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Overview
Comment:Handle overflow and rounding cases in sqlite4_num_to_int64.
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SHA1: de7fb192cbd9aadba2c6608ff3d80f85177ece6c
User & Date: peterreid 2013-06-01 23:42:30
Context
2013-06-03
15:23
Merge overflow and rounding fixes for sqlite4_num_to_int64(). check-in: e8db1e81a4 user: dan tags: trunk
2013-06-01
23:42
Handle overflow and rounding cases in sqlite4_num_to_int64. check-in: de7fb192cb user: peterreid tags: trunk
23:35
Add tests for sqlite4_num_to_int64. check-in: 11fd3e7ec4 user: peterreid tags: trunk
Changes
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Changes to src/math.c.

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}

/*
** Convert the number passed as the first argument to a signed 64-bit
** integer and return the value. If the second argument is not NULL,
** then set the value that it points to 1 if data was lost as part
** of the conversion, or 0 otherwise.




*/
sqlite4_int64 sqlite4_num_to_int64(sqlite4_num num, int *pbLossy){
  static const i64 L10 = (LARGEST_INT64 / 10);
  i64 iRet;
  int i;
  iRet = num.m;

  if( pbLossy ){
    *pbLossy = (num.m==LARGEST_UINT64 || (num.m+num.sign)>(u64)LARGEST_INT64);


  }
  for(i=num.e; i<0; i++){
    if( pbLossy && (iRet % 10) ) *pbLossy = 1;
    iRet = iRet / 10;
  }
  for(i=0; i<num.e; i++){
    if( pbLossy && iRet>L10 ) *pbLossy = 1;
    iRet = iRet * 10;
  }








#define LARGEST_INT64  (0xffffffff|(((i64)0x7fffffff)<<32))
#define SMALLEST_INT64 (((i64)-1) - LARGEST_INT64)
#define LARGEST_UINT64  (0xffffffff|(((u64)0xffffffff)<<32))


  if( num.sign ) iRet = iRet*-1;
  return iRet;
}


/*
** Convert an integer into text in the buffer supplied. The
** text is zero-terminated and right-justified in the buffer.
** A pointer to the first character of text is returned.







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}

/*
** Convert the number passed as the first argument to a signed 64-bit
** integer and return the value. If the second argument is not NULL,
** then set the value that it points to 1 if data was lost as part
** of the conversion, or 0 otherwise.
**
** Values round towards 0. If the number is outside the range that a
** signed 64-bit integer can represent, it is clamped to be inside
** that range.
*/
sqlite4_int64 sqlite4_num_to_int64(sqlite4_num num, int *pbLossy){
  static const i64 L10 = (LARGEST_INT64 / 10);
  u64 iRet;
  int i;
  iRet = num.m;

  if( pbLossy ) *pbLossy = 0;
  for(i=0; i<num.e; i++){
    if( iRet>L10 ) goto overflow;
    iRet = iRet * 10;
  }
  for(i=num.e; i<0; i++){
    if( pbLossy && (iRet % 10) ) *pbLossy = 1;
    iRet = iRet / 10;
  }




  if( num.sign ){
    if( iRet>(u64)LARGEST_INT64+1 ) goto overflow;
    return -(i64)iRet;
  }else{
    if( iRet>(u64)LARGEST_INT64 ) goto overflow; 
    return (i64)iRet;
  }





overflow:
  if( pbLossy ) *pbLossy = 1;
  return num.sign ? -LARGEST_INT64-1 : LARGEST_INT64;
}


/*
** Convert an integer into text in the buffer supplied. The
** text is zero-terminated and right-justified in the buffer.
** A pointer to the first character of text is returned.

Changes to test/num.test.

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foreach {tn in out} {
  0     50                                            50
  1     -94                                           -94
  2     {sign:0 approx:0 e:4 m:2}                     20000
  3     9223372036854775807                           9223372036854775807
  4     -9223372036854775808                          -9223372036854775808
  5     {sign:0 approx:0 e:-1 m:51}                   ~5











} {
  do_test num-10.1.$tn { sqlite4_num_to_int64 $in } [list {*}$out]
}


#-------------------------------------------------------------------------
finish_test









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foreach {tn in out} {
  0     50                                            50
  1     -94                                           -94
  2     {sign:0 approx:0 e:4 m:2}                     20000
  3     9223372036854775807                           9223372036854775807
  4     -9223372036854775808                          -9223372036854775808
  5     {sign:0 approx:0 e:-1 m:51}                   ~5
  6     {sign:0 approx:0 e:0 m:9223372036854775808}  ~9223372036854775807
  7     9223372036854775808                          ~9223372036854775807
  8     10000000000000000000                         ~9223372036854775807
  9     -10000000000000000000                        ~-9223372036854775808
  10    {sign:0 approx:0 e:50 m:244}                 ~9223372036854775807
  11    {sign:1 approx:0 e:50 m:34220}               ~-9223372036854775808
  12    50.1                                         ~50
  13    10.9                                         ~10
  14    .995                                         ~0
  15    -93.9                                        ~-93
  16    -12.1                                        ~-12
} {
  do_test num-10.1.$tn { sqlite4_num_to_int64 $in } [list {*}$out]
}


#-------------------------------------------------------------------------
finish_test