From: drh <>
Date: Sat, 19 Jul 2025 20:10:07 +0000 (+0000)
Subject: Factor out the unusual encoding-change case from vdbeCompareMemString() for
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2445ee0e37c4efcd567411bb35915667d042b410;p=thirdparty%2Fsqlite.git

Factor out the unusual encoding-change case from vdbeCompareMemString() for
a performance improvement in the common case, and a small size reduction.

FossilOrigin-Name: cbd46ab8a8b4622f42dd9f87f28b812c1d6fa5ea73a4e8f1253514455f397783
---

diff --git a/manifest b/manifest
index b68d6dceba..3615113d22 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Small\sperformance\soptimization\sin\ssqlite3VdbeRecordUnpack().
-D 2025-07-19T19:54:44.334
+C Factor\sout\sthe\sunusual\sencoding-change\scase\sfrom\svdbeCompareMemString()\sfor\na\sperformance\simprovement\sin\sthe\scommon\scase,\sand\sa\ssmall\ssize\sreduction.
+D 2025-07-19T20:10:07.198
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -857,7 +857,7 @@ F src/vdbe.c a5873cd566a0e2a0344a86dd946add9d34fae3feeae8b126277ef7af8dc11f91
 F src/vdbe.h ea1f1b52f0efe422f80d88da3c57e4eadc72856e29a22f1ff08e502ec6ba5f08
 F src/vdbeInt.h d604607ce8c958fb66b8cb5a6915ba2f09a352c7dc38fee7e3157b951c84eac5
 F src/vdbeapi.c f9a4881a9674fec3fa13da35044a1484d3c4b95f9ec891cc8ffb02ef2b7a41df
-F src/vdbeaux.c 01193486aa0981036c13c273bce4f15ff10a4e3929532a2c01ee208499652038
+F src/vdbeaux.c d5a92c04deb8ec843a2449bc894cb377f0d13f3b6733a2b59d4df9e761c511a9
 F src/vdbeblob.c b3f0640db9642fbdc88bd6ebcc83d6009514cafc98f062f675f2c8d505d82692
 F src/vdbemem.c e67d9c6484d868c879d20c70d00bf4a9058082f1d4058607ca15d50eb3aebc21
 F src/vdbesort.c cb6f472e83ca12c46aa7de0ac0a9d11458b357986f2617a1c90dfb19a542ecbe
@@ -2213,8 +2213,8 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
 F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
 F tool/warnings.sh 1ad0169b022b280bcaaf94a7fa231591be96b514230ab5c98fbf15cd7df842dd
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 872b1b52ed93ef85911c2ef87b15673f9e102aef564f208e0a916af62671df93
-R 4246d37a682cbc8ba602315d42a01886
+P eae168def2ff11f57f730f8a3bd86748b0943077e37b2709c10de0aecff664ec
+R 657b20316a29fe916e58f39ea638cc42
 U drh
-Z 855a391ab5fed2279d013bd12273cbc3
+Z fe88cda3a10f1d9d2ca9e40a67c11d18
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 242dd2a601..22b9062e7d 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-eae168def2ff11f57f730f8a3bd86748b0943077e37b2709c10de0aecff664ec
+cbd46ab8a8b4622f42dd9f87f28b812c1d6fa5ea73a4e8f1253514455f397783
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index 179924de09..94e83d97a5 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -4443,6 +4443,32 @@ static void vdbeAssertFieldCountWithinLimits(
 ** or positive value if *pMem1 is less than, equal to or greater than
 ** *pMem2, respectively. Similar in spirit to "rc = (*pMem1) - (*pMem2);".
 */
+static SQLITE_NOINLINE int vdbeCompareMemStringWithEncodingChange(
+  const Mem *pMem1,
+  const Mem *pMem2,
+  const CollSeq *pColl,
+  u8 *prcErr                      /* If an OOM occurs, set to SQLITE_NOMEM */
+){
+  int rc;
+  const void *v1, *v2;
+  Mem c1;
+  Mem c2;
+  sqlite3VdbeMemInit(&c1, pMem1->db, MEM_Null);
+  sqlite3VdbeMemInit(&c2, pMem1->db, MEM_Null);
+  sqlite3VdbeMemShallowCopy(&c1, pMem1, MEM_Ephem);
+  sqlite3VdbeMemShallowCopy(&c2, pMem2, MEM_Ephem);
+  v1 = sqlite3ValueText((sqlite3_value*)&c1, pColl->enc);
+  v2 = sqlite3ValueText((sqlite3_value*)&c2, pColl->enc);
+  if( (v1==0 || v2==0) ){
+    if( prcErr ) *prcErr = SQLITE_NOMEM_BKPT;
+    rc = 0;
+  }else{
+    rc = pColl->xCmp(pColl->pUser, c1.n, v1, c2.n, v2);
+  }
+  sqlite3VdbeMemReleaseMalloc(&c1);
+  sqlite3VdbeMemReleaseMalloc(&c2);
+  return rc;
+}
 static int vdbeCompareMemString(
   const Mem *pMem1,
   const Mem *pMem2,
@@ -4454,25 +4480,7 @@ static int vdbeCompareMemString(
      ** comparison function directly */
     return pColl->xCmp(pColl->pUser,pMem1->n,pMem1->z,pMem2->n,pMem2->z);
   }else{
-    int rc;
-    const void *v1, *v2;
-    Mem c1;
-    Mem c2;
-    sqlite3VdbeMemInit(&c1, pMem1->db, MEM_Null);
-    sqlite3VdbeMemInit(&c2, pMem1->db, MEM_Null);
-    sqlite3VdbeMemShallowCopy(&c1, pMem1, MEM_Ephem);
-    sqlite3VdbeMemShallowCopy(&c2, pMem2, MEM_Ephem);
-    v1 = sqlite3ValueText((sqlite3_value*)&c1, pColl->enc);
-    v2 = sqlite3ValueText((sqlite3_value*)&c2, pColl->enc);
-    if( (v1==0 || v2==0) ){
-      if( prcErr ) *prcErr = SQLITE_NOMEM_BKPT;
-      rc = 0;
-    }else{
-      rc = pColl->xCmp(pColl->pUser, c1.n, v1, c2.n, v2);
-    }
-    sqlite3VdbeMemReleaseMalloc(&c1);
-    sqlite3VdbeMemReleaseMalloc(&c2);
-    return rc;
+    return vdbeCompareMemStringWithEncodingChange(pMem1,pMem2,pColl,prcErr);
   }
 }