thodg/libgit2/src/array.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/array.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_array_h__
  #define INCLUDE_array_h__
  
  #include "common.h"
  
  /*
   * Use this to declare a typesafe resizable array of items, a la:
   *
   *     git_array_t(int) my_ints = GIT_ARRAY_INIT;
   *     ...
   *     int *i = git_array_alloc(my_ints);
   *     GITERR_CHECK_ALLOC(i);
   *     ...
   *     git_array_clear(my_ints);
   *
   * You may also want to do things like:
   *
   *     typedef git_array_t(my_struct) my_struct_array_t;
   */
  #define git_array_t(type) struct { type *ptr; size_t size, asize; }
  
  #define GIT_ARRAY_INIT { NULL, 0, 0 }
  
  #define git_array_init(a) \
  	do { (a).size = (a).asize = 0; (a).ptr = NULL; } while (0)
  
  #define git_array_init_to_size(a, desired) \
  	do { (a).size = 0; (a).asize = desired; (a).ptr = git__calloc(desired, sizeof(*(a).ptr)); } while (0)
  
  #define git_array_clear(a) \
  	do { git__free((a).ptr); git_array_init(a); } while (0)
  
  #define GITERR_CHECK_ARRAY(a) GITERR_CHECK_ALLOC((a).ptr)
  
  
  typedef git_array_t(char) git_array_generic_t;
  
  /* use a generic array for growth so this can return the new item */
  GIT_INLINE(void *) git_array_grow(void *_a, size_t item_size)
  {
  	volatile git_array_generic_t *a = _a;
  	size_t new_size;
  	char *new_array;
  
  	if (a->size < 8) {
  		new_size = 8;
  	} else {
  		if (GIT_MULTIPLY_SIZET_OVERFLOW(&new_size, a->size, 3))
  			goto on_oom;
  		new_size /= 2;
  	}
  
  	if ((new_array = git__reallocarray(a->ptr, new_size, item_size)) == NULL)
  		goto on_oom;
  
  	a->ptr = new_array; a->asize = new_size; a->size++;
  	return a->ptr + (a->size - 1) * item_size;
  
  on_oom:
  	git_array_clear(*a);
  	return NULL;
  }
  
  #define git_array_alloc(a) \
  	(((a).size >= (a).asize) ? \
  	git_array_grow(&(a), sizeof(*(a).ptr)) : \
  	((a).ptr ? &(a).ptr[(a).size++] : NULL))
  
  #define git_array_last(a) ((a).size ? &(a).ptr[(a).size - 1] : NULL)
  
  #define git_array_pop(a) ((a).size ? &(a).ptr[--(a).size] : NULL)
  
  #define git_array_get(a, i) (((i) < (a).size) ? &(a).ptr[(i)] : NULL)
  
  #define git_array_size(a) (a).size
  
  #define git_array_valid_index(a, i) ((i) < (a).size)
  
  #endif
  

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