mirror of https://github.com/lua/lua
121 lines
3.3 KiB
C
121 lines
3.3 KiB
C
/*
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** $Id: lstring.c,v 1.50 2001/01/11 18:59:20 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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#define lmod(s,size) ((int)((s) & ((size)-1)))
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void luaS_init (lua_State *L) {
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luaS_resize(L, &G(L)->strt, MINPOWER2);
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luaS_resize(L, &G(L)->udt, MINPOWER2);
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}
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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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lua_assert(G(L)->udt.nuse==0);
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luaM_freearray(L, G(L)->udt.hash, G(L)->udt.size, TString *);
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}
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void luaS_resize (lua_State *L, stringtable *tb, int newsize) {
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TString **newhash = luaM_newvector(L, newsize, TString *);
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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->nexthash; /* save next */
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luint32 h = (tb == &G(L)->strt) ? p->u.s.hash : IntPoint(p->u.d.value);
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int h1 = lmod(h, newsize); /* new position */
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lua_assert((int)(h%newsize) == lmod(h, newsize));
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p->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 void newentry (lua_State *L, stringtable *tb, TString *ts, int h) {
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ts->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 > (luint32)tb->size && tb->size < MAX_INT/2) /* too crowded? */
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luaS_resize(L, tb, tb->size*2);
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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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luint32 h = 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)]; ts; ts = ts->nexthash) {
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if (ts->len == l && (memcmp(str, ts->str, l) == 0))
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return ts;
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}
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/* not found */
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ts = (TString *)luaM_malloc(L, sizestring(l));
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ts->marked = 0;
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ts->nexthash = NULL;
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ts->len = l;
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ts->u.s.hash = h;
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ts->u.s.constindex = 0;
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memcpy(ts->str, str, l);
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ts->str[l] = 0; /* ending 0 */
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newentry(L, &G(L)->strt, ts, lmod(h, G(L)->strt.size)); /* insert it */
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return ts;
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}
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TString *luaS_newudata (lua_State *L, size_t s, void *udata) {
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union L_UTString *uts = (union L_UTString *)luaM_malloc(L, sizeudata(s));
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TString *ts = &uts->ts;
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ts->marked = 0;
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ts->nexthash = NULL;
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ts->len = s;
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ts->u.d.tag = 0;
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ts->u.d.value = (udata == NULL) ? uts+1 : udata;
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/* insert it on table */
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newentry(L, &G(L)->udt, ts, lmod(IntPoint(ts->u.d.value), G(L)->udt.size));
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return ts;
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}
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TString *luaS_createudata (lua_State *L, void *udata, int tag) {
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int h1 = lmod(IntPoint(udata), G(L)->udt.size);
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TString *ts;
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for (ts = G(L)->udt.hash[h1]; ts; ts = ts->nexthash) {
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if (udata == ts->u.d.value && (tag == ts->u.d.tag || tag == LUA_ANYTAG))
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return ts;
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}
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/* not found */
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ts = luaS_newudata(L, 0, udata);
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if (tag != LUA_ANYTAG)
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ts->u.d.tag = tag;
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return ts;
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}
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