136 lines
4.0 KiB
C
136 lines
4.0 KiB
C
/* Read-only tables for Lua */
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#include "c_string.h"
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#include "lrotable.h"
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#include "lua.h"
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#include "lauxlib.h"
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#include "lstring.h"
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#include "lobject.h"
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#include "lapi.h"
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/* Local defines */
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#define LUAR_FINDFUNCTION 0
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#define LUAR_FINDVALUE 1
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/* Externally defined read-only table array */
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extern const luaR_table lua_rotable[];
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/* Find a global "read only table" in the constant lua_rotable array */
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void* luaR_findglobal(const char *name, unsigned len) {
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unsigned i;
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if (c_strlen(name) > LUA_MAX_ROTABLE_NAME)
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return NULL;
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for (i=0; lua_rotable[i].name; i ++)
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if (*lua_rotable[i].name != '\0' && c_strlen(lua_rotable[i].name) == len && !c_strncmp(lua_rotable[i].name, name, len)) {
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return (void*)(lua_rotable[i].pentries);
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}
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return NULL;
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}
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/* Find an entry in a rotable and return it */
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static const TValue* luaR_auxfind(const luaR_entry *pentry, const char *strkey, luaR_numkey numkey, unsigned *ppos) {
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const TValue *res = NULL;
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unsigned i = 0;
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if (pentry == NULL)
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return NULL;
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while(pentry->key.type != LUA_TNIL) {
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if ((strkey && (pentry->key.type == LUA_TSTRING) && (!c_strcmp(pentry->key.id.strkey, strkey))) ||
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(!strkey && (pentry->key.type == LUA_TNUMBER) && ((luaR_numkey)pentry->key.id.numkey == numkey))) {
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res = &pentry->value;
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break;
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}
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i ++; pentry ++;
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}
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if (res && ppos)
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*ppos = i;
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return res;
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}
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int luaR_findfunction(lua_State *L, const luaR_entry *ptable) {
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const TValue *res = NULL;
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const char *key = luaL_checkstring(L, 2);
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res = luaR_auxfind(ptable, key, 0, NULL);
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if (res && ttislightfunction(res)) {
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luaA_pushobject(L, res);
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return 1;
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}
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else
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return 0;
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}
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/* Find an entry in a rotable and return its type
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If "strkey" is not NULL, the function will look for a string key,
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otherwise it will look for a number key */
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const TValue* luaR_findentry(void *data, const char *strkey, luaR_numkey numkey, unsigned *ppos) {
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return luaR_auxfind((const luaR_entry*)data, strkey, numkey, ppos);
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}
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/* Find the metatable of a given table */
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void* luaR_getmeta(void *data) {
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#ifdef LUA_META_ROTABLES
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const TValue *res = luaR_auxfind((const luaR_entry*)data, "__metatable", 0, NULL);
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return res && ttisrotable(res) ? rvalue(res) : NULL;
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#else
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return NULL;
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#endif
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}
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static void luaR_next_helper(lua_State *L, const luaR_entry *pentries, int pos, TValue *key, TValue *val) {
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setnilvalue(key);
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setnilvalue(val);
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if (pentries[pos].key.type != LUA_TNIL) {
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/* Found an entry */
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if (pentries[pos].key.type == LUA_TSTRING)
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setsvalue(L, key, luaS_newro(L, pentries[pos].key.id.strkey))
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else
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setnvalue(key, (lua_Number)pentries[pos].key.id.numkey)
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setobj2s(L, val, &pentries[pos].value);
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}
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}
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/* next (used for iteration) */
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void luaR_next(lua_State *L, void *data, TValue *key, TValue *val) {
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const luaR_entry* pentries = (const luaR_entry*)data;
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char strkey[LUA_MAX_ROTABLE_NAME + 1], *pstrkey = NULL;
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luaR_numkey numkey = 0;
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unsigned keypos;
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/* Special case: if key is nil, return the first element of the rotable */
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if (ttisnil(key))
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luaR_next_helper(L, pentries, 0, key, val);
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else if (ttisstring(key) || ttisnumber(key)) {
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/* Find the previoud key again */
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if (ttisstring(key)) {
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luaR_getcstr(strkey, rawtsvalue(key), LUA_MAX_ROTABLE_NAME);
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pstrkey = strkey;
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} else
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numkey = (luaR_numkey)nvalue(key);
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luaR_findentry(data, pstrkey, numkey, &keypos);
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/* Advance to next key */
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keypos ++;
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luaR_next_helper(L, pentries, keypos, key, val);
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}
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}
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/* Convert a Lua string to a C string */
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void luaR_getcstr(char *dest, const TString *src, size_t maxsize) {
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if (src->tsv.len+1 > maxsize)
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dest[0] = '\0';
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else {
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c_memcpy(dest, getstr(src), src->tsv.len);
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dest[src->tsv.len] = '\0';
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}
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}
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/* Return 1 if the given pointer is a rotable */
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#ifdef LUA_META_ROTABLES
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#include "compiler.h"
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int luaR_isrotable(void *p) {
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return RODATA_START_ADDRESS <= (char*)p && (char*)p <= RODATA_END_ADDRESS;
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}
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#endif
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