Add scalar SQL function unhex().

FossilOrigin-Name: 890e9629a7480138c9c1d3acc2d1e7b3c05e0d156e5c5fba428bc1aeb790fbfb

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\sproblem\swith\susing\sfts3\sauxiliary\sfunctions\swith\sexpressions\slike\s"E\sAND\s...",\swhere\sE\sis\sa\sNEAR\sexpression\sthat\sconsists\sentirely\sof\sdeferred\stokens.
+C Add\sscalar\sSQL\sfunction\sunhex().
-D 2023-01-24T11:24:28.082
+D 2023-01-24T20:17:43.328
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -573,7 +573,7 @@ F src/delete.c 86573edae75e3d3e9a8b590d87db8e47222103029df4f3e11fa56044459b514e
 F src/expr.c 204af6a83c191f5ac19ec4af6ecc546f188cc2dd1c76fc5280982f710ec4b9c4
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 722f20779f5342a787922deded3628d8c74b5249cab04098cf17ee2f2aaff002
-F src/func.c 68f610a44962814a4ba593fc95137a6682cb7e65086f22167e167b75ee3432e7
+F src/func.c 0bf5b82df41ffa1afe2bc67c3d0d361761c56c9e1785c999e24a15ba04c28d2b
 F src/global.c e06ff8e0acd85aec13563c9ecb44fbbf38232ccf73594998fd880b92d619594b
 F src/hash.c c6af5f96a7a76d000f07c5402c48c318c2566beecdee9e78b9d9f60ce7119565
 F src/hash.h 3340ab6e1d13e725571d7cee6d3e3135f0779a7d8e76a9ce0a85971fa3953c51
@@ -976,7 +976,7 @@ F test/exec.test e949714dc127eaa5ecc7d723efec1ec27118fdd7
 F test/exists.test 79a75323c78f02bbe9c251ea502a092f9ef63dac
 F test/expr.test 5c06696478212e5a04e04b043f993373f6f8e5ce5a80f5548a84703b123b6caa
 F test/expr2.test c27327ae9c017a7ff6280123f67aff496f912da74d78c888926d68b46ec75fd8
-F test/exprfault.test 497cc0b8fe6a677f49b55cb485e040f709ec2834b84f25912fe9c2dfeeda33db
+F test/exprfault.test da33606d799718e2f8e34efd0e5858884a1ad87f608774c552a7f5517cc27181
 F test/extension01.test 00d13cec817f331a687a243e0e5a2d87b0e358c9
 F test/external_reader.test c7d34694f1b25c32d866f56ac80c1e29edddc42b4ef90cad589263ffac2cde0c
 F test/extraquick.test cb254400bd42bfb777ff675356aabf3287978f79
@@ -1758,6 +1758,7 @@ F test/tt3_vacuum.c 71b254cde1fc49d6c8c44efd54f4668f3e57d7b3a8f4601ade069f75a999
 F test/types.test bf816ce73c7dfcfe26b700c19f97ef4050d194ff
 F test/types2.test 1aeb81976841a91eef292723649b5c4fe3bc3cac
 F test/types3.test 99e009491a54f4dc02c06bdbc0c5eea56ae3e25a
+F test/unhex.test 47b547f4b35e4f6525ecac7c7839bd3ae4eb4613d4e8932592eff55da83308f1
 F test/unionall.test eb9afa030897af75fd2f0dd28354ef63c8a5897b6c76aa1f15acae61a12eabcf
 F test/unionall2.test 71e8fa08d5699d50dc9f9dc0c9799c2e7a6bb7931a330d369307a4df7f157fa1
 F test/unionallfault.test 652bfbb630e6c43135965dc1e8f0a9a791da83aec885d626a632fe1909c56f73
@@ -2043,8 +2044,9 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 48bb7c88787bf5de1d70cf3cc81ada38c6c02e476dbdff12c8676c6d5ee19aed
+P 39bfae4c4698a13e07c4a0725f2790955e03b601fe64e17a000c691def1bdcb8 66c8562690b19f17972589611810e1dccad3a48777acb05208289c1f77076f71
-R da240f1feb163c267019691c0e1aa949
+R e4f755d732b8075e7847f3615f7f161a
+T +closed 66c8562690b19f17972589611810e1dccad3a48777acb05208289c1f77076f71
 U dan
-Z a4ad18532eeaa7e5926d4df8858c0bf9
+Z b2c1f41f5ac4263ca444db1f00dc6050
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-39bfae4c4698a13e07c4a0725f2790955e03b601fe64e17a000c691def1bdcb8
+890e9629a7480138c9c1d3acc2d1e7b3c05e0d156e5c5fba428bc1aeb790fbfb

src/func.c

@@ -1223,6 +1223,96 @@ static void hexFunc(
   }
 }
 
+/*
+** Buffer zStr contains nStr bytes of utf-8 encoded text. Return 1 if zStr
+** contains character ch, or 0 if it does not.
+*/
+static int strContainsChar(const u8 *zStr, int nStr, u32 ch){
+  const u8 *zEnd = &zStr[nStr];
+  const u8 *z = zStr;
+  while( z<zEnd ){
+    u32 tst = Utf8Read(z);
+    if( tst==ch ) return 1;
+  }
+  return 0;
+}
+
+/*
+** The unhex() function. This function may be invoked with either one or
+** two arguments. In both cases the first argument is interpreted as text
+** a text value containing a set of pairs of hexadecimal digits which are
+** decoded and returned as a blob.
+**
+** If there is only a single argument, then it must consist only of an
+** even number of hexadeximal digits. Otherwise, return NULL.
+**
+** Or, if there is a second argument, then any character that appears in
+** the second argument is also allowed to appear between pairs of hexadecimal
+** digits in the first argument. If any other character appears in the
+** first argument, or if one of the allowed characters appears between 
+** two hexadecimal digits that make up a single byte, NULL is returned.
+**
+** The following expressions are all true:
+**
+**     unhex('ABCD')       IS x'ABCD'
+**     unhex('AB CD')      IS NULL
+**     unhex('AB CD', ' ') IS x'ABCD'
+**     unhex('A BCD', ' ') IS NULL
+*/
+static void unhexFunc(
+  sqlite3_context *pCtx,
+  int argc,
+  sqlite3_value **argv
+){
+  const u8 *zPass = (const u8*)"";
+  int nPass = 0;
+  const u8 *zHex = sqlite3_value_text(argv[0]);
+  int nHex = sqlite3_value_bytes(argv[0]);
+#ifdef SQLITE_DEBUG
+  const u8 *zEnd = &zHex[nHex];
+#endif
+  u8 *pBlob = 0;
+  u8 *p = 0;
+
+  assert( argc==1 || argc==2 );
+  if( argc==2 ){
+    zPass = sqlite3_value_text(argv[1]);
+    nPass = sqlite3_value_bytes(argv[1]);
+  }
+  if( !zHex || !zPass ) return;
+
+  p = pBlob = contextMalloc(pCtx, (nHex/2)+1);
+  if( pBlob ){
+    u8 c;                         /* Most significant digit of next byte */
+    u8 d;                         /* Least significant digit of next byte */
+
+    while( (c = *zHex)!=0x00 ){
+      while( !sqlite3Isxdigit(c) ){
+        u32 ch = Utf8Read(zHex);
+        assert( zHex<=zEnd );
+        if( !strContainsChar(zPass, nPass, ch) ) goto unhex_null;
+        c = *zHex;
+        if( c==0x00 ) goto unhex_done;
+      }
+      zHex++;
+      assert( *zEnd==0x00 );
+      assert( zHex<=zEnd );
+      d = *(zHex++);
+      if( !sqlite3Isxdigit(d) ) goto unhex_null;
+      *(p++) = (sqlite3HexToInt(c)<<4) | sqlite3HexToInt(d);
+    }
+  }
+
+ unhex_done:
+  sqlite3_result_blob(pCtx, pBlob, (p - pBlob), sqlite3_free);
+  return;
+
+ unhex_null:
+  sqlite3_free(pBlob);
+  return;
+}
+
+
 /*
 ** The zeroblob(N) function returns a zero-filled blob of size N bytes.
 */
@@ -2287,6 +2377,8 @@ void sqlite3RegisterBuiltinFunctions(void){
     FUNCTION(upper,              1, 0, 0, upperFunc        ),
     FUNCTION(lower,              1, 0, 0, lowerFunc        ),
     FUNCTION(hex,                1, 0, 0, hexFunc          ),
+    FUNCTION(unhex,              1, 0, 0, unhexFunc        ),
+    FUNCTION(unhex,              2, 0, 0, unhexFunc        ),
     INLINE_FUNC(ifnull,          2, INLINEFUNC_coalesce, 0 ),
     VFUNCTION(random,            0, 0, 0, randomFunc       ),
     VFUNCTION(randomblob,        1, 0, 0, randomBlob       ),

test/exprfault.test

@@ -31,5 +31,15 @@ do_faultsim_test 1.1 -faults oom* -prep {
   faultsim_test_result {0 {}}
 }
 
+do_faultsim_test 2 -faults oom* -prep {
+  faultsim_restore_and_reopen
+} -body {
+  execsql {
+    SELECT hex ( unhex('ABCDEF') );
+  }
+} -test {
+  faultsim_test_result {0 ABCDEF}
+}
+
 
 finish_test

test/unhex.test

@@ -0,0 +1,102 @@
+# 2023 January 23
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+
+set testdir [file dirname $argv0]
+source [file join $testdir tester.tcl]
+
+set testprefix unhex
+
+
+foreach {tn hex} {
+  1  0000
+  2  FFFF
+  3  0123456789ABCDEF
+} {
+  do_execsql_test 1.$tn.1 {
+    SELECT hex( unhex( $hex ) );
+  } $hex
+
+  do_execsql_test 1.$tn.2 {
+    SELECT hex( unhex( lower( $hex ) ) );
+  } $hex
+}
+
+do_execsql_test 2.0 {
+  SELECT typeof( unhex('') ), length( unhex('') );
+} {blob 0}
+
+foreach {tn hex} {
+  1  ABC
+  2  hello
+  3  123456x7
+  4  0xff
+} {
+  do_execsql_test 2.$tn {
+    SELECT unhex( $hex ) IS NULL;
+  } 1
+}
+
+do_catchsql_test 3.0 {
+  SELECT unhex();
+} {1 {wrong number of arguments to function unhex()}}
+do_catchsql_test 3.1 {
+  SELECT unhex('ABCD', '1234', '');
+} {1 {wrong number of arguments to function unhex()}}
+
+#--------------------------------------------------------------------------
+# Test the 2-argument version.
+#
+foreach {tn hex} {
+  1 "FFFF  ABCD"
+  2 "FFFF ABCD"
+  3 "FFFFABCD "
+  4 " FFFFABCD"
+  5 "--FFFF AB- -CD- "
+  6 "--"
+  7 " --"
+} {
+  set out ""
+  foreach x [split $hex ""] {
+    if {[string is xdigit $x]} { append out $x }
+  }
+
+  do_execsql_test 5.$tn.1 {
+    SELECT hex( unhex($hex, ' -') );
+  } [list $out]
+}
+
+do_execsql_test 6.0 {
+  SELECT typeof( unhex(' ', ' -') ), length( unhex('-', ' -') );
+} {blob 0}
+
+
+do_execsql_test 6.1 "
+  SELECT hex( unhex('\u0E01ABCD\u0E02', '\uE01\uE02') )
+" {ABCD}
+do_execsql_test 6.2 "
+  SELECT typeof( unhex('\u0E01ABCD\u0E02', '\uE03\uE02') )
+" {null}
+do_execsql_test 6.3 "
+  SELECT hex( unhex('\u0E01AB CD\uE02\uE01', '\uE01 \uE02') )
+" {ABCD}
+
+#--------------------------------------------------------------------------
+# Test that if either argument is NULL, the returned value is also NULL.
+#
+do_execsql_test 6.4.1 { SELECT typeof(unhex(NULL)) } {null}
+do_execsql_test 6.4.2 { SELECT typeof(unhex(NULL, ' ')) } {null}
+do_execsql_test 6.4.3 { SELECT typeof(unhex('1234', NULL)) } {null}
+
+
+finish_test
+
+