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first implementation for 'table.copy'

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This commit is contained in:
Roberto Ierusalimschy 2014-07-25 15:46:00 -03:00
parent f9037ae8c1
commit 03bbe1baf1
1 changed files with 39 additions and 1 deletions
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40
ltablib.c
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@ -1,5 +1,5 @@
/*
** $Id: ltablib.c,v 1.70 2014/05/16 18:53:25 roberto Exp roberto $
** $Id: ltablib.c,v 1.71 2014/07/16 12:44:52 roberto Exp roberto $
** Library for Table Manipulation
** See Copyright Notice in lua.h
*/
@ -132,6 +132,43 @@ static int tremove (lua_State *L) {
}
static int tcopy (lua_State *L) {
TabA ta;
lua_Integer f = luaL_checkinteger(L, 2);
lua_Integer e = luaL_checkinteger(L, 3);
lua_Integer t;
int tt = 4; /* destination table */
/* the following restriction avoids several problems with overflows */
luaL_argcheck(L, f > 0, 2, "initial position must be positive");
if (lua_istable(L, tt))
t = luaL_checkinteger(L, 5);
else {
tt = 1; /* destination table is equal to source */
t = luaL_checkinteger(L, 4);
}
if (e >= f) { /* otherwise, nothing to move */
lua_Integer n, i;
ta.geti = (!luaL_getmetafield(L, 1, "__index")) ? lua_rawgeti : geti;
ta.seti = (!luaL_getmetafield(L, tt, "__newindex")) ? lua_rawseti : seti;
n = e - f + 1; /* number of elements to move */
if (t > f) {
for (i = n - 1; i >= 0; i--) {
(*ta.geti)(L, 1, f + i);
(*ta.seti)(L, tt, t + i);
}
}
else {
for (i = 0; i < n; i++) {
(*ta.geti)(L, 1, f + i);
(*ta.seti)(L, tt, t + i);
}
}
}
lua_pushvalue(L, tt); /* return "to table" */
return 1;
}
static void addfield (lua_State *L, luaL_Buffer *b, TabA *ta, lua_Integer i) {
(*ta->geti)(L, 1, i);
if (!lua_isstring(L, -1))
@ -318,6 +355,7 @@ static const luaL_Reg tab_funcs[] = {
{"pack", pack},
{"unpack", unpack},
{"remove", tremove},
{"copy", tcopy},
{"sort", sort},
{NULL, NULL}
};