Enhancements to the date and time functions so that they optionally support

a 5-digit year.  Not sure we want to include this in trunk.  Saved in a branch
for future reference.

FossilOrigin-Name: 2029a396dcdb928f79780ec80c808fda6e3285a1

manifest

@@ -1,5 +1,5 @@
-C Comment\stweaks\son\sthe\stest\scase\sfor\sthe\s[b75a9ca6b0]\sbug\sfix.
-D 2014-04-21T13:36:54.639
+C Enhancements\sto\sthe\sdate\sand\stime\sfunctions\sso\sthat\sthey\soptionally\ssupport\na\s5-digit\syear.\s\sNot\ssure\swe\swant\sto\sinclude\sthis\sin\strunk.\s\sSaved\sin\sa\sbranch\nfor\sfuture\sreference.
+D 2014-04-23T12:00:20.142
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 2ef13430cd359f7b361bb863504e227b25cc7f81
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -171,7 +171,7 @@ F src/build.c 5bfeea8f302ec2926c9eea321a61daea92a29fa4
 F src/callback.c 174e3c8656bc29f91d710ab61550d16eea34be98
 F src/complete.c dc1d136c0feee03c2f7550bafc0d29075e36deac
 F src/ctime.c 0231df905e2c4abba4483ee18ffc05adc321df2a
-F src/date.c 593c744b2623971e45affd0bde347631bdfa4625
+F src/date.c 483fd9eeb74e06c2ddc4b33ade4a8a9611230386
 F src/delete.c bcf8f72126cea80fc3d5bc5494cf19b3f8935aaf
 F src/expr.c 4f9e497c66e2f25a4d139357a778c84d5713207c
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
@@ -1161,7 +1161,10 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P de9a490f594183f337a2ec9e0f87792eac83548b
-R ce888b84132e0cad3bcca115a32951d3
+P 65d2544af9adc1e2f1d193e57f8be0422fb0d5eb
+R 65a7ac109a1878f6dcc92cd296f64cbc
+T *branch * five-digit-year
+T *sym-five-digit-year *
+T -sym-trunk *
 U drh
-Z cf9f241149456ab1fa24984e95a412d2
+Z 20a358e6aab334ebda712a29750f60b8

manifest.uuid

@@ -1 +1 @@
-65d2544af9adc1e2f1d193e57f8be0422fb0d5eb
+2029a396dcdb928f79780ec80c808fda6e3285a1

src/date.c

@@ -229,7 +229,7 @@ static void computeJD(DateTime *p){
   }
   A = Y/100;
   B = 2 - A + (A/4);
-  X1 = 36525*(Y+4716)/100;
+  X1 = 365*(Y+4716) + 25*(Y+4716)/100;
   X2 = 306001*(M+1)/10000;
   p->iJD = (sqlite3_int64)((X1 + X2 + D + B - 1524.5 ) * 86400000);
   p->validJD = 1;
@@ -258,18 +258,23 @@ static void computeJD(DateTime *p){
 */
 static int parseYyyyMmDd(const char *zDate, DateTime *p){
   int Y, M, D, neg;
+  char c;
 
   if( zDate[0]=='-' ){
     zDate++;
     neg = 1;
   }else{
     neg = 0;
+    if( zDate[0]=='+' ) zDate++;
   }
-  if( getDigits(zDate,4,0,9999,'-',&Y,2,1,12,'-',&M,2,1,31,0,&D)!=3 ){
+  if( getDigits(zDate,4,0,9999,'-',&Y,2,1,12,'-',&M,2,1,31,0,&D)==3 ){
+    zDate += 10;
+  }else if( getDigits(zDate,5,0,99999,'-',&Y,2,1,12,'-',&M,2,1,31,0,&D)==3 ){
+    zDate += 11;
+  }else{
     return 1;
   }
-  zDate += 10;
-  while( sqlite3Isspace(*zDate) || 'T'==*(u8*)zDate ){ zDate++; }
+  while( (c = zDate[0])=='T' || c=='t' || sqlite3Isspace(c) ){ zDate++; }
   if( parseHhMmSs(zDate, p)==0 ){
     /* We got the time */
   }else if( *zDate==0 ){
@@ -355,7 +360,7 @@ static void computeYMD(DateTime *p){
     A = Z + 1 + A - (A/4);
     B = A + 1524;
     C = (int)((B - 122.1)/365.25);
-    D = (36525*C)/100;
+    D = 365*C + (25*C)/100;
     E = (int)((B-D)/30.6001);
     X1 = (int)(30.6001*E);
     p->D = B - D - X1;
@@ -577,19 +582,8 @@ static int parseModifier(sqlite3_context *pCtx, const char *zMod, DateTime *p){
     }
 #endif
     case 'u': {
-      /*
-      **    unixepoch
-      **
-      ** Treat the current value of p->iJD as the number of
-      ** seconds since 1970.  Convert to a real julian day number.
-      */
-      if( strcmp(z, "unixepoch")==0 && p->validJD ){
-        p->iJD = (p->iJD + 43200)/86400 + 21086676*(i64)10000000;
-        clearYMD_HMS_TZ(p);
-        rc = 0;
-      }
 #ifndef SQLITE_OMIT_LOCALTIME
-      else if( strcmp(z, "utc")==0 ){
+      if( strcmp(z, "utc")==0 ){
         sqlite3_int64 c1;
         computeJD(p);
         c1 = localtimeOffset(p, pCtx, &rc);
@@ -761,7 +755,7 @@ static int isDate(
   sqlite3_value **argv, 
   DateTime *p
 ){
-  int i;
+  int i = 1;
   const unsigned char *z;
   int eType;
   memset(p, 0, sizeof(*p));
@@ -770,7 +764,14 @@ static int isDate(
   }
   if( (eType = sqlite3_value_type(argv[0]))==SQLITE_FLOAT
                    || eType==SQLITE_INTEGER ){
-    p->iJD = (sqlite3_int64)(sqlite3_value_double(argv[0])*86400000.0 + 0.5);
+    if( argc>=2 && sqlite3_value_type(argv[1])==SQLITE_TEXT
+       && strcmp((const char*)sqlite3_value_text(argv[1]),"unixepoch")==0 ){
+      i = 2;
+      p->iJD = (sqlite3_int64)(sqlite3_value_double(argv[0])*1000.0) +
+                21086676*(i64)10000000;
+    }else{
+      p->iJD = (sqlite3_int64)(sqlite3_value_double(argv[0])*86400000.0 + 0.5);
+    }
     p->validJD = 1;
   }else{
     z = sqlite3_value_text(argv[0]);
@@ -778,8 +779,8 @@ static int isDate(
       return 1;
     }
   }
-  for(i=1; i<argc; i++){
-    z = sqlite3_value_text(argv[i]);
+  while( i<argc ){
+    z = sqlite3_value_text(argv[i++]);
     if( z==0 || parseModifier(context, (char*)z, p) ) return 1;
   }
   return 0;
@@ -808,10 +809,27 @@ static void juliandayFunc(
   }
 }
 
+/*
+** Render an ISO-8601 year value into the given buffer.  Return the
+** number of characters.
+**
+** Years are rendered differently depending on magnitude:
+**
+**      0..9999        YYYY
+**  10000..99999     +YYYYY
+**  -9999..-1         -YYYY
+** -99999..-10000    -YYYYY
+*/
+static int renderYear(char *zBuf, int Y){
+  sqlite3_snprintf(10, zBuf, Y<0 ? "%05d" : Y>=10000 ? "%+05d" : "%04d", Y);
+  return sqlite3Strlen30(zBuf);
+}
+
 /*
 **    datetime( TIMESTRING, MOD, MOD, ...)
 **
-** Return YYYY-MM-DD HH:MM:SS
+** Return YYYY-MM-DD HH:MM:SS.  The YYYY might be +YYYYY or -YYYY or -YYYYY
+** depending on the year.
 */
 static void datetimeFunc(
   sqlite3_context *context,
@@ -820,10 +838,12 @@ static void datetimeFunc(
 ){
   DateTime x;
   if( isDate(context, argc, argv, &x)==0 ){
+    int i;
     char zBuf[100];
     computeYMD_HMS(&x);
-    sqlite3_snprintf(sizeof(zBuf), zBuf, "%04d-%02d-%02d %02d:%02d:%02d",
-                     x.Y, x.M, x.D, x.h, x.m, (int)(x.s));
+    i = renderYear(zBuf, x.Y);
+    sqlite3_snprintf(sizeof(zBuf)-i, zBuf+i, "-%02d-%02d %02d:%02d:%02d",
+                     x.M, x.D, x.h, x.m, (int)(x.s));
     sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
   }
 }
@@ -850,7 +870,10 @@ static void timeFunc(
 /*
 **    date( TIMESTRING, MOD, MOD, ...)
 **
-** Return YYYY-MM-DD
+** Return   YYYY-MM-DD
+** or     +YYYYY-MM-DD
+** or      -YYYY-MM-DD
+** or     -YYYYY-MM-DD
 */
 static void dateFunc(
   sqlite3_context *context,
@@ -859,9 +882,11 @@ static void dateFunc(
 ){
   DateTime x;
   if( isDate(context, argc, argv, &x)==0 ){
+    int i;
     char zBuf[100];
     computeYMD(&x);
-    sqlite3_snprintf(sizeof(zBuf), zBuf, "%04d-%02d-%02d", x.Y, x.M, x.D);
+    i = renderYear(zBuf, x.Y);
+    sqlite3_snprintf(sizeof(zBuf)-i, zBuf+i, "-%02d-%02d", x.M, x.D);
     sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);
   }
 }