BSON-XS
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bson/bson-decimal128.c view on Meta::CPAN
* Side effects:
* None.
*
*------------------------------------------------------------------------------
*/
static void
_bson_uint128_divide1B (_bson_uint128_t value, /* IN */
_bson_uint128_t *quotient, /* OUT */
uint32_t *rem) /* OUT */
{
const uint32_t DIVISOR = 1000 * 1000 * 1000;
uint64_t _rem = 0;
int i = 0;
if (!value.parts[0] && !value.parts[1] &&
!value.parts[2] && !value.parts[3]) {
*quotient = value;
*rem = 0;
return;
}
for (i = 0; i <= 3; i++) {
_rem <<= 32; /* Adjust remainder to match value of next dividend */
_rem += value.parts[i]; /* Add the divided to _rem */
value.parts[i] = (uint32_t)(_rem / DIVISOR);
_rem %= DIVISOR; /* Store the remainder */
}
*quotient = value;
*rem = _rem;
}
/**
*------------------------------------------------------------------------------
*
* bson_decimal128_to_string --
*
* This function converts a BID formatted decimal128 value to string,
* accepting a &bson_decimal128_t as @dec. The string is stored at @str.
*
* @dec : The BID formatted decimal to convert.
* @str : The output decimal128 string. At least %BSON_DECIMAL128_STRING characters.
*
* Returns:
* None.
*
* Side effects:
* None.
*
*------------------------------------------------------------------------------
*/
void
bson_decimal128_to_string (const bson_decimal128_t *dec, /* IN */
char *str) /* OUT */
{
uint32_t COMBINATION_MASK = 0x1f; /* Extract least significant 5 bits */
uint32_t EXPONENT_MASK = 0x3fff; /* Extract least significant 14 bits */
uint32_t COMBINATION_INFINITY = 30; /* Value of combination field for Inf */
uint32_t COMBINATION_NAN = 31; /* Value of combination field for NaN */
uint32_t EXPONENT_BIAS = 6176; /* decimal128 exponent bias */
char *str_out = str; /* output pointer in string */
char significand_str[35]; /* decoded significand digits */
/* Note: bits in this routine are referred to starting at 0, */
/* from the sign bit, towards the coefficient. */
uint32_t high; /* bits 0 - 31 */
uint32_t midh; /* bits 32 - 63 */
uint32_t midl; /* bits 64 - 95 */
uint32_t low; /* bits 96 - 127 */
uint32_t combination; /* bits 1 - 5 */
uint32_t biased_exponent; /* decoded biased exponent (14 bits) */
uint32_t significand_digits = 0; /* the number of significand digits */
uint32_t significand[36] = { 0 }; /* the base-10 digits in the significand */
uint32_t *significand_read = significand; /* read pointer into significand */
int32_t exponent; /* unbiased exponent */
int32_t scientific_exponent; /* the exponent if scientific notation is
* used */
bool is_zero = false; /* true if the number is zero */
uint8_t significand_msb; /* the most signifcant significand bits (50-46) */
_bson_uint128_t significand128; /* temporary storage for significand decoding */
size_t i; /* indexing variables */
int j, k;
memset (significand_str, 0, sizeof (significand_str));
if ((int64_t)dec->high < 0) { /* negative */
*(str_out++) = '-';
}
low = (uint32_t)dec->low,
midl = (uint32_t)(dec->low >> 32),
midh = (uint32_t)dec->high,
high = (uint32_t)(dec->high >> 32);
/* Decode combination field and exponent */
combination = (high >> 26) & COMBINATION_MASK;
if (BSON_UNLIKELY ((combination >> 3) == 3)) {
/* Check for 'special' values */
if (combination == COMBINATION_INFINITY) { /* Infinity */
strcpy (str_out, "Inf");
return;
} else if (combination == COMBINATION_NAN) { /* NaN */
/* str, not str_out, to erase the sign */
strcpy (str, "NaN");
/* we don't care about the NaN payload. */
return;
} else {
biased_exponent = (high >> 15) & EXPONENT_MASK;
significand_msb = 0x8 + ((high >> 14) & 0x1);
}
} else {
significand_msb = (high >> 14) & 0x7;
biased_exponent = (high >> 17) & EXPONENT_MASK;
}
exponent = biased_exponent - EXPONENT_BIAS;
/* Create string of significand digits */
/* Convert the 114-bit binary number represented by */
/* (high, midh, midl, low) to at most 34 decimal */
/* digits through modulo and division. */
significand128.parts[0] = (high & 0x3fff) + ((significand_msb & 0xf) << 14);
significand128.parts[1] = midh;
significand128.parts[2] = midl;
significand128.parts[3] = low;
if (significand128.parts[0] == 0 && significand128.parts[1] == 0 &&
significand128.parts[2] == 0 && significand128.parts[3] == 0) {
is_zero = true;
} else if (significand128.parts[0] >= (1 << 17)) {
/* The significand is non-canonical or zero.
* In order to preserve compatability with the densely packed decimal
* format, the maximum value for the significand of decimal128 is
* 1e34 - 1. If the value is greater than 1e34 - 1, the IEEE 754
* standard dictates that the significand is interpreted as zero.
*/
is_zero = true;
} else {
for (k = 3; k >= 0; k--) {
uint32_t least_digits = 0;
_bson_uint128_divide1B (significand128, &significand128,
&least_digits);
/* We now have the 9 least significant digits (in base 2). */
/* Convert and output to string. */
if (!least_digits) { continue; }
for (j = 8; j >= 0; j--) {
significand[k * 9 + j] = least_digits % 10;
least_digits /= 10;
}
}
}
/* Output format options: */
/* Scientific - [-]d.dddE(+/-)dd or [-]dE(+/-)dd */
/* Regular - ddd.ddd */
if (is_zero) {
significand_digits = 1;
*significand_read = 0;
} else {
significand_digits = 36;
while (!(*significand_read)) {
significand_digits--;
bson/bson-decimal128.c view on Meta::CPAN
/**
*------------------------------------------------------------------------------
*
* _dec128_tolower --
*
* This function converts the ASCII character @c to lowercase. It is locale
* insensitive (unlike the stdlib tolower).
*
* Returns:
* The lowercased character.
*/
char
_dec128_tolower (char c)
{
if (isupper (c)) {
c += 32;
}
return c;
}
/**
*------------------------------------------------------------------------------
*
* _dec128_istreq --
*
* This function compares the null-terminated *ASCII* strings @a and @b
* for case-insensitive equality.
*
* Returns:
* true if the strings are equal, false otherwise.
*/
bool
_dec128_istreq (const char *a, /* IN */
const char *b /* IN */)
{
while (*a != '\0' || *b != '\0') {
/* strings are different lengths. */
if (*a == '\0' || *b == '\0') {
return false;
}
if (_dec128_tolower (*a) != _dec128_tolower (*b)) {
return false;
}
a++;
b++;
}
return true;
}
/**
*------------------------------------------------------------------------------
*
* bson_decimal128_from_string --
*
* This function converts @string in the format [+-]ddd[.]ddd[E][+-]dddd to
* decimal128. Out of range values are converted to +/-Infinity. Invalid
* strings are converted to NaN.
*
* If more digits are provided than the available precision allows,
* round to the nearest expressable decimal128 with ties going to even will
* occur.
*
* Note: @string must be ASCII only!
*
* Returns:
* true on success, or false on failure. @dec will be NaN if @str was invalid
* The &bson_decimal128_t converted from @string at @dec.
*
* Side effects:
* None.
*
*------------------------------------------------------------------------------
*/
bool
bson_decimal128_from_string (const char *string, /* IN */
bson_decimal128_t *dec) /* OUT */
{
_bson_uint128_6464_t significand = { 0 };
const char *str_read = string; /* Read pointer for consuming str. */
/* Parsing state tracking */
bool is_negative = false;
bool saw_radix = false;
bool includes_sign = false; /* True if the input string contains a sign. */
bool found_nonzero = false;
size_t significant_digits = 0; /* Total number of significant digits
* (no leading or trailing zero) */
size_t ndigits_read = 0; /* Total number of significand digits read */
size_t ndigits = 0; /* Total number of digits (no leading zeros) */
size_t radix_position = 0; /* The number of the digits after radix */
size_t first_nonzero = 0; /* The index of the first non-zero in *str* */
uint16_t digits[BSON_DECIMAL128_MAX_DIGITS] = { 0 };
uint16_t ndigits_stored = 0; /* The number of digits in digits */
uint16_t *digits_insert = digits; /* Insertion pointer for digits */
size_t first_digit = 0; /* The index of the first non-zero digit */
size_t last_digit = 0; /* The index of the last digit */
int32_t exponent = 0;
size_t i = 0; /* loop index over array */
uint64_t significand_high = 0; /* The high 17 digits of the significand */
uint64_t significand_low = 0; /* The low 17 digits of the significand */
uint16_t biased_exponent = 0; /* The biased exponent */
BSON_ASSERT (dec);
dec->high = 0;
dec->low = 0;
if (*str_read == '+' || *str_read == '-') {
is_negative = *(str_read++) == '-';
includes_sign = true;
}
/* Check for Infinity or NaN */
if (!isdigit (*str_read) && *str_read != '.') {
if (_dec128_istreq (str_read, "inf") ||
_dec128_istreq (str_read, "infinity")) {
BSON_DECIMAL128_SET_INF (*dec, is_negative);
return true;
} else if (_dec128_istreq (str_read, "nan")) {
BSON_DECIMAL128_SET_NAN (*dec);
return true;
}
BSON_DECIMAL128_SET_NAN (*dec);
return false;
}
/* Read digits */
while (isdigit (*str_read) || *str_read == '.') {
if (*str_read == '.') {
if (saw_radix) {
BSON_DECIMAL128_SET_NAN (*dec);
return false;
}
saw_radix = true;
str_read++;
continue;
}
if (ndigits_stored < 34) {
if (*str_read != '0' || found_nonzero) {
if (!found_nonzero) {
first_nonzero = ndigits_read;
}
found_nonzero = true;
*(digits_insert++) = *(str_read) - '0'; /* Only store 34 digits */
ndigits_stored++;
}
}
if (found_nonzero) {
ndigits++;
}
if (saw_radix) {
radix_position++;
}
ndigits_read++;
str_read++;
}
if (saw_radix && !ndigits_read) {
BSON_DECIMAL128_SET_NAN (*dec);
return false;
}
/* Read exponent if exists */
if (*str_read == 'e' || *str_read == 'E') {
int nread = 0;
#ifdef _MSC_VER
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