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Overview
Comment:Improved rounding accuracy on text-to-float conversions.
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SHA1:699b792c6a0e989994549959b11ec1bfad8bbd92
User & Date: drh 2012-06-19 00:45:16
Original Comment: Improved rounding accuracy on test-to-float conversions.
Context
2012-06-19
06:35
Add tests to check that the "unicode61" and "icu" tokenizers both identify white-space codepoints outside the ASCII range. check-in: bfb2d473 user: dan tags: trunk
03:11
Improved accuracy on text-to-real and real-to-text conversions. Most conversions now round-trip correctly. Still need to fix some corner cases. check-in: 8ecffca9 user: drh tags: floating-point-conversions
00:45
Improved rounding accuracy on text-to-float conversions. check-in: 699b792c user: drh tags: trunk
2012-06-18
20:52
Fix a problem with identifying white-space characters outside of the ascii range in the ICU tokenizer. check-in: 892b7411 user: dan tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/test_func.c.

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    sqlite3_result_error_nomem(pCtx);
  }else{
    testHexToBin(zIn, zOut);
    sqlite3_result_text16le(pCtx, zOut, n/2, sqlite3_free);
  }
}
#endif






































static int registerTestFunctions(sqlite3 *db){
  static const struct {
     char *zName;
     signed char nArg;
     unsigned char eTextRep; /* 1: UTF-16.  0: UTF-8 */
     void (*xFunc)(sqlite3_context*,int,sqlite3_value **);
................................................................................
    { "test_destructor_count", 0, SQLITE_UTF8, test_destructor_count},
    { "test_auxdata",         -1, SQLITE_UTF8, test_auxdata},
    { "test_error",            1, SQLITE_UTF8, test_error},
    { "test_error",            2, SQLITE_UTF8, test_error},
    { "test_eval",             1, SQLITE_UTF8, test_eval},
    { "test_isolation",        2, SQLITE_UTF8, test_isolation},
    { "test_counter",          1, SQLITE_UTF8, counterFunc},

  };
  int i;

  for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
    sqlite3_create_function(db, aFuncs[i].zName, aFuncs[i].nArg,
        aFuncs[i].eTextRep, 0, aFuncs[i].xFunc, 0, 0);
  }







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    sqlite3_result_error_nomem(pCtx);
  }else{
    testHexToBin(zIn, zOut);
    sqlite3_result_text16le(pCtx, zOut, n/2, sqlite3_free);
  }
}
#endif

/*
** SQL function:   real2hex(X)
**
** If argument X is a real number, then convert it into a string which is
** the big-endian hexadecimal representation of the ieee754 encoding of
** that number.  If X is not a real number, return NULL.
*/
static void real2hex(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  union {
    sqlite3_uint64 i;
    double r;
    unsigned char x[8];
  } v;
  char zOut[20];
  int i;
  int bigEndian;
  v.i = 1;
  bigEndian = v.x[0]==0;
  v.r = sqlite3_value_double(argv[0]);
  for(i=0; i<8; i++){
    if( bigEndian ){
      zOut[i*2]   = "0123456789abcdef"[v.x[i]>>4];
      zOut[i*2+1] = "0123456789abcdef"[v.x[i]&0xf];
    }else{
      zOut[14-i*2]   = "0123456789abcdef"[v.x[i]>>4];
      zOut[14-i*2+1] = "0123456789abcdef"[v.x[i]&0xf];
    }
  }
  zOut[16] = 0;
  sqlite3_result_text(context, zOut, -1, SQLITE_TRANSIENT);
}


static int registerTestFunctions(sqlite3 *db){
  static const struct {
     char *zName;
     signed char nArg;
     unsigned char eTextRep; /* 1: UTF-16.  0: UTF-8 */
     void (*xFunc)(sqlite3_context*,int,sqlite3_value **);
................................................................................
    { "test_destructor_count", 0, SQLITE_UTF8, test_destructor_count},
    { "test_auxdata",         -1, SQLITE_UTF8, test_auxdata},
    { "test_error",            1, SQLITE_UTF8, test_error},
    { "test_error",            2, SQLITE_UTF8, test_error},
    { "test_eval",             1, SQLITE_UTF8, test_eval},
    { "test_isolation",        2, SQLITE_UTF8, test_isolation},
    { "test_counter",          1, SQLITE_UTF8, counterFunc},
    { "real2hex",              1, SQLITE_UTF8, real2hex},
  };
  int i;

  for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
    sqlite3_create_function(db, aFuncs[i].zName, aFuncs[i].nArg,
        aFuncs[i].eTextRep, 0, aFuncs[i].xFunc, 0, 0);
  }

Changes to src/util.c.

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    /* adjust the sign of significand */
    s = sign<0 ? -s : s;

    /* if exponent, scale significand as appropriate
    ** and store in result. */
    if( e ){
      double scale = 1.0;
      /* attempt to handle extremely small/large numbers better */
      if( e>307 && e<342 ){
        while( e%308 ) { scale *= 1.0e+1; e -= 1; }
        if( esign<0 ){
          result = s / scale;
          result /= 1.0e+308;
        }else{







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    /* adjust the sign of significand */
    s = sign<0 ? -s : s;

    /* if exponent, scale significand as appropriate
    ** and store in result. */
    if( e ){
      LONGDOUBLE_TYPE scale = 1.0;
      /* attempt to handle extremely small/large numbers better */
      if( e>307 && e<342 ){
        while( e%308 ) { scale *= 1.0e+1; e -= 1; }
        if( esign<0 ){
          result = s / scale;
          result /= 1.0e+308;
        }else{

Added test/atof1.test.









































































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# 2012 June 18
#
# 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.
#
#***********************************************************************
# 
# Tests of the sqlite3AtoF() function.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

expr srand(1)
for {set i 1} {$i<10000} {incr i} {
  do_test 1.$i {
    set pow [expr {int((rand()-0.5)*100)}]
    set x [expr {pow((rand()-0.5)*2*rand(),$pow)}]
    set xf [format %.45e $x]
    set y [db eval "SELECT $xf=\$x"]
    if {!$y} {
      puts -nonewline \173[db eval "SELECT real2hex($xf), real2hex(\$x)"]\175
      db eval "SELECT $xf+0.0 AS a, \$x AS b" {
        puts [format "\n%.60e\n%.60e\n%.60e" $x $a $b]
      }
    }
    set y
  } {1}
}


finish_test