to raw
  38 ** or non-raw according to the presence of corresponding metamethods.
  39 */
  40 static void checktab (lua_State *L, int arg, TabA *ta) {
  41   ta->geti = NULL; ta->seti = NULL;
  42   if (lua_getmetatable(L, arg)) {
  43     lua_pushliteral(L, "__index");  /* 'index' metamethod */
  44     if (lua_rawget(L, -2) != LUA_TNIL)
  45       ta->geti = lua_geti;
  46     lua_pushliteral(L, "__newindex");  /* 'newindex' metamethod */
  47     if (lua_rawget(L, -3) != LUA_TNIL)
  48       ta->seti = lua_seti;
  49     lua_pop(L, 3);  /* pop metatable plus both metamethods */
  50   }
  51   if (ta->geti == NULL || ta->seti == NULL) {
  52     luaL_checktype(L, arg, LUA_TTABLE);  /* must be table for raw methods */
  53     if (ta->geti == NULL) ta->geti = lua_rawgeti;
  54     if (ta->seti == NULL) ta->seti = lua_rawseti;
  55   }
  56 }
  57
  58
  59 #define aux_getn(L,n,ta)        (checktab(L, n, ta), luaL_len(L, n))
  60
  61
  62 #if defined(LUA_COMPAT_MAXN)
  63 static int maxn (lua_State *L) {
  64   lua_Number max = 0;
  65   luaL_checktype(L, 1, LUA_TTABLE);
  66   lua_pushnil(L);  /* first key */
  67   while (lua_next(L, 1)) {
  68     lua_pop(L, 1);  /* remove value */
  69     if (lua_type(L, -1) == LUA_TNUMBER) {
  70       lua_Number v = lua_tonumber(L, -1);
  71       if (v > max) max = v;
  72     }
  73   }
  74   lua_pushnumber(L, max);
  75   return 1;
  76 }
  77 #endif
  78
  79
  80 static int tinsert (lua_State *L) {
  81   TabA ta;
  82   lua_Integer e = aux_getn(L, 1, &ta) + 1;  /* first empty element */
  83   lua_Integer pos;  /* where to insert new element */
  84   switch (lua_gettop(L)) {
  85     case 2: {  /* called with only 2 arguments */
  86       pos = e;  /* insert new element at the end */
  87       break;
  88     }
  89     case 3: {
  90       lua_Integer i;
  91       pos = luaL_checkinteger(L, 2);  /* 2nd argument is the position */
  92       luaL_argcheck(L, 1 <= pos && pos <= e, 2, "position out of bounds");
  93       for (i = e; i > pos; i--) {  /* move up elements */
  94         (*ta.geti)(L, 1, i - 1);
  95         (*ta.seti)(L, 1, i);  /* t[i] = t[i - 1] */
  96       }
  97       break;
  98     }
  99     default: {
 100       return luaL_error(L, "wrong number of arguments to 'insert'");
 101     }
 102   }
 103   (*ta.seti)(L, 1, pos);  /* t[pos] = v */
 104   return 0;
 105 }
 106
 107
 108 static int tremove (lua_State *L) {
 109   TabA ta;
 110   lua_Integer size = aux_getn(L, 1, &ta);
 111   lua_Integer pos = luaL_optinteger(L, 2, size);
 112   if (pos != size)  /* validate 'pos' if given */
 113     luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, "position out of bounds");
 114   (*ta.geti)(L, 1, pos);  /* result = t[pos] */
 115   for ( ; pos < size; pos++) {
 116     (*ta.geti)(L, 1, pos + 1);
 117     (*ta.seti)(L, 1, pos);  /* t[pos] = t[pos + 1] */
 118   }
 119   lua_pushnil(L);
 120   (*ta.seti)(L, 1, pos);  /* t[pos] = nil */
 121   return 1;
 122 }
 123
 124
 125 static int tmove (lua_State *L) {
 126   TabA ta;
 127   lua_Integer f = luaL_checkinteger(L, 2);
 128   lua_Integer e = luaL_checkinteger(L, 3);
 129   lua_Integer t = luaL_checkinteger(L, 4);
 130   int tt = !lua_isnoneornil(L, 5) ? 5 : 1;  /* destination table */
 131   if (e >= f) {  /* otherwise, nothing to move */
 132     lua_Integer n, i;
 133     ta.geti = (luaL_getmetafield(L, 1, "__index") == LUA_TNIL)
 134       ? (luaL_checktype(L, 1, LUA_TTABLE), lua_rawgeti)
 135       : lua_geti;
 136     ta.seti = (luaL_getmetafield(L, tt, "__newindex") == LUA_TNIL)
 137       ? (luaL_checktype(L, tt, LUA_TTABLE), lua_rawseti)
 138       : lua_seti;
 139     luaL_argcheck(L, f > 0 || e < LUA_MAXINTEGER + f, 3,
 140                   "too many elements to move");
 141     n = e - f + 1;  /* number of elements to move */
 142     luaL_argcheck(L, t <= LUA_MAXINTEGER - n + 1, 4,
 143                   "destination wrap around");
 144     if (t > f) {
 145       for (i = n - 1; i >= 0; i--) {
 146         (*ta.geti)(L, 1, f + i);
 147         (*ta.seti)(L, tt, t + i);
 148       }
 149     }
 150     else {
 151       for (i = 0; i < n; i++) {
 152         (*ta.geti)(L, 1, f + i);
 153         (*ta.seti)(L, tt, t + i);
 154       }
 155     }
 156   }
 157   lua_pushvalue(L, tt);  /* return "to table" */
 158   return 1;
 159 }
 160
 161
 162 static void addfield (lua_State *L, luaL_Buffer *b, TabA *ta, lua_Integer i) {
 163   (*ta->geti)(L, 1, i);
 164   if (!lua_isstring(L, -1))
 165     luaL_error(L, "invalid value (%s) at index %d in table for 'concat'",
 166                   luaL_typename(L, -1), i);
 167   luaL_addvalue(b);
 168 }
 169
 170
 171 static int tconcat (lua_State *L) {
 172   TabA ta;
 173   luaL_Buffer b;
 174   size_t lsep;
 175   lua_Integer i, last;
 176   const char *sep = luaL_optlstring(L, 2, "", &lsep);
 177   checktab(L, 1, &ta);
 178   i = luaL_optinteger(L, 3, 1);
 179   last = luaL_opt(L, luaL_checkinteger, 4, luaL_len(L, 1));
 180   luaL_buffinit(L, &b);
 181   for (; i < last; i++) {
 182     addfield(L, &b, &ta, i);
 183     luaL_addlstring(&b, sep, lsep);
 184   }
 185   if (i == last)  /* add last value (if interval was not empty) */
 186     addfield(L, &b, &ta, i);
 187   luaL_pushresult(&b);
 188   return 1;
 189 }
 190
 191
 192 /*
 193 ** {======================================================
 194 ** Pack/unpack
 195 ** =======================================================
 196 */
 197
 198 static int pack (lua_State *L) {
 199   int i;
 200   int n = lua_gettop(L);  /* number of elements to pack */
 201   lua_createtable(L, n, 1);  /* create result table */
 202   lua_insert(L, 1);  /* put it at index 1 */
 203   for (i = n; i >= 1; i--)  /* assign elements */
 204     lua_rawseti(L, 1, i);
 205   lua_pushinteger(L, n);
 206   lua_setfield(L, 1, "n");  /* t.n = number of elements */
 207   return 1;  /* return table */
 208 }
 209
 210
 211 static int unpack (lua_State *L) {
 212   TabA ta;
 213   lua_Integer i, e;
 214   lua_Unsigned n;
 215   checktab(L, 1, &ta);
 216   i = luaL_optinteger(L, 2, 1);
 217   e = luaL_opt(L, luaL_checkinteger, 3, luaL_len(L, 1));
 218   if (i > e) return 0;  /* empty range */
 219   n = (lua_Unsigned)e - i;  /* number of elements minus 1 (avoid overflows) */
 220   if (n >= (unsigned int)INT_MAX  || !lua_checkstack(L, (int)(++n)))
 221     return luaL_error(L, "too many results to unpack");
 222   do {  /* must have at least one element */
 223     (*ta.geti)(L, 1, i);  /* push arg[i..e] */
 224   } while (i++ < e);
 225
 226   return (int)n;
 227 }
 228
 229 /* }====================================================== */
 230
 231
 232
 233 /*
 234 ** {======================================================
 235 ** Quicksort
 236 ** (based on 'Algorithms in MODULA-3', Robert Sedgewick;
 237 **  Addison-Wesley, 1993.)
 238 ** =======================================================
 239 */
 240
 241
 242 static void set2 (lua_State *L, TabA *ta, int i, int j) {
 243   (*ta->seti)(L, 1, i);
 244   (*ta->seti)(L, 1, j);
 245 }
 246
 247 static int sort_comp (lua_State *L, int a, int b) {
 248   if (!lua_isnil(L, 2)) {  /* function? */
 249     int res;
 250     lua_pushvalue(L, 2);
 251     lua_pushvalue(L, a-1);  /* -1 to compensate function */
 252     lua_pushvalue(L, b-2);  /* -2 to compensate function and 'a' */
 253     lua_call(L, 2, 1);
 254     res = lua_toboolean(L, -1);
 255     lua_pop(L, 1);
 256     return res;
 257   }
 258   else  /* a < b? */
 259     return lua_compare(L, a, b, LUA_OPLT);
 260 }
 261
 262 static void auxsort (lua_State *L, TabA *ta, int l, int u) {
 263   while (l < u) {  /* for tail recursion */
 264     int i, j;
 265     /* sort elements a[l], a[(l+u)/2] and a[u] */
 266     (*ta->geti)(L, 1, l);
 267     (*ta->geti)(L, 1, u);
 268     if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
 269       set2(L, ta, l, u);  /* swap a[l] - a[u] */
 270     else
 271       lua_pop(L, 2);
 272     if (u-l == 1) break;  /* only 2 elements */
 273     i = (l+u)/2;
 274     (*ta->geti)(L, 1, i);
 275     (*ta->geti)(L, 1, l);
 276     if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
 277       set2(L, ta, i, l);
 278     else {
 279       lua_pop(L, 1);  /* remove a[l] */
 280       (*ta->geti)(L, 1, u);
 281       if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
 282         set2(L, ta, i, u);
 283       else
 284         lua_pop(L, 2);
 285     }
 286     if (u-l == 2) break;  /* only 3 elements */
 287     (*ta->geti)(L, 1, i);  /* Pivot */
 288     lua_pushvalue(L, -1);
 289     (*ta->geti)(L, 1, u-1);
 290     set2(L, ta, i, u-1);
 291     /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
 292     i = l; j = u-1;
 293     for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
 294       /* repeat ++i until a[i] >= P */
 295       while ((*ta->geti)(L, 1, ++i), sort_comp(L, -1, -2)) {
 296         if (i>=u) luaL_error(L, "invalid order function for sorting");
 297         lua_pop(L, 1);  /* remove a[i] */
 298       }
 299       /* repeat --j until a[j] <= P */
 300       while ((*ta->geti)(L, 1, --j), sort_comp(L, -3, -1)) {
 301         if (j<=l) luaL_error(L, "invalid order function for sorting");
 302         lua_pop(L, 1);  /* remove a[j] */
 303       }
 304       if (j<i) {
 305         lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
 306         break;
 307       }
 308       set2(L, ta, i, j);
 309     }
 310     (*ta->geti)(L, 1, u-1);
 311     (*ta->geti)(L, 1, i);
 312     set2(L, ta, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
 313     /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
 314     /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
 315     if (i-l < u-i) {
 316       j=l; i=i-1; l=i+2;
 317     }
 318     else {
 319       j=i+1; i=u; u=j-2;
 320     }
 321     auxsort(L, ta, j, i);  /* call recursively the smaller one */
 322   }  /* repeat the routine for the larger one */
 323 }
 324
 325 static int sort (lua_State *L) {
 326   TabA ta;
 327   int n = (int)aux_getn(L, 1, &ta);
 328   luaL_checkstack(L, 50, "");  /* assume array is smaller than 2^50 */
 329   if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
 330     luaL_checktype(L, 2, LUA_TFUNCTION);
 331   lua_settop(L, 2);  /* make sure there are two arguments */
 332   auxsort(L, &ta, 1, n);
 333   return 0;
 334 }
 335
 336 /* }====================================================== */
 337
 338
 339 static const luaL_Reg tab_funcs[] = {
 340   {"concat", tconcat},
 341 #if defined(LUA_COMPAT_MAXN)
 342   {"maxn", maxn},
 343 #endif
 344   {"insert", tinsert},
 345   {"pack", pack},
 346   {"unpack", unpack},
 347   {"remove", tremove},
 348   {"move", tmove},
 349   {"sort", sort},
 350   {NULL, NULL}
 351 };
 352
 353
 354 LUAMOD_API int luaopen_table (lua_State *L) {
 355   luaL_newlib(L, tab_funcs);
 356 #if defined(LUA_COMPAT_UNPACK)
 357   /* _G.unpack = table.unpack */
 358   lua_getfield(L, -1, "unpack");
 359   lua_setglobal(L, "unpack");
 360 #endif
 361   return 1;
 362 }
 363