nanocoat/lib/3rdparty/lua/ltablib.c

   1 /*
   2 ** $Id: ltablib.c $
   3 ** Library for Table Manipulation
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #define ltablib_c
   8 #define LUA_LIB
   9
  10 #include "lprefix.h"
  11
  12
  13 #include <limits.h>
  14 #include <stddef.h>
  15 #include <string.h>
  16
  17 #include "lua.h"
  18
  19 #include "lauxlib.h"
  20 #include "lualib.h"
  21
  22
  23 /*
  24 ** Operations that an object must define to mimic a table
  25 ** (some functions only need some of them)
  26 */
  27 #define TAB_R   1                       /* read */
  28 #define TAB_W   2                       /* write */
  29 #define TAB_L   4                       /* length */
  30 #define TAB_RW  (TAB_R | TAB_W)         /* read/write */
  31
  32
  33 #define aux_getn(L,n,w) (checktab(L, n, (w) | TAB_L), luaL_len(L, n))
  34
  35
  36 static int checkfield (lua_State *L, const char *key, int n) {
  37   lua_pushstring(L, key);
  38   return (lua_rawget(L, -n) != LUA_TNIL);
  39 }
  40
  41
  42 /*
  43 ** Check that 'arg' either is a table or can behave like one (that is,
  44 ** has a metatable with the required metamethods)
  45 */
  46 static void checktab (lua_State *L, int arg, int what) {
  47   if (lua_type(L, arg) != LUA_TTABLE) {  /* is it not a table? */
  48     int n = 1;  /* number of elements to pop */
  49     if (lua_getmetatable(L, arg) &&  /* must have metatable */
  50         (!(what & TAB_R) || checkfield(L, "__index", ++n)) &&
  51         (!(what & TAB_W) || checkfield(L, "__newindex", ++n)) &&
  52         (!(what & TAB_L) || checkfield(L, "__len", ++n))) {
  53       lua_pop(L, n);  /* pop metatable and tested metamethods */
  54     }
  55     else
  56       luaL_checktype(L, arg, LUA_TTABLE);  /* force an error */
  57   }
  58 }
  59
  60
  61 static int tinsert (lua_State *L) {
  62   lua_Integer pos;  /* where to insert new element */
  63   lua_Integer e = aux_getn(L, 1, TAB_RW);
  64   e = luaL_intop(+, e, 1);  /* first empty element */
  65   switch (lua_gettop(L)) {
  66     case 2: {  /* called with only 2 arguments */
  67       pos = e;  /* insert new element at the end */
  68       break;
  69     }
  70     case 3: {
  71       lua_Integer i;
  72       pos = luaL_checkinteger(L, 2);  /* 2nd argument is the position */
  73       /* check whether 'pos' is in [1, e] */
  74       luaL_argcheck(L, (lua_Unsigned)pos - 1u < (lua_Unsigned)e, 2,
  75                        "position out of bounds");
  76       for (i = e; i > pos; i--) {  /* move up elements */
  77         lua_geti(L, 1, i - 1);
  78         lua_seti(L, 1, i);  /* t[i] = t[i - 1] */
  79       }
  80       break;
  81     }
  82     default: {
  83       return luaL_error(L, "wrong number of arguments to 'insert'");
  84     }
  85   }
  86   lua_seti(L, 1, pos);  /* t[pos] = v */
  87   return 0;
  88 }
  89
  90
  91 static int tremove (lua_State *L) {
  92   lua_Integer size = aux_getn(L, 1, TAB_RW);
  93   lua_Integer pos = luaL_optinteger(L, 2, size);
  94   if (pos != size)  /* validate 'pos' if given */
  95     /* check whether 'pos' is in [1, size + 1] */
  96     luaL_argcheck(L, (lua_Unsigned)pos - 1u <= (lua_Unsigned)size, 2,
  97                      "position out of bounds");
  98   lua_geti(L, 1, pos);  /* result = t[pos] */
  99   for ( ; pos < size; pos++) {
 100     lua_geti(L, 1, pos + 1);
 101     lua_seti(L, 1, pos);  /* t[pos] = t[pos + 1] */
 102   }
 103   lua_pushnil(L);
 104   lua_seti(L, 1, pos);  /* remove entry t[pos] */
 105   return 1;
 106 }
 107
 108
 109 /*
 110 ** Copy elements (1[f], ..., 1[e]) into (tt[t], tt[t+1], ...). Whenever
 111 ** possible, copy in increasing order, which is better for rehashing.
 112 ** "possible" means destination after original range, or smaller
 113 ** than origin, or copying to another table.
 114 */
 115 static int tmove (lua_State *L) {
 116   lua_Integer f = luaL_checkinteger(L, 2);
 117   lua_Integer e = luaL_checkinteger(L, 3);
 118   lua_Integer t = luaL_checkinteger(L, 4);
 119   int tt = !lua_isnoneornil(L, 5) ? 5 : 1;  /* destination table */
 120   checktab(L, 1, TAB_R);
 121   checktab(L, tt, TAB_W);
 122   if (e >= f) {  /* otherwise, nothing to move */
 123     lua_Integer n, i;
 124     luaL_argcheck(L, f > 0 || e < LUA_MAXINTEGER + f, 3,
 125                   "too many elements to move");
 126     n = e - f + 1;  /* number of elements to move */
 127     luaL_argcheck(L, t <= LUA_MAXINTEGER - n + 1, 4,
 128                   "destination wrap around");
 129     if (t > e || t <= f || (tt != 1 && !lua_compare(L, 1, tt, LUA_OPEQ))) {
 130       for (i = 0; i < n; i++) {
 131         lua_geti(L, 1, f + i);
 132         lua_seti(L, tt, t + i);
 133       }
 134     }
 135     else {
 136       for (i = n - 1; i >= 0; i--) {
 137         lua_geti(L, 1, f + i);
 138         lua_seti(L, tt, t + i);
 139       }
 140     }
 141   }
 142   lua_pushvalue(L, tt);  /* return destination table */
 143   return 1;
 144 }
 145
 146
 147 static void addfield (lua_State *L, luaL_Buffer *b, lua_Integer i) {
 148   lua_geti(L, 1, i);
 149   if (l_unlikely(!lua_isstring(L, -1)))
 150     luaL_error(L, "invalid value (%s) at index %I in table for 'concat'",
 151                   luaL_typename(L, -1), (LUAI_UACINT)i);
 152   luaL_addvalue(b);
 153 }
 154
 155
 156 static int tconcat (lua_State *L) {
 157   luaL_Buffer b;
 158   lua_Integer last = aux_getn(L, 1, TAB_R);
 159   size_t lsep;
 160   const char *sep = luaL_optlstring(L, 2, "", &lsep);
 161   lua_Integer i = luaL_optinteger(L, 3, 1);
 162   last = luaL_optinteger(L, 4, last);
 163   luaL_buffinit(L, &b);
 164   for (; i < last; i++) {
 165     addfield(L, &b, i);
 166     luaL_addlstring(&b, sep, lsep);
 167   }
 168   if (i == last)  /* add last value (if interval was not empty) */
 169     addfield(L, &b, i);
 170   luaL_pushresult(&b);
 171   return 1;
 172 }
 173
 174
 175 /*
 176 ** {======================================================
 177 ** Pack/unpack
 178 ** =======================================================
 179 */
 180
 181 static int tpack (lua_State *L) {
 182   int i;
 183   int n = lua_gettop(L);  /* number of elements to pack */
 184   lua_createtable(L, n, 1);  /* create result table */
 185   lua_insert(L, 1);  /* put it at index 1 */
 186   for (i = n; i >= 1; i--)  /* assign elements */
 187     lua_seti(L, 1, i);
 188   lua_pushinteger(L, n);
 189   lua_setfield(L, 1, "n");  /* t.n = number of elements */
 190   return 1;  /* return table */
 191 }
 192
 193
 194 static int tunpack (lua_State *L) {
 195   lua_Unsigned n;
 196   lua_Integer i = luaL_optinteger(L, 2, 1);
 197   lua_Integer e = luaL_opt(L, luaL_checkinteger, 3, luaL_len(L, 1));
 198   if (i > e) return 0;  /* empty range */
 199   n = (lua_Unsigned)e - i;  /* number of elements minus 1 (avoid overflows) */
 200   if (l_unlikely(n >= (unsigned int)INT_MAX  ||
 201                  !lua_checkstack(L, (int)(++n))))
 202     return luaL_error(L, "too many results to unpack");
 203   for (; i < e; i++) {  /* push arg[i..e - 1] (to avoid overflows) */
 204     lua_geti(L, 1, i);
 205   }
 206   lua_geti(L, 1, e);  /* push last element */
 207   return (int)n;
 208 }
 209
 210 /* }====================================================== */
 211
 212
 213
 214 /*
 215 ** {======================================================
 216 ** Quicksort
 217 ** (based on 'Algorithms in MODULA-3', Robert Sedgewick;
 218 **  Addison-Wesley, 1993.)
 219 ** =======================================================
 220 */
 221
 222
 223 /* type for array indices */
 224 typedef unsigned int IdxT;
 225
 226
 227 /*
 228 ** Produce a "random" 'unsigned int' to randomize pivot choice. This
 229 ** macro is used only when 'sort' detects a big imbalance in the result
 230 ** of a partition. (If you don't want/need this "randomness", ~0 is a
 231 ** good choice.)
 232 */
 233 #if !defined(l_randomizePivot)          /* { */
 234
 235 #include <time.h>
 236
 237 /* size of 'e' measured in number of 'unsigned int's */
 238 #define sof(e)          (sizeof(e) / sizeof(unsigned int))
 239
 240 /*
 241 ** Use 'time' and 'clock' as sources of "randomness". Because we don't
 242 ** know the types 'clock_t' and 'time_t', we cannot cast them to
 243 ** anything without risking overflows. A safe way to use their values
 244 ** is to copy them to an array of a known type and use the array values.
 245 */
 246 static unsigned int l_randomizePivot (void) {
 247   clock_t c = clock();
 248   time_t t = time(NULL);
 249   unsigned int buff[sof(c) + sof(t)];
 250   unsigned int i, rnd = 0;
 251   memcpy(buff, &c, sof(c) * sizeof(unsigned int));
 252   memcpy(buff + sof(c), &t, sof(t) * sizeof(unsigned int));
 253   for (i = 0; i < sof(buff); i++)
 254     rnd += buff[i];
 255   return rnd;
 256 }
 257
 258 #endif                                  /* } */
 259
 260
 261 /* arrays larger than 'RANLIMIT' may use randomized pivots */
 262 #define RANLIMIT        100u
 263
 264
 265 static void set2 (lua_State *L, IdxT i, IdxT j) {
 266   lua_seti(L, 1, i);
 267   lua_seti(L, 1, j);
 268 }
 269
 270
 271 /*
 272 ** Return true iff value at stack index 'a' is less than the value at
 273 ** index 'b' (according to the order of the sort).
 274 */
 275 static int sort_comp (lua_State *L, int a, int b) {
 276   if (lua_isnil(L, 2))  /* no function? */
 277     return lua_compare(L, a, b, LUA_OPLT);  /* a < b */
 278   else {  /* function */
 279     int res;
 280     lua_pushvalue(L, 2);    /* push function */
 281     lua_pushvalue(L, a-1);  /* -1 to compensate function */
 282     lua_pushvalue(L, b-2);  /* -2 to compensate function and 'a' */
 283     lua_call(L, 2, 1);      /* call function */
 284     res = lua_toboolean(L, -1);  /* get result */
 285     lua_pop(L, 1);          /* pop result */
 286     return res;
 287   }
 288 }
 289
 290
 291 /*
 292 ** Does the partition: Pivot P is at the top of the stack.
 293 ** precondition: a[lo] <= P == a[up-1] <= a[up],
 294 ** so it only needs to do the partition from lo + 1 to up - 2.
 295 ** Pos-condition: a[lo .. i - 1] <= a[i] == P <= a[i + 1 .. up]
 296 ** returns 'i'.
 297 */
 298 static IdxT partition (lua_State *L, IdxT lo, IdxT up) {
 299   IdxT i = lo;  /* will be incremented before first use */
 300   IdxT j = up - 1;  /* will be decremented before first use */
 301   /* loop invariant: a[lo .. i] <= P <= a[j .. up] */
 302   for (;;) {
 303     /* next loop: repeat ++i while a[i] < P */
 304     while ((void)lua_geti(L, 1, ++i), sort_comp(L, -1, -2)) {
 305       if (l_unlikely(i == up - 1))  /* a[i] < P  but a[up - 1] == P  ?? */
 306         luaL_error(L, "invalid order function for sorting");
 307       lua_pop(L, 1);  /* remove a[i] */
 308     }
 309     /* after the loop, a[i] >= P and a[lo .. i - 1] < P */
 310     /* next loop: repeat --j while P < a[j] */
 311     while ((void)lua_geti(L, 1, --j), sort_comp(L, -3, -1)) {
 312       if (l_unlikely(j < i))  /* j < i  but  a[j] > P ?? */
 313         luaL_error(L, "invalid order function for sorting");
 314       lua_pop(L, 1);  /* remove a[j] */
 315     }
 316     /* after the loop, a[j] <= P and a[j + 1 .. up] >= P */
 317     if (j < i) {  /* no elements out of place? */
 318       /* a[lo .. i - 1] <= P <= a[j + 1 .. i .. up] */
 319       lua_pop(L, 1);  /* pop a[j] */
 320       /* swap pivot (a[up - 1]) with a[i] to satisfy pos-condition */
 321       set2(L, up - 1, i);
 322       return i;
 323     }
 324     /* otherwise, swap a[i] - a[j] to restore invariant and repeat */
 325     set2(L, i, j);
 326   }
 327 }
 328
 329
 330 /*
 331 ** Choose an element in the middle (2nd-3th quarters) of [lo,up]
 332 ** "randomized" by 'rnd'
 333 */
 334 static IdxT choosePivot (IdxT lo, IdxT up, unsigned int rnd) {
 335   IdxT r4 = (up - lo) / 4;  /* range/4 */
 336   IdxT p = rnd % (r4 * 2) + (lo + r4);
 337   lua_assert(lo + r4 <= p && p <= up - r4);
 338   return p;
 339 }
 340
 341
 342 /*
 343 ** Quicksort algorithm (recursive function)
 344 */
 345 static void auxsort (lua_State *L, IdxT lo, IdxT up,
 346                                    unsigned int rnd) {
 347   while (lo < up) {  /* loop for tail recursion */
 348     IdxT p;  /* Pivot index */
 349     IdxT n;  /* to be used later */
 350     /* sort elements 'lo', 'p', and 'up' */
 351     lua_geti(L, 1, lo);
 352     lua_geti(L, 1, up);
 353     if (sort_comp(L, -1, -2))  /* a[up] < a[lo]? */
 354       set2(L, lo, up);  /* swap a[lo] - a[up] */
 355     else
 356       lua_pop(L, 2);  /* remove both values */
 357     if (up - lo == 1)  /* only 2 elements? */
 358       return;  /* already sorted */
 359     if (up - lo < RANLIMIT || rnd == 0)  /* small interval or no randomize? */
 360       p = (lo + up)/2;  /* middle element is a good pivot */
 361     else  /* for larger intervals, it is worth a random pivot */
 362       p = choosePivot(lo, up, rnd);
 363     lua_geti(L, 1, p);
 364     lua_geti(L, 1, lo);
 365     if (sort_comp(L, -2, -1))  /* a[p] < a[lo]? */
 366       set2(L, p, lo);  /* swap a[p] - a[lo] */
 367     else {
 368       lua_pop(L, 1);  /* remove a[lo] */
 369       lua_geti(L, 1, up);
 370       if (sort_comp(L, -1, -2))  /* a[up] < a[p]? */
 371         set2(L, p, up);  /* swap a[up] - a[p] */
 372       else
 373         lua_pop(L, 2);
 374     }
 375     if (up - lo == 2)  /* only 3 elements? */
 376       return;  /* already sorted */
 377     lua_geti(L, 1, p);  /* get middle element (Pivot) */
 378     lua_pushvalue(L, -1);  /* push Pivot */
 379     lua_geti(L, 1, up - 1);  /* push a[up - 1] */
 380     set2(L, p, up - 1);  /* swap Pivot (a[p]) with a[up - 1] */
 381     p = partition(L, lo, up);
 382     /* a[lo .. p - 1] <= a[p] == P <= a[p + 1 .. up] */
 383     if (p - lo < up - p) {  /* lower interval is smaller? */
 384       auxsort(L, lo, p - 1, rnd);  /* call recursively for lower interval */
 385       n = p - lo;  /* size of smaller interval */
 386       lo = p + 1;  /* tail call for [p + 1 .. up] (upper interval) */
 387     }
 388     else {
 389       auxsort(L, p + 1, up, rnd);  /* call recursively for upper interval */
 390       n = up - p;  /* size of smaller interval */
 391       up = p - 1;  /* tail call for [lo .. p - 1]  (lower interval) */
 392     }
 393     if ((up - lo) / 128 > n) /* partition too imbalanced? */
 394       rnd = l_randomizePivot();  /* try a new randomization */
 395   }  /* tail call auxsort(L, lo, up, rnd) */
 396 }
 397
 398
 399 static int sort (lua_State *L) {
 400   lua_Integer n = aux_getn(L, 1, TAB_RW);
 401   if (n > 1) {  /* non-trivial interval? */
 402     luaL_argcheck(L, n < INT_MAX, 1, "array too big");
 403     if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
 404       luaL_checktype(L, 2, LUA_TFUNCTION);  /* must be a function */
 405     lua_settop(L, 2);  /* make sure there are two arguments */
 406     auxsort(L, 1, (IdxT)n, 0);
 407   }
 408   return 0;
 409 }
 410
 411 /* }====================================================== */
 412
 413
 414 static const luaL_Reg tab_funcs[] = {
 415   {"concat", tconcat},
 416   {"insert", tinsert},
 417   {"pack", tpack},
 418   {"unpack", tunpack},
 419   {"remove", tremove},
 420   {"move", tmove},
 421   {"sort", sort},
 422   {NULL, NULL}
 423 };
 424
 425
 426 LUAMOD_API int luaopen_table (lua_State *L) {
 427   luaL_newlib(L, tab_funcs);
 428   return 1;
 429 }
 430