mercurial/bitmanipulation.h

bookmarks: cache reverse mapping (issue5868)

I chose a simpler implementation. If the initial cost of building reverse
mapping is significant, we'll have to move it under @propertycache.

The nodemap could be a dict of sets, but I think keeping a sorted list is
better since each node is likely to have zero/one bookmark.

Micro-benchmark with 1001 bookmarks and 1001 revisions:

  $ for n in `seq 0 1000`; do touch $n; hg book book$n; hg ci -qAm$n; done
  $ hg bookmarks --time > /dev/null
  (orig) time: real 0.040 secs (user 0.050+0.000 sys 0.000+0.000)
  (new)  time: real 0.040 secs (user 0.040+0.000 sys 0.010+0.000)
  $ hg log -T '{bookmarks}\n' --time > /dev/null
  (orig) time: real 0.160 secs (user 0.160+0.000 sys 0.000+0.000)
  (new)  time: real 0.090 secs (user 0.100+0.000 sys 0.000+0.000)

#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 ((d[0] << 24) | (d[1] << 16) | (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