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Improve number to string conversions #400

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Merged
merged 1 commit into from
May 26, 2024
Merged

Improve number to string conversions #400

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31 changes: 27 additions & 4 deletions cutils.c
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Original file line number Diff line number Diff line change
Expand Up @@ -575,6 +575,9 @@ size_t utf8_encode_buf16(char *dest, size_t dest_len, const uint16_t *src, size_
/* 2 <= base <= 36 */
char const digits36[36] = "0123456789abcdefghijklmnopqrstuvwxyz";

#define USE_SPECIAL_RADIX_10 1 // special case base 10 radix conversions
#define USE_SINGLE_CASE_FAST 1 // special case single digit numbers

/* using u32toa_shift variant */

#define gen_digit(buf, c) if (is_be()) \
Expand Down Expand Up @@ -613,11 +616,13 @@ size_t u07toa_shift(char dest[minimum_length(8)], uint32_t n, size_t len)

size_t u32toa(char buf[minimum_length(11)], uint32_t n)
{
#ifdef USE_SINGLE_CASE_FAST /* 10% */
if (n < 10) {
buf[0] = (char)('0' + n);
buf[1] = '\0';
return 1;
}
#endif
#define TEN_POW_7 10000000
if (n >= TEN_POW_7) {
uint32_t quo = n / TEN_POW_7;
Expand Down Expand Up @@ -679,6 +684,8 @@ static uint8_t const radix_shift[64] = {

size_t u32toa_radix(char buf[minimum_length(33)], uint32_t n, unsigned base)
{
int shift;

#ifdef USE_SPECIAL_RADIX_10
if (likely(base == 10))
return u32toa(buf, n);
Expand All @@ -688,13 +695,13 @@ size_t u32toa_radix(char buf[minimum_length(33)], uint32_t n, unsigned base)
buf[1] = '\0';
return 1;
}
int shift = radix_shift[base & 63];
shift = radix_shift[base & 63];
if (shift) {
uint32_t mask = (1 << shift) - 1;
size_t len = (32 - clz32(n) + shift - 1) / shift;
size_t last = n & mask;
n /= base;
char *end = buf + len;
n >>= shift;
*end-- = '\0';
*end-- = digits36[last];
while (n >= base) {
Expand Down Expand Up @@ -728,11 +735,13 @@ size_t u32toa_radix(char buf[minimum_length(33)], uint32_t n, unsigned base)

size_t u64toa_radix(char buf[minimum_length(65)], uint64_t n, unsigned base)
{
int shift;

#ifdef USE_SPECIAL_RADIX_10
if (likely(base == 10))
return u64toa(buf, n);
#endif
int shift = radix_shift[base & 63];
shift = radix_shift[base & 63];
if (shift) {
if (n < base) {
buf[0] = digits36[n];
Expand All @@ -742,8 +751,8 @@ size_t u64toa_radix(char buf[minimum_length(65)], uint64_t n, unsigned base)
uint64_t mask = (1 << shift) - 1;
size_t len = (64 - clz64(n) + shift - 1) / shift;
size_t last = n & mask;
n /= base;
char *end = buf + len;
n >>= shift;
*end-- = '\0';
*end-- = digits36[last];
while (n >= base) {
Expand Down Expand Up @@ -777,6 +786,15 @@ size_t u64toa_radix(char buf[minimum_length(65)], uint64_t n, unsigned base)
}
}

size_t i32toa_radix(char buf[minimum_length(34)], int32_t n, unsigned int base)
{
if (likely(n >= 0))
return u32toa_radix(buf, n, base);

buf[0] = '-';
return 1 + u32toa_radix(buf + 1, -(uint32_t)n, base);
}

size_t i64toa_radix(char buf[minimum_length(66)], int64_t n, unsigned int base)
{
if (likely(n >= 0))
Expand All @@ -786,6 +804,11 @@ size_t i64toa_radix(char buf[minimum_length(66)], int64_t n, unsigned int base)
return 1 + u64toa_radix(buf + 1, -(uint64_t)n, base);
}

#undef gen_digit
#undef TEN_POW_7
#undef USE_SPECIAL_RADIX_10
#undef USE_SINGLE_CASE_FAST

/*---- sorting with opaque argument ----*/

typedef void (*exchange_f)(void *a, void *b, size_t size);
Expand Down
1 change: 1 addition & 0 deletions cutils.h
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Original file line number Diff line number Diff line change
Expand Up @@ -463,6 +463,7 @@ size_t i32toa(char buf[minimum_length(12)], int32_t n);
size_t u64toa(char buf[minimum_length(21)], uint64_t n);
size_t i64toa(char buf[minimum_length(22)], int64_t n);
size_t u32toa_radix(char buf[minimum_length(33)], uint32_t n, unsigned int base);
size_t i32toa_radix(char buf[minimum_length(34)], int32_t n, unsigned base);
size_t u64toa_radix(char buf[minimum_length(65)], uint64_t n, unsigned int base);
size_t i64toa_radix(char buf[minimum_length(66)], int64_t n, unsigned int base);

Expand Down
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