client/deps/liblua/ltablib.c

   1 /*
   2 ** $Id: ltablib.c,v 1.65 2013/03/07 18:17:24 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_len(L, n))
  20
  21
  22
  23 #if defined(LUA_COMPAT_MAXN)
  24 static int maxn(lua_State *L) {
  25     lua_Number max = 0;
  26     luaL_checktype(L, 1, LUA_TTABLE);
  27     lua_pushnil(L);  /* first key */
  28     while (lua_next(L, 1)) {
  29         lua_pop(L, 1);  /* remove value */
  30         if (lua_type(L, -1) == LUA_TNUMBER) {
  31             lua_Number v = lua_tonumber(L, -1);
  32             if (v > max) max = v;
  33         }
  34     }
  35     lua_pushnumber(L, max);
  36     return 1;
  37 }
  38 #endif
  39
  40
  41 static int tinsert(lua_State *L) {
  42     int e = aux_getn(L, 1) + 1;  /* first empty element */
  43     int pos;  /* where to insert new element */
  44     switch (lua_gettop(L)) {
  45         case 2: {  /* called with only 2 arguments */
  46             pos = e;  /* insert new element at the end */
  47             break;
  48         }
  49         case 3: {
  50             int i;
  51             pos = luaL_checkint(L, 2);  /* 2nd argument is the position */
  52             luaL_argcheck(L, 1 <= pos && pos <= e, 2, "position out of bounds");
  53             for (i = e; i > pos; i--) {  /* move up elements */
  54                 lua_rawgeti(L, 1, i - 1);
  55                 lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */
  56             }
  57             break;
  58         }
  59         default: {
  60             return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
  61         }
  62     }
  63     lua_rawseti(L, 1, pos);  /* t[pos] = v */
  64     return 0;
  65 }
  66
  67
  68 static int tremove(lua_State *L) {
  69     int size = aux_getn(L, 1);
  70     int pos = luaL_optint(L, 2, size);
  71     if (pos != size)  /* validate 'pos' if given */
  72         luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, "position out of bounds");
  73     lua_rawgeti(L, 1, pos);  /* result = t[pos] */
  74     for (; pos < size; pos++) {
  75         lua_rawgeti(L, 1, pos + 1);
  76         lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
  77     }
  78     lua_pushnil(L);
  79     lua_rawseti(L, 1, pos);  /* t[pos] = nil */
  80     return 1;
  81 }
  82
  83
  84 static void addfield(lua_State *L, luaL_Buffer *b, int i) {
  85     lua_rawgeti(L, 1, i);
  86     if (!lua_isstring(L, -1))
  87         luaL_error(L, "invalid value (%s) at index %d in table for "
  88                    LUA_QL("concat"), luaL_typename(L, -1), i);
  89     luaL_addvalue(b);
  90 }
  91
  92
  93 static int tconcat(lua_State *L) {
  94     luaL_Buffer b;
  95     size_t lsep;
  96     int i, last;
  97     const char *sep = luaL_optlstring(L, 2, "", &lsep);
  98     luaL_checktype(L, 1, LUA_TTABLE);
  99     i = luaL_optint(L, 3, 1);
 100     last = luaL_opt(L, luaL_checkint, 4, luaL_len(L, 1));
 101     luaL_buffinit(L, &b);
 102     for (; i < last; i++) {
 103         addfield(L, &b, i);
 104         luaL_addlstring(&b, sep, lsep);
 105     }
 106     if (i == last)  /* add last value (if interval was not empty) */
 107         addfield(L, &b, i);
 108     luaL_pushresult(&b);
 109     return 1;
 110 }
 111
 112
 113 /*
 114 ** {======================================================
 115 ** Pack/unpack
 116 ** =======================================================
 117 */
 118
 119 static int pack(lua_State *L) {
 120     int n = lua_gettop(L);  /* number of elements to pack */
 121     lua_createtable(L, n, 1);  /* create result table */
 122     lua_pushinteger(L, n);
 123     lua_setfield(L, -2, "n");  /* t.n = number of elements */
 124     if (n > 0) {  /* at least one element? */
 125         int i;
 126         lua_pushvalue(L, 1);
 127         lua_rawseti(L, -2, 1);  /* insert first element */
 128         lua_replace(L, 1);  /* move table into index 1 */
 129         for (i = n; i >= 2; i--)  /* assign other elements */
 130             lua_rawseti(L, 1, i);
 131     }
 132     return 1;  /* return table */
 133 }
 134
 135
 136 static int unpack(lua_State *L) {
 137     int i, e, n;
 138     luaL_checktype(L, 1, LUA_TTABLE);
 139     i = luaL_optint(L, 2, 1);
 140     e = luaL_opt(L, luaL_checkint, 3, luaL_len(L, 1));
 141     if (i > e) return 0;  /* empty range */
 142     n = e - i + 1;  /* number of elements */
 143     if (n <= 0 || !lua_checkstack(L, n))  /* n <= 0 means arith. overflow */
 144         return luaL_error(L, "too many results to unpack");
 145     lua_rawgeti(L, 1, i);  /* push arg[i] (avoiding overflow problems) */
 146     while (i++ < e)  /* push arg[i + 1...e] */
 147         lua_rawgeti(L, 1, i);
 148     return n;
 149 }
 150
 151 /* }====================================================== */
 152
 153
 154
 155 /*
 156 ** {======================================================
 157 ** Quicksort
 158 ** (based on `Algorithms in MODULA-3', Robert Sedgewick;
 159 **  Addison-Wesley, 1993.)
 160 ** =======================================================
 161 */
 162
 163
 164 static void set2(lua_State *L, int i, int j) {
 165     lua_rawseti(L, 1, i);
 166     lua_rawseti(L, 1, j);
 167 }
 168
 169 static int sort_comp(lua_State *L, int a, int b) {
 170     if (!lua_isnil(L, 2)) {  /* function? */
 171         int res;
 172         lua_pushvalue(L, 2);
 173         lua_pushvalue(L, a - 1); /* -1 to compensate function */
 174         lua_pushvalue(L, b - 2); /* -2 to compensate function and `a' */
 175         lua_call(L, 2, 1);
 176         res = lua_toboolean(L, -1);
 177         lua_pop(L, 1);
 178         return res;
 179     } else /* a < b? */
 180         return lua_compare(L, a, b, LUA_OPLT);
 181 }
 182
 183 static void auxsort(lua_State *L, int l, int u) {
 184     while (l < u) {  /* for tail recursion */
 185         int i, j;
 186         /* sort elements a[l], a[(l+u)/2] and a[u] */
 187         lua_rawgeti(L, 1, l);
 188         lua_rawgeti(L, 1, u);
 189         if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
 190             set2(L, l, u);  /* swap a[l] - a[u] */
 191         else
 192             lua_pop(L, 2);
 193         if (u - l == 1) break; /* only 2 elements */
 194         i = (l + u) / 2;
 195         lua_rawgeti(L, 1, i);
 196         lua_rawgeti(L, 1, l);
 197         if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
 198             set2(L, i, l);
 199         else {
 200             lua_pop(L, 1);  /* remove a[l] */
 201             lua_rawgeti(L, 1, u);
 202             if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
 203                 set2(L, i, u);
 204             else
 205                 lua_pop(L, 2);
 206         }
 207         if (u - l == 2) break; /* only 3 elements */
 208         lua_rawgeti(L, 1, i);  /* Pivot */
 209         lua_pushvalue(L, -1);
 210         lua_rawgeti(L, 1, u - 1);
 211         set2(L, i, u - 1);
 212         /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
 213         i = l;
 214         j = u - 1;
 215         for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
 216             /* repeat ++i until a[i] >= P */
 217             while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
 218                 if (i >= u) luaL_error(L, "invalid order function for sorting");
 219                 lua_pop(L, 1);  /* remove a[i] */
 220             }
 221             /* repeat --j until a[j] <= P */
 222             while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
 223                 if (j <= l) luaL_error(L, "invalid order function for sorting");
 224                 lua_pop(L, 1);  /* remove a[j] */
 225             }
 226             if (j < i) {
 227                 lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
 228                 break;
 229             }
 230             set2(L, i, j);
 231         }
 232         lua_rawgeti(L, 1, u - 1);
 233         lua_rawgeti(L, 1, i);
 234         set2(L, u - 1, i); /* swap pivot (a[u-1]) with a[i] */
 235         /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
 236         /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
 237         if (i - l < u - i) {
 238             j = l;
 239             i = i - 1;
 240             l = i + 2;
 241         } else {
 242             j = i + 1;
 243             i = u;
 244             u = j - 2;
 245         }
 246         auxsort(L, j, i);  /* call recursively the smaller one */
 247     }  /* repeat the routine for the larger one */
 248 }
 249
 250 static int sort(lua_State *L) {
 251     int n = aux_getn(L, 1);
 252     luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
 253     if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
 254         luaL_checktype(L, 2, LUA_TFUNCTION);
 255     lua_settop(L, 2);  /* make sure there is two arguments */
 256     auxsort(L, 1, n);
 257     return 0;
 258 }
 259
 260 /* }====================================================== */
 261
 262
 263 static const luaL_Reg tab_funcs[] = {
 264     {"concat", tconcat},
 265 #if defined(LUA_COMPAT_MAXN)
 266     {"maxn", maxn},
 267 #endif
 268     {"insert", tinsert},
 269     {"pack", pack},
 270     {"unpack", unpack},
 271     {"remove", tremove},
 272     {"sort", sort},
 273     {NULL, NULL}
 274 };
 275
 276
 277 LUAMOD_API int luaopen_table(lua_State *L) {
 278     luaL_newlib(L, tab_funcs);
 279 #if defined(LUA_COMPAT_UNPACK)
 280     /* _G.unpack = table.unpack */
 281     lua_getfield(L, -1, "unpack");
 282     lua_setglobal(L, "unpack");
 283 #endif
 284     return 1;
 285 }
 286