From f7257b9f0fbcf0d9f7abc90cc54d85b92cb1784c Mon Sep 17 00:00:00 2001
From: Karl Williamson <khw@cpan.org>
Date: Sat, 12 Oct 2024 05:28:33 -0600
Subject: [PATCH] refcounted_he_(new|fetch)_pvn: Don't roll-own code

The new function utf8_to_bytes_temp_pv() does a better job than these
code sections that are nearly duplicates of each other.

It's better for several reasons, such as that for long keys, it checks a
word at a time if it is downgradable.

This is a follow on to #22638, which was closed without the original
commits that this replaces.
---
 hv.c | 72 +++++++-----------------------------------------------------
 1 file changed, 8 insertions(+), 64 deletions(-)

diff --git a/hv.c b/hv.c
index 1703084d7dd6..30eafc274c72 100644
--- a/hv.c
+++ b/hv.c
@@ -3686,39 +3686,11 @@ Perl_refcounted_he_fetch_pvn(pTHX_ const struct refcounted_he *chain,
             (UV)flags);
     if (!chain)
         goto ret;
-    if (flags & REFCOUNTED_HE_KEY_UTF8) {
-        /* For searching purposes, canonicalise to Latin-1 where possible. */
-        const char *keyend = keypv + keylen, *p;
-        STRLEN nonascii_count = 0;
-        for (p = keypv; p != keyend; p++) {
-            if (! UTF8_IS_INVARIANT(*p)) {
-                if (! UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(p, keyend)) {
-                    goto canonicalised_key;
-                }
-                nonascii_count++;
-                p++;
-            }
-        }
-        if (nonascii_count) {
-            char *q;
-            const char *p = keypv, *keyend = keypv + keylen;
-            keylen -= nonascii_count;
-            Newx(q, keylen, char);
-            SAVEFREEPV(q);
-            keypv = q;
-            for (; p != keyend; p++, q++) {
-                U8 c = (U8)*p;
-                if (UTF8_IS_INVARIANT(c)) {
-                    *q = (char) c;
-                }
-                else {
-                    p++;
-                    *q = (char) EIGHT_BIT_UTF8_TO_NATIVE(c, *p);
-                }
-            }
-        }
+    /* For searching purposes, canonicalise to Latin-1 where possible. */
+    if (   flags & REFCOUNTED_HE_KEY_UTF8
+        && utf8_to_bytes_temp_pv(&keypv, &keylen))
+    {
         flags &= ~REFCOUNTED_HE_KEY_UTF8;
-        canonicalised_key: ;
     }
     utf8_flag = (flags & REFCOUNTED_HE_KEY_UTF8) ? HVhek_UTF8 : 0;
     if (!hash)
@@ -3861,39 +3833,11 @@ Perl_refcounted_he_new_pvn(pTHX_ struct refcounted_he *parent,
     }
     hekflags = value_type;
 
-    if (flags & REFCOUNTED_HE_KEY_UTF8) {
-        /* Canonicalise to Latin-1 where possible. */
-        const char *keyend = keypv + keylen, *p;
-        STRLEN nonascii_count = 0;
-        for (p = keypv; p != keyend; p++) {
-            if (! UTF8_IS_INVARIANT(*p)) {
-                if (! UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(p, keyend)) {
-                    goto canonicalised_key;
-                }
-                nonascii_count++;
-                p++;
-            }
-        }
-        if (nonascii_count) {
-            char *q;
-            const char *p = keypv, *keyend = keypv + keylen;
-            keylen -= nonascii_count;
-            Newx(q, keylen, char);
-            SAVEFREEPV(q);
-            keypv = q;
-            for (; p != keyend; p++, q++) {
-                U8 c = (U8)*p;
-                if (UTF8_IS_INVARIANT(c)) {
-                    *q = (char) c;
-                }
-                else {
-                    p++;
-                    *q = (char) EIGHT_BIT_UTF8_TO_NATIVE(c, *p);
-                }
-            }
-        }
+    /* Canonicalise to Latin-1 where possible. */
+    if (   (flags & REFCOUNTED_HE_KEY_UTF8)
+        && utf8_to_bytes_temp_pv(&keypv, &keylen))
+    {
         flags &= ~REFCOUNTED_HE_KEY_UTF8;
-        canonicalised_key: ;
     }
     if (flags & REFCOUNTED_HE_KEY_UTF8)
         hekflags |= HVhek_UTF8;