module/lua/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 #define ltablib_c
   9 #define LUA_LIB
  10
  11 #include <sys/lua/lua.h>
  12
  13 #include <sys/lua/lauxlib.h>
  14 #include <sys/lua/lualib.h>
  15
  16
  17 #define aux_getn(L,n)   (luaL_checktype(L, n, LUA_TTABLE), luaL_len(L, n))
  18
  19
  20
  21 #if defined(LUA_COMPAT_MAXN)
  22 static int maxn (lua_State *L) {
  23   lua_Number max = 0;
  24   luaL_checktype(L, 1, LUA_TTABLE);
  25   lua_pushnil(L);  /* first key */
  26   while (lua_next(L, 1)) {
  27     lua_pop(L, 1);  /* remove value */
  28     if (lua_type(L, -1) == LUA_TNUMBER) {
  29       lua_Number v = lua_tonumber(L, -1);
  30       if (v > max) max = v;
  31     }
  32   }
  33   lua_pushnumber(L, max);
  34   return 1;
  35 }
  36 #endif
  37
  38
  39 static int tinsert (lua_State *L) {
  40   int e = aux_getn(L, 1) + 1;  /* first empty element */
  41   int pos;  /* where to insert new element */
  42   switch (lua_gettop(L)) {
  43     case 2: {  /* called with only 2 arguments */
  44       pos = e;  /* insert new element at the end */
  45       break;
  46     }
  47     case 3: {
  48       int i;
  49       pos = luaL_checkint(L, 2);  /* 2nd argument is the position */
  50       luaL_argcheck(L, 1 <= pos && pos <= e, 2, "position out of bounds");
  51       for (i = e; i > pos; i--) {  /* move up elements */
  52         lua_rawgeti(L, 1, i-1);
  53         lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */
  54       }
  55       break;
  56     }
  57     default: {
  58       return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
  59     }
  60   }
  61   lua_rawseti(L, 1, pos);  /* t[pos] = v */
  62   return 0;
  63 }
  64
  65
  66 static int tremove (lua_State *L) {
  67   int size = aux_getn(L, 1);
  68   int pos = luaL_optint(L, 2, size);
  69   if (pos != size)  /* validate 'pos' if given */
  70     luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, "position out of bounds");
  71   lua_rawgeti(L, 1, pos);  /* result = t[pos] */
  72   for ( ; pos < size; pos++) {
  73     lua_rawgeti(L, 1, pos+1);
  74     lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
  75   }
  76   lua_pushnil(L);
  77   lua_rawseti(L, 1, pos);  /* t[pos] = nil */
  78   return 1;
  79 }
  80
  81
  82 static void addfield (lua_State *L, luaL_Buffer *b, int i) {
  83   lua_rawgeti(L, 1, i);
  84   if (!lua_isstring(L, -1))
  85     luaL_error(L, "invalid value (%s) at index %d in table for "
  86                   LUA_QL("concat"), luaL_typename(L, -1), i);
  87   luaL_addvalue(b);
  88 }
  89
  90
  91 static int tconcat (lua_State *L) {
  92   luaL_Buffer b;
  93   size_t lsep;
  94   int i, last;
  95   const char *sep = luaL_optlstring(L, 2, "", &lsep);
  96   luaL_checktype(L, 1, LUA_TTABLE);
  97   i = luaL_optint(L, 3, 1);
  98   last = luaL_opt(L, luaL_checkint, 4, luaL_len(L, 1));
  99   luaL_buffinit(L, &b);
 100   for (; i < last; i++) {
 101     addfield(L, &b, i);
 102     luaL_addlstring(&b, sep, lsep);
 103   }
 104   if (i == last)  /* add last value (if interval was not empty) */
 105     addfield(L, &b, i);
 106   luaL_pushresult(&b);
 107   return 1;
 108 }
 109
 110
 111 /*
 112 ** {======================================================
 113 ** Pack/unpack
 114 ** =======================================================
 115 */
 116
 117 static int pack (lua_State *L) {
 118   int n = lua_gettop(L);  /* number of elements to pack */
 119   lua_createtable(L, n, 1);  /* create result table */
 120   lua_pushinteger(L, n);
 121   lua_setfield(L, -2, "n");  /* t.n = number of elements */
 122   if (n > 0) {  /* at least one element? */
 123     int i;
 124     lua_pushvalue(L, 1);
 125     lua_rawseti(L, -2, 1);  /* insert first element */
 126     lua_replace(L, 1);  /* move table into index 1 */
 127     for (i = n; i >= 2; i--)  /* assign other elements */
 128       lua_rawseti(L, 1, i);
 129   }
 130   return 1;  /* return table */
 131 }
 132
 133
 134 static int unpack (lua_State *L) {
 135   int i, e;
 136   unsigned int n;
 137   luaL_checktype(L, 1, LUA_TTABLE);
 138   i = luaL_optint(L, 2, 1);
 139   e = luaL_opt(L, luaL_checkint, 3, luaL_len(L, 1));
 140   if (i > e) return 0;  /* empty range */
 141   n = (unsigned int)e - (unsigned int)i;  /* number of elements minus 1 */
 142   if (n > (INT_MAX - 10) || !lua_checkstack(L, ++n))
 143     return luaL_error(L, "too many results to unpack");
 144   lua_rawgeti(L, 1, i);  /* push arg[i] (avoiding overflow problems) */
 145   while (i++ < e)  /* push arg[i + 1...e] */
 146     lua_rawgeti(L, 1, i);
 147   return n;
 148 }
 149
 150 /* }====================================================== */
 151
 152
 153
 154 /*
 155 ** {======================================================
 156 ** Quicksort
 157 ** (based on `Algorithms in MODULA-3', Robert Sedgewick;
 158 **  Addison-Wesley, 1993.)
 159 ** =======================================================
 160 */
 161
 162
 163 static void set2 (lua_State *L, int i, int j) {
 164   lua_rawseti(L, 1, i);
 165   lua_rawseti(L, 1, j);
 166 }
 167
 168 static int sort_comp (lua_State *L, int a, int b) {
 169   if (!lua_isnil(L, 2)) {  /* function? */
 170     int res;
 171     lua_pushvalue(L, 2);
 172     lua_pushvalue(L, a-1);  /* -1 to compensate function */
 173     lua_pushvalue(L, b-2);  /* -2 to compensate function and `a' */
 174     lua_call(L, 2, 1);
 175     res = lua_toboolean(L, -1);
 176     lua_pop(L, 1);
 177     return res;
 178   }
 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; j = u-1;
 214     for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
 215       /* repeat ++i until a[i] >= P */
 216       while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
 217         if (i>=u) luaL_error(L, "invalid order function for sorting");
 218         lua_pop(L, 1);  /* remove a[i] */
 219       }
 220       /* repeat --j until a[j] <= P */
 221       while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
 222         if (j<=l) luaL_error(L, "invalid order function for sorting");
 223         lua_pop(L, 1);  /* remove a[j] */
 224       }
 225       if (j<i) {
 226         lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
 227         break;
 228       }
 229       set2(L, i, j);
 230     }
 231     lua_rawgeti(L, 1, u-1);
 232     lua_rawgeti(L, 1, i);
 233     set2(L, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
 234     /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
 235     /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
 236     if (i-l < u-i) {
 237       j=l; i=i-1; l=i+2;
 238     }
 239     else {
 240       j=i+1; i=u; u=j-2;
 241     }
 242     auxsort(L, j, i);  /* call recursively the smaller one */
 243   }  /* repeat the routine for the larger one */
 244 }
 245
 246 static int tsort (lua_State *L) {
 247   int n = aux_getn(L, 1);
 248   luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
 249   if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
 250     luaL_checktype(L, 2, LUA_TFUNCTION);
 251   lua_settop(L, 2);  /* make sure there is two arguments */
 252   auxsort(L, 1, n);
 253   return 0;
 254 }
 255
 256 /* }====================================================== */
 257
 258
 259 static const luaL_Reg tab_funcs[] = {
 260   {"concat", tconcat},
 261 #if defined(LUA_COMPAT_MAXN)
 262   {"maxn", maxn},
 263 #endif
 264   {"insert", tinsert},
 265   {"pack", pack},
 266   {"unpack", unpack},
 267   {"remove", tremove},
 268   {"sort", tsort},
 269   {NULL, NULL}
 270 };
 271
 272
 273 LUAMOD_API int luaopen_table (lua_State *L) {
 274   luaL_newlib(L, tab_funcs);
 275 #if defined(LUA_COMPAT_UNPACK)
 276   /* _G.unpack = table.unpack */
 277   lua_getfield(L, -1, "unpack");
 278   lua_setglobal(L, "unpack");
 279 #endif
 280   return 1;
 281 }
 282
 283 #if defined(_KERNEL)
 284
 285 EXPORT_SYMBOL(luaopen_table);
 286
 287 #endif