module/lua/ltablib.c

   1 /* BEGIN CSTYLED */
   2 /*
   3 ** $Id: ltablib.c,v 1.65.1.2 2014/05/07 16:32:55 roberto Exp $
   4 ** Library for Table Manipulation
   5 ** See Copyright Notice in lua.h
   6 */
   7
   8
   9 #define ltablib_c
  10 #define LUA_LIB
  11
  12 #include <sys/lua/lua.h>
  13
  14 #include <sys/lua/lauxlib.h>
  15 #include <sys/lua/lualib.h>
  16
  17
  18 #define aux_getn(L,n)   (luaL_checktype(L, n, LUA_TTABLE), luaL_len(L, n))
  19
  20
  21
  22 #if defined(LUA_COMPAT_MAXN)
  23 static int maxn (lua_State *L) {
  24   lua_Number max = 0;
  25   luaL_checktype(L, 1, LUA_TTABLE);
  26   lua_pushnil(L);  /* first key */
  27   while (lua_next(L, 1)) {
  28     lua_pop(L, 1);  /* remove value */
  29     if (lua_type(L, -1) == LUA_TNUMBER) {
  30       lua_Number v = lua_tonumber(L, -1);
  31       if (v > max) max = v;
  32     }
  33   }
  34   lua_pushnumber(L, max);
  35   return 1;
  36 }
  37 #endif
  38
  39
  40 static int tinsert (lua_State *L) {
  41   int e = aux_getn(L, 1) + 1;  /* first empty element */
  42   int pos;  /* where to insert new element */
  43   switch (lua_gettop(L)) {
  44     case 2: {  /* called with only 2 arguments */
  45       pos = e;  /* insert new element at the end */
  46       break;
  47     }
  48     case 3: {
  49       int i;
  50       pos = luaL_checkint(L, 2);  /* 2nd argument is the position */
  51       luaL_argcheck(L, 1 <= pos && pos <= e, 2, "position out of bounds");
  52       for (i = e; i > pos; i--) {  /* move up elements */
  53         lua_rawgeti(L, 1, i-1);
  54         lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */
  55       }
  56       break;
  57     }
  58     default: {
  59       return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
  60     }
  61   }
  62   lua_rawseti(L, 1, pos);  /* t[pos] = v */
  63   return 0;
  64 }
  65
  66
  67 static int tremove (lua_State *L) {
  68   int size = aux_getn(L, 1);
  69   int pos = luaL_optint(L, 2, size);
  70   if (pos != size)  /* validate 'pos' if given */
  71     luaL_argcheck(L, 1 <= pos && pos <= size + 1, 1, "position out of bounds");
  72   lua_rawgeti(L, 1, pos);  /* result = t[pos] */
  73   for ( ; pos < size; pos++) {
  74     lua_rawgeti(L, 1, pos+1);
  75     lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
  76   }
  77   lua_pushnil(L);
  78   lua_rawseti(L, 1, pos);  /* t[pos] = nil */
  79   return 1;
  80 }
  81
  82
  83 static void addfield (lua_State *L, luaL_Buffer *b, int i) {
  84   lua_rawgeti(L, 1, i);
  85   if (!lua_isstring(L, -1))
  86     luaL_error(L, "invalid value (%s) at index %d in table for "
  87                   LUA_QL("concat"), luaL_typename(L, -1), i);
  88   luaL_addvalue(b);
  89 }
  90
  91
  92 static int tconcat (lua_State *L) {
  93   luaL_Buffer b;
  94   size_t lsep;
  95   int i, last;
  96   const char *sep = luaL_optlstring(L, 2, "", &lsep);
  97   luaL_checktype(L, 1, LUA_TTABLE);
  98   i = luaL_optint(L, 3, 1);
  99   last = luaL_opt(L, luaL_checkint, 4, luaL_len(L, 1));
 100   luaL_buffinit(L, &b);
 101   for (; i < last; i++) {
 102     addfield(L, &b, i);
 103     luaL_addlstring(&b, sep, lsep);
 104   }
 105   if (i == last)  /* add last value (if interval was not empty) */
 106     addfield(L, &b, i);
 107   luaL_pushresult(&b);
 108   return 1;
 109 }
 110
 111
 112 /*
 113 ** {======================================================
 114 ** Pack/unpack
 115 ** =======================================================
 116 */
 117
 118 static int pack (lua_State *L) {
 119   int n = lua_gettop(L);  /* number of elements to pack */
 120   lua_createtable(L, n, 1);  /* create result table */
 121   lua_pushinteger(L, n);
 122   lua_setfield(L, -2, "n");  /* t.n = number of elements */
 123   if (n > 0) {  /* at least one element? */
 124     int i;
 125     lua_pushvalue(L, 1);
 126     lua_rawseti(L, -2, 1);  /* insert first element */
 127     lua_replace(L, 1);  /* move table into index 1 */
 128     for (i = n; i >= 2; i--)  /* assign other elements */
 129       lua_rawseti(L, 1, i);
 130   }
 131   return 1;  /* return table */
 132 }
 133
 134
 135 static int unpack (lua_State *L) {
 136   int i, e;
 137   unsigned int 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 = (unsigned int)e - (unsigned int)i;  /* number of elements minus 1 */
 143   if (n > (INT_MAX - 10) || !lua_checkstack(L, ++n))
 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   }
 180   else  /* a < b? */
 181     return lua_compare(L, a, b, LUA_OPLT);
 182 }
 183
 184 static void auxsort (lua_State *L, int l, int u) {
 185   while (l < u) {  /* for tail recursion */
 186     int i, j;
 187     /* sort elements a[l], a[(l+u)/2] and a[u] */
 188     lua_rawgeti(L, 1, l);
 189     lua_rawgeti(L, 1, u);
 190     if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
 191       set2(L, l, u);  /* swap a[l] - a[u] */
 192     else
 193       lua_pop(L, 2);
 194     if (u-l == 1) break;  /* only 2 elements */
 195     i = (l+u)/2;
 196     lua_rawgeti(L, 1, i);
 197     lua_rawgeti(L, 1, l);
 198     if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
 199       set2(L, i, l);
 200     else {
 201       lua_pop(L, 1);  /* remove a[l] */
 202       lua_rawgeti(L, 1, u);
 203       if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
 204         set2(L, i, u);
 205       else
 206         lua_pop(L, 2);
 207     }
 208     if (u-l == 2) break;  /* only 3 elements */
 209     lua_rawgeti(L, 1, i);  /* Pivot */
 210     lua_pushvalue(L, -1);
 211     lua_rawgeti(L, 1, u-1);
 212     set2(L, i, u-1);
 213     /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
 214     i = l; 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; i=i-1; l=i+2;
 239     }
 240     else {
 241       j=i+1; i=u; u=j-2;
 242     }
 243     auxsort(L, j, i);  /* call recursively the smaller one */
 244   }  /* repeat the routine for the larger one */
 245 }
 246
 247 static int sort (lua_State *L) {
 248   int n = aux_getn(L, 1);
 249   luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
 250   if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
 251     luaL_checktype(L, 2, LUA_TFUNCTION);
 252   lua_settop(L, 2);  /* make sure there is two arguments */
 253   auxsort(L, 1, n);
 254   return 0;
 255 }
 256
 257 /* }====================================================== */
 258
 259
 260 static const luaL_Reg tab_funcs[] = {
 261   {"concat", tconcat},
 262 #if defined(LUA_COMPAT_MAXN)
 263   {"maxn", maxn},
 264 #endif
 265   {"insert", tinsert},
 266   {"pack", pack},
 267   {"unpack", unpack},
 268   {"remove", tremove},
 269   {"sort", sort},
 270   {NULL, NULL}
 271 };
 272
 273
 274 LUAMOD_API int luaopen_table (lua_State *L) {
 275   luaL_newlib(L, tab_funcs);
 276 #if defined(LUA_COMPAT_UNPACK)
 277   /* _G.unpack = table.unpack */
 278   lua_getfield(L, -1, "unpack");
 279   lua_setglobal(L, "unpack");
 280 #endif
 281   return 1;
 282 }
 283
 284 #if defined(_KERNEL) && defined(HAVE_SPL)
 285
 286 EXPORT_SYMBOL(luaopen_table);
 287
 288 #endif
 289 /* END CSTYLED */