thodg/libgit2/src/util.c

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• Hash : de18f276
  Author :
  Date : 2011-07-07T01:46:20
  

  vector: Timsort all of the things Drop the GLibc implementation of Merge Sort and replace it with Timsort. The algorithm has been tuned to work on arrays of pointers (void **), so there's no longer a need to abstract the byte-width of each element in the array. All the comparison callbacks now take pointers-to-elements, not pointers-to-pointers, so there's now one less level of dereferencing. E.g. int index_cmp(const void *a, const void *b) { - const git_index_entry *entry_a = *(const git_index_entry **)(a); + const git_index_entry *entry_a = (const git_index_entry *)(a); The result is up to a 40% speed-up when sorting vectors. Memory usage remains lineal. A new `bsearch` implementation has been added, whose callback also supplies pointer-to-elements, to uniform the Vector API again.

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• src/util.c

• #include <git2.h>
  #include "common.h"
  #include <stdarg.h>
  #include <stdio.h>
  #include <ctype.h>
  #include "posix.h"
  
  #ifdef _MSV_VER
  # include <Shlwapi.h>
  #endif
  
  void git_libgit2_version(int *major, int *minor, int *rev)
  {
  	*major = LIBGIT2_VER_MAJOR;
  	*minor = LIBGIT2_VER_MINOR;
  	*rev = LIBGIT2_VER_REVISION;
  }
  
  void git_strarray_free(git_strarray *array)
  {
  	size_t i;
  	for (i = 0; i < array->count; ++i)
  		free(array->strings[i]);
  
  	free(array->strings);
  }
  
  int git__fnmatch(const char *pattern, const char *name, int flags)
  {
  	int ret;
  
  	ret = p_fnmatch(pattern, name, flags);
  	switch (ret) {
  	case 0:
  		return GIT_SUCCESS;
  	case FNM_NOMATCH:
  		return GIT_ENOMATCH;
  	default:
  		return git__throw(GIT_EOSERR, "Error trying to match path");
  	}
  }
  
  int git__strtol32(long *result, const char *nptr, const char **endptr, int base)
  {
  	const char *p;
  	long n, nn;
  	int c, ovfl, v, neg, ndig;
  
  	p = nptr;
  	neg = 0;
  	n = 0;
  	ndig = 0;
  	ovfl = 0;
  
  	/*
  	 * White space
  	 */
  	while (isspace(*p))
  		p++;
  
  	/*
  	 * Sign
  	 */
  	if (*p == '-' || *p == '+')
  		if (*p++ == '-')
  			neg = 1;
  
  	/*
  	 * Base
  	 */
  	if (base == 0) {
  		if (*p != '0')
  			base = 10;
  		else {
  			base = 8;
  			if (p[1] == 'x' || p[1] == 'X') {
  				p += 2;
  				base = 16;
  			}
  		}
  	} else if (base == 16 && *p == '0') {
  		if (p[1] == 'x' || p[1] == 'X')
  			p += 2;
  	} else if (base < 0 || 36 < base)
  		goto Return;
  
  	/*
  	 * Non-empty sequence of digits
  	 */
  	for (;; p++,ndig++) {
  		c = *p;
  		v = base;
  		if ('0'<=c && c<='9')
  			v = c - '0';
  		else if ('a'<=c && c<='z')
  			v = c - 'a' + 10;
  		else if ('A'<=c && c<='Z')
  			v = c - 'A' + 10;
  		if (v >= base)
  			break;
  		nn = n*base + v;
  		if (nn < n)
  			ovfl = 1;
  		n = nn;
  	}
  
  Return:
  	if (ndig == 0)
  		return git__throw(GIT_ENOTNUM, "Failed to convert string to long. Not a number");
  
  	if (endptr)
  		*endptr = p;
  
  	if (ovfl)
  		return git__throw(GIT_EOVERFLOW, "Failed to convert string to long. Overflow error");
  
  	*result = neg ? -n : n;
  	return GIT_SUCCESS;
  }
  
  int git__fmt(char *buf, size_t buf_sz, const char *fmt, ...)
  {
  	va_list va;
  	int r;
  
  	va_start(va, fmt);
  	r = vsnprintf(buf, buf_sz, fmt, va);
  	va_end(va);
  	if (r < 0 || ((size_t) r) >= buf_sz)
  		return git__throw(GIT_ERROR, "Failed to format string");
  	return r;
  }
  
  void git__strntolower(char *str, int len)
  {
  	int i;
  
  	for (i = 0; i < len; ++i) {
  		str[i] = (char) tolower(str[i]);
  	}
  }
  
  void git__strtolower(char *str)
  {
  	git__strntolower(str, strlen(str));
  }
  
  int git__prefixcmp(const char *str, const char *prefix)
  {
  	for (;;) {
  		char p = *(prefix++), s;
  		if (!p)
  			return 0;
  		if ((s = *(str++)) != p)
  			return s - p;
  	}
  }
  
  int git__suffixcmp(const char *str, const char *suffix)
  {
  	size_t a = strlen(str);
  	size_t b = strlen(suffix);
  	if (a < b)
  		return -1;
  	return strcmp(str + (a - b), suffix);
  }
  
  char *git__strtok(char **end, const char *sep)
  {
  	char *ptr = *end;
  
  	while (*ptr && strchr(sep, *ptr))
  		++ptr;
  
  	if (*ptr) {
  		char *start = ptr;
  		*end = start + 1;
  
  		while (**end && !strchr(sep, **end))
  			++*end;
  
  		if (**end) {
  			**end = '\0';
  			++*end;
  		}
  
  		return start;
  	}
  
  	return NULL;
  }
  
  void git__hexdump(const char *buffer, size_t len)
  {
  	static const size_t LINE_WIDTH = 16;
  
  	size_t line_count, last_line, i, j;
  	const char *line;
  
  	line_count = (len / LINE_WIDTH);
  	last_line = (len % LINE_WIDTH);
  
  	for (i = 0; i < line_count; ++i) {
  		line = buffer + (i * LINE_WIDTH);
  		for (j = 0; j < LINE_WIDTH; ++j, ++line)
  			printf("%02X ", (unsigned char)*line & 0xFF);
  
  		printf("| ");
  
  		line = buffer + (i * LINE_WIDTH);
  		for (j = 0; j < LINE_WIDTH; ++j, ++line)
  			printf("%c", (*line >= 32 && *line <= 126) ? *line : '.');
  
  		printf("\n");
  	}
  
  	if (last_line > 0) {
  
  		line = buffer + (line_count * LINE_WIDTH);
  		for (j = 0; j < last_line; ++j, ++line)
  			printf("%02X ", (unsigned char)*line & 0xFF);
  
  		for (j = 0; j < (LINE_WIDTH - last_line); ++j)
  			printf("   ");
  
  		printf("| ");
  
  		line = buffer + (line_count * LINE_WIDTH);
  		for (j = 0; j < last_line; ++j, ++line)
  			printf("%c", (*line >= 32 && *line <= 126) ? *line : '.');
  
  		printf("\n");
  	}
  
  	printf("\n");
  }
  
  #ifdef GIT_LEGACY_HASH
  uint32_t git__hash(const void *key, int len, unsigned int seed)
  {
  	const uint32_t m = 0x5bd1e995;
  	const int r = 24;
  	uint32_t h = seed ^ len;
  
  	const unsigned char *data = (const unsigned char *)key;
  
  	while(len >= 4) {
  		uint32_t k = *(uint32_t *)data;
  
  		k *= m;
  		k ^= k >> r;
  		k *= m;
  
  		h *= m;
  		h ^= k;
  
  		data += 4;
  		len -= 4;
  	}
  
  	switch(len) {
  	case 3: h ^= data[2] << 16;
  	case 2: h ^= data[1] << 8;
  	case 1: h ^= data[0];
  	        h *= m;
  	};
  
  	h ^= h >> 13;
  	h *= m;
  	h ^= h >> 15;
  
  	return h;
  }
  #else
  /*
  	Cross-platform version of Murmurhash3
  	http://code.google.com/p/smhasher/wiki/MurmurHash3
  	by Austin Appleby (aappleby@gmail.com)
  
  	This code is on the public domain.
  */
  uint32_t git__hash(const void *key, int len, uint32_t seed)
  {
  
  #define MURMUR_BLOCK() {\
      k1 *= c1; \
      k1  = git__rotl(k1,11);\
      k1 *= c2;\
      h1 ^= k1;\
      h1 = h1*3 + 0x52dce729;\
      c1 = c1*5 + 0x7b7d159c;\
      c2 = c2*5 + 0x6bce6396;\
  }
  
  	const uint8_t *data = (const uint8_t*)key;
  	const int nblocks = len / 4;
  
  	const uint32_t *blocks = (const uint32_t *)(data + nblocks * 4);
  	const uint8_t *tail = (const uint8_t *)(data + nblocks * 4);
  
  	uint32_t h1 = 0x971e137b ^ seed;
  	uint32_t k1;
  
  	uint32_t c1 = 0x95543787;
  	uint32_t c2 = 0x2ad7eb25;
  
  	int i;
  
  	for (i = -nblocks; i; i++) {
  		k1 = blocks[i];
  		MURMUR_BLOCK();
  	}
  
  	k1 = 0;
  
  	switch(len & 3) {
  	case 3: k1 ^= tail[2] << 16;
  	case 2: k1 ^= tail[1] << 8;
  	case 1: k1 ^= tail[0];
  			MURMUR_BLOCK();
  	}
  
  	h1 ^= len;
  	h1 ^= h1 >> 16;
  	h1 *= 0x85ebca6b;
  	h1 ^= h1 >> 13;
  	h1 *= 0xc2b2ae35;
  	h1 ^= h1 >> 16;
  
  	return h1;
  }
  #endif
  
  /**
   * A modified `bsearch` from the BSD glibc.
   *
   * Copyright (c) 1990 Regents of the University of California.
   * All rights reserved.
   */
  void **git__bsearch(const void *key, void **base, size_t nmemb, int (*compar)(const void *, const void *))
  {
          int lim, cmp;
          void **p;
  
          for (lim = nmemb; lim != 0; lim >>= 1) {
                  p = base + (lim >> 1);
                  cmp = (*compar)(key, *p);
                  if (cmp > 0) {  /* key > p: move right */
                          base = p + 1;
                          lim--;
                  } else if (cmp == 0) {
                          return (void **)p;
                  } /* else move left */
          }
          return NULL;
  }
  
  

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