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fixed problems with parse_float() (fd.o bug 2520)

This commit is contained in:
Brian Paul 2005-02-16 15:08:29 +00:00
parent 2c28dd892c
commit 1ff8f50f2f
1 changed files with 48 additions and 27 deletions
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75
src/mesa/shader/arbprogparse.c
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@ -686,39 +686,60 @@ parse_integer (GLubyte ** inst, struct arb_program *Program)
}
/**
Accumulate this string of digits, and return them as
a large integer represented in floating point (for range).
If scale is not NULL, also accumulates a power-of-ten
integer scale factor that represents the number of digits
in the string.
*/
static GLdouble
parse_float_string(GLubyte ** inst, struct arb_program *Program, GLdouble *scale)
{
GLdouble value = 0.0;
GLdouble oscale = 1.0;
if (**inst == 0) { /* this string of digits is empty-- do nothing */
(*inst)++;
}
else { /* nonempty string-- parse out the digits */
while (isdigit(**inst)) {
GLubyte digit = *((*inst)++);
value = value * 10.0 + (GLint) (digit - '0');
oscale *= 10.0;
}
assert(**inst == 0); /* integer string should end with 0 */
(*inst)++; /* skip over terminating 0 */
Program->Position = parse_position(inst); /* skip position (from integer) */
}
if (scale)
*scale = oscale;
return value;
}
/**
Parse an unsigned floating-point number from this stream of tokenized
characters. Example floating-point formats supported:
12.34
12
0.34
.34
12.34e-4
*/
static GLfloat
parse_float (GLubyte ** inst, struct arb_program *Program)
{
GLint tmp[5], denom;
GLuint leading_zeros =0;
GLfloat value = 0;
GLint exponent;
GLdouble whole, fraction, fracScale = 1.0;
tmp[1] = parse_integer (inst, Program); /* This is the integer portion of the number */
whole = parse_float_string(inst, Program, 0);
fraction = parse_float_string(inst, Program, &fracScale);
/* Parse signed exponent */
exponent = parse_integer(inst, Program); /* This is the exponent */
/* Now we grab the fractional portion of the number (the digits after
* the .). We can have leading 0's here, which parse_integer will ignore,
* so we'll check for those first
*/
while ((**inst == '0') && ( *(*inst+1) != 0))
{
leading_zeros++;
(*inst)++;
}
tmp[2] = parse_integer (inst, Program); /* This is the fractional portion of the number */
tmp[3] = parse_sign (inst); /* This is the sign of the exponent */
tmp[4] = parse_integer (inst, Program); /* This is the exponent */
value = (GLfloat) tmp[1];
denom = 1;
while (denom < tmp[2])
denom *= 10;
denom *= (GLint) _mesa_pow( 10, leading_zeros );
value += (GLfloat) tmp[2] / (GLfloat) denom;
value *= (GLfloat) _mesa_pow (10, (GLfloat) tmp[3] * (GLfloat) tmp[4]);
return value;
/* Assemble parts of floating-point number: */
return (GLfloat) ((whole + fraction / fracScale) *
_mesa_pow(10.0, (GLfloat) exponent));
}