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/* See LICENSE file for copyright and license details. */
#include "internals.h"
#include <stdio.h>
#define num libzahl_tmp_str_num
#define rem libzahl_tmp_str_rem
/* All 19 you see here is derived from that 10¹⁹ is the largest
* power of than < 2⁶⁴, and 64 is the number of bits in
* zahl_char_t. If zahl_char_t is chanced, the value 19, and
* the cast to unsigned long long must be changed accordingly. */
#define S1(P) P"0" P"1" P"2" P"3" P"4" P"5" P"6" P"7" P"8" P"9"
#define S2(P) S1(P"0")S1(P"1")S1(P"2")S1(P"3")S1(P"4")S1(P"5")S1(P"6")S1(P"7")S1(P"8")S1(P"9")
static inline O2 void
sprintint_fix(char *buf, zahl_char_t v)
{
const char *partials = S2("");
uint16_t *buffer = (uint16_t *)(buf + 1);
buffer[8] = *(const uint16_t *)(partials + 2 * (v % 100)), v /= 100;
buffer[7] = *(const uint16_t *)(partials + 2 * (v % 100)), v /= 100;
buffer[6] = *(const uint16_t *)(partials + 2 * (v % 100)), v /= 100;
buffer[5] = *(const uint16_t *)(partials + 2 * (v % 100)), v /= 100;
buffer[4] = *(const uint16_t *)(partials + 2 * (v % 100)), v /= 100;
buffer[3] = *(const uint16_t *)(partials + 2 * (v % 100)), v /= 100;
buffer[2] = *(const uint16_t *)(partials + 2 * (v % 100)), v /= 100;
buffer[1] = *(const uint16_t *)(partials + 2 * (v % 100)), v /= 100;
buffer[0] = *(const uint16_t *)(partials + 2 * (v % 100)), v /= 100;
*buf = (char)('0' + v);
buf[19] = 0;
}
static inline void
cmemmove(char *d, const char *s, long n)
{
while (n--)
*d++ = *s++;
}
static inline size_t
sprintint_min(char *buf, zahl_char_t v)
{
long i = 0, j;
sprintint_fix(buf, v);
for (; buf[i] == '0'; i++);
cmemmove(buf, buf + i, j = 19 - i);
buf[j] = 0;
return (size_t)j;
}
char *
zstr(z_t a, char *b)
{
char buf[19 + 1];
size_t n, len, neg;
char overridden = 0;
if (unlikely(zzero(a))) {
if (unlikely(!b) && unlikely(!(b = malloc(2))))
libzahl_memfailure();
b[0] = '0';
b[1] = 0;
return b;
}
n = zstr_length(a, 10);
if (unlikely(!b) && unlikely(!(b = malloc(n + 1))))
libzahl_memfailure();
neg = znegative(a);
zabs(num, a);
b[0] = '-';
b += neg;
n -= neg;
n = n > 19 ? (n - 19) : 0;
for (;;) {
zdivmod(num, rem, num, libzahl_const_1e19);
if (likely(!zzero(num))) {
sprintint_fix(b + n, zzero(rem) ? 0 : rem->chars[0]);
b[n + 19] = overridden;
overridden = b[n];
n = n > 19 ? (n - 19) : 0;
} else {
len = sprintint_min(buf, rem->chars[0]);
if (overridden)
buf[len] = b[n + len];
memcpy(b + n, buf, len + 1);
break;
}
}
return b - neg;
}
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