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Change -scanDouble: to call GSScanDouble() to perform conversion. Fix GSScanDouble to cope with leading zeros.

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This commit is contained in:
Richard Frith-Macdonald 2020-12-29 11:54:34 +00:00
parent 3a4948e1a2
commit 81021528e1
1 changed files with 63 additions and 47 deletions
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110
Source/NSScanner.m
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@ -113,6 +113,8 @@ typedef GSString *ivars;
(_scanLocation >= myLength()) ? NO : YES;\
})
BOOL GSScanDouble(unichar *buf, unsigned length, double *result);
/**
* <p>
* The <code>NSScanner</code> class cluster (currently a single class in
@ -787,12 +789,11 @@ typedef GSString *ivars;
*/
- (BOOL) scanDouble: (double *)value
{
unichar buf[2000];
unsigned pos = 0;
unichar c = 0;
double num = 0.0;
long int exponent = 0;
BOOL negative = NO;
BOOL got_dot = NO;
BOOL got_digit = NO;
BOOL digits = 0;
unsigned int saveScanLocation = _scanLocation;
/* Skip whitespace */
@ -811,37 +812,24 @@ typedef GSString *ivars;
_scanLocation++;
break;
case '-':
negative = YES;
_scanLocation++;
buf[pos++] = '-';
break;
}
}
/* Process number */
while (_scanLocation < myLength())
while (_scanLocation < myLength() && pos < 1050)
{
c = myCharacter(_scanLocation);
if ((c >= '0') && (c <= '9'))
{
/* Ensure that the number being accumulated will not overflow. */
if (num >= (DBL_MAX / 10.000000001))
{
++exponent;
}
else
{
num = (num * 10.0) + (c - '0');
got_digit = YES;
}
/* Keep track of the number of digits after the decimal point.
If we just divided by 10 here, we would lose precision. */
if (got_dot)
--exponent;
digits++;
buf[pos++] = c;
}
else if (!got_dot && (c == _decimal))
{
/* Note that we have found the decimal point. */
got_dot = YES;
buf[pos++] = '.';
}
else
{
@ -850,7 +838,7 @@ typedef GSString *ivars;
}
_scanLocation++;
}
if (!got_digit)
if (0 == digits)
{
_scanLocation = saveScanLocation;
return NO;
@ -859,38 +847,49 @@ typedef GSString *ivars;
/* Check for trailing exponent */
if ((_scanLocation < myLength()) && ((c == 'e') || (c == 'E')))
{
unsigned int expScanLocation = _scanLocation;
int expval;
unsigned saveExpLoc = _scanLocation;
unsigned saveExpPos = pos;
BOOL got_exp = NO;
buf[pos++] = c;
_scanLocation++;
if ([self _scanInt: &expval])
if (_scanLocation < myLength())
{
/* Check for exponent overflow */
if (num)
{
if ((exponent > 0) && (expval > (LONG_MAX - exponent)))
exponent = LONG_MAX;
else if ((exponent < 0) && (expval < (LONG_MIN - exponent)))
exponent = LONG_MIN;
else
exponent += expval;
}
switch (myCharacter(_scanLocation))
{
case '+':
_scanLocation++;
break;
case '-':
_scanLocation++;
buf[pos++] = '-';
break;
}
}
else
while (_scanLocation < myLength() && pos < 1060)
{
/* Numbers like 1.23eFOO are accepted (as 1.23). */
_scanLocation = expScanLocation;
c = myCharacter(_scanLocation);
if ((c < '0') || (c > '9'))
{
break;
}
got_exp = YES;
_scanLocation++;
buf[pos++] = c;
}
if (!got_exp)
{
/* No exponent found: the e/E terminated the number
*/
_scanLocation = saveExpLoc;
pos = saveExpPos;
}
}
if (value)
if (NO == GSScanDouble(buf, pos, value))
{
if (num && exponent)
num *= pow(10.0, (double) exponent);
if (negative)
*value = -num;
else
*value = num;
_scanLocation = saveScanLocation;
return NO;
}
return YES;
}
@ -1375,6 +1374,7 @@ GSScanDouble(unichar *buf, unsigned length, double *result)
int exponent = 0;
BOOL negativeMantissa = NO;
BOOL negativeExponent = NO;
unsigned shift = 0;
unsigned pos = 0;
int mantissaLength;
int dotPos = -1;
@ -1424,6 +1424,21 @@ GSScanDouble(unichar *buf, unsigned length, double *result)
{
mantissaLength++;
}
if (19 == mantissaLength)
{
if (dotPos > 0 && '0' == mantissa[0])
{
dotPos--;
mantissaLength--;
memmove(mantissa, mantissa + 1, 18);
}
else if (0 == dotPos && '0' == mantissa[1])
{
mantissaLength--;
shift++;
memmove(mantissa + 1, mantissa + 2, 17);
}
}
}
if (0 == mantissaLength)
{
@ -1506,6 +1521,7 @@ GSScanDouble(unichar *buf, unsigned length, double *result)
{
exponent = dotPos + exponent;
}
exponent -= shift;
if (exponent < 0)
{
negativeExponent = YES;