From: drh <>
Date: Mon, 13 Jul 2026 14:52:13 +0000 (+0000)
Subject: Add assert()s and a testcase() to and fix and improve comments in
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=cb704c0ad6e4188d16c1704dc9cb408289153a27;p=thirdparty%2Fsqlite.git

Add assert()s and a testcase() to and fix and improve comments in
the percentSort() routine.

FossilOrigin-Name: be673351ebdeba8e78ee11941ecb3e178e4d5212ff07f1d2790320af1d52e6a0
---

diff --git a/manifest b/manifest
index 9a9722b72f..ebe18636a5 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Improve\sdocumentation\sfor\ssqlite3_result_zeroblob64().\s\sNo\schanges\nto\scode.
-D 2026-07-12T07:42:55.910
+C Add\sassert()s\sand\sa\stestcase()\sto\sand\sfix\sand\simprove\scomments\sin\nthe\spercentSort()\sroutine.
+D 2026-07-13T14:52:13.130
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -696,7 +696,7 @@ F src/delete.c 59eeca3fb88c29329afc41bb803ee568b120d9dd7470b5f38ab55cc38390b451
 F src/expr.c db0f3e084f4bb2b249a5890dc9a0d3614d503cda009357bfdeb040f96322ccfe
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 931f74cec1dc8038a0217ef340c91ce147dd1bbed08dc40c47ee0ec6edfffb08
-F src/func.c bb839e662478ffcc9f0377258f32ac9e8257c8e67f1539e08bc5fa3dd185184a
+F src/func.c 208b4d073a1e823df8d0e19d0529093c09a9984851dcfda9808445541cefe6d0
 F src/global.c 7eea537ac0c113ac55cb2dd4d8fc2a6a91ae478be34231b4efaffc46817fee85
 F src/hash.c 03c8c0f4be9e8bcb6de65aa26d34a61d48a9430747084a69f9469fbb00ea52ca
 F src/hash.h 46b92795a95bfefb210f52f0c316e9d7cdbcdd7e7fcfb0d8be796d3a5767cddf
@@ -2214,8 +2214,8 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P 121f54c532d51af017d93996c40a694227064f1204429a7df1f1e2daff862eba
-R adafdd5dc444c44b804148afe9cc12c3
+P c3d307d1367ba08c9ddb9fc26c95131d3e124d7e97896383f21b48cdc154a50a
+R dce27a71b4f05a6c5b80250cb2210f1a
 U drh
-Z 9630336b271ae6962b7266ee1d33edbd
+Z 6e47befc1532a9c16e5b5298466e897a
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index a63aabc7a5..08f44100e8 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-c3d307d1367ba08c9ddb9fc26c95131d3e124d7e97896383f21b48cdc154a50a
+be673351ebdeba8e78ee11941ecb3e178e4d5212ff07f1d2790320af1d52e6a0
diff --git a/src/func.c b/src/func.c
index 12641e9f12..689c462034 100644
--- a/src/func.c
+++ b/src/func.c
@@ -2951,13 +2951,17 @@ static void percentSort(
   unsigned int n,                 /* Number of elements in array a[] */
   int iReq                        /* Element caller cares about (or -ve) */
 ){
-  int iLt;  /* Entries before a[iLt] are less than rPivot */
-  int iGt;  /* Entries at or after a[iGt] are greater than rPivot */
+  int iLt;       /* Entries before a[iLt] are less than or equal to rPivot */
+  int iGt;       /* Entries a[iGt] and after are greater or equal to rPivot */
   int i;         /* Loop counter */
   double rPivot; /* The pivot value */
 
   assert( n>=2 );
   do{
+    /* Put the first, middle, and last elements in sorted order.
+    ** After doing so, return immediately if the array contains
+    ** three or fewer elements as there is nothing more to do.
+    */
     if( a[0]>a[n-1] ){
       SWAP_DOUBLE(a[0],a[n-1])
     }
@@ -2970,6 +2974,11 @@ static void percentSort(
       SWAP_DOUBLE(a[i],a[iGt])
     }
     if( n==3 ) return;
+
+    /* Take the value of the middle element as the pivot.  Shuffle
+    ** values around so that all elements less than the pivot come
+    ** before all elements greater than the pivot.
+    */
     rPivot = a[i];
     iLt = i = 1;
     do{
@@ -2987,8 +2996,12 @@ static void percentSort(
       }
     }while( i<iGt );
 
+    assert( iLt>0 && iLt<iGt && iGt<n );
+    testcase( iGt>iLt+1 );
     assert( a[iLt]==rPivot );
-    assert( iGt>iLt );
+    assert( a[iLt-1]<=rPivot );
+    assert( a[iGt]>=rPivot );
+    assert( a[iLt+1]>=rPivot );
 
     if( iReq>=0 ){
       /* In this case, the only elements that the caller requires sorted into