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- /*
- ** $Id: lstring.c,v 2.8.1.1 2007/12/27 13:02:25 roberto Exp $
- ** String table (keeps all strings handled by Lua)
- ** See Copyright Notice in lua.h
- */
- #define lstring_c
- #define LUA_CORE
- #define LUAC_CROSS_FILE
- #include "lua.h"
- #include C_HEADER_STRING
- #include "lmem.h"
- #include "lobject.h"
- #include "lstate.h"
- #include "lstring.h"
- #define LUAS_READONLY_STRING 1
- #define LUAS_REGULAR_STRING 0
- void luaS_resize (lua_State *L, int newsize) {
- stringtable *tb;
- int i;
- tb = &G(L)->strt;
- if (luaC_sweepstrgc(L) || newsize == tb->size || is_resizing_strings_gc(L))
- return; /* cannot resize during GC traverse or doesn't need to be resized */
- set_resizing_strings_gc(L);
- if (newsize > tb->size) {
- luaM_reallocvector(L, tb->hash, tb->size, newsize, GCObject *);
- for (i=tb->size; i<newsize; i++) tb->hash[i] = NULL;
- }
- /* rehash */
- for (i=0; i<tb->size; i++) {
- GCObject *p = tb->hash[i];
- tb->hash[i] = NULL;
- while (p) { /* for each node in the list */
- GCObject *next = p->gch.next; /* save next */
- unsigned int h = gco2ts(p)->hash;
- int h1 = lmod(h, newsize); /* new position */
- lua_assert(cast_int(h%newsize) == lmod(h, newsize));
- p->gch.next = tb->hash[h1]; /* chain it */
- tb->hash[h1] = p;
- p = next;
- }
- }
- if (newsize < tb->size)
- luaM_reallocvector(L, tb->hash, tb->size, newsize, GCObject *);
- tb->size = newsize;
- unset_resizing_strings_gc(L);
- }
- static TString *newlstr (lua_State *L, const char *str, size_t l,
- unsigned int h, int readonly) {
- TString *ts;
- stringtable *tb;
- if (l+1 > (MAX_SIZET - sizeof(TString))/sizeof(char))
- luaM_toobig(L);
- tb = &G(L)->strt;
- if ((tb->nuse + 1) > cast(lu_int32, tb->size) && tb->size <= MAX_INT/2)
- luaS_resize(L, tb->size*2); /* too crowded */
- ts = cast(TString *, luaM_malloc(L, readonly ? sizeof(char**)+sizeof(TString) : (l+1)*sizeof(char)+sizeof(TString)));
- ts->tsv.len = l;
- ts->tsv.hash = h;
- ts->tsv.marked = luaC_white(G(L));
- ts->tsv.tt = LUA_TSTRING;
- if (!readonly) {
- c_memcpy(ts+1, str, l*sizeof(char));
- ((char *)(ts+1))[l] = '\0'; /* ending 0 */
- } else {
- *(char **)(ts+1) = (char *)str;
- luaS_readonly(ts);
- }
- h = lmod(h, tb->size);
- ts->tsv.next = tb->hash[h]; /* chain new entry */
- tb->hash[h] = obj2gco(ts);
- tb->nuse++;
- return ts;
- }
- static TString *luaS_newlstr_helper (lua_State *L, const char *str, size_t l, int readonly) {
- GCObject *o;
- unsigned int h = cast(unsigned int, l); /* seed */
- size_t step = (l>>5)+1; /* if string is too long, don't hash all its chars */
- size_t l1;
- for (l1=l; l1>=step; l1-=step) /* compute hash */
- h = h ^ ((h<<5)+(h>>2)+cast(unsigned char, str[l1-1]));
- for (o = G(L)->strt.hash[lmod(h, G(L)->strt.size)];
- o != NULL;
- o = o->gch.next) {
- TString *ts = rawgco2ts(o);
- if (ts->tsv.len == l && (c_memcmp(str, getstr(ts), l) == 0)) {
- /* string may be dead */
- if (isdead(G(L), o)) changewhite(o);
- return ts;
- }
- }
- return newlstr(L, str, l, h, readonly); /* not found */
- }
- static int lua_is_ptr_in_ro_area(const char *p) {
- #ifdef LUA_CROSS_COMPILER
- return 0;
- #else
- #include "compiler.h"
- return p >= RODATA_START_ADDRESS && p <= RODATA_END_ADDRESS;
- #endif
- }
- TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
- // If the pointer is in a read-only memory and the string is at least 4 chars in length,
- // create it as a read-only string instead
- if(lua_is_ptr_in_ro_area(str) && l+1 > sizeof(char**) && l == c_strlen(str))
- return luaS_newlstr_helper(L, str, l, LUAS_READONLY_STRING);
- else
- return luaS_newlstr_helper(L, str, l, LUAS_REGULAR_STRING);
- }
- LUAI_FUNC TString *luaS_newrolstr (lua_State *L, const char *str, size_t l) {
- if(l+1 > sizeof(char**) && l == c_strlen(str))
- return luaS_newlstr_helper(L, str, l, LUAS_READONLY_STRING);
- else // no point in creating a RO string, as it would actually be larger
- return luaS_newlstr_helper(L, str, l, LUAS_REGULAR_STRING);
- }
- Udata *luaS_newudata (lua_State *L, size_t s, Table *e) {
- Udata *u;
- if (s > MAX_SIZET - sizeof(Udata))
- luaM_toobig(L);
- u = cast(Udata *, luaM_malloc(L, s + sizeof(Udata)));
- u->uv.marked = luaC_white(G(L)); /* is not finalized */
- u->uv.tt = LUA_TUSERDATA;
- u->uv.len = s;
- u->uv.metatable = NULL;
- u->uv.env = e;
- /* chain it on udata list (after main thread) */
- u->uv.next = G(L)->mainthread->next;
- G(L)->mainthread->next = obj2gco(u);
- return u;
- }
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