1/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
2 * Use of this source code is governed by a BSD-style license that can be
3 * found in the LICENSE file.
4 */
5
6#ifndef CRAS_ARRAY_H_
7#define CRAS_ARRAY_H_
8
9#ifdef __cplusplus
10extern "C" {
11#endif
12
13#include <string.h>
14
15/*
16
17Sample usage:
18
19DECLARE_ARRAY_TYPE(double, double_array);
20
21void f()
22{
23	int i;
24	double *p;
25	double_array a = ARRAY_INIT;
26
27	ARRAY_APPEND(&a, 1.0);
28	*ARRAY_APPEND_ZERO(&a) = 2.0;
29
30	FOR_ARRAY_ELEMENT(&a, i, p) {
31		printf("%f\n", *p);  // prints 1.0 2.0
32	}
33
34	ARRAY_FREE(&a);
35}
36
37*/
38
39/* Define a type for the array given the element type */
40#define DECLARE_ARRAY_TYPE(element_type, array_type) \
41	typedef struct { \
42		int count; \
43		int size; \
44		element_type *element; \
45	} array_type;
46
47/* The initializer for an empty array is the zero value. */
48#define ARRAY_INIT {}
49
50#define _ARRAY_EXTEND(a)						\
51	({								\
52		if ((a)->count >= (a)->size) {				\
53			if ((a)->size == 0)				\
54				(a)->size = 4;				\
55			else						\
56				(a)->size *= 2;				\
57			(a)->element = (__typeof((a)->element))		\
58				realloc((a)->element,			\
59					(a)->size *			\
60					sizeof((a)->element[0]));	\
61		}							\
62		&(a)->element[((a)->count)++];				\
63	})
64
65/* Append an element with the given value to the array a */
66#define ARRAY_APPEND(a, value)						\
67	do {								\
68		*_ARRAY_EXTEND(a) = (value);				\
69	} while (0)
70
71/* Append a zero element to the array a and return the pointer to the element */
72#define ARRAY_APPEND_ZERO(a)					    \
73	({							    \
74		typeof((a)->element) _tmp_ptr = _ARRAY_EXTEND(a);   \
75		memset(_tmp_ptr, 0, sizeof(*_tmp_ptr));		    \
76		_tmp_ptr;					    \
77	})
78
79/* Return the number of elements in the array a */
80#define ARRAY_COUNT(a) ((a)->count)
81
82/* Return a pointer to the i-th element in the array a */
83#define ARRAY_ELEMENT(a, i) ((a)->element + (i))
84
85/* Return the index of the element pointed by p in the array a */
86#define ARRAY_INDEX(a, p) ((p) - (a)->element)
87
88/* Go through each element in the array a and assign index and pointer
89   to the element to the variable i and ptr */
90#define FOR_ARRAY_ELEMENT(a, i, ptr)				    \
91	for ((i) = 0, (ptr) = (a)->element; (i) < (a)->count;	    \
92	     (i)++, (ptr)++)
93
94/* Free the memory used by the array a. The array becomes an empty array. */
95#define ARRAY_FREE(a)				\
96	do {					\
97		free((a)->element);		\
98		(a)->element = NULL;		\
99		(a)->size = 0;			\
100		(a)->count = 0;			\
101	} while (0)
102
103
104/* Return the index of the element with the value x. -1 if not found */
105#define ARRAY_FIND(a, x)						\
106	({								\
107		typeof((a)->element) _bptr = (a)->element;		\
108		typeof((a)->element) _eptr = (a)->element + (a)->count; \
109		for (; _bptr != _eptr && *_bptr != x; _bptr++)		\
110			;						\
111		(_bptr == _eptr) ? -1 : (_bptr - (a)->element);		\
112	})
113
114#ifdef __cplusplus
115} /* extern "C" */
116#endif
117
118#endif /* CRAS_ARRAY_H_ */
119