SQLite

** floating point value of rValue.  Return true and set *piValue to the
** integer value if the string is in range to be an integer.  Otherwise,
** return false.
*/
static int alsoAnInt(Mem *pRec, double rValue, i64 *piValue){
  i64 iValue = (double)rValue;
  if( sqlite3RealSameAsInt(rValue,iValue) ){








    *piValue = iValue;
    return 1;

  }
  return 0==sqlite3Atoi64(pRec->z, piValue, pRec->n, pRec->enc);
}

/*
** Try to convert a value into a numeric representation if we can
** do so without loss of information.  In other words, if the string

**
** For some versions of GCC on 32-bit machines, if you do the more obvious
** comparison of "r1==(double)i" you sometimes get an answer of false even
** though the r1 and (double)i values are bit-for-bit the same.
*/
int sqlite3RealSameAsInt(double r1, sqlite3_int64 i){
  double r2 = (double)i;
  return memcmp(&r1, &r2, sizeof(r1))==0
      && i > -2251799813685248 && i < 2251799813685248;
}

/*
** Convert pMem so that it has type MEM_Real or MEM_Int.
** Invalidate any prior representations.
**
** Every effort is made to force the conversion, even if the input

  testcase( pMem->flags & MEM_Null );
  if( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null))==0 ){
    int rc;
    sqlite3_int64 ix;
    assert( (pMem->flags & (MEM_Blob|MEM_Str))!=0 );
    assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
    rc = sqlite3AtoF(pMem->z, &pMem->u.r, pMem->n, pMem->enc);

    if( ((rc==0 || rc==1) && sqlite3Atoi64(pMem->z, &ix, pMem->n, pMem->enc)<=1)
     || sqlite3RealSameAsInt(pMem->u.r, (ix = (i64)pMem->u.r))





    ){
      pMem->u.i = ix;
      MemSetTypeFlag(pMem, MEM_Int);
    }else{
      MemSetTypeFlag(pMem, MEM_Real);
    }
  }
  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null))!=0 );

# 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);
  SELECT CAST('123e+5' AS REAL);
} {123 12300000 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;

} {-2851427734582196970}
do_execsql_test case-7.11 {
  SELECT 0 - 2851427734582196970;
} {-2851427734582196970}
do_execsql_test case-7.12 {
  SELECT '' - 1;
} {-1}

# 2019-06-10
# https://www.sqlite.org/src/info/dd6bffbfb6e61db9
#
# EVIDENCE-OF: R-09295-61337 Casting a TEXT or BLOB value into NUMERIC
# first does a forced conversion into REAL but then further converts the
# result into INTEGER if and only if the conversion from REAL to INTEGER
# is lossless and reversible.
#
do_execsql_test cast-7.20 {
  DROP TABLE IF EXISTS t0;
  CREATE TABLE t0 (c0 TEXT);
  INSERT INTO t0(c0) VALUES ('1.0');
  SELECT CAST(c0 AS NUMERIC) FROM t0;
} {1}

finish_test

# EVIDENCE-OF: R-09295-61337 Casting a TEXT or BLOB value into NUMERIC
# first does a forced conversion into REAL but then further converts the
# result into INTEGER if and only if the conversion from REAL to INTEGER
# is lossless and reversible.
#
do_expr_test e_expr-32.1.1 { CAST('45'   AS NUMERIC)  } integer 45
do_expr_test e_expr-32.1.2 { CAST('45.0' AS NUMERIC)  } integer 45
do_expr_test e_expr-32.1.3 { CAST('45.2' AS NUMERIC)  } real 45.2
do_expr_test e_expr-32.1.4 { CAST('11abc' AS NUMERIC) } integer 11
do_expr_test e_expr-32.1.5 { CAST('11.1abc' AS NUMERIC) } real 11.1

# EVIDENCE-OF: R-30347-18702 Casting a REAL or INTEGER value to NUMERIC
# is a no-op, even if a real value could be losslessly converted to an
# integer.

 integer 9223372036854775807 \
 integer 9223372036854775807 \
 integer 9223372036854775807 \
 real 9.22337203685478e+18 \
 real 9.22337203685478e+18 \
 real 9.22337203685478e+18 \
 real 9.22337203685478e+18 \
 integer -5 \
 integer -5 \
]

# EVIDENCE-OF: R-64550-29191 Note that the result from casting any
# non-BLOB value into a BLOB and the result from casting any BLOB value
# into a non-BLOB value may be different depending on whether the
# database encoding is UTF-8, UTF-16be, or UTF-16le.
#