Create S_sv_pos_u2b_cached, which abstracts away utf-8 to byte

conversions, hiding the complexity of any cache lookup.

p4raw-id: //depot/perl@27572

diff --git a/sv.c b/sv.c
index dfaf433..27f2b80 100644 (file)
--- a/sv.c
+++ b/sv.c
@@ -5517,6 +5517,21 @@ S_sv_pos_u2b_forwards(pTHX_ const U8 *const start, const U8 *const send,
     return s - start;
 }
 
+static STRLEN
+S_sv_pos_u2b_cached(pTHX_ SV *sv, MAGIC **mgp, const U8 *const start,
+                   const U8 *const send, STRLEN uoffset,
+                   STRLEN uoffset0, STRLEN boffset0) {
+    STRLEN boffset;
+    if (uoffset >= uoffset0) {
+       boffset = boffset0 + S_sv_pos_u2b_forwards(aTHX_ start + boffset0,
+                                                  send, uoffset - uoffset0);
+    }
+    else {
+       boffset = S_sv_pos_u2b_forwards(aTHX_ start, send, uoffset);
+    }
+    return boffset;
+}
+
 void
 Perl_sv_pos_u2b(pTHX_ register SV *sv, I32* offsetp, I32* lenp)
 {
@@ -5530,18 +5545,20 @@ Perl_sv_pos_u2b(pTHX_ register SV *sv, I32* offsetp, I32* lenp)
     if (len) {
        STRLEN uoffset = (STRLEN) *offsetp;
        const U8 * const send = start + len;
-       STRLEN boffset = S_sv_pos_u2b_forwards(aTHX_ start, send, uoffset);
+       MAGIC *mg;
+       STRLEN boffset = S_sv_pos_u2b_cached(aTHX_ sv, &mg, start, send,
+                                            uoffset, 0, 0);
 
        *offsetp = (I32) boffset;
 
        if (lenp) {
-           /* Recalculate things relative to the previously found pair,
-              as if the string started from here.  */
-           start += boffset;
-           uoffset = *lenp;
+           /* Convert the relative offset to absolute.  */
+           STRLEN uoffset2 = uoffset + (STRLEN) *lenp;
+           STRLEN boffset2
+               = S_sv_pos_u2b_cached(aTHX_ sv, &mg, start, send, uoffset2,
+                                     uoffset, boffset) - boffset;
 
-           boffset = S_sv_pos_u2b_forwards(aTHX_ start, send, uoffset);
-           *lenp = boffset;
+           *lenp = boffset2;
        }
     }
     else {