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Feature #13712
closedString#start_with? with regexp
Status:
Closed
Assignee:
-
Target version:
-
Description
String#start_with? should receive regexp.
When I write a parser, I want to check a string is start with a pattern or not.
It's just the same thing with StringScanner#match
If I want to do the same thing with normal string method, it needs to write like /\A#{re}/.match(…)
.
But if re is argument, it needs to create a new temporary regexp every time.
Though we have a workaround as follows but it's bit tricky.
"foo ".rindex(/fo+./, 0)
A patch is following:
diff --git a/re.c b/re.c
index d0aa2a792e..f672ba75ec 100644
--- a/re.c
+++ b/re.c
@@ -1588,6 +1588,84 @@ rb_reg_search(VALUE re, VALUE str, long pos, int reverse)
return rb_reg_search0(re, str, pos, reverse, 1);
}
+bool
+rb_reg_start_with_p(VALUE re, VALUE str)
+{
+ long pos = 0;
+ long result;
+ VALUE match;
+ struct re_registers regi, *regs = ®i;
+ regex_t *reg;
+ int tmpreg;
+ onig_errmsg_buffer err = "";
+
+ reg = rb_reg_prepare_re0(re, str, err);
+ tmpreg = reg != RREGEXP_PTR(re);
+ if (!tmpreg) RREGEXP(re)->usecnt++;
+
+ match = rb_backref_get();
+ if (!NIL_P(match)) {
+ if (FL_TEST(match, MATCH_BUSY)) {
+ match = Qnil;
+ }
+ else {
+ regs = RMATCH_REGS(match);
+ }
+ }
+ if (NIL_P(match)) {
+ MEMZERO(regs, struct re_registers, 1);
+ }
+ result = onig_match(reg,
+ (UChar*)(RSTRING_PTR(str)),
+ ((UChar*)(RSTRING_PTR(str)) + RSTRING_LEN(str)),
+ (UChar*)(RSTRING_PTR(str)),
+ regs, ONIG_OPTION_NONE);
+ if (!tmpreg) RREGEXP(re)->usecnt--;
+ if (tmpreg) {
+ if (RREGEXP(re)->usecnt) {
+ onig_free(reg);
+ }
+ else {
+ onig_free(RREGEXP_PTR(re));
+ RREGEXP_PTR(re) = reg;
+ }
+ }
+ if (result < 0) {
+ if (regs == ®i)
+ onig_region_free(regs, 0);
+ if (result == ONIG_MISMATCH) {
+ rb_backref_set(Qnil);
+ return false;
+ }
+ else {
+ onig_error_code_to_str((UChar*)err, (int)result);
+ rb_reg_raise(RREGEXP_SRC_PTR(re), RREGEXP_SRC_LEN(re), err, re);
+ }
+ }
+
+ if (NIL_P(match)) {
+ int err;
+ match = match_alloc(rb_cMatch);
+ err = rb_reg_region_copy(RMATCH_REGS(match), regs);
+ onig_region_free(regs, 0);
+ if (err) rb_memerror();
+ }
+ else {
+ FL_UNSET(match, FL_TAINT);
+ }
+
+ RMATCH(match)->str = rb_str_new4(str);
+ OBJ_INFECT(match, str);
+
+ RMATCH(match)->regexp = re;
+ RMATCH(match)->rmatch->char_offset_updated = 0;
+ rb_backref_set(match);
+
+ OBJ_INFECT(match, re);
+
+ return true;
+}
+
VALUE
rb_reg_nth_defined(int nth, VALUE match)
{
diff --git a/string.c b/string.c
index 072f1329ee..6542a4acb1 100644
--- a/string.c
+++ b/string.c
@@ -9126,6 +9126,7 @@ rb_str_rpartition(VALUE str, VALUE sep)
RSTRING_LEN(str)-pos-RSTRING_LEN(sep)));
}
+extern bool rb_reg_start_with_p(VALUE re, VALUE str);
/*
* call-seq:
* str.start_with?([prefixes]+) -> true or false
@@ -9146,11 +9147,20 @@ rb_str_start_with(int argc, VALUE *argv, VALUE str)
for (i=0; i<argc; i++) {
VALUE tmp = argv[i];
- StringValue(tmp);
- rb_enc_check(str, tmp);
- if (RSTRING_LEN(str) < RSTRING_LEN(tmp)) continue;
- if (memcmp(RSTRING_PTR(str), RSTRING_PTR(tmp), RSTRING_LEN(tmp)) == 0)
- return Qtrue;
+ switch (BUILTIN_TYPE(tmp)) {
+ case T_REGEXP:
+ {
+ bool r = rb_reg_start_with_p(tmp, str);
+ if (r) return Qtrue;
+ }
+ break;
+ default:
+ StringValue(tmp);
+ rb_enc_check(str, tmp);
+ if (RSTRING_LEN(str) < RSTRING_LEN(tmp)) continue;
+ if (memcmp(RSTRING_PTR(str), RSTRING_PTR(tmp), RSTRING_LEN(tmp)) == 0)
+ return Qtrue;
+ }
}
return Qfalse;
}
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