From aa2258e35b3df3dcd49220f2fed53725b150ac2b Mon Sep 17 00:00:00 2001
From: drh <>
Date: Mon, 19 Aug 2024 12:54:12 +0000
Subject: [PATCH] Attempt to fix date/time calculations for days earlier than
 0400-03-01. See [forum:/forumpost/eaa0a09786c6368b|forum thread
 eaa0a09786c6368b].

FossilOrigin-Name: 00cae11fffaf50e2133915e851d41098d00b6b1458e1438bcb6664e1411d8498
---
 manifest      | 15 +++++++++------
 manifest.uuid |  2 +-
 src/date.c    | 10 +++++-----
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/manifest b/manifest
index 15c9bb1203..7e115d9526 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Automatically\sdisable\sdirectory\sfsync\swhen\scompiling\sfor\sAIX.
-D 2024-08-18T09:53:37.962
+C Attempt\sto\sfix\sdate/time\scalculations\sfor\sdays\searlier\sthan\s0400-03-01.\nSee\s[forum:/forumpost/eaa0a09786c6368b|forum\sthread\seaa0a09786c6368b].
+D 2024-08-19T12:54:12.528
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -706,7 +706,7 @@ F src/build.c 237ccc0290d131d646be722f418e92ee0a38043aee25e7dfdc75f8ce5b3abe4e
 F src/callback.c db3a45e376deff6a16c0058163fe0ae2b73a2945f3f408ca32cf74960b28d490
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 64e4b1227b4ed123146f0aa2989131d1fbd9b927b11e80c9d58c6a68f9cd5ce3
-F src/date.c 13dd752847afb32ed70510ad7345a5b9c841f51ad904dba5d010f1fa3a6a324e
+F src/date.c 89ce1ff20512a7fa5070ba6e7dd5c171148ca7d580955795bf97c79c2456144a
 F src/dbpage.c 80e46e1df623ec40486da7a5086cb723b0275a6e2a7b01d9f9b5da0f04ba2782
 F src/dbstat.c 3b677254d512fcafd4d0b341bf267b38b235ccfddbef24f9154e19360fa22e43
 F src/delete.c cb766727c78e715f9fb7ec8a7d03658ed2a3016343ca687acfcec9083cdca500
@@ -2205,8 +2205,11 @@ F vsixtest/vsixtest.tcl 6195aba1f12a5e10efc2b8c0009532167be5e301abe5b31385638080
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P a4043cbeb8a08fca2fdd2ea703e030d3a5574cc6002292ecc6f0e88c116472a3
-R cd57173ec450b44036cf8242b7c2fe1f
+P 8d170e07e20c21a5bb97fdc8c2d01d92178f5fe740e60d203e4621747cfce33e
+R 63b5eb42616efb9e489a03771c227de0
+T *branch * ancient-date-fix
+T *sym-ancient-date-fix *
+T -sym-trunk *
 U drh
-Z a06494827a8461d8ba3867ea1f761ae1
+Z baa6c6f17edc1a9ecec4f4cec4c126b5
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 1dca61d1bd..358b550bd1 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-8d170e07e20c21a5bb97fdc8c2d01d92178f5fe740e60d203e4621747cfce33e
+00cae11fffaf50e2133915e851d41098d00b6b1458e1438bcb6664e1411d8498
diff --git a/src/date.c b/src/date.c
index 8a609ae3cc..8c48a81fa5 100644
--- a/src/date.c
+++ b/src/date.c
@@ -271,8 +271,8 @@ static void computeJD(DateTime *p){
     Y--;
     M += 12;
   }
-  A = Y/100;
-  B = 2 - A + (A/4);
+  A = (Y+4800)/100;
+  B = 38 - A + (A/4);
   X1 = 36525*(Y+4716)/100;
   X2 = 306001*(M+1)/10000;
   p->iJD = (sqlite3_int64)((X1 + X2 + D + B - 1524.5 ) * 86400000);
@@ -456,7 +456,7 @@ static int validJulianDay(sqlite3_int64 iJD){
 ** Compute the Year, Month, and Day from the julian day number.
 */
 static void computeYMD(DateTime *p){
-  int Z, A, B, C, D, E, X1;
+  int Z, alpha, A, B, C, D, E, X1;
   if( p->validYMD ) return;
   if( !p->validJD ){
     p->Y = 2000;
@@ -467,8 +467,8 @@ static void computeYMD(DateTime *p){
     return;
   }else{
     Z = (int)((p->iJD + 43200000)/86400000);
-    A = (int)((Z - 1867216.25)/36524.25);
-    A = Z + 1 + A - (A/4);
+    alpha = (int)((Z + 32044.75)/36524.25) - 52;
+    A = Z + 1 + alpha - ((alpha+100)/4) + 25;
     B = A + 1524;
     C = (int)((B - 122.1)/365.25);
     D = (36525*(C&32767))/100;