1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
/*
** $Id: lstring.c,v 1.3 2001/11/26 23:00:26 darkgod Exp $
** String table (keeps all strings handled by Lua)
** See Copyright Notice in lua.h
*/
#include <string.h>
#include "lua.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
/*
** type equivalent to TString, but with maximum alignment requirements
*/
union L_UTString {
TString ts;
union L_Umaxalign dummy; /* ensures maximum alignment for `local' udata */
};
void luaS_init (lua_State *L) {
L->strt.hash = luaM_newvector(L, 1, TString *);
L->udt.hash = luaM_newvector(L, 1, TString *);
L->nblocks += 2*sizeof(TString *);
L->strt.size = L->udt.size = 1;
L->strt.nuse = L->udt.nuse = 0;
L->strt.hash[0] = L->udt.hash[0] = NULL;
}
void luaS_freeall (lua_State *L) {
LUA_ASSERT(L->strt.nuse==0, "non-empty string table");
L->nblocks -= (L->strt.size + L->udt.size)*sizeof(TString *);
luaM_free(L, L->strt.hash);
LUA_ASSERT(L->udt.nuse==0, "non-empty udata table");
luaM_free(L, L->udt.hash);
}
static unsigned long hash_s (const char *s, size_t l) {
unsigned long h = l; /* seed */
size_t step = (l>>5)|1; /* if string is too long, don't hash all its chars */
for (; l>=step; l-=step)
h = h ^ ((h<<5)+(h>>2)+(unsigned char)*(s++));
return h;
}
void luaS_resize (lua_State *L, stringtable *tb, int newsize) {
TString **newhash = luaM_newvector(L, newsize, TString *);
int i;
for (i=0; i<newsize; i++) newhash[i] = NULL;
/* rehash */
for (i=0; i<tb->size; i++) {
TString *p = tb->hash[i];
while (p) { /* for each node in the list */
TString *next = p->nexthash; /* save next */
unsigned long h = (tb == &L->strt) ? p->u.s.hash : IntPoint(p->u.d.value);
int h1 = h&(newsize-1); /* new position */
LUA_ASSERT(h%newsize == (h&(newsize-1)),
"a&(x-1) == a%x, for x power of 2");
p->nexthash = newhash[h1]; /* chain it in new position */
newhash[h1] = p;
p = next;
}
}
luaM_free(L, tb->hash);
L->nblocks += (newsize - tb->size)*sizeof(TString *);
tb->size = newsize;
tb->hash = newhash;
}
static void newentry (lua_State *L, stringtable *tb, TString *ts, int h) {
ts->nexthash = tb->hash[h]; /* chain new entry */
tb->hash[h] = ts;
tb->nuse++;
if (tb->nuse > (lint32)tb->size && tb->size < MAX_INT/2) /* too crowded? */
luaS_resize(L, tb, tb->size*2);
}
TString *luaS_newlstr (lua_State *L, const char *str, size_t l) {
unsigned long h = hash_s(str, l);
int h1 = h & (L->strt.size-1);
TString *ts;
for (ts = L->strt.hash[h1]; ts; ts = ts->nexthash) {
if (ts->len == l && (memcmp(str, ts->str, l) == 0))
return ts;
}
/* not found */
ts = (TString *)luaM_malloc(L, sizestring(l));
ts->marked = 0;
ts->nexthash = NULL;
ts->len = l;
ts->u.s.hash = h;
ts->u.s.constindex = 0;
memcpy(ts->str, str, l);
ts->str[l] = 0; /* ending 0 */
L->nblocks += sizestring(l);
newentry(L, &L->strt, ts, h1); /* insert it on table */
return ts;
}
TString *luaS_newudata (lua_State *L, size_t s, void *udata) {
union L_UTString *uts = (union L_UTString *)luaM_malloc(L,
(lint32)sizeof(union L_UTString)+s);
TString *ts = &uts->ts;
ts->marked = 0;
ts->nexthash = NULL;
ts->len = s;
ts->u.d.tag = 0;
ts->u.d.value = (udata == NULL) ? uts+1 : udata;
L->nblocks += sizestring(s);
/* insert it on table */
newentry(L, &L->udt, ts, IntPoint(ts->u.d.value) & (L->udt.size-1));
return ts;
}
TString *luaS_createudata (lua_State *L, void *udata, int tag) {
int h1 = IntPoint(udata) & (L->udt.size-1);
TString *ts;
for (ts = L->udt.hash[h1]; ts; ts = ts->nexthash) {
if (udata == ts->u.d.value && (tag == ts->u.d.tag || tag == LUA_ANYTAG))
return ts;
}
/* not found */
ts = luaS_newudata(L, 0, udata);
if (tag != LUA_ANYTAG)
ts->u.d.tag = tag;
return ts;
}
TString *luaS_new (lua_State *L, const char *str) {
return luaS_newlstr(L, str, strlen(str));
}
TString *luaS_newfixed (lua_State *L, const char *str) {
TString *ts = luaS_new(L, str);
if (ts->marked == 0) ts->marked = FIXMARK; /* avoid GC */
return ts;
}
|