diff options
Diffstat (limited to 'source/luametatex/source/luacore/lua54/src/lstring.c')
-rw-r--r-- | source/luametatex/source/luacore/lua54/src/lstring.c | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/source/luametatex/source/luacore/lua54/src/lstring.c b/source/luametatex/source/luacore/lua54/src/lstring.c new file mode 100644 index 000000000..13dcaf425 --- /dev/null +++ b/source/luametatex/source/luacore/lua54/src/lstring.c @@ -0,0 +1,273 @@ +/* +** $Id: lstring.c $ +** String table (keeps all strings handled by Lua) +** See Copyright Notice in lua.h +*/ + +#define lstring_c +#define LUA_CORE + +#include "lprefix.h" + + +#include <string.h> + +#include "lua.h" + +#include "ldebug.h" +#include "ldo.h" +#include "lmem.h" +#include "lobject.h" +#include "lstate.h" +#include "lstring.h" + + +/* +** Maximum size for string table. +*/ +#define MAXSTRTB cast_int(luaM_limitN(MAX_INT, TString*)) + + +/* +** equality for long strings +*/ +int luaS_eqlngstr (TString *a, TString *b) { + size_t len = a->u.lnglen; + lua_assert(a->tt == LUA_VLNGSTR && b->tt == LUA_VLNGSTR); + return (a == b) || /* same instance or... */ + ((len == b->u.lnglen) && /* equal length and ... */ + (memcmp(getstr(a), getstr(b), len) == 0)); /* equal contents */ +} + + +unsigned int luaS_hash (const char *str, size_t l, unsigned int seed) { + unsigned int h = seed ^ cast_uint(l); + for (; l > 0; l--) + h ^= ((h<<5) + (h>>2) + cast_byte(str[l - 1])); + return h; +} + + +unsigned int luaS_hashlongstr (TString *ts) { + lua_assert(ts->tt == LUA_VLNGSTR); + if (ts->extra == 0) { /* no hash? */ + size_t len = ts->u.lnglen; + ts->hash = luaS_hash(getstr(ts), len, ts->hash); + ts->extra = 1; /* now it has its hash */ + } + return ts->hash; +} + + +static void tablerehash (TString **vect, int osize, int nsize) { + int i; + for (i = osize; i < nsize; i++) /* clear new elements */ + vect[i] = NULL; + for (i = 0; i < osize; i++) { /* rehash old part of the array */ + TString *p = vect[i]; + vect[i] = NULL; + while (p) { /* for each string in the list */ + TString *hnext = p->u.hnext; /* save next */ + unsigned int h = lmod(p->hash, nsize); /* new position */ + p->u.hnext = vect[h]; /* chain it into array */ + vect[h] = p; + p = hnext; + } + } +} + + +/* +** Resize the string table. If allocation fails, keep the current size. +** (This can degrade performance, but any non-zero size should work +** correctly.) +*/ +void luaS_resize (lua_State *L, int nsize) { + stringtable *tb = &G(L)->strt; + int osize = tb->size; + TString **newvect; + if (nsize < osize) /* shrinking table? */ + tablerehash(tb->hash, osize, nsize); /* depopulate shrinking part */ + newvect = luaM_reallocvector(L, tb->hash, osize, nsize, TString*); + if (l_unlikely(newvect == NULL)) { /* reallocation failed? */ + if (nsize < osize) /* was it shrinking table? */ + tablerehash(tb->hash, nsize, osize); /* restore to original size */ + /* leave table as it was */ + } + else { /* allocation succeeded */ + tb->hash = newvect; + tb->size = nsize; + if (nsize > osize) + tablerehash(newvect, osize, nsize); /* rehash for new size */ + } +} + + +/* +** Clear API string cache. (Entries cannot be empty, so fill them with +** a non-collectable string.) +*/ +void luaS_clearcache (global_State *g) { + int i, j; + for (i = 0; i < STRCACHE_N; i++) + for (j = 0; j < STRCACHE_M; j++) { + if (iswhite(g->strcache[i][j])) /* will entry be collected? */ + g->strcache[i][j] = g->memerrmsg; /* replace it with something fixed */ + } +} + + +/* +** Initialize the string table and the string cache +*/ +void luaS_init (lua_State *L) { + global_State *g = G(L); + int i, j; + stringtable *tb = &G(L)->strt; + tb->hash = luaM_newvector(L, MINSTRTABSIZE, TString*); + tablerehash(tb->hash, 0, MINSTRTABSIZE); /* clear array */ + tb->size = MINSTRTABSIZE; + /* pre-create memory-error message */ + g->memerrmsg = luaS_newliteral(L, MEMERRMSG); + luaC_fix(L, obj2gco(g->memerrmsg)); /* it should never be collected */ + for (i = 0; i < STRCACHE_N; i++) /* fill cache with valid strings */ + for (j = 0; j < STRCACHE_M; j++) + g->strcache[i][j] = g->memerrmsg; +} + + + +/* +** creates a new string object +*/ +static TString *createstrobj (lua_State *L, size_t l, int tag, unsigned int h) { + TString *ts; + GCObject *o; + size_t totalsize; /* total size of TString object */ + totalsize = sizelstring(l); + o = luaC_newobj(L, tag, totalsize); + ts = gco2ts(o); + ts->hash = h; + ts->extra = 0; + getstr(ts)[l] = '\0'; /* ending 0 */ + return ts; +} + + +TString *luaS_createlngstrobj (lua_State *L, size_t l) { + TString *ts = createstrobj(L, l, LUA_VLNGSTR, G(L)->seed); + ts->u.lnglen = l; + return ts; +} + + +void luaS_remove (lua_State *L, TString *ts) { + stringtable *tb = &G(L)->strt; + TString **p = &tb->hash[lmod(ts->hash, tb->size)]; + while (*p != ts) /* find previous element */ + p = &(*p)->u.hnext; + *p = (*p)->u.hnext; /* remove element from its list */ + tb->nuse--; +} + + +static void growstrtab (lua_State *L, stringtable *tb) { + if (l_unlikely(tb->nuse == MAX_INT)) { /* too many strings? */ + luaC_fullgc(L, 1); /* try to free some... */ + if (tb->nuse == MAX_INT) /* still too many? */ + luaM_error(L); /* cannot even create a message... */ + } + if (tb->size <= MAXSTRTB / 2) /* can grow string table? */ + luaS_resize(L, tb->size * 2); +} + + +/* +** Checks whether short string exists and reuses it or creates a new one. +*/ +static TString *internshrstr (lua_State *L, const char *str, size_t l) { + TString *ts; + global_State *g = G(L); + stringtable *tb = &g->strt; + unsigned int h = luaS_hash(str, l, g->seed); + TString **list = &tb->hash[lmod(h, tb->size)]; + lua_assert(str != NULL); /* otherwise 'memcmp'/'memcpy' are undefined */ + for (ts = *list; ts != NULL; ts = ts->u.hnext) { + if (l == ts->shrlen && (memcmp(str, getstr(ts), l * sizeof(char)) == 0)) { + /* found! */ + if (isdead(g, ts)) /* dead (but not collected yet)? */ + changewhite(ts); /* resurrect it */ + return ts; + } + } + /* else must create a new string */ + if (tb->nuse >= tb->size) { /* need to grow string table? */ + growstrtab(L, tb); + list = &tb->hash[lmod(h, tb->size)]; /* rehash with new size */ + } + ts = createstrobj(L, l, LUA_VSHRSTR, h); + memcpy(getstr(ts), str, l * sizeof(char)); + ts->shrlen = cast_byte(l); + ts->u.hnext = *list; + *list = ts; + tb->nuse++; + return ts; +} + + +/* +** new string (with explicit length) +*/ +TString *luaS_newlstr (lua_State *L, const char *str, size_t l) { + if (l <= LUAI_MAXSHORTLEN) /* short string? */ + return internshrstr(L, str, l); + else { + TString *ts; + if (l_unlikely(l >= (MAX_SIZE - sizeof(TString))/sizeof(char))) + luaM_toobig(L); + ts = luaS_createlngstrobj(L, l); + memcpy(getstr(ts), str, l * sizeof(char)); + return ts; + } +} + + +/* +** Create or reuse a zero-terminated string, first checking in the +** cache (using the string address as a key). The cache can contain +** only zero-terminated strings, so it is safe to use 'strcmp' to +** check hits. +*/ +TString *luaS_new (lua_State *L, const char *str) { + unsigned int i = point2uint(str) % STRCACHE_N; /* hash */ + int j; + TString **p = G(L)->strcache[i]; + for (j = 0; j < STRCACHE_M; j++) { + if (strcmp(str, getstr(p[j])) == 0) /* hit? */ + return p[j]; /* that is it */ + } + /* normal route */ + for (j = STRCACHE_M - 1; j > 0; j--) + p[j] = p[j - 1]; /* move out last element */ + /* new element is first in the list */ + p[0] = luaS_newlstr(L, str, strlen(str)); + return p[0]; +} + + +Udata *luaS_newudata (lua_State *L, size_t s, int nuvalue) { + Udata *u; + int i; + GCObject *o; + if (l_unlikely(s > MAX_SIZE - udatamemoffset(nuvalue))) + luaM_toobig(L); + o = luaC_newobj(L, LUA_VUSERDATA, sizeudata(nuvalue, s)); + u = gco2u(o); + u->len = s; + u->nuvalue = nuvalue; + u->metatable = NULL; + for (i = 0; i < nuvalue; i++) + setnilvalue(&u->uv[i].uv); + return u; +} + |