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https://github.com/LuaJIT/LuaJIT.git
synced 2025-02-12 09:24:07 +00:00
Partially refactor string.find().
This commit is contained in:
Mike Pall
parent
2be1c2658f
commit
43de451d78
@ -155,7 +155,6 @@ typedef struct MatchState {
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} MatchState;
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#define L_ESC '%'
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#define SPECIALS "^$*+?.([%-"
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static int check_capture(MatchState *ms, int l)
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{
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@ -422,30 +421,6 @@ static const char *match(MatchState *ms, const char *s, const char *p)
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return s;
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}
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static const char *lmemfind(const char *s1, size_t l1,
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const char *s2, size_t l2)
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{
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if (l2 == 0) {
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return s1; /* empty strings are everywhere */
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} else if (l2 > l1) {
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return NULL; /* avoids a negative `l1' */
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} else {
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const char *init; /* to search for a `*s2' inside `s1' */
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l2--; /* 1st char will be checked by `memchr' */
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l1 = l1-l2; /* `s2' cannot be found after that */
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while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
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init++; /* 1st char is already checked */
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if (memcmp(init, s2+1, l2) == 0) {
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return init-1;
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} else { /* correct `l1' and `s1' to try again */
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l1 -= (size_t)(init-s1);
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s1 = init;
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}
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}
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return NULL; /* not found */
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}
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}
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static void push_onecapture(MatchState *ms, int i, const char *s, const char *e)
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{
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if (i >= ms->level) {
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@ -473,60 +448,56 @@ static int push_captures(MatchState *ms, const char *s, const char *e)
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return nlevels; /* number of strings pushed */
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}
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static ptrdiff_t posrelat(ptrdiff_t pos, size_t len)
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{
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/* relative string position: negative means back from end */
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if (pos < 0) pos += (ptrdiff_t)len + 1;
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return (pos >= 0) ? pos : 0;
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}
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static int str_find_aux(lua_State *L, int find)
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{
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size_t l1, l2;
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const char *s = luaL_checklstring(L, 1, &l1);
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const char *p = luaL_checklstring(L, 2, &l2);
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ptrdiff_t init = posrelat(luaL_optinteger(L, 3, 1), l1) - 1;
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if (init < 0) {
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init = 0;
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} else if ((size_t)(init) > l1) {
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GCstr *s = lj_lib_checkstr(L, 1);
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GCstr *p = lj_lib_checkstr(L, 2);
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int32_t start = lj_lib_optint(L, 3, 1);
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MSize st;
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if (start < 0) start += (int32_t)s->len; else start--;
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if (start < 0) start = 0;
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st = (MSize)start;
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if (st > s->len) {
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#if LJ_52
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setnilV(L->top-1);
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return 1;
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#else
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init = (ptrdiff_t)l1;
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st = s->len;
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#endif
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}
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if (find && (lua_toboolean(L, 4) || /* explicit request? */
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strpbrk(p, SPECIALS) == NULL)) { /* or no special characters? */
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/* do a plain search */
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const char *s2 = lmemfind(s+init, l1-(size_t)init, p, l2);
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if (s2) {
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lua_pushinteger(L, s2-s+1);
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lua_pushinteger(L, s2-s+(ptrdiff_t)l2);
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if (find && ((L->base+3 < L->top && tvistruecond(L->base+3)) ||
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!lj_str_haspattern(p))) { /* Search for fixed string. */
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const char *q = lj_str_find(strdata(s)+st, strdata(p), s->len-st, p->len);
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if (q) {
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setintV(L->top-2, (int32_t)(q-strdata(s)) + 1);
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setintV(L->top-1, (int32_t)(q-strdata(s)) + (int32_t)p->len);
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return 2;
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}
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} else {
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} else { /* Search for pattern. */
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MatchState ms;
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int anchor = (*p == '^') ? (p++, 1) : 0;
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const char *s1=s+init;
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const char *pstr = strdata(p);
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const char *sstr = strdata(s) + st;
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int anchor = 0;
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if (*pstr == '^') { pstr++; anchor = 1; }
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ms.L = L;
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ms.src_init = s;
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ms.src_end = s+l1;
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do {
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const char *res;
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ms.src_init = strdata(s);
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ms.src_end = strdata(s) + s->len;
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do { /* Loop through string and try to match the pattern. */
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const char *q;
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ms.level = ms.depth = 0;
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if ((res=match(&ms, s1, p)) != NULL) {
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q = match(&ms, sstr, pstr);
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if (q) {
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if (find) {
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lua_pushinteger(L, s1-s+1); /* start */
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lua_pushinteger(L, res-s); /* end */
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return push_captures(&ms, NULL, 0) + 2;
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setintV(L->top++, (int32_t)(sstr-(strdata(s)-1)));
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setintV(L->top++, (int32_t)(q-strdata(s)));
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return push_captures(&ms, NULL, NULL) + 2;
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} else {
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return push_captures(&ms, s1, res);
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return push_captures(&ms, sstr, q);
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}
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}
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} while (s1++ < ms.src_end && !anchor);
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} while (sstr++ < ms.src_end && !anchor);
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}
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lua_pushnil(L); /* not found */
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setnilV(L->top-1); /* Not found. */
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return 1;
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}
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36
src/lj_str.c
36
src/lj_str.c
@ -16,7 +16,7 @@
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#include "lj_state.h"
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#include "lj_char.h"
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/* -- String interning ---------------------------------------------------- */
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/* -- String helpers ------------------------------------------------------ */
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/* Ordered compare of strings. Assumes string data is 4-byte aligned. */
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int32_t LJ_FASTCALL lj_str_cmp(GCstr *a, GCstr *b)
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@ -62,6 +62,40 @@ static LJ_AINLINE int str_fastcmp(const char *a, const char *b, MSize len)
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return 0;
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}
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/* Find fixed string p inside string s. */
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const char *lj_str_find(const char *s, const char *p, MSize slen, MSize plen)
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{
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if (plen <= slen) {
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if (plen == 0) {
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return s;
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} else {
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int c = *(const uint8_t *)p++;
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plen--; slen -= plen;
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while (slen) {
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const char *q = (const char *)memchr(s, c, slen);
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if (!q) break;
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if (memcmp(q+1, p, plen) == 0) return q;
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q++; slen -= (MSize)(q-s); s = q;
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}
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}
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}
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return NULL;
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}
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/* Check whether a string has a pattern matching character. */
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int lj_str_haspattern(GCstr *s)
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{
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const char *p = strdata(s), *q = p + s->len;
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while (p < q) {
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int c = *(const uint8_t *)p++;
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if (lj_char_ispunct(c) && strchr("^$*+?.([%-", c))
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return 1; /* Found a pattern matching char. */
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}
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return 0; /* No pattern matching chars found. */
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}
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/* -- String interning ---------------------------------------------------- */
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/* Resize the string hash table (grow and shrink). */
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void lj_str_resize(lua_State *L, MSize newmask)
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{
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@ -10,8 +10,13 @@
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#include "lj_obj.h"
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/* String interning. */
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/* String helpers. */
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LJ_FUNC int32_t LJ_FASTCALL lj_str_cmp(GCstr *a, GCstr *b);
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LJ_FUNC const char *lj_str_find(const char *s, const char *f,
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MSize slen, MSize flen);
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LJ_FUNC int lj_str_haspattern(GCstr *s);
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/* String interning. */
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LJ_FUNC void lj_str_resize(lua_State *L, MSize newmask);
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LJ_FUNCA GCstr *lj_str_new(lua_State *L, const char *str, size_t len);
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LJ_FUNC void LJ_FASTCALL lj_str_free(global_State *g, GCstr *s);
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