1 /* png.c
2 * PNG decoding
3 * (c) 2002 Karel 'Clock' Kulhavy
4 * This is a part of the Links program, released under GPL.
5 */
6 #include "cfg.h"
7
8 #ifdef G
9 #include "links.h"
10
11 #ifdef REPACK_16
12 #undef REPACK_16
13 #endif /* #ifdef REPACK_16 */
14
15 #if SIZEOF_UNSIGNED_SHORT != 2
16 #define REPACK_16
17 #endif /* #if SIZEOF_UNSIGNED_SHORT != 2 */
18
19 #ifndef REPACK_16
20 #ifndef C_LITTLE_ENDIAN
21 #ifndef C_BIG_ENDIAN
22 #define REPACK_16
23 #endif /* #ifndef C_BIG_ENDIAN */
24 #endif /* #ifndef C_LITTLE_ENDIAN */
25 #endif /* #ifndef REPACK_16 */
26
27 /* Decoder structs */
28
29 struct png_decoder{
30 png_structp png_ptr;
31 png_infop info_ptr;
32 };
33
34 /* Warning for from-web PNG images */
img_my_png_warning(png_structp a,png_const_charp b)35 static void img_my_png_warning(png_structp a, png_const_charp b)
36 {
37 }
38
39 /* Error for from-web PNG images. */
img_my_png_error(png_structp png_ptr,png_const_charp error_string)40 static void img_my_png_error(png_structp png_ptr, png_const_charp error_string)
41 {
42 #if (PNG_LIBPNG_VER < 10500)
43 longjmp(png_ptr->jmpbuf,1);
44 #else
45 png_longjmp(png_ptr,1);
46 #endif
47 }
48
png_info_callback(png_structp png_ptr,png_infop info_ptr)49 static void png_info_callback(png_structp png_ptr, png_infop info_ptr)
50 {
51 int bit_depth, color_type, intent;
52 double gamma;
53 unsigned char bytes_per_pixel=3;
54 struct cached_image *cimg;
55
56 cimg=global_cimg;
57
58 bit_depth=png_get_bit_depth(png_ptr, info_ptr);
59 color_type=png_get_color_type(png_ptr, info_ptr);
60 if (color_type == PNG_COLOR_TYPE_PALETTE)
61 png_set_expand(png_ptr);
62 if (color_type == PNG_COLOR_TYPE_GRAY &&
63 bit_depth < 8) png_set_expand(png_ptr);
64 if (png_get_valid(png_ptr, info_ptr,
65 PNG_INFO_tRNS)){
66 png_set_expand(png_ptr); /* Legacy version of
67 png_set_tRNS_to_alpha(png_ptr); */
68 bytes_per_pixel++;
69 }
70 if (color_type == PNG_COLOR_TYPE_GRAY ||
71 color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
72 png_set_gray_to_rgb(png_ptr);
73 if (bit_depth==16){
74 #ifndef REPACK_16
75 #ifdef C_LITTLE_ENDIAN
76 /* We use native endianity only if unsigned short is 2-byte
77 * because otherwise we have to reassemble the buffer so we
78 * will leave in the libpng-native big endian.
79 */
80 png_set_swap(png_ptr);
81 #endif /* #ifdef C_LITTLE_ENDIAN */
82 #endif /* #ifndef REPACK_16 */
83 bytes_per_pixel*=(int)sizeof(unsigned short);
84 }
85 png_set_interlace_handling(png_ptr);
86 if (color_type==PNG_COLOR_TYPE_RGB_ALPHA
87 ||color_type==PNG_COLOR_TYPE_GRAY_ALPHA){
88 if (bytes_per_pixel==3
89 ||bytes_per_pixel==3*sizeof(unsigned short))
90 bytes_per_pixel=4*bytes_per_pixel/3;
91 }
92 cimg->width=(int)png_get_image_width(png_ptr,info_ptr);
93 cimg->height=(int)png_get_image_height(png_ptr,info_ptr);
94 cimg->buffer_bytes_per_pixel=bytes_per_pixel;
95 if (png_get_sRGB(png_ptr, info_ptr, &intent)){
96 gamma=sRGB_gamma;
97 }
98 else
99 {
100 if (!png_get_gAMA(png_ptr, info_ptr, &gamma)){
101 gamma=sRGB_gamma;
102 }
103 }
104 if (gamma < 0.01 || gamma > 100)
105 gamma = sRGB_gamma;
106 cimg->red_gamma=(float)gamma;
107 cimg->green_gamma=(float)gamma;
108 cimg->blue_gamma=(float)gamma;
109 png_read_update_info(png_ptr,info_ptr);
110 cimg->strip_optimized=0;
111 if (header_dimensions_known(cimg))
112 img_my_png_error(png_ptr, "bad image size");
113 }
114
115 #ifdef REPACK_16
116 /* Converts unsigned shorts to doublechars (in big endian) */
a2char_from_unsigned_short(unsigned char * chr,unsigned short * shrt,int len)117 static void a2char_from_unsigned_short(unsigned char *chr, unsigned short *shrt, int len)
118 {
119 unsigned short s;
120
121 for (;len;len--,shrt++,chr+=2){
122 s=*shrt;
123 *chr=s>>8;
124 chr[1]=s;
125 }
126 }
127
128 /* Converts doublechars (in big endian) to unsigned shorts */
unsigned_short_from_2char(unsigned short * shrt,unsigned char * chr,int len)129 static void unsigned_short_from_2char(unsigned short *shrt, unsigned char *chr, int len)
130 {
131 unsigned short s;
132
133 for (;len;len--,shrt++,chr+=2){
134 s=((*chr)<<8)|chr[1];
135 *shrt=s;
136 }
137 }
138 #endif
139
png_row_callback(png_structp png_ptr,png_bytep new_row,png_uint_32 row_num,int pass)140 static void png_row_callback(png_structp png_ptr, png_bytep new_row, png_uint_32
141 row_num, int pass)
142 {
143 struct cached_image *cimg;
144 #ifdef REPACK_16
145 unsigned char *tmp;
146 int channels;
147 #endif /* #ifdef REPACK_16 */
148
149 cimg=global_cimg;
150 #ifdef REPACK_16
151 if (cimg->buffer_bytes_per_pixel>4)
152 {
153 channels=cimg->buffer_bytes_per_pixel/sizeof(unsigned
154 short);
155 if (PNG_INTERLACE_NONE==png_get_interlace_type(png_ptr,
156 ((struct png_decoder *)cimg->decoder)->info_ptr))
157 {
158 unsigned_short_from_2char((unsigned short *)(cimg->buffer+cimg
159 ->buffer_bytes_per_pixel *cimg->width
160 *row_num), new_row, cimg->width
161 *channels);
162 }else{
163 if ((unsigned)cimg->width > (unsigned)MAXINT / 2 / channels) overalloc();
164 tmp=mem_alloc(cimg->width*2*channels);
165 a2char_from_unsigned_short(tmp, (unsigned short *)(cimg->buffer
166 +cimg->buffer_bytes_per_pixel
167 *cimg->width*row_num), cimg->width*channels);
168 png_progressive_combine_row(png_ptr, tmp, new_row);
169 unsigned_short_from_2char((unsigned short *)(cimg->buffer
170 +cimg->buffer_bytes_per_pixel
171 *cimg->width*row_num), tmp, cimg->width*channels);
172 mem_free(tmp);
173 }
174 }else
175 #endif /* #ifdef REPACK_16 */
176 {
177 png_progressive_combine_row(png_ptr,
178 cimg->buffer+cimg->buffer_bytes_per_pixel
179 *cimg->width*row_num, new_row);
180 }
181 cimg->rows_added=1;
182 }
183
png_end_callback(png_structp png_ptr,png_infop info)184 static void png_end_callback(png_structp png_ptr, png_infop info)
185 {
186 end_callback_hit=1;
187 }
188
189 /* Decoder structs */
190
png_start(struct cached_image * cimg)191 void png_start(struct cached_image *cimg)
192 {
193 png_structp png_ptr;
194 png_infop info_ptr;
195 struct png_decoder *decoder;
196
197 retry1:
198 #ifdef PNG_USER_MEM_SUPPORTED
199 png_ptr=png_create_read_struct_2(PNG_LIBPNG_VER_STRING,
200 NULL, img_my_png_error, img_my_png_warning,
201 NULL, my_png_alloc, my_png_free);
202 #else
203 png_ptr=png_create_read_struct(PNG_LIBPNG_VER_STRING,
204 NULL, img_my_png_error, img_my_png_warning);
205 #endif
206 if (!png_ptr) {
207 if (out_of_memory(0, NULL, 0)) goto retry1;
208 fatal_exit("png_create_read_struct failed");
209 }
210 retry2:
211 info_ptr=png_create_info_struct(png_ptr);
212 if (!info_ptr) {
213 if (out_of_memory(0, NULL, 0)) goto retry2;
214 fatal_exit("png_create_info_struct failed");
215 }
216 if (setjmp(png_jmpbuf(png_ptr))){
217 error:
218 png_destroy_read_struct(&png_ptr, &info_ptr,
219 (png_infopp)NULL);
220 img_end(cimg);
221 return;
222 }
223 png_set_progressive_read_fn(png_ptr, NULL,
224 png_info_callback, &png_row_callback,
225 png_end_callback);
226 if (setjmp(png_jmpbuf(png_ptr))) goto error;
227 decoder=mem_alloc(sizeof(*decoder));
228 decoder->png_ptr=png_ptr;
229 decoder->info_ptr=info_ptr;
230 cimg->decoder=decoder;
231 }
232
png_restart(struct cached_image * cimg,unsigned char * data,int length)233 void png_restart(struct cached_image *cimg, unsigned char *data, int length)
234 {
235 png_structp png_ptr;
236 png_infop info_ptr;
237 volatile int h;
238
239 #ifdef DEBUG
240 if (!cimg->decoder)
241 internal_error("decoder NULL in png_restart\n");
242
243 #endif /* #ifdef DEBUG */
244 h = close_std_handle(2);
245 png_ptr=((struct png_decoder *)(cimg->decoder))->png_ptr;
246 info_ptr=((struct png_decoder *)(cimg->decoder))->info_ptr;
247 end_callback_hit=0;
248 if (setjmp(png_jmpbuf(png_ptr))) {
249 restore_std_handle(2, h);
250 img_end(cimg);
251 return;
252 }
253 png_process_data(png_ptr, info_ptr, data, length);
254 restore_std_handle(2, h);
255 if (end_callback_hit) img_end(cimg);
256 }
257
png_destroy_decoder(struct cached_image * cimg)258 void png_destroy_decoder(struct cached_image *cimg)
259 {
260 struct png_decoder *decoder = (struct png_decoder *)cimg->decoder;
261 png_destroy_read_struct(&decoder->png_ptr, &decoder->info_ptr, NULL);
262 }
263
add_png_version(unsigned char ** s,int * l)264 void add_png_version(unsigned char **s, int *l)
265 {
266 add_to_str(s, l, cast_uchar "PNG (");
267 #ifdef HAVE_PNG_GET_LIBPNG_VER
268 add_to_str(s, l, cast_uchar png_get_libpng_ver(NULL));
269 #else
270 add_to_str(s, l, cast_uchar PNG_LIBPNG_VER_STRING);
271 #endif
272 add_chr_to_str(s, l, ')');
273 }
274
275 #endif /* #ifdef G */
276