Fix a Makefile typo.
[fjl] / driver.c
1 #include <stdio.h>
2 #include <string.h>
3 #include <stdlib.h>
4
5 #include "bytesource.h"
6 #include "choice.h"
7 #include "dehuff.h"
8 #include "idct.h"
9 #include "input.h"
10 #include "zigzag.h"
11
12 struct jpeg_image {
13         unsigned precision;
14         unsigned width, height;
15         unsigned num_components;
16         unsigned hsample[256], vsample[256], qtable[256];
17         unsigned max_hsample, max_vsample;
18         unsigned stride[256];
19         unsigned num_blocks_horizontal, num_blocks_vertical;
20         uint32_t qvalues[256][DCTSIZE2];
21         void* idct_data[256];
22         uint8_t* pixel_data[256];
23         uint8_t* pixel_write_pointer[256];
24 };
25
26 ssize_t stdio_read(void* userdata, uint8_t* buf, size_t count) 
27 {
28         return fread(buf, 1, count, (FILE*)userdata);
29 }
30
31 void read_dqt(struct byte_source* source, struct jpeg_image* image)
32 {
33         unsigned len = read_uint16(byte_source_input_func, source);
34         assert(len >= 67);
35         uint8_t precision_table = read_uint8(byte_source_input_func, source);
36         int precision = precision_table >> 4;  // 0 = 8 bits, otherwise 16 bits.
37         int table = precision_table & 0x0f;
38
39         if (image->idct_data[table] != NULL) {
40                 idct_choice_free(image->idct_data[table]);
41         }
42
43         if (precision != 0) {
44                 assert(len == 131);
45                 fprintf(stderr, "Quantization table %u: 16 bits/entry\n", table);
46         } else {
47                 assert(len == 67);
48                 fprintf(stderr, "Quantization table %u: 8 bits/entry\n", table);
49         }
50         
51         for (unsigned i = 0; i < 64; ++i) {
52                 if (precision != 0) {
53                         image->qvalues[table][unzigzag[i]] =
54                                 read_uint16(byte_source_input_func, source);
55                 } else {
56                         image->qvalues[table][unzigzag[i]] =
57                                 read_uint8(byte_source_input_func, source);
58                 }       
59         }
60
61         image->idct_data[table] = idct_choice_alloc(image->qvalues[table]);
62 }
63
64 void read_sof(struct byte_source* source, struct jpeg_image* image)
65 {
66         unsigned len = read_uint16(byte_source_input_func, source);
67         assert(len >= 8);
68         image->precision = read_uint8(byte_source_input_func, source);
69         assert(image->precision == 8);
70         image->height = read_uint16(byte_source_input_func, source);
71         image->width = read_uint16(byte_source_input_func, source);
72         image->num_components = read_uint8(byte_source_input_func, source);
73         len -= 8;
74
75         fprintf(stderr, "%u-bit %ux%u JPEG with %u components\n",
76                 image->precision, image->width, image->height, image->num_components);
77
78         for (unsigned i = 0; i < image->num_components; ++i) {
79                 assert(len >= 3);
80                 unsigned c = read_uint8(byte_source_input_func, source);
81                 unsigned sampling_factors = read_uint8(byte_source_input_func, source);
82                 image->hsample[c] = sampling_factors >> 4;
83                 image->vsample[c] = sampling_factors & 0x0f;
84                 image->qtable[c] = read_uint8(byte_source_input_func, source);
85                 len -= 3;
86
87                 if (image->hsample[c] > image->max_hsample) {
88                         image->max_hsample = image->hsample[c];
89                 }
90                 if (image->vsample[c] > image->max_vsample) {
91                         image->max_vsample = image->vsample[c];
92                 }
93
94                 fprintf(stderr, "Component %u: sampling factors %u x %x, quantization table %u\n",
95                         c, image->hsample[c], image->vsample[c], image->qtable[c]);
96         }
97         
98         image->num_blocks_horizontal = (image->width + image->max_hsample * DCTSIZE - 1) / (image->max_hsample * DCTSIZE);
99         image->num_blocks_vertical = (image->height + image->max_vsample * DCTSIZE - 1) / (image->max_vsample * DCTSIZE);
100
101         for (unsigned c = 0; c < 256; ++c) {
102                 if (image->hsample[c] == 0) {
103                         continue;
104                 }
105
106                 unsigned width = image->num_blocks_horizontal * image->hsample[c] * DCTSIZE;
107                 unsigned height = image->num_blocks_vertical * image->vsample[c] * DCTSIZE;
108                 image->stride[c] = width;
109                 image->pixel_data[c] = (uint8_t*)malloc(width * height);
110                 assert(image->pixel_data[c] != NULL);
111                 image->pixel_write_pointer[c] = image->pixel_data[c];
112
113                 fprintf(stderr, "Component %u: allocating %d x %d\n", c, width, height);
114         }
115 }
116
117 void decode_ac_coefficients(const struct huffman_table* tbl, struct bit_source* bits, int16_t* coeff)
118 {
119         for (unsigned i = 1; i < DCTSIZE2; ++i) {
120                 possibly_refill(bits, DEHUF_AC_TABLE_BITS);
121                 unsigned lookup = peek_bits(bits, DEHUF_AC_TABLE_BITS);
122                 int code = tbl->ac_table_codes[lookup];
123
124                 if (__builtin_expect(code == AC_DEHUF_SLOW_PATH, 0)) {
125                         unsigned rs = read_huffman_symbol_no_refill(tbl, bits);
126                         unsigned r = rs >> 4;
127                         unsigned s = rs & 0xf;
128                         i += r;
129                         possibly_refill(bits, s);
130
131                         if (rs == 0x00) {
132                                 assert(code == AC_DEHUF_SLOW_PATH || code == AC_END_OF_BLOCK);
133                                 /* end of block */
134                                 break;
135                         }
136                         if (rs == 0xf0) {
137                                 assert(code == AC_DEHUF_SLOW_PATH || code == AC_SIXTEEN_ZEROS);
138                                 /* 16 zero coefficients */
139                                 continue;
140                         }
141
142                         coeff[unzigzag[i]] = extend(read_bits(bits, s), s);
143                 } else {
144                         unsigned length = tbl->ac_table_length[lookup];
145                         int r = tbl->ac_table_skip[lookup];
146                         assert(r >= 0);
147                         i += r;
148                         assert(bits->bits_available >= length);
149                         read_bits(bits, length);
150                         if (code == AC_END_OF_BLOCK) {
151                                 break;
152                         }
153                         if (code == AC_SIXTEEN_ZEROS) {
154                                 continue;
155                         }
156                         coeff[unzigzag[i]] = code;
157                 }
158         }
159 }
160
161 void read_scan(struct byte_source* source, struct jpeg_image* image, huffman_tables_t* tables)
162 {
163         unsigned len = read_uint16(byte_source_input_func, source);
164         assert(len >= 2);
165         len -= 2;
166
167         assert(len >= 1);
168         unsigned num_components = read_uint8(byte_source_input_func, source);
169         --len;
170
171         unsigned component_num[256];
172         unsigned dc_huffman_table[256], ac_huffman_table[256];
173         unsigned ss, se, ah_al;
174         int last_dc[256];
175
176         for (unsigned i = 0; i < num_components; ++i) {
177                 unsigned char td_ta;
178                 assert(len >= 2);
179                 component_num[i] = read_uint8(byte_source_input_func, source);
180                 td_ta = read_uint8(byte_source_input_func, source);
181                 len -= 2;
182                 dc_huffman_table[i] = td_ta >> 4;
183                 ac_huffman_table[i] = td_ta & 0x0f;
184                 last_dc[i] = 0;
185         }
186
187         assert(len >= 3);
188         ss = read_uint8(byte_source_input_func, source);
189         se = read_uint8(byte_source_input_func, source);
190         ah_al = read_uint8(byte_source_input_func, source);
191         len -= 3;
192
193         if (len != 0) {
194                 fprintf(stderr, "Error: %u unused bytes at end of SOS segment\n", len);
195         }
196
197         struct bit_source bits;
198         init_bit_source(&bits, byte_source_input_func, 8, source);
199                 
200         unsigned mcu_x = 0, mcu_y = 0;
201
202         while (!bits.source_eof) {
203                 for (unsigned c = 0; c < num_components; ++c) {
204                         unsigned cn = component_num[c];
205                         assert(image->idct_data[image->qtable[cn]] != NULL);
206
207                         uint8_t* pixel_write_pointer_y = image->pixel_write_pointer[cn];
208                         for (unsigned local_yb = 0; local_yb < image->vsample[cn]; ++local_yb, pixel_write_pointer_y += image->stride[cn] * DCTSIZE) {
209                                 uint8_t* pixel_write_pointer = pixel_write_pointer_y;
210                                 for (unsigned local_xb = 0; local_xb < image->hsample[cn]; ++local_xb, pixel_write_pointer += DCTSIZE) {
211                                         const struct huffman_table* dc_table = &((*tables)[DC_CLASS][dc_huffman_table[c]]);
212                                         const struct huffman_table* ac_table = &((*tables)[AC_CLASS][ac_huffman_table[c]]);
213
214                                         // decode DC component
215                                         unsigned dc_category = read_huffman_symbol(dc_table, &bits);
216                                         possibly_refill(&bits, dc_category);
217                                         last_dc[c] += extend(read_bits(&bits, dc_category), dc_category);
218                                         
219                                         int16_t coeff[DCTSIZE2] = { 0 };
220                                         coeff[0] = last_dc[c];
221                                         decode_ac_coefficients(ac_table, &bits, coeff);
222
223                                         uint8_t pixdata[DCTSIZE2];      
224                                         idct_choice(coeff, image->idct_data[image->qtable[cn]], pixdata);
225
226                                         uint8_t* dest_pixdata = pixel_write_pointer;
227                                         for (unsigned y = 0; y < DCTSIZE; ++y, dest_pixdata += image->stride[cn]) {
228                                                 memcpy(dest_pixdata, pixdata + y * DCTSIZE, DCTSIZE);
229                                         }
230                                 }
231                         }
232                         image->pixel_write_pointer[cn] += DCTSIZE * image->hsample[cn];
233                 }
234         
235                 if (++mcu_x == image->num_blocks_horizontal) {
236                         ++mcu_y;
237                         mcu_x = 0;
238                 
239                         for (unsigned c = 0; c < num_components; ++c) {
240                                 unsigned cn = component_num[c];
241                                 image->pixel_write_pointer[cn] += (image->vsample[cn] * DCTSIZE - 1) * image->stride[cn];
242                         }
243
244                         // Some debug code.
245                         const int c = 1;
246                         if (mcu_y == image->num_blocks_vertical) {
247                                 unsigned stride = image->num_blocks_horizontal * image->hsample[c] * DCTSIZE;
248                                 unsigned height = image->num_blocks_vertical * image->vsample[c] * DCTSIZE;
249                                 printf("P5\n%u %u\n255\n", stride, height);
250                                 fwrite(image->pixel_data[c], stride * height, 1, stdout);
251                         }
252                 }
253         }
254         if (len != 0) {
255                 fprintf(stderr, "Error: %u unused bytes at end of SOS segment\n", len);
256         }
257 }
258                         
259 void skip_segment(struct byte_source* source)
260 {
261         uint8_t buf[4096];
262         for ( ;; ) {
263                 ssize_t ret = byte_source_input_func(source, buf, 4096);
264                 if (ret == -1) {
265                         fprintf(stderr, "Input error!\n");
266                         exit(1);
267                 }
268                 if (ret == 0) {
269                         return;
270                 }
271         }
272 }
273         
274 int main(void)
275 {
276         struct jpeg_image jpeg;
277         memset(&jpeg, 0, sizeof(jpeg));
278         init_choices();
279
280         struct byte_source source;
281         init_byte_source(&source, stdio_read, stdin);
282
283         huffman_tables_t tables;
284
285         for ( ;; ) {
286                 uint8_t m2 = byte_source_read_marker(&source);
287                 assert(m2 != 0x00);
288
289                 fprintf(stderr, "Marker 0x%02x, at position %ld\n", m2, ftell(stdin) - source.bytes_available);
290
291                 switch (m2) {
292                 case 0xe0:
293                 case 0xe1:
294                 case 0xe2:
295                 case 0xe3:
296                 case 0xe4:
297                 case 0xe5:
298                 case 0xe6:
299                 case 0xe7:
300                 case 0xe8:
301                 case 0xe9:
302                 case 0xea:
303                 case 0xeb:
304                 case 0xec:
305                 case 0xed:
306                 case 0xee:
307                 case 0xef:
308                         /* APP0 through APPF */
309                 case 0xfc:
310                         /* some EXIF stuff */
311                 case 0xfe:
312                         /* comment */
313                 case 0xff:
314                         /* ignore */
315                         skip_segment(&source);
316                         break;
317                 case 0xdb:
318                         /* DQT */
319                         read_dqt(&source, &jpeg);
320                         break;
321                 case 0xc0:
322                         /* SOF0 (baseline DCT, Huffman encoded) */
323                         read_sof(&source, &jpeg);
324                         break;
325                 case 0xd8:
326                         /* SOI */
327                         break;
328                 case 0xd9:
329                         /* EOI */
330                         exit(0);
331                 case 0xc4:
332                         /* DHT (define Huffman tables) */
333                         read_huffman_tables(&tables, byte_source_input_func, &source);
334                         break;
335                 case 0xda:
336                         /* SOS (start of scan) */
337                         read_scan(&source, &jpeg, &tables);
338                         break;
339                 default:
340                         fprintf(stderr, "Error: Unknown marker 0x%02x\n", m2);
341                         exit(1);
342                 }
343         }
344 }