/src/ghostpdl/xps/xpspng.c

Source
/* Copyright (C) 2001-2026 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  39 Mesa Street, Suite 108A, San Francisco,
   CA 94129, USA, for further information.
*/


/* XPS interpreter - PNG image support */

#include "ghostxps.h"

#include "stream.h"
#include "strimpl.h"
#include "gsstate.h"
#include "setjmp_.h"

/* silence a warning where #if SHARE_LIBPNG is used when it's undefined */
#ifndef SHARE_LIBPNG
#define SHARE_LIBPNG 0
#endif
#include "png_.h"

/*
 * PNG using libpng directly (no gs wrappers)
 */

struct xps_png_io_s
{
    byte *ptr;
    byte *lim;
};

static void
xps_png_read(png_structp png, png_bytep data, png_size_t length)
{
    struct xps_png_io_s *io = png_get_io_ptr(png);
    if (io->ptr + length > io->lim)
        png_error(png, "Read Error");
    memcpy(data, io->ptr, length);
    io->ptr += length;
}

#define PNG_MEM_ALIGN 16
static png_voidp
xps_png_malloc(png_structp png, png_size_t size)
{
    gs_memory_t *mem = png_get_mem_ptr(png);
    uchar *unaligned;
    uchar *aligned;

    if (size == 0)
        return NULL;
    unaligned = gs_alloc_bytes(mem, size + PNG_MEM_ALIGN, "libpng");
    if (unaligned == NULL)
        return NULL;

    aligned = (uchar *)((intptr_t)(unaligned + PNG_MEM_ALIGN) & ~(PNG_MEM_ALIGN - 1));
    aligned[-1] = (uchar)(aligned - unaligned);

    return aligned;
}

static void
xps_png_free(png_structp png, png_voidp ptr)
{
    gs_memory_t *mem = png_get_mem_ptr(png);
    uchar *aligned = ptr;
    if (aligned == NULL)
        return;
    gs_free_object(mem, aligned - aligned[-1], "libpng");
}

/* This only determines if we have an alpha value */
OPTIMIZE_SETJMP
int
xps_png_has_alpha(xps_context_t *ctx, byte *rbuf, int rlen)
{
    png_structp png;
    png_infop info;
    struct xps_png_io_s io;
    int has_alpha;

    /*
     * Set up PNG structs and input source
     */

    io.ptr = rbuf;
    io.lim = rbuf + rlen;

    png = png_create_read_struct_2(PNG_LIBPNG_VER_STRING,
            NULL, NULL, NULL,
            ctx->memory, xps_png_malloc, xps_png_free);
    if (!png) {
        gs_warn("png_create_read_struct");
        return 0;
    }

    info = png_create_info_struct(png);
    if (!info) {
        gs_warn("png_create_info_struct");
        return 0;
    }

    png_set_read_fn(png, &io, xps_png_read);
    png_set_crc_action(png, PNG_CRC_WARN_USE, PNG_CRC_WARN_USE);

    /*
     * Jump to here on errors.
     */

    if (setjmp(png_jmpbuf(png)))
    {
        png_destroy_read_struct(&png, &info, NULL);
        gs_warn("png reading failed");
        return 0;
    }

    /*
     * Read PNG header
     */
    png_read_info(png, info);
    if (png_get_valid(png, info, PNG_INFO_tRNS))
    {
        /* this will also expand the depth to 8-bits */
        png_set_tRNS_to_alpha(png);
    }
    png_read_update_info(png, info);

    switch (png_get_color_type(png, info))
    {
    case PNG_COLOR_TYPE_PALETTE:
    case PNG_COLOR_TYPE_GRAY:
    case PNG_COLOR_TYPE_RGB:
        has_alpha = 0;
        break;

    case PNG_COLOR_TYPE_GRAY_ALPHA:
    case PNG_COLOR_TYPE_RGB_ALPHA:
        has_alpha = 1;
        break;

    default:
        gs_warn("cannot handle this png color type");
        has_alpha = 0;
        break;
    }

    /*
     * Clean up memory.
     */

    png_destroy_read_struct(&png, &info, NULL);

    return has_alpha;
}

OPTIMIZE_SETJMP
int
xps_decode_png(xps_context_t *ctx, byte *rbuf, int rlen, xps_image_t *image)
{
    png_structp png;
    png_infop info;
    struct xps_png_io_s io;
    int npasses;
    int pass;
    int y;
    int compression = 0; /* dummy as of libpng 1.5.x */
    char *iccname = NULL;
    char *iccprofile = NULL;
    unsigned int iccproflen = 0;
    png_uint_32 xres, yres;
    int unit;
    uint32_t size;

    /*
     * Set up PNG structs and input source
     */

    io.ptr = rbuf;
    io.lim = rbuf + rlen;

    png = png_create_read_struct_2(PNG_LIBPNG_VER_STRING,
            NULL, NULL, NULL,
            ctx->memory, xps_png_malloc, xps_png_free);
    if (!png)
        return gs_throw(-1, "png_create_read_struct");

    info = png_create_info_struct(png);
    if (!info)
        return gs_throw(-1, "png_create_info_struct");

    png_set_read_fn(png, &io, xps_png_read);
    png_set_crc_action(png, PNG_CRC_WARN_USE, PNG_CRC_WARN_USE);

    /*
     * Jump to here on errors.
     */

    if (setjmp(png_jmpbuf(png)))
    {
        png_destroy_read_struct(&png, &info, NULL);
        return gs_throw(-1, "png reading failed");
    }

    /*
     * Read PNG header
     */

    png_read_info(png, info);

    if (png_get_interlace_type(png, info) == PNG_INTERLACE_ADAM7)
    {
        npasses = png_set_interlace_handling(png);
    }
    else
    {
        npasses = 1;
    }

    if (png_get_color_type(png, info) == PNG_COLOR_TYPE_PALETTE)
    {
        png_set_palette_to_rgb(png);
    }

    if (png_get_valid(png, info, PNG_INFO_tRNS))
    {
        /* this will also expand the depth to 8-bits */
        png_set_tRNS_to_alpha(png);
    }

    png_read_update_info(png, info);

    image->width = png_get_image_width(png, info);
    image->height = png_get_image_height(png, info);
    image->comps = png_get_channels(png, info);
    image->bits = png_get_bit_depth(png, info);
    image->invert_decode = false;
    if (image->width <= 0 || image->height <= 0 || image->comps <= 0 || image->bits <= 0)
        return gs_throw(-1, "bad image dimension");

    /* See if we have an icc profile */
#if PNG_LIBPNG_VER_MINOR >= 5
    /* ignore the return value */
    (void)png_get_iCCP(png, info, (png_charpp)&iccname, &compression, (png_bytepp)&iccprofile, (png_uint_32 *)&iccproflen);
#else
    iccprofile = info->iccp_profile;
    iccproflen = info->iccp_proflen;
#endif
    if (iccprofile != NULL)
    {
        image->profilesize = iccproflen;
        image->profile = xps_alloc(ctx, iccproflen);
        if (image->profile)
        {
            /* If we can't create it, just ignore */
            memcpy(image->profile, iccprofile, iccproflen);
        }
    }

    switch (png_get_color_type(png, info))
    {
    case PNG_COLOR_TYPE_GRAY:
        rc_increment(ctx->gray);
        image->colorspace = ctx->gray;
        image->hasalpha = 0;
        break;

    case PNG_COLOR_TYPE_RGB:
        rc_increment(ctx->srgb);
        image->colorspace = ctx->srgb;
        image->hasalpha = 0;
        break;

    case PNG_COLOR_TYPE_GRAY_ALPHA:
        rc_increment(ctx->gray);
        image->colorspace = ctx->gray;
        image->hasalpha = 1;
        break;

    case PNG_COLOR_TYPE_RGB_ALPHA:
        rc_increment(ctx->srgb);
        image->colorspace = ctx->srgb;
        image->hasalpha = 1;
        break;

    default:
        return gs_throw(-1, "cannot handle this png color type");
    }

    /*
     * Extract DPI, default to 96 dpi
     */

    image->xres = 96;
    image->yres = 96;

    if (png_get_pHYs(png, info, &xres, &yres, &unit) & PNG_INFO_pHYs)
    {
        if (unit == PNG_RESOLUTION_METER)
        {
            image->xres = (int)(xres * 0.0254 + 0.5);
            image->yres = (int)(yres * 0.0254 + 0.5);
        }
    }

    /*
     * Read rows, filling transformed output into image buffer.
     */

    if (check_uint32_multiply((uint32_t)image->width, ((uint32_t)image->bits), &size) != 0)
        return gs_throw(-1, "image  is too large");

    if (size > INT_MAX / image->comps)
        return gs_throw(-1, "image  is too large");

    image->stride = (size * image->comps + 7) / 8;

    if (check_uint32_multiply((uint32_t)image->stride, (uint32_t)image->height, &size) != 0)
        return gs_throw(-1, "image  is too large");

    image->samples = xps_alloc(ctx, size);
    if (!image->samples)
        return gs_throw(gs_error_VMerror, "out of memory.\n");

    for (pass = 0; pass < npasses; pass++)
    {
        for (y = 0; y < image->height; y++)
        {
            png_read_row(png, image->samples + (y * image->stride), NULL);
        }
    }

    /*
     * Clean up memory.
     */

    png_destroy_read_struct(&png, &info, NULL);

    return gs_okay;
}

Coverage Report

Created: 2026-04-09 07:06

Line	Count	Source
1		/* Copyright (C) 2001-2026 Artifex Software, Inc.
2		All Rights Reserved.
3
4		This software is provided AS-IS with no warranty, either express or
5		implied.
6
7		This software is distributed under license and may not be copied,
8		modified or distributed except as expressly authorized under the terms
9		of the license contained in the file LICENSE in this distribution.
10
11		Refer to licensing information at http://www.artifex.com or contact
12		Artifex Software, Inc., 39 Mesa Street, Suite 108A, San Francisco,
13		CA 94129, USA, for further information.
14		*/
15
16
17		/* XPS interpreter - PNG image support */
18
19		#include "ghostxps.h"
20
21		#include "stream.h"
22		#include "strimpl.h"
23		#include "gsstate.h"
24		#include "setjmp_.h"
25
26		/* silence a warning where #if SHARE_LIBPNG is used when it's undefined */
27		#ifndef SHARE_LIBPNG
28		#define SHARE_LIBPNG 0
29		#endif
30		#include "png_.h"
31
32		/*
33		* PNG using libpng directly (no gs wrappers)
34		*/
35
36		struct xps_png_io_s
37		{
38		byte *ptr;
39		byte *lim;
40		};
41
42		static void
43		xps_png_read(png_structp png, png_bytep data, png_size_t length)
44	0	{
45	0	struct xps_png_io_s *io = png_get_io_ptr(png);
46	0	if (io->ptr + length > io->lim)
47	0	png_error(png, "Read Error");
48	0	memcpy(data, io->ptr, length);
49	0	io->ptr += length;
50	0	}
51
52	0	#define PNG_MEM_ALIGN 16
53		static png_voidp
54		xps_png_malloc(png_structp png, png_size_t size)
55	0	{
56	0	gs_memory_t *mem = png_get_mem_ptr(png);
57	0	uchar *unaligned;
58	0	uchar *aligned;
59
60	0	if (size == 0)
61	0	return NULL;
62	0	unaligned = gs_alloc_bytes(mem, size + PNG_MEM_ALIGN, "libpng");
63	0	if (unaligned == NULL)
64	0	return NULL;
65
66	0	aligned = (uchar *)((intptr_t)(unaligned + PNG_MEM_ALIGN) & ~(PNG_MEM_ALIGN - 1));
67	0	aligned[-1] = (uchar)(aligned - unaligned);
68
69	0	return aligned;
70	0	}
71
72		static void
73		xps_png_free(png_structp png, png_voidp ptr)
74	0	{
75	0	gs_memory_t *mem = png_get_mem_ptr(png);
76	0	uchar *aligned = ptr;
77	0	if (aligned == NULL)
78	0	return;
79	0	gs_free_object(mem, aligned - aligned[-1], "libpng");
80	0	}
81
82		/* This only determines if we have an alpha value */
83		OPTIMIZE_SETJMP
84		int
85		xps_png_has_alpha(xps_context_t ctx, byte rbuf, int rlen)
86	0	{
87	0	png_structp png;
88	0	png_infop info;
89	0	struct xps_png_io_s io;
90	0	int has_alpha;
91
92		/*
93		* Set up PNG structs and input source
94		*/
95
96	0	io.ptr = rbuf;
97	0	io.lim = rbuf + rlen;
98
99	0	png = png_create_read_struct_2(PNG_LIBPNG_VER_STRING,
100	0	NULL, NULL, NULL,
101	0	ctx->memory, xps_png_malloc, xps_png_free);
102	0	if (!png) {
103	0	gs_warn("png_create_read_struct");
104	0	return 0;
105	0	}
106
107	0	info = png_create_info_struct(png);
108	0	if (!info) {
109	0	gs_warn("png_create_info_struct");
110	0	return 0;
111	0	}
112
113	0	png_set_read_fn(png, &io, xps_png_read);
114	0	png_set_crc_action(png, PNG_CRC_WARN_USE, PNG_CRC_WARN_USE);
115
116		/*
117		* Jump to here on errors.
118		*/
119
120	0	if (setjmp(png_jmpbuf(png)))
121	0	{
122	0	png_destroy_read_struct(&png, &info, NULL);
123	0	gs_warn("png reading failed");
124	0	return 0;
125	0	}
126
127		/*
128		* Read PNG header
129		*/
130	0	png_read_info(png, info);
131	0	if (png_get_valid(png, info, PNG_INFO_tRNS))
132	0	{
133		/* this will also expand the depth to 8-bits */
134	0	png_set_tRNS_to_alpha(png);
135	0	}
136	0	png_read_update_info(png, info);
137
138	0	switch (png_get_color_type(png, info))
139	0	{
140	0	case PNG_COLOR_TYPE_PALETTE:
141	0	case PNG_COLOR_TYPE_GRAY:
142	0	case PNG_COLOR_TYPE_RGB:
143	0	has_alpha = 0;
144	0	break;
145
146	0	case PNG_COLOR_TYPE_GRAY_ALPHA:
147	0	case PNG_COLOR_TYPE_RGB_ALPHA:
148	0	has_alpha = 1;
149	0	break;
150
151	0	default:
152	0	gs_warn("cannot handle this png color type");
153	0	has_alpha = 0;
154	0	break;
155	0	}
156
157		/*
158		* Clean up memory.
159		*/
160
161	0	png_destroy_read_struct(&png, &info, NULL);
162
163	0	return has_alpha;
164	0	}
165
166		OPTIMIZE_SETJMP
167		int
168		xps_decode_png(xps_context_t ctx, byte rbuf, int rlen, xps_image_t *image)
169	0	{
170	0	png_structp png;
171	0	png_infop info;
172	0	struct xps_png_io_s io;
173	0	int npasses;
174	0	int pass;
175	0	int y;
176	0	int compression = 0; /* dummy as of libpng 1.5.x */
177	0	char *iccname = NULL;
178	0	char *iccprofile = NULL;
179	0	unsigned int iccproflen = 0;
180	0	png_uint_32 xres, yres;
181	0	int unit;
182	0	uint32_t size;
183
184		/*
185		* Set up PNG structs and input source
186		*/
187
188	0	io.ptr = rbuf;
189	0	io.lim = rbuf + rlen;
190
191	0	png = png_create_read_struct_2(PNG_LIBPNG_VER_STRING,
192	0	NULL, NULL, NULL,
193	0	ctx->memory, xps_png_malloc, xps_png_free);
194	0	if (!png)
195	0	return gs_throw(-1, "png_create_read_struct");
196
197	0	info = png_create_info_struct(png);
198	0	if (!info)
199	0	return gs_throw(-1, "png_create_info_struct");
200
201	0	png_set_read_fn(png, &io, xps_png_read);
202	0	png_set_crc_action(png, PNG_CRC_WARN_USE, PNG_CRC_WARN_USE);
203
204		/*
205		* Jump to here on errors.
206		*/
207
208	0	if (setjmp(png_jmpbuf(png)))
209	0	{
210	0	png_destroy_read_struct(&png, &info, NULL);
211	0	return gs_throw(-1, "png reading failed");
212	0	}
213
214		/*
215		* Read PNG header
216		*/
217
218	0	png_read_info(png, info);
219
220	0	if (png_get_interlace_type(png, info) == PNG_INTERLACE_ADAM7)
221	0	{
222	0	npasses = png_set_interlace_handling(png);
223	0	}
224	0	else
225	0	{
226	0	npasses = 1;
227	0	}
228
229	0	if (png_get_color_type(png, info) == PNG_COLOR_TYPE_PALETTE)
230	0	{
231	0	png_set_palette_to_rgb(png);
232	0	}
233
234	0	if (png_get_valid(png, info, PNG_INFO_tRNS))
235	0	{
236		/* this will also expand the depth to 8-bits */
237	0	png_set_tRNS_to_alpha(png);
238	0	}
239
240	0	png_read_update_info(png, info);
241
242	0	image->width = png_get_image_width(png, info);
243	0	image->height = png_get_image_height(png, info);
244	0	image->comps = png_get_channels(png, info);
245	0	image->bits = png_get_bit_depth(png, info);
246	0	image->invert_decode = false;
247	0	if (image->width <= 0 \|\| image->height <= 0 \|\| image->comps <= 0 \|\| image->bits <= 0)
248	0	return gs_throw(-1, "bad image dimension");
249
250		/* See if we have an icc profile */
251	0	#if PNG_LIBPNG_VER_MINOR >= 5
252		/* ignore the return value */
253	0	(void)png_get_iCCP(png, info, (png_charpp)&iccname, &compression, (png_bytepp)&iccprofile, (png_uint_32 *)&iccproflen);
254		#else
255		iccprofile = info->iccp_profile;
256		iccproflen = info->iccp_proflen;
257		#endif
258	0	if (iccprofile != NULL)
259	0	{
260	0	image->profilesize = iccproflen;
261	0	image->profile = xps_alloc(ctx, iccproflen);
262	0	if (image->profile)
263	0	{
264		/* If we can't create it, just ignore */
265	0	memcpy(image->profile, iccprofile, iccproflen);
266	0	}
267	0	}
268
269	0	switch (png_get_color_type(png, info))
270	0	{
271	0	case PNG_COLOR_TYPE_GRAY:
272	0	rc_increment(ctx->gray);
273	0	image->colorspace = ctx->gray;
274	0	image->hasalpha = 0;
275	0	break;
276
277	0	case PNG_COLOR_TYPE_RGB:
278	0	rc_increment(ctx->srgb);
279	0	image->colorspace = ctx->srgb;
280	0	image->hasalpha = 0;
281	0	break;
282
283	0	case PNG_COLOR_TYPE_GRAY_ALPHA:
284	0	rc_increment(ctx->gray);
285	0	image->colorspace = ctx->gray;
286	0	image->hasalpha = 1;
287	0	break;
288
289	0	case PNG_COLOR_TYPE_RGB_ALPHA:
290	0	rc_increment(ctx->srgb);
291	0	image->colorspace = ctx->srgb;
292	0	image->hasalpha = 1;
293	0	break;
294
295	0	default:
296	0	return gs_throw(-1, "cannot handle this png color type");
297	0	}
298
299		/*
300		* Extract DPI, default to 96 dpi
301		*/
302
303	0	image->xres = 96;
304	0	image->yres = 96;
305
306	0	if (png_get_pHYs(png, info, &xres, &yres, &unit) & PNG_INFO_pHYs)
307	0	{
308	0	if (unit == PNG_RESOLUTION_METER)
309	0	{
310	0	image->xres = (int)(xres * 0.0254 + 0.5);
311	0	image->yres = (int)(yres * 0.0254 + 0.5);
312	0	}
313	0	}
314
315		/*
316		* Read rows, filling transformed output into image buffer.
317		*/
318
319	0	if (check_uint32_multiply((uint32_t)image->width, ((uint32_t)image->bits), &size) != 0)
320	0	return gs_throw(-1, "image is too large");
321
322	0	if (size > INT_MAX / image->comps)
323	0	return gs_throw(-1, "image is too large");
324
325	0	image->stride = (size * image->comps + 7) / 8;
326
327	0	if (check_uint32_multiply((uint32_t)image->stride, (uint32_t)image->height, &size) != 0)
328	0	return gs_throw(-1, "image is too large");
329
330	0	image->samples = xps_alloc(ctx, size);
331	0	if (!image->samples)
332	0	return gs_throw(gs_error_VMerror, "out of memory.\n");
333
334	0	for (pass = 0; pass < npasses; pass++)
335	0	{
336	0	for (y = 0; y < image->height; y++)
337	0	{
338	0	png_read_row(png, image->samples + (y * image->stride), NULL);
339	0	}
340	0	}
341
342		/*
343		* Clean up memory.
344		*/
345
346	0	png_destroy_read_struct(&png, &info, NULL);
347
348	0	return gs_okay;
349	0	}