0,0 → 1,114 |
/* |
** $Id: lstring.c,v 2.19 2011/05/03 16:01:57 roberto Exp $ |
** String table (keeps all strings handled by Lua) |
** See Copyright Notice in lua.h |
*/ |
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#include <string.h> |
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#define lstring_c |
#define LUA_CORE |
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#include "lua.h" |
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#include "lmem.h" |
#include "lobject.h" |
#include "lstate.h" |
#include "lstring.h" |
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void luaS_resize (lua_State *L, int newsize) { |
int i; |
stringtable *tb = &G(L)->strt; |
/* cannot resize while GC is traversing strings */ |
luaC_runtilstate(L, ~bitmask(GCSsweepstring)); |
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 = gch(p)->next; /* save next */ |
unsigned int h = lmod(gco2ts(p)->hash, newsize); /* new position */ |
gch(p)->next = tb->hash[h]; /* chain it */ |
tb->hash[h] = p; |
resetoldbit(p); /* see MOVE OLD rule */ |
p = next; |
} |
} |
if (newsize < tb->size) { |
/* shrinking slice must be empty */ |
lua_assert(tb->hash[newsize] == NULL && tb->hash[tb->size - 1] == NULL); |
luaM_reallocvector(L, tb->hash, tb->size, newsize, GCObject *); |
} |
tb->size = newsize; |
} |
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static TString *newlstr (lua_State *L, const char *str, size_t l, |
unsigned int h) { |
size_t totalsize; /* total size of TString object */ |
GCObject **list; /* (pointer to) list where it will be inserted */ |
TString *ts; |
stringtable *tb = &G(L)->strt; |
if (l+1 > (MAX_SIZET - sizeof(TString))/sizeof(char)) |
luaM_toobig(L); |
if (tb->nuse >= cast(lu_int32, tb->size) && tb->size <= MAX_INT/2) |
luaS_resize(L, tb->size*2); /* too crowded */ |
totalsize = sizeof(TString) + ((l + 1) * sizeof(char)); |
list = &tb->hash[lmod(h, tb->size)]; |
ts = &luaC_newobj(L, LUA_TSTRING, totalsize, list, 0)->ts; |
ts->tsv.len = l; |
ts->tsv.hash = h; |
ts->tsv.reserved = 0; |
memcpy(ts+1, str, l*sizeof(char)); |
((char *)(ts+1))[l] = '\0'; /* ending 0 */ |
tb->nuse++; |
return ts; |
} |
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TString *luaS_newlstr (lua_State *L, const char *str, size_t l) { |
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 = gch(o)->next) { |
TString *ts = rawgco2ts(o); |
if (h == ts->tsv.hash && |
ts->tsv.len == l && |
(memcmp(str, getstr(ts), l * sizeof(char)) == 0)) { |
if (isdead(G(L), o)) /* string is dead (but was not collected yet)? */ |
changewhite(o); /* resurrect it */ |
return ts; |
} |
} |
return newlstr(L, str, l, h); /* not found; create a new string */ |
} |
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TString *luaS_new (lua_State *L, const char *str) { |
return luaS_newlstr(L, str, strlen(str)); |
} |
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Udata *luaS_newudata (lua_State *L, size_t s, Table *e) { |
Udata *u; |
if (s > MAX_SIZET - sizeof(Udata)) |
luaM_toobig(L); |
u = &luaC_newobj(L, LUA_TUSERDATA, sizeof(Udata) + s, NULL, 0)->u; |
u->uv.len = s; |
u->uv.metatable = NULL; |
u->uv.env = e; |
return u; |
} |
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