thodg/libgit2/src/integer.h

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• Hash : f1453c59
  Author :
  Date : 2015-02-12T12:19:37
  

  Make our overflow check look more like gcc/clang's
  
  Make our overflow checking look more like gcc and clang's, so that
  we can substitute it out with the compiler instrinsics on platforms
  that support it.  This means dropping the ability to pass `NULL` as
  an out parameter.
  
  As a result, the macros also get updated to reflect this as well.
  

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• src/integer.h

• /*
   * 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.
   */
  #ifndef INCLUDE_integer_h__
  #define INCLUDE_integer_h__
  
  /** @return true if p fits into the range of a size_t */
  GIT_INLINE(int) git__is_sizet(git_off_t p)
  {
  	size_t r = (size_t)p;
  	return p == (git_off_t)r;
  }
  
  /** @return true if p fits into the range of an ssize_t */
  GIT_INLINE(int) git__is_ssizet(size_t p)
  {
  	ssize_t r = (ssize_t)p;
  	return p == (size_t)r;
  }
  
  /** @return true if p fits into the range of a uint32_t */
  GIT_INLINE(int) git__is_uint32(size_t p)
  {
  	uint32_t r = (uint32_t)p;
  	return p == (size_t)r;
  }
  
  /** @return true if p fits into the range of an unsigned long */
  GIT_INLINE(int) git__is_ulong(git_off_t p)
  {
  	unsigned long r = (unsigned long)p;
  	return p == (git_off_t)r;
  }
  
  /** @return true if p fits into the range of an int */
  GIT_INLINE(int) git__is_int(long long p)
  {
  	int r = (int)p;
  	return p == (long long)r;
  }
  
  /**
   * Sets `one + two` into `out`, unless the arithmetic would overflow.
   * @return true if the result fits in a `uint64_t`, false on overflow.
   */
  GIT_INLINE(bool) git__add_uint64_overflow(uint64_t *out, uint64_t one, uint64_t two)
  {
  	if (UINT64_MAX - one < two)
  		return true;
  	*out = one + two;
  	return false;
  }
  
  /**
   * Sets `one + two` into `out`, unless the arithmetic would overflow.
   * @return true if the result fits in a `size_t`, false on overflow.
   */
  GIT_INLINE(bool) git__add_sizet_overflow(size_t *out, size_t one, size_t two)
  {
  	if (SIZE_MAX - one < two)
  		return true;
  	*out = one + two;
  	return false;
  }
  
  /**
   * Sets `one * two` into `out`, unless the arithmetic would overflow.
   * @return true if the result fits in a `size_t`, false on overflow.
   */
  GIT_INLINE(bool) git__multiply_sizet_overflow(size_t *out, size_t one, size_t two)
  {
  	if (one && SIZE_MAX / one < two)
  		return true;
  	*out = one * two;
  	return false;
  }
  
  #endif /* INCLUDE_integer_h__ */
  

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