| 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 | } |
| 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 | |