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-rw-r--r--lstring.c44
1 files changed, 14 insertions, 30 deletions
diff --git a/lstring.c b/lstring.c
index c8cd17b1..a8c57cd9 100644
--- a/lstring.c
+++ b/lstring.c
@@ -1,5 +1,5 @@
1/* 1/*
2** $Id: lstring.c,v 1.47 2000/12/22 16:57:46 roberto Exp roberto $ 2** $Id: lstring.c,v 1.48 2000/12/28 12:55:41 roberto Exp roberto $
3** String table (keeps all strings handled by Lua) 3** String table (keeps all strings handled by Lua)
4** See Copyright Notice in lua.h 4** See Copyright Notice in lua.h
5*/ 5*/
@@ -15,6 +15,8 @@
15#include "lstring.h" 15#include "lstring.h"
16 16
17 17
18#define lmod(s,size) ((int)((s) & ((size)-1)))
19
18 20
19void luaS_init (lua_State *L) { 21void luaS_init (lua_State *L) {
20 luaS_resize(L, &L->strt, MINPOWER2); 22 luaS_resize(L, &L->strt, MINPOWER2);
@@ -30,15 +32,6 @@ void luaS_freeall (lua_State *L) {
30} 32}
31 33
32 34
33static luint32 hash_s (const char *s, size_t l) {
34 luint32 h = l; /* seed */
35 size_t step = (l>>5)|1; /* if string is too long, don't hash all its chars */
36 for (; l>=step; l-=step)
37 h = h ^ ((h<<5)+(h>>2)+(unsigned char)*(s++));
38 return h;
39}
40
41
42void luaS_resize (lua_State *L, stringtable *tb, int newsize) { 35void luaS_resize (lua_State *L, stringtable *tb, int newsize) {
43 TString **newhash = luaM_newvector(L, newsize, TString *); 36 TString **newhash = luaM_newvector(L, newsize, TString *);
44 int i; 37 int i;
@@ -49,8 +42,8 @@ void luaS_resize (lua_State *L, stringtable *tb, int newsize) {
49 while (p) { /* for each node in the list */ 42 while (p) { /* for each node in the list */
50 TString *next = p->nexthash; /* save next */ 43 TString *next = p->nexthash; /* save next */
51 luint32 h = (tb == &L->strt) ? p->u.s.hash : IntPoint(p->u.d.value); 44 luint32 h = (tb == &L->strt) ? p->u.s.hash : IntPoint(p->u.d.value);
52 int h1 = h&(newsize-1); /* new position */ 45 int h1 = lmod(h, newsize); /* new position */
53 LUA_ASSERT(h%newsize == (h&(newsize-1)), 46 LUA_ASSERT(h%newsize == lmod(h, newsize),
54 "a&(x-1) == a%x, for x power of 2"); 47 "a&(x-1) == a%x, for x power of 2");
55 p->nexthash = newhash[h1]; /* chain it in new position */ 48 p->nexthash = newhash[h1]; /* chain it in new position */
56 newhash[h1] = p; 49 newhash[h1] = p;
@@ -74,10 +67,13 @@ static void newentry (lua_State *L, stringtable *tb, TString *ts, int h) {
74 67
75 68
76TString *luaS_newlstr (lua_State *L, const char *str, size_t l) { 69TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
77 luint32 h = hash_s(str, l);
78 int h1 = h & (L->strt.size-1);
79 TString *ts; 70 TString *ts;
80 for (ts = L->strt.hash[h1]; ts; ts = ts->nexthash) { 71 luint32 h = l; /* seed */
72 size_t step = (l>>5)+1; /* if string is too long, don't hash all its chars */
73 size_t l1;
74 for (l1=l; l1>=step; l1-=step) /* compute hash */
75 h = h ^ ((h<<5)+(h>>2)+(unsigned char)str[l1-1]);
76 for (ts = L->strt.hash[lmod(h, L->strt.size)]; ts; ts = ts->nexthash) {
81 if (ts->len == l && (memcmp(str, ts->str, l) == 0)) 77 if (ts->len == l && (memcmp(str, ts->str, l) == 0))
82 return ts; 78 return ts;
83 } 79 }
@@ -90,7 +86,7 @@ TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
90 ts->u.s.constindex = 0; 86 ts->u.s.constindex = 0;
91 memcpy(ts->str, str, l); 87 memcpy(ts->str, str, l);
92 ts->str[l] = 0; /* ending 0 */ 88 ts->str[l] = 0; /* ending 0 */
93 newentry(L, &L->strt, ts, h1); /* insert it on table */ 89 newentry(L, &L->strt, ts, lmod(h, L->strt.size)); /* insert it on table */
94 return ts; 90 return ts;
95} 91}
96 92
@@ -104,13 +100,13 @@ TString *luaS_newudata (lua_State *L, size_t s, void *udata) {
104 ts->u.d.tag = 0; 100 ts->u.d.tag = 0;
105 ts->u.d.value = (udata == NULL) ? uts+1 : udata; 101 ts->u.d.value = (udata == NULL) ? uts+1 : udata;
106 /* insert it on table */ 102 /* insert it on table */
107 newentry(L, &L->udt, ts, IntPoint(ts->u.d.value) & (L->udt.size-1)); 103 newentry(L, &L->udt, ts, lmod(IntPoint(ts->u.d.value), L->udt.size));
108 return ts; 104 return ts;
109} 105}
110 106
111 107
112TString *luaS_createudata (lua_State *L, void *udata, int tag) { 108TString *luaS_createudata (lua_State *L, void *udata, int tag) {
113 int h1 = IntPoint(udata) & (L->udt.size-1); 109 int h1 = lmod(IntPoint(udata), L->udt.size);
114 TString *ts; 110 TString *ts;
115 for (ts = L->udt.hash[h1]; ts; ts = ts->nexthash) { 111 for (ts = L->udt.hash[h1]; ts; ts = ts->nexthash) {
116 if (udata == ts->u.d.value && (tag == ts->u.d.tag || tag == LUA_ANYTAG)) 112 if (udata == ts->u.d.value && (tag == ts->u.d.tag || tag == LUA_ANYTAG))
@@ -123,15 +119,3 @@ TString *luaS_createudata (lua_State *L, void *udata, int tag) {
123 return ts; 119 return ts;
124} 120}
125 121
126
127TString *luaS_new (lua_State *L, const char *str) {
128 return luaS_newlstr(L, str, strlen(str));
129}
130
131
132TString *luaS_newfixed (lua_State *L, const char *str) {
133 TString *ts = luaS_new(L, str);
134 if (ts->marked == 0) ts->marked = FIXMARK; /* avoid GC */
135 return ts;
136}
137