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#include <assert.h>
#include <stdlib.h>
#include <float.h>
#include "xmlrpc-c/util.h"
#include "xmlrpc-c/util_int.h"
#include "double.h"
typedef struct {
char * bytes;
char * next;
char * end;
} buffer;
static void
bufferInit(buffer * const bufferP) {
unsigned int const initialSize = 64;
bufferP->bytes = calloc(1,initialSize);
if (bufferP->bytes) {
bufferP->next = bufferP->bytes;
bufferP->end = bufferP->bytes + initialSize;
}
}
static void
bufferConcat(buffer * const bufferP,
char const newChar) {
if (bufferP->bytes) {
if (bufferP->next >= bufferP->end) {
unsigned int const oldSize = bufferP->end - bufferP->bytes;
unsigned int const newSize = oldSize + 64;
bufferP->bytes = realloc(bufferP->bytes, newSize);
bufferP->next = bufferP->bytes + oldSize;
bufferP->end = bufferP->bytes + newSize;
}
if (bufferP->bytes)
*(bufferP->next++) = newChar;
}
}
static char
digitChar(unsigned int const digitValue) {
assert(digitValue < 10);
return '0' + digitValue;
}
static unsigned int
leadDigit(double const arg,
double const precision) {
/*----------------------------------------------------------------------------
Assuming 'arg' has one digit before the decimal point (which may be zero),
return that digit.
We assume the precision of 'arg' is plus or minus 'precision', and bias our
estimation of the first digit up. We do that bias in order to bias toward
shorter decimal ciphers: It's cleaner to consider 2.9999999 to be 3 than to
consider 3 to be 2.999999.
-----------------------------------------------------------------------------*/
return MIN(9, (unsigned int)(arg + precision));
}
static void
floatWhole(double const value,
buffer * const formattedP,
double * const formattedAmountP,
double * const precisionP) {
if (value < 1.0) {
/* No digits to add to the whole part */
*formattedAmountP = 0;
*precisionP = DBL_EPSILON;
} else {
double nonLeastAmount;
double nonLeastPrecision;
unsigned int leastValue;
/* Add all digits but the least significant to *formattedP */
floatWhole(value/10.0, formattedP, &nonLeastAmount,
&nonLeastPrecision);
/* Add the least significant digit to *formattedP */
if (nonLeastPrecision > 0.1) {
/* We're down in the noise now; no point in showing any more
significant digits (and we couldn't if we wanted to, because
nonLeastPrecision * 10 might be more than 10 less than
'value').
*/
leastValue = 0;
} else
leastValue = leadDigit(value - nonLeastAmount * 10,
nonLeastPrecision * 10);
bufferConcat(formattedP, digitChar(leastValue));
*formattedAmountP = nonLeastAmount * 10 + leastValue;
*precisionP = nonLeastPrecision * 10;
}
}
static void
floatFractionPart(double const value,
double const wholePrecision,
buffer * const formattedP) {
/*----------------------------------------------------------------------------
Serialize the part that comes after the decimal point, assuming there
is something (nonzero) before the decimal point that uses up all but
'wholePrecision' of the available precision.
-----------------------------------------------------------------------------*/
double precision;
double d;
assert(value < 1.0);
for (d = value, precision = wholePrecision;
d > precision;
precision *= 10) {
unsigned int digitValue;
d *= 10;
digitValue = leadDigit(d, precision);
d -= digitValue;
assert(d < 1.0);
bufferConcat(formattedP, digitChar(digitValue));
}
}
static void
floatFraction(double const value,
buffer * const formattedP) {
/*----------------------------------------------------------------------------
Serialize the part that comes after the decimal point, assuming there
is nothing before the decimal point.
-----------------------------------------------------------------------------*/
double precision;
double d;
assert(0.0 < value && value < 1.0);
/* Do the leading zeroes, which eat no precision */
for (d = value * 10; d < 1.0; d *= 10)
bufferConcat(formattedP, '0');
/* Now the significant digits */
precision = DBL_EPSILON;
while (d > precision) {
unsigned int const digitValue = leadDigit(d, precision);
bufferConcat(formattedP, digitChar(digitValue));
d -= digitValue;
assert(d < 1.0);
d *= 10;
precision *= 10;
}
}
void
xmlrpc_formatFloat(xmlrpc_env * const envP,
double const value,
const char ** const formattedP) {
double absvalue;
buffer formatted;
bufferInit(&formatted);
if (value < 0.0) {
bufferConcat(&formatted, '-');
absvalue = - value;
} else
absvalue = value;
if (absvalue >= 1.0) {
double wholePart, fractionPart;
double wholePrecision;
floatWhole(absvalue, &formatted, &wholePart, &wholePrecision);
fractionPart = absvalue - wholePart;
if (fractionPart > wholePrecision) {
bufferConcat(&formatted, '.');
floatFractionPart(fractionPart, wholePrecision, &formatted);
}
} else {
bufferConcat(&formatted, '0');
if (absvalue > 0.0) {
bufferConcat(&formatted, '.');
floatFraction(absvalue, &formatted);
}
}
bufferConcat(&formatted, '\0');
if (formatted.bytes == NULL)
xmlrpc_faultf(envP, "Couldn't allocate memory to format %g", value);
else
*formattedP = formatted.bytes;
}
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