1 /* 2 ** $Id: ltablib.c,v 1.65.1.1 2013/04/12 18:48:47 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 } 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
