pixman/pixman-utils.c - third_party/pixman - Git at Google

 /*
  * Copyright © 2000 SuSE, Inc.
  * Copyright © 1999 Keith Packard
  *
  * Permission to use, copy, modify, distribute, and sell this software and its
  * documentation for any purpose is hereby granted without fee, provided that
  * the above copyright notice appear in all copies and that both that
  * copyright notice and this permission notice appear in supporting
  * documentation, and that the name of SuSE not be used in advertising or
  * publicity pertaining to distribution of the software without specific,
  * written prior permission.  SuSE makes no representations about the
  * suitability of this software for any purpose.  It is provided "as is"
  * without express or implied warranty.
  *
  * SuSE DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL SuSE
  * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
  * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  *
  * Author:  Keith Packard, SuSE, Inc.
  */

 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
 #include <stdio.h>
 #include <stdlib.h>

 #include "pixman-private.h"

 pixman_bool_t
 pixman_multiply_overflows_int (unsigned int a,
                                unsigned int b)
 {
     return a >= INT32_MAX / b;
 }

 pixman_bool_t
 pixman_addition_overflows_int (unsigned int a,
                                unsigned int b)
 {
     return a > INT32_MAX - b;
 }

 void *
 pixman_malloc_ab (unsigned int a,
                   unsigned int b)
 {
     if (a >= INT32_MAX / b)
 	return NULL;

     return malloc (a * b);
 }

 void *
 pixman_malloc_abc (unsigned int a,
                    unsigned int b,
                    unsigned int c)
 {
     if (a >= INT32_MAX / b)
 	return NULL;
     else if (a * b >= INT32_MAX / c)
 	return NULL;
     else
 	return malloc (a * b * c);
 }

 /*
  * Helper routine to expand a color component from 0 < n <= 8 bits to 16
  * bits by replication.
  */
 static inline uint64_t
 expand16 (const uint8_t val, int nbits)
 {
     /* Start out with the high bit of val in the high bit of result. */
     uint16_t result = (uint16_t)val << (16 - nbits);

     if (nbits == 0)
 	return 0;

     /* Copy the bits in result, doubling the number of bits each time, until
      * we fill all 16 bits.
      */
     while (nbits < 16)
     {
 	result |= result >> nbits;
 	nbits *= 2;
     }

     return result;
 }

 /*
  * This function expands images from ARGB8 format to ARGB16.  To preserve
  * precision, it needs to know the original source format.  For example, if the
  * source was PIXMAN_x1r5g5b5 and the red component contained bits 12345, then
  * the expanded value is 12345123.  To correctly expand this to 16 bits, it
  * should be 1234512345123451 and not 1234512312345123.
  */
 void
 pixman_expand (uint64_t *           dst,
                const uint32_t *     src,
                pixman_format_code_t format,
                int                  width)
 {
     /*
      * Determine the sizes of each component and the masks and shifts
      * required to extract them from the source pixel.
      */
     const int a_size = PIXMAN_FORMAT_A (format),
               r_size = PIXMAN_FORMAT_R (format),
               g_size = PIXMAN_FORMAT_G (format),
               b_size = PIXMAN_FORMAT_B (format);
     const int a_shift = 32 - a_size,
               r_shift = 24 - r_size,
               g_shift = 16 - g_size,
               b_shift =  8 - b_size;
     const uint8_t a_mask = ~(~0 << a_size),
                   r_mask = ~(~0 << r_size),
                   g_mask = ~(~0 << g_size),
                   b_mask = ~(~0 << b_size);
     int i;

     /* Start at the end so that we can do the expansion in place
      * when src == dst
      */
     for (i = width - 1; i >= 0; i--)
     {
 	const uint32_t pixel = src[i];
 	const uint8_t a = (pixel >> a_shift) & a_mask,
 	              r = (pixel >> r_shift) & r_mask,
 	              g = (pixel >> g_shift) & g_mask,
 	              b = (pixel >> b_shift) & b_mask;
 	const uint64_t a16 = a_size ? expand16 (a, a_size) : 0xffff,
 	               r16 = expand16 (r, r_size),
 	               g16 = expand16 (g, g_size),
 	               b16 = expand16 (b, b_size);

 	dst[i] = a16 << 48 | r16 << 32 | g16 << 16 | b16;
     }
 }

 /*
  * Contracting is easier than expanding.  We just need to truncate the
  * components.
  */
 void
 pixman_contract (uint32_t *      dst,
                  const uint64_t *src,
                  int             width)
 {
     int i;

     /* Start at the beginning so that we can do the contraction in
      * place when src == dst
      */
     for (i = 0; i < width; i++)
     {
 	const uint8_t a = src[i] >> 56,
 	              r = src[i] >> 40,
 	              g = src[i] >> 24,
 	              b = src[i] >> 8;

 	dst[i] = a << 24 | r << 16 | g << 8 | b;
     }
 }

 #define N_TMP_BOXES (16)

 pixman_bool_t
 pixman_region16_copy_from_region32 (pixman_region16_t *dst,
                                     pixman_region32_t *src)
 {
     int n_boxes, i;
     pixman_box32_t *boxes32;
     pixman_box16_t *boxes16;
     pixman_bool_t retval;

     boxes32 = pixman_region32_rectangles (src, &n_boxes);

     boxes16 = pixman_malloc_ab (n_boxes, sizeof (pixman_box16_t));

     if (!boxes16)
 	return FALSE;

     for (i = 0; i < n_boxes; ++i)
     {
 	boxes16[i].x1 = boxes32[i].x1;
 	boxes16[i].y1 = boxes32[i].y1;
 	boxes16[i].x2 = boxes32[i].x2;
 	boxes16[i].y2 = boxes32[i].y2;
     }

     pixman_region_fini (dst);
     retval = pixman_region_init_rects (dst, boxes16, n_boxes);
     free (boxes16);
     return retval;
 }

 pixman_bool_t
 pixman_region32_copy_from_region16 (pixman_region32_t *dst,
                                     pixman_region16_t *src)
 {
     int n_boxes, i;
     pixman_box16_t *boxes16;
     pixman_box32_t *boxes32;
     pixman_box32_t tmp_boxes[N_TMP_BOXES];
     pixman_bool_t retval;

     boxes16 = pixman_region_rectangles (src, &n_boxes);

     if (n_boxes > N_TMP_BOXES)
 	boxes32 = pixman_malloc_ab (n_boxes, sizeof (pixman_box32_t));
     else
 	boxes32 = tmp_boxes;

     if (!boxes32)
 	return FALSE;

     for (i = 0; i < n_boxes; ++i)
     {
 	boxes32[i].x1 = boxes16[i].x1;
 	boxes32[i].y1 = boxes16[i].y1;
 	boxes32[i].x2 = boxes16[i].x2;
 	boxes32[i].y2 = boxes16[i].y2;
     }

     pixman_region32_fini (dst);
     retval = pixman_region32_init_rects (dst, boxes32, n_boxes);

     if (boxes32 != tmp_boxes)
 	free (boxes32);

     return retval;
 }

 #ifdef DEBUG

 void
 _pixman_log_error (const char *function, const char *message)
 {
     static int n_messages = 0;

     if (n_messages < 10)
     {
 	fprintf (stderr,
 		 "*** BUG ***\n"
 		 "In %s: %s\n"
 		 "Set a breakpoint on '_pixman_log_error' to debug\n\n",
                  function, message);

 	n_messages++;
     }
 }

 #endif
	/*
	* Copyright © 2000 SuSE, Inc.
	* Copyright © 1999 Keith Packard
	*
	* Permission to use, copy, modify, distribute, and sell this software and its
	* documentation for any purpose is hereby granted without fee, provided that
	* the above copyright notice appear in all copies and that both that
	* copyright notice and this permission notice appear in supporting
	* documentation, and that the name of SuSE not be used in advertising or
	* publicity pertaining to distribution of the software without specific,
	* written prior permission. SuSE makes no representations about the
	* suitability of this software for any purpose. It is provided "as is"
	* without express or implied warranty.
	*
	* SuSE DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL SuSE
	* BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
	* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
	* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	*
	* Author: Keith Packard, SuSE, Inc.
	*/

	#ifdef HAVE_CONFIG_H
	#include <config.h>
	#endif
	#include <stdio.h>
	#include <stdlib.h>

	#include "pixman-private.h"

	pixman_bool_t
	pixman_multiply_overflows_int (unsigned int a,
	unsigned int b)
	{
	return a >= INT32_MAX / b;
	}

	pixman_bool_t
	pixman_addition_overflows_int (unsigned int a,
	unsigned int b)
	{
	return a > INT32_MAX - b;
	}

	void *
	pixman_malloc_ab (unsigned int a,
	unsigned int b)
	{
	if (a >= INT32_MAX / b)
	return NULL;

	return malloc (a * b);
	}

	void *
	pixman_malloc_abc (unsigned int a,
	unsigned int b,
	unsigned int c)
	{
	if (a >= INT32_MAX / b)
	return NULL;
	else if (a * b >= INT32_MAX / c)
	return NULL;
	else
	return malloc (a * b * c);
	}

	/*
	* Helper routine to expand a color component from 0 < n <= 8 bits to 16
	* bits by replication.
	*/
	static inline uint64_t
	expand16 (const uint8_t val, int nbits)
	{
	/* Start out with the high bit of val in the high bit of result. */
	uint16_t result = (uint16_t)val << (16 - nbits);

	if (nbits == 0)
	return 0;

	/* Copy the bits in result, doubling the number of bits each time, until
	* we fill all 16 bits.
	*/
	while (nbits < 16)
	{
	result \|= result >> nbits;
	nbits *= 2;
	}

	return result;
	}

	/*
	* This function expands images from ARGB8 format to ARGB16. To preserve
	* precision, it needs to know the original source format. For example, if the
	* source was PIXMAN_x1r5g5b5 and the red component contained bits 12345, then
	* the expanded value is 12345123. To correctly expand this to 16 bits, it
	* should be 1234512345123451 and not 1234512312345123.
	*/
	void
	pixman_expand (uint64_t * dst,
	const uint32_t * src,
	pixman_format_code_t format,
	int width)
	{
	/*
	* Determine the sizes of each component and the masks and shifts
	* required to extract them from the source pixel.
	*/
	const int a_size = PIXMAN_FORMAT_A (format),
	r_size = PIXMAN_FORMAT_R (format),
	g_size = PIXMAN_FORMAT_G (format),
	b_size = PIXMAN_FORMAT_B (format);
	const int a_shift = 32 - a_size,
	r_shift = 24 - r_size,
	g_shift = 16 - g_size,
	b_shift = 8 - b_size;
	const uint8_t a_mask = ~(~0 << a_size),
	r_mask = ~(~0 << r_size),
	g_mask = ~(~0 << g_size),
	b_mask = ~(~0 << b_size);
	int i;

	/* Start at the end so that we can do the expansion in place
	* when src == dst
	*/
	for (i = width - 1; i >= 0; i--)
	{
	const uint32_t pixel = src[i];
	const uint8_t a = (pixel >> a_shift) & a_mask,
	r = (pixel >> r_shift) & r_mask,
	g = (pixel >> g_shift) & g_mask,
	b = (pixel >> b_shift) & b_mask;
	const uint64_t a16 = a_size ? expand16 (a, a_size) : 0xffff,
	r16 = expand16 (r, r_size),
	g16 = expand16 (g, g_size),
	b16 = expand16 (b, b_size);

	dst[i] = a16 << 48 \| r16 << 32 \| g16 << 16 \| b16;
	}
	}

	/*
	* Contracting is easier than expanding. We just need to truncate the
	* components.
	*/
	void
	pixman_contract (uint32_t * dst,
	const uint64_t *src,
	int width)
	{
	int i;

	/* Start at the beginning so that we can do the contraction in
	* place when src == dst
	*/
	for (i = 0; i < width; i++)
	{
	const uint8_t a = src[i] >> 56,
	r = src[i] >> 40,
	g = src[i] >> 24,
	b = src[i] >> 8;

	dst[i] = a << 24 \| r << 16 \| g << 8 \| b;
	}
	}

	#define N_TMP_BOXES (16)

	pixman_bool_t
	pixman_region16_copy_from_region32 (pixman_region16_t *dst,
	pixman_region32_t *src)
	{
	int n_boxes, i;
	pixman_box32_t *boxes32;
	pixman_box16_t *boxes16;
	pixman_bool_t retval;

	boxes32 = pixman_region32_rectangles (src, &n_boxes);

	boxes16 = pixman_malloc_ab (n_boxes, sizeof (pixman_box16_t));

	if (!boxes16)
	return FALSE;

	for (i = 0; i < n_boxes; ++i)
	{
	boxes16[i].x1 = boxes32[i].x1;
	boxes16[i].y1 = boxes32[i].y1;
	boxes16[i].x2 = boxes32[i].x2;
	boxes16[i].y2 = boxes32[i].y2;
	}

	pixman_region_fini (dst);
	retval = pixman_region_init_rects (dst, boxes16, n_boxes);
	free (boxes16);
	return retval;
	}

	pixman_bool_t
	pixman_region32_copy_from_region16 (pixman_region32_t *dst,
	pixman_region16_t *src)
	{
	int n_boxes, i;
	pixman_box16_t *boxes16;
	pixman_box32_t *boxes32;
	pixman_box32_t tmp_boxes[N_TMP_BOXES];
	pixman_bool_t retval;

	boxes16 = pixman_region_rectangles (src, &n_boxes);

	if (n_boxes > N_TMP_BOXES)
	boxes32 = pixman_malloc_ab (n_boxes, sizeof (pixman_box32_t));
	else
	boxes32 = tmp_boxes;

	if (!boxes32)
	return FALSE;

	for (i = 0; i < n_boxes; ++i)
	{
	boxes32[i].x1 = boxes16[i].x1;
	boxes32[i].y1 = boxes16[i].y1;
	boxes32[i].x2 = boxes16[i].x2;
	boxes32[i].y2 = boxes16[i].y2;
	}

	pixman_region32_fini (dst);
	retval = pixman_region32_init_rects (dst, boxes32, n_boxes);

	if (boxes32 != tmp_boxes)
	free (boxes32);

	return retval;
	}

	#ifdef DEBUG

	void
	_pixman_log_error (const char function, const char message)
	{
	static int n_messages = 0;

	if (n_messages < 10)
	{
	fprintf (stderr,
	"* BUG *\n"
	"In %s: %s\n"
	"Set a breakpoint on '_pixman_log_error' to debug\n\n",
	function, message);

	n_messages++;
	}
	}

	#endif