diff options
Diffstat (limited to 'string.c')
-rw-r--r-- | string.c | 56 |
1 files changed, 29 insertions, 27 deletions
@@ -3990,35 +3990,37 @@ rb_str_setbyte(VALUE str, VALUE index, VALUE value) static VALUE str_byte_substr(VALUE str, long beg, long len) { - char *p, *s = RSTRING_PTR(str), *e = s + RSTRING_LEN(str); - VALUE str2; - if (beg > RSTRING_LEN(str)) return Qnil; - if (beg < 0) { - beg += RSTRING_LEN(str); - if (beg < 0) return Qnil; - } - if (beg + len > RSTRING_LEN(str)) - len = RSTRING_LEN(str) - beg; - if (len <= 0) { - len = 0; - p = 0; - } - else - p = s + beg; + char *p, *s = RSTRING_PTR(str); + long n = RSTRING_LEN(str); + VALUE str2; - if (len > RSTRING_EMBED_LEN_MAX && beg + len == RSTRING_LEN(str)) { - str2 = rb_str_new4(str); - str2 = str_new3(rb_obj_class(str2), str2); - RSTRING(str2)->as.heap.ptr += RSTRING(str2)->as.heap.len - len; - RSTRING(str2)->as.heap.len = len; - } - else { - str2 = rb_str_new5(str, p, len); - rb_enc_cr_str_copy_for_substr(str2, str); - OBJ_INFECT(str2, str); - } + if (beg > n || len < 0) return Qnil; + if (beg < 0) { + beg += n; + if (beg < 0) return Qnil; + } + if (beg + len > n) + len = n - beg; + if (len <= 0) { + len = 0; + p = 0; + } + else + p = s + beg; - return str2; + if (len > RSTRING_EMBED_LEN_MAX && beg + len == n) { + str2 = rb_str_new4(str); + str2 = str_new3(rb_obj_class(str2), str2); + RSTRING(str2)->as.heap.ptr += RSTRING(str2)->as.heap.len - len; + RSTRING(str2)->as.heap.len = len; + } + else { + str2 = rb_str_new5(str, p, len); + rb_enc_cr_str_copy_for_substr(str2, str); + OBJ_INFECT(str2, str); + } + + return str2; } static VALUE |