blender-archive/source/blender/blenlib/intern/array_utils.c

/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/blenlib/intern/array_utils.c
 *  \ingroup bli
 *  \brief Generic array manipulation API.
 *
 * \warning Some array operations here are inherently inefficient,
 * and only included for the cases where the performance is acceptable.
 * Use with care.
 */
#include <string.h>
#include <stdlib.h>

#include "MEM_guardedalloc.h"

#include "BLI_array_utils.h"

#include "BLI_sys_types.h"
#include "BLI_utildefines.h"
#include "BLI_alloca.h"

#include "BLI_strict_flags.h"

/**
 *In-place array reverse.
 *
 * Access via #BLI_array_reverse
 */
void _bli_array_reverse(void *arr_v, unsigned int arr_len, size_t arr_stride)
{
	const unsigned int arr_stride_uint = (unsigned int)arr_stride;
	const unsigned int arr_half_stride = (arr_len / 2) * arr_stride_uint;
	unsigned int i, i_end;
	char *arr = arr_v;
	char *buf = BLI_array_alloca(buf, arr_stride);

	for (i = 0, i_end = (arr_len - 1) * arr_stride_uint;
	     i < arr_half_stride;
	     i += arr_stride_uint, i_end -= arr_stride_uint)
	{
		memcpy(buf, &arr[i], arr_stride);
		memcpy(&arr[i], &arr[i_end], arr_stride);
		memcpy(&arr[i_end], buf, arr_stride);
	}
}

/**
 * In-place array wrap.
 * (rotate the array one step forward or backwards).
 *
 * Access via #BLI_array_wrap
 */
void _bli_array_wrap(void *arr_v, unsigned int arr_len, size_t arr_stride, int dir)
{
	char *arr = arr_v;
	char *buf = BLI_array_alloca(buf, arr_stride);

	if (dir == -1) {
		memcpy(buf, arr, arr_stride);
		memmove(arr, arr + arr_stride, arr_stride * (arr_len - 1));
		memcpy(arr + (arr_stride * (arr_len - 1)), buf, arr_stride);
	}
	else if (dir == 1) {
		memcpy(buf, arr + (arr_stride * (arr_len - 1)), arr_stride);
		memmove(arr + arr_stride, arr, arr_stride * (arr_len - 1));
		memcpy(arr, buf, arr_stride);
	}
	else {
		BLI_assert(0);
	}
}

/**
 *In-place array permute.
 * (re-arrange elements based on an array of indices).
 *
 * Access via #BLI_array_wrap
 */
void _bli_array_permute(
        void *arr_v, const unsigned int arr_len, const size_t arr_stride,
        const unsigned int *order, void *arr_temp)
{
	const size_t len = arr_len * arr_stride;
	const unsigned int arr_stride_uint = (unsigned int)arr_stride;
	void *arr_orig;
	unsigned int i;

	if (arr_temp == NULL) {
		arr_orig = MEM_mallocN(len, __func__);
	}
	else {
		arr_orig = arr_temp;
	}

	memcpy(arr_orig, arr_v, len);

	for (i = 0; i < arr_len; i++) {
		BLI_assert(order[i] < arr_len);
		memcpy(POINTER_OFFSET(arr_v,    arr_stride_uint * i),
		       POINTER_OFFSET(arr_orig, arr_stride_uint * order[i]),
		       arr_stride);
	}

	if (arr_temp == NULL) {
		MEM_freeN(arr_orig);
	}
}

/**
 * Find the first index of an item in an array.
 *
 * Access via #BLI_array_findindex
 *
 * \note Not efficient, use for error checks/asserts.
 */
int _bli_array_findindex(const void *arr, unsigned int arr_len, size_t arr_stride, const void *p)
{
	const char *arr_step = (const char *)arr;
	unsigned int i;
	for (i = 0; i < arr_len; i++, arr_step += arr_stride) {
		if (memcmp(arr_step, p, arr_stride) == 0) {
			return (int)i;
		}
	}
	return -1;
}