bitmanipulation: fix undefined behavior in bit shift in getbe32
OSS-Fuzz caught this in its ubsan mode[0]. I'm not worried about a
security issue here because in practice this should work out the way
we naively expected, we're just making things explicit to the
compiler with the casts.
0: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=8876
Differential Revision: https://phab.mercurial-scm.org/D3729
#ifndef _HG_BITMANIPULATION_H_
#define _HG_BITMANIPULATION_H_
#include <string.h>
#include "compat.h"
static inline uint32_t getbe32(const char *c)
{
const unsigned char *d = (const unsigned char *)c;
return ((((uint32_t)d[0]) << 24) | (((uint32_t)d[1]) << 16) |
(((uint32_t)d[2]) << 8) | (d[3]));
}
static inline int16_t getbeint16(const char *c)
{
const unsigned char *d = (const unsigned char *)c;
return ((d[0] << 8) | (d[1]));
}
static inline uint16_t getbeuint16(const char *c)
{
const unsigned char *d = (const unsigned char *)c;
return ((d[0] << 8) | (d[1]));
}
static inline void putbe32(uint32_t x, char *c)
{
c[0] = (x >> 24) & 0xff;
c[1] = (x >> 16) & 0xff;
c[2] = (x >> 8) & 0xff;
c[3] = (x)&0xff;
}
static inline double getbefloat64(const char *c)
{
const unsigned char *d = (const unsigned char *)c;
double ret;
int i;
uint64_t t = 0;
for (i = 0; i < 8; i++) {
t = (t << 8) + d[i];
}
memcpy(&ret, &t, sizeof(t));
return ret;
}
#endif