ltablib.c

   1 /*
   2 ** $Id: ltablib.c,v 1.38.1.3 2008/02/14 16:46:58 roberto Exp $
   3 ** Library for Table Manipulation
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7 #if 0
   8 #include <stddef.h>
   9 #endif
  10
  11 #define ltablib_c
  12 #define LUA_LIB
  13
  14 #include "lua.h"
  15
  16 #include "lauxlib.h"
  17 #include "lualib.h"
  18
  19
  20 #define aux_getn(L,n)   (luaL_checktype(L, n, LUA_TTABLE), luaL_getn(L, n))
  21
  22
  23 static int foreachi (lua_State *L) {
  24   int i;
  25   int n = aux_getn(L, 1);
  26   luaL_checktype(L, 2, LUA_TFUNCTION);
  27   for (i=1; i <= n; i++) {
  28     lua_pushvalue(L, 2);  /* function */
  29     lua_pushinteger(L, i);  /* 1st argument */
  30     lua_rawgeti(L, 1, i);  /* 2nd argument */
  31     lua_call(L, 2, 1);
  32     if (!lua_isnil(L, -1))
  33       return 1;
  34     lua_pop(L, 1);  /* remove nil result */
  35   }
  36   return 0;
  37 }
  38
  39
  40 static int foreach (lua_State *L) {
  41   luaL_checktype(L, 1, LUA_TTABLE);
  42   luaL_checktype(L, 2, LUA_TFUNCTION);
  43   lua_pushnil(L);  /* first key */
  44   while (lua_next(L, 1)) {
  45     lua_pushvalue(L, 2);  /* function */
  46     lua_pushvalue(L, -3);  /* key */
  47     lua_pushvalue(L, -3);  /* value */
  48     lua_call(L, 2, 1);
  49     if (!lua_isnil(L, -1))
  50       return 1;
  51     lua_pop(L, 2);  /* remove value and result */
  52   }
  53   return 0;
  54 }
  55
  56
  57 static int maxn (lua_State *L) {
  58   lua_Number max = 0;
  59   luaL_checktype(L, 1, LUA_TTABLE);
  60   lua_pushnil(L);  /* first key */
  61   while (lua_next(L, 1)) {
  62     lua_pop(L, 1);  /* remove value */
  63     if (lua_type(L, -1) == LUA_TNUMBER) {
  64       lua_Number v = lua_tonumber(L, -1);
  65       if (v > max) max = v;
  66     }
  67   }
  68   lua_pushnumber(L, max);
  69   return 1;
  70 }
  71
  72
  73 static int getn (lua_State *L) {
  74   lua_pushinteger(L, aux_getn(L, 1));
  75   return 1;
  76 }
  77
  78
  79 static int setn (lua_State *L) {
  80   luaL_checktype(L, 1, LUA_TTABLE);
  81 #ifndef luaL_setn
  82   luaL_setn(L, 1, luaL_checkint(L, 2));
  83 #else
  84   luaL_error(L, LUA_QL("setn") " is obsolete");
  85 #endif
  86   lua_pushvalue(L, 1);
  87   return 1;
  88 }
  89
  90
  91 static int tinsert (lua_State *L) {
  92   int e = aux_getn(L, 1) + 1;  /* first empty element */
  93   int pos;  /* where to insert new element */
  94   switch (lua_gettop(L)) {
  95     case 2: {  /* called with only 2 arguments */
  96       pos = e;  /* insert new element at the end */
  97       break;
  98     }
  99     case 3: {
 100       int i;
 101       pos = luaL_checkint(L, 2);  /* 2nd argument is the position */
 102       if (pos > e) e = pos;  /* `grow' array if necessary */
 103       for (i = e; i > pos; i--) {  /* move up elements */
 104         lua_rawgeti(L, 1, i-1);
 105         lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */
 106       }
 107       break;
 108     }
 109     default: {
 110       return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
 111     }
 112   }
 113   luaL_setn(L, 1, e);  /* new size */
 114   lua_rawseti(L, 1, pos);  /* t[pos] = v */
 115   return 0;
 116 }
 117
 118
 119 static int tremove (lua_State *L) {
 120   int e = aux_getn(L, 1);
 121   int pos = luaL_optint(L, 2, e);
 122   if (!(1 <= pos && pos <= e))  /* position is outside bounds? */
 123    return 0;  /* nothing to remove */
 124   luaL_setn(L, 1, e - 1);  /* t.n = n-1 */
 125   lua_rawgeti(L, 1, pos);  /* result = t[pos] */
 126   for ( ;pos<e; pos++) {
 127     lua_rawgeti(L, 1, pos+1);
 128     lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
 129   }
 130   lua_pushnil(L);
 131   lua_rawseti(L, 1, e);  /* t[e] = nil */
 132   return 1;
 133 }
 134
 135
 136 static void addfield (lua_State *L, luaL_Buffer *b, int i) {
 137   lua_rawgeti(L, 1, i);
 138   if (!lua_isstring(L, -1))
 139     luaL_error(L, "invalid value (%s) at index %d in table for "
 140                   LUA_QL("concat"), luaL_typename(L, -1), i);
 141     luaL_addvalue(b);
 142 }
 143
 144
 145 static int tconcat (lua_State *L) {
 146   luaL_Buffer b;
 147   size_t lsep;
 148   int i, last;
 149   const char *sep = luaL_optlstring(L, 2, "", &lsep);
 150   luaL_checktype(L, 1, LUA_TTABLE);
 151   i = luaL_optint(L, 3, 1);
 152   last = luaL_opt(L, luaL_checkint, 4, luaL_getn(L, 1));
 153   luaL_buffinit(L, &b);
 154   for (; i < last; i++) {
 155     addfield(L, &b, i);
 156     luaL_addlstring(&b, sep, lsep);
 157   }
 158   if (i == last)  /* add last value (if interval was not empty) */
 159     addfield(L, &b, i);
 160   luaL_pushresult(&b);
 161   return 1;
 162 }
 163
 164
 165
 166 /*
 167 ** {======================================================
 168 ** Quicksort
 169 ** (based on `Algorithms in MODULA-3', Robert Sedgewick;
 170 **  Addison-Wesley, 1993.)
 171 */
 172
 173
 174 static void set2 (lua_State *L, int i, int j) {
 175   lua_rawseti(L, 1, i);
 176   lua_rawseti(L, 1, j);
 177 }
 178
 179 static int sort_comp (lua_State *L, int a, int b) {
 180   if (!lua_isnil(L, 2)) {  /* function? */
 181     int res;
 182     lua_pushvalue(L, 2);
 183     lua_pushvalue(L, a-1);  /* -1 to compensate function */
 184     lua_pushvalue(L, b-2);  /* -2 to compensate function and `a' */
 185     lua_call(L, 2, 1);
 186     res = lua_toboolean(L, -1);
 187     lua_pop(L, 1);
 188     return res;
 189   }
 190   else  /* a < b? */
 191     return lua_lessthan(L, a, b);
 192 }
 193
 194 static void auxsort (lua_State *L, int l, int u) {
 195   while (l < u) {  /* for tail recursion */
 196     int i, j;
 197     /* sort elements a[l], a[(l+u)/2] and a[u] */
 198     lua_rawgeti(L, 1, l);
 199     lua_rawgeti(L, 1, u);
 200     if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
 201       set2(L, l, u);  /* swap a[l] - a[u] */
 202     else
 203       lua_pop(L, 2);
 204     if (u-l == 1) break;  /* only 2 elements */
 205     i = (l+u)/2;
 206     lua_rawgeti(L, 1, i);
 207     lua_rawgeti(L, 1, l);
 208     if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
 209       set2(L, i, l);
 210     else {
 211       lua_pop(L, 1);  /* remove a[l] */
 212       lua_rawgeti(L, 1, u);
 213       if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
 214         set2(L, i, u);
 215       else
 216         lua_pop(L, 2);
 217     }
 218     if (u-l == 2) break;  /* only 3 elements */
 219     lua_rawgeti(L, 1, i);  /* Pivot */
 220     lua_pushvalue(L, -1);
 221     lua_rawgeti(L, 1, u-1);
 222     set2(L, i, u-1);
 223     /* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
 224     i = l; j = u-1;
 225     for (;;) {  /* invariant: a[l..i] <= P <= a[j..u] */
 226       /* repeat ++i until a[i] >= P */
 227       while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) {
 228         if (i>u) luaL_error(L, "invalid order function for sorting");
 229         lua_pop(L, 1);  /* remove a[i] */
 230       }
 231       /* repeat --j until a[j] <= P */
 232       while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1)) {
 233         if (j<l) luaL_error(L, "invalid order function for sorting");
 234         lua_pop(L, 1);  /* remove a[j] */
 235       }
 236       if (j<i) {
 237         lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
 238         break;
 239       }
 240       set2(L, i, j);
 241     }
 242     lua_rawgeti(L, 1, u-1);
 243     lua_rawgeti(L, 1, i);
 244     set2(L, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
 245     /* a[l..i-1] <= a[i] == P <= a[i+1..u] */
 246     /* adjust so that smaller half is in [j..i] and larger one in [l..u] */
 247     if (i-l < u-i) {
 248       j=l; i=i-1; l=i+2;
 249     }
 250     else {
 251       j=i+1; i=u; u=j-2;
 252     }
 253     auxsort(L, j, i);  /* call recursively the smaller one */
 254   }  /* repeat the routine for the larger one */
 255 }
 256
 257 static int sort (lua_State *L) {
 258   int n = aux_getn(L, 1);
 259   luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
 260   if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
 261     luaL_checktype(L, 2, LUA_TFUNCTION);
 262   lua_settop(L, 2);  /* make sure there is two arguments */
 263   auxsort(L, 1, n);
 264   return 0;
 265 }
 266
 267 /* }====================================================== */
 268
 269
 270 static const luaL_Reg tab_funcs[] = {
 271   {"concat", tconcat},
 272   {"foreach", foreach},
 273   {"foreachi", foreachi},
 274   {"getn", getn},
 275   {"maxn", maxn},
 276   {"insert", tinsert},
 277   {"remove", tremove},
 278   {"setn", setn},
 279   {"sort", sort},
 280   {NULL, NULL}
 281 };
 282
 283
 284 LUALIB_API int luaopen_table (lua_State *L) {
 285   luaL_register(L, LUA_TABLIBNAME, tab_funcs);
 286   return 1;
 287 }
 288