mirror of https://github.com/lua/lua
98 lines
2.6 KiB
C
98 lines
2.6 KiB
C
/*
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** $Id: lstring.c,v 1.73 2002/03/20 18:37:13 roberto Exp roberto $
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** String table (keeps all strings handled by Lua)
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** See Copyright Notice in lua.h
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*/
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#include <string.h>
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#include "lua.h"
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#include "lmem.h"
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#include "lobject.h"
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#include "lstate.h"
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#include "lstring.h"
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void luaS_freeall (lua_State *L) {
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lua_assert(G(L)->strt.nuse==0);
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luaM_freearray(L, G(L)->strt.hash, G(L)->strt.size, TString *);
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}
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void luaS_resize (lua_State *L, int newsize) {
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TString **newhash = luaM_newvector(L, newsize, TString *);
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stringtable *tb = &G(L)->strt;
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int i;
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for (i=0; i<newsize; i++) newhash[i] = NULL;
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/* rehash */
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for (i=0; i<tb->size; i++) {
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TString *p = tb->hash[i];
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while (p) { /* for each node in the list */
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TString *next = p->tsv.nexthash; /* save next */
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lu_hash h = p->tsv.hash;
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int h1 = lmod(h, newsize); /* new position */
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lua_assert(cast(int, h%newsize) == lmod(h, newsize));
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p->tsv.nexthash = newhash[h1]; /* chain it in new position */
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newhash[h1] = p;
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p = next;
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}
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}
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luaM_freearray(L, tb->hash, tb->size, TString *);
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tb->size = newsize;
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tb->hash = newhash;
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}
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static TString *newlstr (lua_State *L, const char *str, size_t l, lu_hash h) {
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TString *ts = cast(TString *, luaM_malloc(L, sizestring(l)));
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stringtable *tb;
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ts->tsv.nexthash = NULL;
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ts->tsv.len = l;
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ts->tsv.hash = h;
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ts->tsv.marked = 0;
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memcpy(ts+1, str, l*sizeof(char));
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((char *)(ts+1))[l] = '\0'; /* ending 0 */
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tb = &G(L)->strt;
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h = lmod(h, tb->size);
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ts->tsv.nexthash = tb->hash[h]; /* chain new entry */
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tb->hash[h] = ts;
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tb->nuse++;
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if (tb->nuse > cast(ls_nstr, tb->size) && tb->size <= MAX_INT/2)
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luaS_resize(L, tb->size*2); /* too crowded */
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return ts;
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}
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TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
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TString *ts;
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lu_hash h = (lu_hash)l; /* seed */
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size_t step = (l>>5)+1; /* if string is too long, don't hash all its chars */
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size_t l1;
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for (l1=l; l1>=step; l1-=step) /* compute hash */
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h = h ^ ((h<<5)+(h>>2)+(unsigned char)(str[l1-1]));
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for (ts = G(L)->strt.hash[lmod(h, G(L)->strt.size)];
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ts != NULL;
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ts = ts->tsv.nexthash) {
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if (ts->tsv.len == l && (memcmp(str, getstr(ts), l) == 0))
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return ts;
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}
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return newlstr(L, str, l, h); /* not found */
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}
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Udata *luaS_newudata (lua_State *L, size_t s) {
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Udata *u;
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s = (s+3) & (~(size_t)3); /* make sure size is multiple of 4 */
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u = cast(Udata *, luaM_malloc(L, sizeudata(s)));
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u->uv.len = s;
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u->uv.metatable = hvalue(defaultmeta(L));
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/* chain it on udata list */
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u->uv.next = G(L)->rootudata;
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G(L)->rootudata = u;
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return u;
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}
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