SQLite

/*
** Convert zNum to a 64-bit signed integer.  zNum must be decimal. This
** routine does *not* accept hexadecimal notation.
**
** Returns:
**
**     0    Successful transformation.  Fits in a 64-bit signed integer.
**     1    Excess non-space text after the integer value
**     2    Integer too large for a 64-bit signed integer or is malformed
**     3    Special case of 9223372036854775808
**
** 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.
*/

    }
  }
  zStart = zNum;
  while( zNum<zEnd && zNum[0]=='0' ){ zNum+=incr; } /* Skip leading zeros. */
  for(i=0; &zNum[i]<zEnd && (c=zNum[i])>='0' && c<='9'; i+=incr){
    u = u*10 + c - '0';
  }
  testcase( i==18*incr );
  testcase( i==19*incr );
  testcase( i==20*incr );
  if( neg ){
    *pNum = -(i64)u;
  }else{
    *pNum = (i64)u;
  }
  rc = 0;



  if( (i==0 && zStart==zNum)     /* No digits */
   || nonNum                     /* UTF16 with high-order bytes non-zero */
  ){
    rc = 1;
  }else if( &zNum[i]<zEnd ){     /* Extra bytes at the end */
    int jj = i;
    do{
      if( !sqlite3Isspace(zNum[jj]) ){
        rc = 1;          /* Extra non-space text after the integer */
        break;
      }
      jj += incr;
    }while( &zNum[jj]<zEnd );


  }
  if( i<19*incr ){
    /* Less than 19 digits, so we know that it fits in 64 bits */
    assert( u<=LARGEST_INT64 );
    return rc;
  }else{
    /* zNum is a 19-digit numbers.  Compare it against 9223372036854775808. */
    c = i>19*incr ? 1 : compare2pow63(zNum, incr);
    if( c<0 ){
      /* zNum is less than 9223372036854775808 so it fits */
      assert( u<=LARGEST_INT64 );
      return rc;
    }else{
      *pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
      if( c>0 ){
        /* zNum is greater than 9223372036854775808 so it overflows */
        return 2;
      }else{
        /* zNum is exactly 9223372036854775808.  Fits if negative.  The
        ** special case 2 overflow if positive */
        assert( u-1==LARGEST_INT64 );
        return neg ? rc : 3;
      }
    }
  }
}

/*
** Transform a UTF-8 integer literal, in either decimal or hexadecimal,
** into a 64-bit signed integer.  This routine accepts hexadecimal literals,

} {abc 0 abc}
do_test cast-4.4 {
  db eval {
    SELECT CAST(a AS integer), a, CAST(a AS real), a FROM t1;
  }
} {0 abc 0.0 abc}

# Added 2018-01-26
#
# EVIDENCE-OF: R-48741-32454 If the prefix integer is greater than
# +9223372036854775807 then the result of the cast is exactly
# +9223372036854775807.
do_execsql_test cast-5.1 {
  SELECT CAST('9223372036854775808' AS integer);
  SELECT CAST('  +000009223372036854775808' AS integer);
  SELECT CAST('12345678901234567890123' AS INTEGER);
} {9223372036854775807 9223372036854775807 9223372036854775807}

# EVIDENCE-OF: R-06028-16857 Similarly, if the prefix integer is less
# than -9223372036854775808 then the result of the cast is exactly
# -9223372036854775808.
do_execsql_test cast-5.2 {
  SELECT CAST('-9223372036854775808' AS integer);
  SELECT CAST('-9223372036854775809' AS integer);
  SELECT CAST('-12345678901234567890123' AS INTEGER);
} {-9223372036854775808 -9223372036854775808 -9223372036854775808}

# EVIDENCE-OF: R-33990-33527 When casting to INTEGER, if the text looks
# like a floating point value with an exponent, the exponent will be
# ignored because it is no part of the integer prefix.
# EVIDENCE-OF: R-24225-46995 For example, "(CAST '123e+5' AS INTEGER)"
# results in 123, not in 12300000.
do_execsql_test case-5.3 {
  SELECT CAST('123e+5' AS INTEGER);
  SELECT CAST('123e+5' AS NUMERIC);
} {123 12300000.0}


# The following does not have anything to do with the CAST operator,
# but it does deal with affinity transformations.
#
do_execsql_test case-6.1 {
  DROP TABLE IF EXISTS t1;
  CREATE TABLE t1(a NUMERIC);
  INSERT INTO t1 VALUES
     ('9000000000000000001'),
     ('9000000000000000001 '),
     (' 9000000000000000001'),
     (' 9000000000000000001 ');
  SELECT * FROM t1;
} {9000000000000000001 9000000000000000001 9000000000000000001 9000000000000000001}

finish_test