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#include <gu/bits.h>
#include <limits.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
unsigned gu_ceil2e(unsigned u)
{
u--;
u |= u >> 1;
u |= u >> 2;
u |= u >> 4;
u |= u >> 8;
#if UINT_MAX > UINT16_MAX
u |= u >> 16;
#endif
#if UINT_MAX > UINT32_MAX
u |= u >> 32;
#endif
u++;
return u;
}
GU_DEFINE_TYPE(GuIntDecodeExn, abstract, _);
double
gu_decode_double(uint64_t u)
{
bool sign = u >> 63;
unsigned rawexp = u >> 52 & 0x7ff;
uint64_t mantissa = u & 0xfffffffffffff;
double ret;
if (rawexp == 0x7ff) {
if (mantissa == 0) {
ret = INFINITY;
} else {
// At least glibc supports specifying the
// mantissa like this.
int len = snprintf(NULL, 0, "0x%" PRIx64, mantissa);
char buf[len + 1];
snprintf(buf, len + 1, "0x%" PRIx64, mantissa);
ret = nan(buf);
}
} else {
uint64_t m = rawexp ? 1ULL << 52 | mantissa : mantissa << 1;
ret = ldexp((double) m, rawexp - 1075);
}
return sign ? copysign(ret, -1.0) : ret;
}
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