/*
* Parse the whole number portion of a number.
*
* 0
* [1-9][0-9]*
*/
static bool
_parseWholeNumber(PARCJSONParser *parser, int64_t *value)
{
bool result = false;
int sign = 1;
char nextCharacter;
if (parcJSONParser_Next(parser, &nextCharacter)) {
if (nextCharacter == '0') {
*value = 0;
result = true;
} else if (isdigit(nextCharacter)) {
*value = _digittoint(nextCharacter);
while (parcJSONParser_Next(parser, &nextCharacter)) {
if (!isdigit(nextCharacter)) {
parcJSONParser_Advance(parser, -1);
break;
}
*value = *value * 10 + _digittoint(nextCharacter);
}
*value = *value * sign;
result = true;
}
}
return result;
}
/*
* Scan a string of hexadecimal digits (the format nan(3) expects) and
* make a bit array (using the local endianness). We stop when we
* encounter an invalid character, NUL, etc. If we overflow, we do
* the same as gcc's __builtin_nan(), namely, discard the high order bits.
*
* The format this routine accepts needs to be compatible with what is used
* in contrib/gdtoa/hexnan.c (for strtod/scanf) and what is used in
* __builtin_nan(). In fact, we're only 100% compatible for strings we
* consider valid, so we might be violating the C standard. But it's
* impossible to use nan(3) portably anyway, so this seems good enough.
*/
void
_scan_nan(uint32_t *words, int num_words, const char *s)
{
int si; /* index into s */
int bitpos; /* index into words (in bits) */
bzero(words, num_words * sizeof(uint32_t));
/* Allow a leading '0x'. (It's expected, but redundant.) */
if (s[0] == '0' && (s[1] == 'x' || s[1] == 'X'))
s += 2;
/* Scan forwards in the string, looking for the end of the sequence. */
for (si = 0; isxdigit(s[si]); si++)
;
/* Scan backwards, filling in the bits in words[] as we go. */
#if _BYTE_ORDER == _LITTLE_ENDIAN
for (bitpos = 0; bitpos < 32 * num_words; bitpos += 4) {
#else
for (bitpos = 32 * num_words - 4; bitpos >= 0; bitpos -= 4) {
#endif
if (--si < 0)
break;
words[bitpos / 32] |= _digittoint(s[si]) << (bitpos % 32);
}
}
double
nan(const char *s)
{
union {
double d;
uint32_t bits[2];
} u;
_scan_nan(u.bits, 2, s);
#if _BYTE_ORDER == _LITTLE_ENDIAN
u.bits[1] |= 0x7ff80000;
#else
u.bits[0] |= 0x7ff80000;
#endif
return (u.d);
}
float
nanf(const char *s)
{
union {
float f;
uint32_t bits[1];
} u;
_scan_nan(u.bits, 1, s);
u.bits[0] |= 0x7fc00000;
return (u.f);
}
#if LDBL_MANT_DIG == DBL_MANT_DIG
__strong_alias(nanl, nan);
/**
* Parse and compute the base 10 value of a a sequence of digits from 0 to 9, inclusive.
*
* @param [in] parser A pointer to a PARCJSONParser instance.
* @param [out] value A pointer to a value that will receive the base 10 value.
*
* @return true If there were parsable digits.
*/
static bool
_parseDigits09(PARCJSONParser *parser, int64_t *value)
{
bool result = false;
*value = 0;
char nextDigit;
while (parcJSONParser_Next(parser, &nextDigit)) {
*value = *value * 10 + _digittoint(nextDigit);
result = true;
}
return result;
}
uint64_t
parcBuffer_ParseDecimalNumber(PARCBuffer *buffer)
{
char *bytes = parcBuffer_Overlay(buffer, 0);
int start = 0;
unsigned count = 0;
uint64_t result = 0;
for (int i = start; i < parcBuffer_Remaining(buffer) && isdigit(bytes[i]); i++) {
result = (result * 10) + _digittoint(bytes[i]);
count++;
}
parcBuffer_SetPosition(buffer, parcBuffer_Position(buffer) + count);
return result;
}
uint64_t
parcBuffer_ParseHexNumber(PARCBuffer *buffer)
{
char *bytes = parcBuffer_Overlay(buffer, 0);
int start = 0;
if (parcBuffer_Remaining(buffer) > 2) {
if (bytes[0] == '0' && bytes[1] == 'x') {
start = 2;
}
}
unsigned count = 0;
uint64_t result = 0;
for (int i = start; i < parcBuffer_Remaining(buffer) && isxdigit(bytes[i]); i++) {
result = (result * 16) + _digittoint(bytes[i]);
count++;
}
parcBuffer_SetPosition(buffer, parcBuffer_Position(buffer) + start + count);
return result;
}
static bool
_parseFractionNumber(PARCJSONParser *parser, int64_t *value, int *log10)
{
bool result = false;
if (parcJSONParser_Remaining(parser) > 0) {
*value = 0;
*log10 = 0;
char nextCharacter;
while (parcJSONParser_Next(parser, &nextCharacter)) {
if (!isdigit(nextCharacter)) {
parcJSONParser_Advance(parser, -1);
break;
}
*value = *value * 10 + _digittoint(nextCharacter);
*log10 = *log10 + 1;
}
result = true;
}
return result;
}
