diff options
Diffstat (limited to 'string.c')
-rw-r--r-- | string.c | 40 |
1 files changed, 3 insertions, 37 deletions
@@ -838,48 +838,14 @@ rb_str_index(str, sub, offset) VALUE str, sub; long offset; { - char *s, *e, *p; - long len; - int d, hx, hy, i; - if (offset < 0) { offset += RSTRING(str)->len; if (offset < 0) return -1; } if (RSTRING(str)->len - offset < RSTRING(sub)->len) return -1; - s = RSTRING(str)->ptr+offset; - p = RSTRING(sub)->ptr; - len = RSTRING(sub)->len; - if (len == 0) return offset; - e = RSTRING(str)->ptr + RSTRING(str)->len - len + 1; - - /* seach using Karp-Rabin algolithm described in: - - EXACT STRING MATCHING ALGORITHMS - http://www-igm.univ-mlv.fr/~lecroq/string/index.html - */ - -#define KR_REHASH(a, b, h) ((((h) - (a)*d) << 1) + (b)) - - /* Preprocessing */ - /* computes d = 2^(m-1) with - the left-shift operator */ - for (d = i = 1; i < len; ++i) - d = (d<<1); - - for (hy = hx = i = 0; i < len; ++i) { - hx = ((hx<<1) + p[i]); - hy = ((hy<<1) + s[i]); - } - - /* Searching */ - while (s < e) { - if (hx == hy && rb_memcmp(p, s, len) == 0) - return (s-(RSTRING(str)->ptr)); - hy = KR_REHASH(*s, *(s+len), hy); - s++; - } - return -1; + if (RSTRING(sub)->len == 0) return offset; + return rb_memsearch(RSTRING(sub)->ptr, RSTRING(sub)->len, + RSTRING(str)->ptr+offset, RSTRING(str)->len-offset); } static VALUE |