1*eda14cbcSMatt Macy /* BEGIN CSTYLED */ 2*eda14cbcSMatt Macy /* 3*eda14cbcSMatt Macy ** $Id: lstring.c,v 2.26.1.1 2013/04/12 18:48:47 roberto Exp $ 4*eda14cbcSMatt Macy ** String table (keeps all strings handled by Lua) 5*eda14cbcSMatt Macy ** See Copyright Notice in lua.h 6*eda14cbcSMatt Macy */ 7*eda14cbcSMatt Macy 8*eda14cbcSMatt Macy 9*eda14cbcSMatt Macy #define lstring_c 10*eda14cbcSMatt Macy #define LUA_CORE 11*eda14cbcSMatt Macy 12*eda14cbcSMatt Macy #include <sys/lua/lua.h> 13*eda14cbcSMatt Macy 14*eda14cbcSMatt Macy #include "lmem.h" 15*eda14cbcSMatt Macy #include "lobject.h" 16*eda14cbcSMatt Macy #include "lstate.h" 17*eda14cbcSMatt Macy #include "lstring.h" 18*eda14cbcSMatt Macy 19*eda14cbcSMatt Macy 20*eda14cbcSMatt Macy /* 21*eda14cbcSMatt Macy ** Lua will use at most ~(2^LUAI_HASHLIMIT) bytes from a string to 22*eda14cbcSMatt Macy ** compute its hash 23*eda14cbcSMatt Macy */ 24*eda14cbcSMatt Macy #if !defined(LUAI_HASHLIMIT) 25*eda14cbcSMatt Macy #define LUAI_HASHLIMIT 5 26*eda14cbcSMatt Macy #endif 27*eda14cbcSMatt Macy 28*eda14cbcSMatt Macy 29*eda14cbcSMatt Macy /* 30*eda14cbcSMatt Macy ** equality for long strings 31*eda14cbcSMatt Macy */ 32*eda14cbcSMatt Macy int luaS_eqlngstr (TString *a, TString *b) { 33*eda14cbcSMatt Macy size_t len = a->tsv.len; 34*eda14cbcSMatt Macy lua_assert(a->tsv.tt == LUA_TLNGSTR && b->tsv.tt == LUA_TLNGSTR); 35*eda14cbcSMatt Macy return (a == b) || /* same instance or... */ 36*eda14cbcSMatt Macy ((len == b->tsv.len) && /* equal length and ... */ 37*eda14cbcSMatt Macy (memcmp(getstr(a), getstr(b), len) == 0)); /* equal contents */ 38*eda14cbcSMatt Macy } 39*eda14cbcSMatt Macy 40*eda14cbcSMatt Macy 41*eda14cbcSMatt Macy /* 42*eda14cbcSMatt Macy ** equality for strings 43*eda14cbcSMatt Macy */ 44*eda14cbcSMatt Macy int luaS_eqstr (TString *a, TString *b) { 45*eda14cbcSMatt Macy return (a->tsv.tt == b->tsv.tt) && 46*eda14cbcSMatt Macy (a->tsv.tt == LUA_TSHRSTR ? eqshrstr(a, b) : luaS_eqlngstr(a, b)); 47*eda14cbcSMatt Macy } 48*eda14cbcSMatt Macy 49*eda14cbcSMatt Macy 50*eda14cbcSMatt Macy unsigned int luaS_hash (const char *str, size_t l, unsigned int seed) { 51*eda14cbcSMatt Macy unsigned int h = seed ^ cast(unsigned int, l); 52*eda14cbcSMatt Macy size_t l1; 53*eda14cbcSMatt Macy size_t step = (l >> LUAI_HASHLIMIT) + 1; 54*eda14cbcSMatt Macy for (l1 = l; l1 >= step; l1 -= step) 55*eda14cbcSMatt Macy h = h ^ ((h<<5) + (h>>2) + cast_byte(str[l1 - 1])); 56*eda14cbcSMatt Macy return h; 57*eda14cbcSMatt Macy } 58*eda14cbcSMatt Macy 59*eda14cbcSMatt Macy 60*eda14cbcSMatt Macy /* 61*eda14cbcSMatt Macy ** resizes the string table 62*eda14cbcSMatt Macy */ 63*eda14cbcSMatt Macy void luaS_resize (lua_State *L, int newsize) { 64*eda14cbcSMatt Macy int i; 65*eda14cbcSMatt Macy stringtable *tb = &G(L)->strt; 66*eda14cbcSMatt Macy /* cannot resize while GC is traversing strings */ 67*eda14cbcSMatt Macy luaC_runtilstate(L, ~bitmask(GCSsweepstring)); 68*eda14cbcSMatt Macy if (newsize > tb->size) { 69*eda14cbcSMatt Macy luaM_reallocvector(L, tb->hash, tb->size, newsize, GCObject *); 70*eda14cbcSMatt Macy for (i = tb->size; i < newsize; i++) tb->hash[i] = NULL; 71*eda14cbcSMatt Macy } 72*eda14cbcSMatt Macy /* rehash */ 73*eda14cbcSMatt Macy for (i=0; i<tb->size; i++) { 74*eda14cbcSMatt Macy GCObject *p = tb->hash[i]; 75*eda14cbcSMatt Macy tb->hash[i] = NULL; 76*eda14cbcSMatt Macy while (p) { /* for each node in the list */ 77*eda14cbcSMatt Macy GCObject *next = gch(p)->next; /* save next */ 78*eda14cbcSMatt Macy unsigned int h = lmod(gco2ts(p)->hash, newsize); /* new position */ 79*eda14cbcSMatt Macy gch(p)->next = tb->hash[h]; /* chain it */ 80*eda14cbcSMatt Macy tb->hash[h] = p; 81*eda14cbcSMatt Macy resetoldbit(p); /* see MOVE OLD rule */ 82*eda14cbcSMatt Macy p = next; 83*eda14cbcSMatt Macy } 84*eda14cbcSMatt Macy } 85*eda14cbcSMatt Macy if (newsize < tb->size) { 86*eda14cbcSMatt Macy /* shrinking slice must be empty */ 87*eda14cbcSMatt Macy lua_assert(tb->hash[newsize] == NULL && tb->hash[tb->size - 1] == NULL); 88*eda14cbcSMatt Macy luaM_reallocvector(L, tb->hash, tb->size, newsize, GCObject *); 89*eda14cbcSMatt Macy } 90*eda14cbcSMatt Macy tb->size = newsize; 91*eda14cbcSMatt Macy } 92*eda14cbcSMatt Macy 93*eda14cbcSMatt Macy 94*eda14cbcSMatt Macy /* 95*eda14cbcSMatt Macy ** creates a new string object 96*eda14cbcSMatt Macy */ 97*eda14cbcSMatt Macy static TString *createstrobj (lua_State *L, const char *str, size_t l, 98*eda14cbcSMatt Macy int tag, unsigned int h, GCObject **list) { 99*eda14cbcSMatt Macy TString *ts; 100*eda14cbcSMatt Macy char *sbuf; 101*eda14cbcSMatt Macy size_t totalsize; /* total size of TString object */ 102*eda14cbcSMatt Macy totalsize = sizeof(TString) + ((l + 1) * sizeof(char)); 103*eda14cbcSMatt Macy ts = &luaC_newobj(L, tag, totalsize, list, 0)->ts; 104*eda14cbcSMatt Macy ts->tsv.len = l; 105*eda14cbcSMatt Macy ts->tsv.hash = h; 106*eda14cbcSMatt Macy ts->tsv.extra = 0; 107*eda14cbcSMatt Macy sbuf = (char *)(TString *)(ts + 1); 108*eda14cbcSMatt Macy memcpy(sbuf, str, l*sizeof(char)); 109*eda14cbcSMatt Macy sbuf[l] = '\0'; /* ending 0 */ 110*eda14cbcSMatt Macy return ts; 111*eda14cbcSMatt Macy } 112*eda14cbcSMatt Macy 113*eda14cbcSMatt Macy 114*eda14cbcSMatt Macy /* 115*eda14cbcSMatt Macy ** creates a new short string, inserting it into string table 116*eda14cbcSMatt Macy */ 117*eda14cbcSMatt Macy static TString *newshrstr (lua_State *L, const char *str, size_t l, 118*eda14cbcSMatt Macy unsigned int h) { 119*eda14cbcSMatt Macy GCObject **list; /* (pointer to) list where it will be inserted */ 120*eda14cbcSMatt Macy stringtable *tb = &G(L)->strt; 121*eda14cbcSMatt Macy TString *s; 122*eda14cbcSMatt Macy if (tb->nuse >= cast(lu_int32, tb->size) && tb->size <= MAX_INT/2) 123*eda14cbcSMatt Macy luaS_resize(L, tb->size*2); /* too crowded */ 124*eda14cbcSMatt Macy list = &tb->hash[lmod(h, tb->size)]; 125*eda14cbcSMatt Macy s = createstrobj(L, str, l, LUA_TSHRSTR, h, list); 126*eda14cbcSMatt Macy tb->nuse++; 127*eda14cbcSMatt Macy return s; 128*eda14cbcSMatt Macy } 129*eda14cbcSMatt Macy 130*eda14cbcSMatt Macy 131*eda14cbcSMatt Macy /* 132*eda14cbcSMatt Macy ** checks whether short string exists and reuses it or creates a new one 133*eda14cbcSMatt Macy */ 134*eda14cbcSMatt Macy static TString *internshrstr (lua_State *L, const char *str, size_t l) { 135*eda14cbcSMatt Macy GCObject *o; 136*eda14cbcSMatt Macy global_State *g = G(L); 137*eda14cbcSMatt Macy unsigned int h = luaS_hash(str, l, g->seed); 138*eda14cbcSMatt Macy for (o = g->strt.hash[lmod(h, g->strt.size)]; 139*eda14cbcSMatt Macy o != NULL; 140*eda14cbcSMatt Macy o = gch(o)->next) { 141*eda14cbcSMatt Macy TString *ts = rawgco2ts(o); 142*eda14cbcSMatt Macy if (h == ts->tsv.hash && 143*eda14cbcSMatt Macy l == ts->tsv.len && 144*eda14cbcSMatt Macy (memcmp(str, getstr(ts), l * sizeof(char)) == 0)) { 145*eda14cbcSMatt Macy if (isdead(G(L), o)) /* string is dead (but was not collected yet)? */ 146*eda14cbcSMatt Macy changewhite(o); /* resurrect it */ 147*eda14cbcSMatt Macy return ts; 148*eda14cbcSMatt Macy } 149*eda14cbcSMatt Macy } 150*eda14cbcSMatt Macy return newshrstr(L, str, l, h); /* not found; create a new string */ 151*eda14cbcSMatt Macy } 152*eda14cbcSMatt Macy 153*eda14cbcSMatt Macy 154*eda14cbcSMatt Macy /* 155*eda14cbcSMatt Macy ** new string (with explicit length) 156*eda14cbcSMatt Macy */ 157*eda14cbcSMatt Macy TString *luaS_newlstr (lua_State *L, const char *str, size_t l) { 158*eda14cbcSMatt Macy if (l <= LUAI_MAXSHORTLEN) /* short string? */ 159*eda14cbcSMatt Macy return internshrstr(L, str, l); 160*eda14cbcSMatt Macy else { 161*eda14cbcSMatt Macy if (l + 1 > (MAX_SIZET - sizeof(TString))/sizeof(char)) 162*eda14cbcSMatt Macy luaM_toobig(L); 163*eda14cbcSMatt Macy return createstrobj(L, str, l, LUA_TLNGSTR, G(L)->seed, NULL); 164*eda14cbcSMatt Macy } 165*eda14cbcSMatt Macy } 166*eda14cbcSMatt Macy 167*eda14cbcSMatt Macy 168*eda14cbcSMatt Macy /* 169*eda14cbcSMatt Macy ** new zero-terminated string 170*eda14cbcSMatt Macy */ 171*eda14cbcSMatt Macy TString *luaS_new (lua_State *L, const char *str) { 172*eda14cbcSMatt Macy return luaS_newlstr(L, str, strlen(str)); 173*eda14cbcSMatt Macy } 174*eda14cbcSMatt Macy 175*eda14cbcSMatt Macy 176*eda14cbcSMatt Macy Udata *luaS_newudata (lua_State *L, size_t s, Table *e) { 177*eda14cbcSMatt Macy Udata *u; 178*eda14cbcSMatt Macy if (s > MAX_SIZET - sizeof(Udata)) 179*eda14cbcSMatt Macy luaM_toobig(L); 180*eda14cbcSMatt Macy u = &luaC_newobj(L, LUA_TUSERDATA, sizeof(Udata) + s, NULL, 0)->u; 181*eda14cbcSMatt Macy u->uv.len = s; 182*eda14cbcSMatt Macy u->uv.metatable = NULL; 183*eda14cbcSMatt Macy u->uv.env = e; 184*eda14cbcSMatt Macy return u; 185*eda14cbcSMatt Macy } 186*eda14cbcSMatt Macy /* END CSTYLED */ 187