thodg/libgit2/src/util/varint.c

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• Hash : c3b7ace9
  Author :
  Date : 2021-11-14T16:43:53
  

  refactor: make util an object library Instead of simply including the utility files directly, make them a cmake object library for easy reusability between other projects within libgit2. Now the top-level `src` is responsible for platform selection, while the next-level `libgit2` and `util` configurations are responsible for identifying what objects they include.

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• src/util/varint.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include "varint.h"
  
  uintmax_t git_decode_varint(const unsigned char *bufp, size_t *varint_len)
  {
  	const unsigned char *buf = bufp;
  	unsigned char c = *buf++;
  	uintmax_t val = c & 127;
  	while (c & 128) {
  		val += 1;
  		if (!val || MSB(val, 7)) {
  			/* This is not a valid varint_len, so it signals
  			   the error */
  			*varint_len = 0;
  			return 0; /* overflow */
  		}
  		c = *buf++;
  		val = (val << 7) + (c & 127);
  	}
  	*varint_len = buf - bufp;
  	return val;
  }
  
  int git_encode_varint(unsigned char *buf, size_t bufsize, uintmax_t value)
  {
  	unsigned char varint[16];
  	unsigned pos = sizeof(varint) - 1;
  	varint[pos] = value & 127;
  	while (value >>= 7)
  		varint[--pos] = 128 | (--value & 127);
  	if (buf) {
  		if (bufsize < (sizeof(varint) - pos))
  			return -1;
  		memcpy(buf, varint + pos, sizeof(varint) - pos);
  	}
  	return sizeof(varint) - pos;
  }
  

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