thodg/libgit2/src/array.h

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• Hash : b62a6a13
  Author :
  Date : 2014-07-25T08:25:41
  

  array: mark the array to grow as volatile
  
  This works around strict aliasing rules letting some versions of
  GCC (particularly on RHEL 6) thinking that they can skip updating the
  size of the array when calculating the next element's offset.
  

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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; uint32_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;
  	uint32_t new_size = (a->size < 8) ? 8 : a->asize * 3 / 2;
  	char *new_array = git__realloc(a->ptr, new_size * item_size);
  	if (!new_array) {
  		git_array_clear(*a);
  		return NULL;
  	} else {
  		a->ptr = new_array; a->asize = new_size; a->size++;
  		return a->ptr + (a->size - 1) * item_size;
  	}
  }
  
  #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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