Add requirements marks on the built-in collating functions.

FossilOrigin-Name: 4b608b62ac8d4eafdb76192b3b5db272332a4bfd

1 files changed, 15 insertions, 4 deletions

diff --git a/src/main.c b/src/main.c
index f223b71f7..1d34b13d6 100644
--- a/src/main.c
+++ b/src/main.c
@@ -773,13 +773,20 @@ static int binCollFunc(
 ){
   int rc, n;
   n = nKey1<nKey2 ? nKey1 : nKey2;
+  /* EVIDENCE-OF: R-65033-28449 The built-in BINARY collation compares
+  ** strings byte by byte using the memcmp() function from the standard C
+  ** library. */
   rc = memcmp(pKey1, pKey2, n);
   if( rc==0 ){
     if( padFlag
      && allSpaces(((char*)pKey1)+n, nKey1-n)
      && allSpaces(((char*)pKey2)+n, nKey2-n)
     ){
-      /* Leave rc unchanged at 0 */
+      /* EVIDENCE-OF: R-31624-24737 RTRIM is like BINARY except that extra
+      ** spaces at the end of either string do not change the result. In other
+      ** words, strings will compare equal to one another as long as they
+      ** differ only in the number of spaces at the end.
+      */
     }else{
       rc = nKey1 - nKey2;
     }
@@ -2730,20 +2737,24 @@ static int openDatabase(
   /* Add the default collation sequence BINARY. BINARY works for both UTF-8
   ** and UTF-16, so add a version for each to avoid any unnecessary
   ** conversions. The only error that can occur here is a malloc() failure.
+  **
+  ** EVIDENCE-OF: R-52786-44878 SQLite defines three built-in collating
+  ** functions:
   */
   createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0);
   createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0);
   createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0);
+  createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
   createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
   if( db->mallocFailed ){
     goto opendb_out;
   }
+  /* EVIDENCE-OF: R-08308-17224 The default collating function for all
+  ** strings is BINARY. 
+  */
   db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 0);
   assert( db->pDfltColl!=0 );
 
-  /* Also add a UTF-8 case-insensitive collation sequence. */
-  createCollation(db, "NOCASE", SQLITE_UTF8, 0, nocaseCollatingFunc, 0);
-
   /* Parse the filename/URI argument. */
   db->openFlags = flags;
   rc = sqlite3ParseUri(zVfs, zFilename, &flags, &db->pVfs, &zOpen, &zErrMsg);