upstream/mercurial-mirror Files · mercurial/bitmanipulation.h

branchmap: avoid ancestor computations in absence of non-continous branches...

branchmap: avoid ancestor computations in absence of non-continous branches The branchhead computation is one of the more heavy operations for bigger repositories as it has to scan all changesets and potentially involves the expensive computation of the ancestor sets. Redo the computation to handle the common cases directly and use tighter conditions for when the ancestor scan is necessary. Most importantly, avoid it completely if the non-continous branches are processed in one update as seen in the initial computation after a clone. For the Mercurial repository, it gives a small 2-3% performance boost. For the NetBSD test repository, it cuts the time in half. Differential Revision: https://phab.mercurial-scm.org/D9631

Augie Fackler - - Load All Authors

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      #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

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				#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