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SQLite training in Houston TX on 2019-11-05 (details)
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Overview
Comment:Fix text-to-numeric type casting so that it works correctly on UTF16 strings that contain characters where the LSB is numeric but the MSB is non-zero. Ticket [689137afb6da41]
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SHA1: 5b22053f918d16f593227a432a5d5b4c195bb0b5
User & Date: drh 2013-03-20 12:04:29
Context
2013-03-21
21:20
Many spelling fixes in comments. No changes to code. check-in: 6f6e2d50 user: mistachkin tags: trunk
2013-03-20
12:04
Fix text-to-numeric type casting so that it works correctly on UTF16 strings that contain characters where the LSB is numeric but the MSB is non-zero. Ticket [689137afb6da41] check-in: 5b22053f user: drh tags: trunk
2013-03-19
16:12
Bring makefiles and build scripts into alignment with the sessions branch. No changes to code. check-in: d1f41089 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/util.c.

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**
** If some prefix of the input string is a valid number, this routine
** returns FALSE but it still converts the prefix and writes the result
** into *pResult.
*/
int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
#ifndef SQLITE_OMIT_FLOATING_POINT
  int incr = (enc==SQLITE_UTF8?1:2);
  const char *zEnd = z + length;
  /* sign * significand * (10 ^ (esign * exponent)) */
  int sign = 1;    /* sign of significand */
  i64 s = 0;       /* significand */
  int d = 0;       /* adjust exponent for shifting decimal point */
  int esign = 1;   /* sign of exponent */
  int e = 0;       /* exponent */
  int eValid = 1;  /* True exponent is either not used or is well-formed */
  double result;
  int nDigits = 0;



  *pResult = 0.0;   /* Default return value, in case of an error */

  if( enc==SQLITE_UTF16BE ) z++;











  /* skip leading spaces */
  while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
  if( z>=zEnd ) return 0;

  /* get sign of significand */
  if( *z=='-' ){
................................................................................
    }
  }

  /* store the result */
  *pResult = result;

  /* return true if number and no extra non-whitespace chracters after */
  return z>=zEnd && nDigits>0 && eValid;
#else
  return !sqlite3Atoi64(z, pResult, length, enc);
#endif /* SQLITE_OMIT_FLOATING_POINT */
}

/*
** Compare the 19-character string zNum against the text representation
................................................................................
** integer, then write that value into *pNum and return 0.
**
** If zNum is exactly 9223372036854665808, return 2.  This special
** case is broken out because while 9223372036854665808 cannot be a 
** signed 64-bit integer, its negative -9223372036854665808 can be.
**
** If zNum is too big for a 64-bit integer and is not

** 9223372036854665808 then return 1.
**
** length is the number of bytes in the string (bytes, not characters).
** The string is not necessarily zero-terminated.  The encoding is
** given by enc.
*/
int sqlite3Atoi64(const char *zNum, i64 *pNum, int length, u8 enc){
  int incr = (enc==SQLITE_UTF8?1:2);
  u64 u = 0;
  int neg = 0; /* assume positive */
  int i;
  int c = 0;

  const char *zStart;
  const char *zEnd = zNum + length;

  if( enc==SQLITE_UTF16BE ) zNum++;









  while( zNum<zEnd && sqlite3Isspace(*zNum) ) zNum+=incr;
  if( zNum<zEnd ){
    if( *zNum=='-' ){
      neg = 1;
      zNum+=incr;
    }else if( *zNum=='+' ){
      zNum+=incr;
................................................................................
    *pNum = -(i64)u;
  }else{
    *pNum = (i64)u;
  }
  testcase( i==18 );
  testcase( i==19 );
  testcase( i==20 );
  if( (c!=0 && &zNum[i]<zEnd) || (i==0 && zStart==zNum) || i>19*incr ){
    /* zNum is empty or contains non-numeric text or is longer
    ** than 19 digits (thus guaranteeing that it is too large) */
    return 1;
  }else if( i<19*incr ){
    /* Less than 19 digits, so we know that it fits in 64 bits */
    assert( u<=LARGEST_INT64 );
    return 0;







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**
** If some prefix of the input string is a valid number, this routine
** returns FALSE but it still converts the prefix and writes the result
** into *pResult.
*/
int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
#ifndef SQLITE_OMIT_FLOATING_POINT
  int incr;
  const char *zEnd = z + length;
  /* sign * significand * (10 ^ (esign * exponent)) */
  int sign = 1;    /* sign of significand */
  i64 s = 0;       /* significand */
  int d = 0;       /* adjust exponent for shifting decimal point */
  int esign = 1;   /* sign of exponent */
  int e = 0;       /* exponent */
  int eValid = 1;  /* True exponent is either not used or is well-formed */
  double result;
  int nDigits = 0;
  int nonNum = 0;

  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
  *pResult = 0.0;   /* Default return value, in case of an error */

  if( enc==SQLITE_UTF8 ){
    incr = 1;
  }else{
    int i;
    incr = 2;
    assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
    for(i=3-enc; i<length && z[i]==0; i+=2){}
    nonNum = i<length;
    zEnd = z+i+enc-3;
    z += (enc&1);
  }

  /* skip leading spaces */
  while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
  if( z>=zEnd ) return 0;

  /* get sign of significand */
  if( *z=='-' ){
................................................................................
    }
  }

  /* store the result */
  *pResult = result;

  /* return true if number and no extra non-whitespace chracters after */
  return z>=zEnd && nDigits>0 && eValid && nonNum==0;
#else
  return !sqlite3Atoi64(z, pResult, length, enc);
#endif /* SQLITE_OMIT_FLOATING_POINT */
}

/*
** Compare the 19-character string zNum against the text representation
................................................................................
** integer, then write that value into *pNum and return 0.
**
** If zNum is exactly 9223372036854665808, return 2.  This special
** case is broken out because while 9223372036854665808 cannot be a 
** signed 64-bit integer, its negative -9223372036854665808 can be.
**
** If zNum is too big for a 64-bit integer and is not
** 9223372036854665808  or if zNum contains any non-numeric text,
** then return 1.
**
** length is the number of bytes in the string (bytes, not characters).
** The string is not necessarily zero-terminated.  The encoding is
** given by enc.
*/
int sqlite3Atoi64(const char *zNum, i64 *pNum, int length, u8 enc){
  int incr;
  u64 u = 0;
  int neg = 0; /* assume positive */
  int i;
  int c = 0;
  int nonNum = 0;
  const char *zStart;
  const char *zEnd = zNum + length;
  assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
  if( enc==SQLITE_UTF8 ){
    incr = 1;
  }else{
    incr = 2;
    assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
    for(i=3-enc; i<length && zNum[i]==0; i+=2){}
    nonNum = i<length;
    zEnd = zNum+i+enc-3;
    zNum += (enc&1);
  }
  while( zNum<zEnd && sqlite3Isspace(*zNum) ) zNum+=incr;
  if( zNum<zEnd ){
    if( *zNum=='-' ){
      neg = 1;
      zNum+=incr;
    }else if( *zNum=='+' ){
      zNum+=incr;
................................................................................
    *pNum = -(i64)u;
  }else{
    *pNum = (i64)u;
  }
  testcase( i==18 );
  testcase( i==19 );
  testcase( i==20 );
  if( (c+nonNum!=0 && &zNum[i]<zEnd) || (i==0 && zStart==zNum) || i>19*incr ){
    /* zNum is empty or contains non-numeric text or is longer
    ** than 19 digits (thus guaranteeing that it is too large) */
    return 1;
  }else if( i<19*incr ){
    /* Less than 19 digits, so we know that it fits in 64 bits */
    assert( u<=LARGEST_INT64 );
    return 0;

Added test/numcast.test.





























































































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# 2013 March 20
#
# 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.
#
#***********************************************************************
# This file implements regression tests for SQLite library. 
# This particular file does testing of casting strings into numeric
# values.
#

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

foreach enc {utf8 utf16le utf16be} {
  do_test numcast-$enc.0 {
    db close
    sqlite3 db :memory:
    db eval "PRAGMA encoding='$enc'"
    set x [db eval {PRAGMA encoding}]
    string map {- {}} [string tolower $x]
  } $enc
  foreach {idx str rval ival} {
     1 12345.0       12345.0    12345
     2 12345.0e0     12345.0    12345
     3 -12345.0e0   -12345.0   -12345
     4 -12345.25    -12345.25  -12345
     5 { -12345.0}  -12345.0   -12345
     6 { 876xyz}       876.0      876
     7 { 456ķ89}       456.0      456
     8 { Ġ 321.5}        0.0        0
  } {
    do_test numcast-$enc.$idx.1 {
      db eval {SELECT CAST($str AS real)}
    } $rval
    do_test numcast-$enc.$idx.2 {
      db eval {SELECT CAST($str AS integer)}
    } $ival
  }
}

finish_test