Fixes to the substr() SQL function so that it can handle ridiculously large

numbers in its 2nd and 3rd arguments without signed integer overflows.

FossilOrigin-Name: c1de8f916ea617109a903c436c57d082756fbb2b933ba9ce6998b9b912b12dea

manifest

@@ -1,5 +1,5 @@
-C In\sthe\s(debugging)\srtreenode()\sfunction,\sdo\snot\soverride\san\serror\scoming\sout\nof\ssqlite3_result_text().
-D 2024-12-22T21:17:27.858
+C Fixes\sto\sthe\ssubstr()\sSQL\sfunction\sso\sthat\sit\scan\shandle\sridiculously\slarge\nnumbers\sin\sits\s2nd\sand\s3rd\sarguments\swithout\ssigned\sinteger\soverflows.
+D 2024-12-28T12:32:01.085
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md e108e1e69ae8e8a59e93c455654b8ac9356a11720d3345df2a4743e9590fb20d
@@ -730,7 +730,7 @@ F src/delete.c 03a77ba20e54f0f42ebd8eddf15411ed6bdb06a2c472ac4b6b336521bf7cea42
 F src/expr.c 3329173aacc6c37da3971b6253827799b32e301673be00126df8271bf018e15f
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 928ed2517e8732113d2b9821aa37af639688d752f4ea9ac6e0e393d713eeb76f
-F src/func.c e6e997efb9ffaf8b07842e745159695669fdfa020f03635a2f774adab8b0f4af
+F src/func.c 89b733a5f513c4bc06b7271384363d5693d62782de8295bc87b97d79862c9714
 F src/global.c a19e4b1ca1335f560e9560e590fc13081e21f670643367f99cb9e8f9dc7d615b
 F src/hash.c 9ee4269fb1d6632a6fecfb9479c93a1f29271bddbbaf215dd60420bcb80c7220
 F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
@@ -2202,8 +2202,8 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
 F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
 F tool/warnings.sh 49a486c5069de041aedcbde4de178293e0463ae9918ecad7539eedf0ec77a139
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 536fff14acb3335ad00fb1165cfb2f97e7a31c36273b9b97ffdb4b572fe72c08
-R 4447fcd0ccb80498c83515e29fbbdcc2
+P 286559dfb3ad01fcf34360991a108dbe6bf81e7919c461ada6c691ee8f43868f
+R 6fd56d72396565e46db9a7e82d5a2906
 U drh
-Z 75ed33204df12b76c729fccd2a0270dd
+Z 2ed81eb220ab467fd47b108b1040a471
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-286559dfb3ad01fcf34360991a108dbe6bf81e7919c461ada6c691ee8f43868f
+c1de8f916ea617109a903c436c57d082756fbb2b933ba9ce6998b9b912b12dea

src/func.c

@@ -354,7 +354,6 @@ static void substrFunc(
   int len;
   int p0type;
   i64 p1, p2;
-  int negP2 = 0;
 
   assert( argc==3 || argc==2 );
   if( sqlite3_value_type(argv[1])==SQLITE_NULL
@@ -389,18 +388,17 @@ static void substrFunc(
 #endif
   if( argc==3 ){
     p2 = sqlite3_value_int64(argv[2]);
-    if( p2<0 ){
-      p2 = -p2;
-      negP2 = 1;
-    }
   }else{
     p2 = sqlite3_context_db_handle(context)->aLimit[SQLITE_LIMIT_LENGTH];
   }
   if( p1<0 ){
     p1 += len;
     if( p1<0 ){
+      if( p2<0 ){
+        p2 = 0;
+      }else{
         p2 += p1;
-      if( p2<0 ) p2 = 0;
+      }
       p1 = 0;
     }
   }else if( p1>0 ){
@@ -408,12 +406,13 @@ static void substrFunc(
   }else if( p2>0 ){
     p2--;
   }
-  if( negP2 ){
-    p1 -= p2;
-    if( p1<0 ){
-      p2 += p1;
-      p1 = 0;
+  if( p2<0 ){
+    if( p2<-p1 ){
+      p2 = p1;
+    }else{
+      p2 = -p2;
     }
+    p1 -= p2;
   }
   assert( p1>=0 && p2>=0 );
   if( p0type!=SQLITE_BLOB ){