1// jpgd.h - C++ class for JPEG decompression.
2// Public domain, Rich Geldreich <richgel99@gmail.com>
3#ifndef JPEG_DECODER_H
4#define JPEG_DECODER_H
5
6#include <stdlib.h>
7#include <stdio.h>
8#include <setjmp.h>
9#include <assert.h>
10#include <stdint.h>
11
12#ifdef _MSC_VER
13#define JPGD_NORETURN __declspec(noreturn)
14#elif defined(__GNUC__)
15#define JPGD_NORETURN __attribute__ ((noreturn))
16#else
17#define JPGD_NORETURN
18#endif
19
20#define JPGD_HUFF_TREE_MAX_LENGTH 512
21#define JPGD_HUFF_CODE_SIZE_MAX_LENGTH 256
22
23namespace jpgd
24{
25 typedef unsigned char uint8;
26 typedef signed short int16;
27 typedef unsigned short uint16;
28 typedef unsigned int uint;
29 typedef signed int int32;
30
31 // Loads a JPEG image from a memory buffer or a file.
32 // req_comps can be 1 (grayscale), 3 (RGB), or 4 (RGBA).
33 // On return, width/height will be set to the image's dimensions, and actual_comps will be set to the either 1 (grayscale) or 3 (RGB).
34 // Notes: For more control over where and how the source data is read, see the decompress_jpeg_image_from_stream() function below, or call the jpeg_decoder class directly.
35 // Requesting a 8 or 32bpp image is currently a little faster than 24bpp because the jpeg_decoder class itself currently always unpacks to either 8 or 32bpp.
36 unsigned char* decompress_jpeg_image_from_memory(const unsigned char* pSrc_data, int src_data_size, int* width, int* height, int* actual_comps, int req_comps, uint32_t flags = 0);
37 unsigned char* decompress_jpeg_image_from_file(const char* pSrc_filename, int* width, int* height, int* actual_comps, int req_comps, uint32_t flags = 0);
38
39 // Success/failure error codes.
40 enum jpgd_status
41 {
42 JPGD_SUCCESS = 0, JPGD_FAILED = -1, JPGD_DONE = 1,
43 JPGD_BAD_DHT_COUNTS = -256, JPGD_BAD_DHT_INDEX, JPGD_BAD_DHT_MARKER, JPGD_BAD_DQT_MARKER, JPGD_BAD_DQT_TABLE,
44 JPGD_BAD_PRECISION, JPGD_BAD_HEIGHT, JPGD_BAD_WIDTH, JPGD_TOO_MANY_COMPONENTS,
45 JPGD_BAD_SOF_LENGTH, JPGD_BAD_VARIABLE_MARKER, JPGD_BAD_DRI_LENGTH, JPGD_BAD_SOS_LENGTH,
46 JPGD_BAD_SOS_COMP_ID, JPGD_W_EXTRA_BYTES_BEFORE_MARKER, JPGD_NO_ARITHMITIC_SUPPORT, JPGD_UNEXPECTED_MARKER,
47 JPGD_NOT_JPEG, JPGD_UNSUPPORTED_MARKER, JPGD_BAD_DQT_LENGTH, JPGD_TOO_MANY_BLOCKS,
48 JPGD_UNDEFINED_QUANT_TABLE, JPGD_UNDEFINED_HUFF_TABLE, JPGD_NOT_SINGLE_SCAN, JPGD_UNSUPPORTED_COLORSPACE,
49 JPGD_UNSUPPORTED_SAMP_FACTORS, JPGD_DECODE_ERROR, JPGD_BAD_RESTART_MARKER,
50 JPGD_BAD_SOS_SPECTRAL, JPGD_BAD_SOS_SUCCESSIVE, JPGD_STREAM_READ, JPGD_NOTENOUGHMEM, JPGD_TOO_MANY_SCANS
51 };
52
53 // Input stream interface.
54 // Derive from this class to read input data from sources other than files or memory. Set m_eof_flag to true when no more data is available.
55 // The decoder is rather greedy: it will keep on calling this method until its internal input buffer is full, or until the EOF flag is set.
56 // It the input stream contains data after the JPEG stream's EOI (end of image) marker it will probably be pulled into the internal buffer.
57 // Call the get_total_bytes_read() method to determine the actual size of the JPEG stream after successful decoding.
58 class jpeg_decoder_stream
59 {
60 public:
61 jpeg_decoder_stream() { }
62 virtual ~jpeg_decoder_stream() { }
63
64 // The read() method is called when the internal input buffer is empty.
65 // Parameters:
66 // pBuf - input buffer
67 // max_bytes_to_read - maximum bytes that can be written to pBuf
68 // pEOF_flag - set this to true if at end of stream (no more bytes remaining)
69 // Returns -1 on error, otherwise return the number of bytes actually written to the buffer (which may be 0).
70 // Notes: This method will be called in a loop until you set *pEOF_flag to true or the internal buffer is full.
71 virtual int read(uint8* pBuf, int max_bytes_to_read, bool* pEOF_flag) = 0;
72 };
73
74 // stdio FILE stream class.
75 class jpeg_decoder_file_stream : public jpeg_decoder_stream
76 {
77 jpeg_decoder_file_stream(const jpeg_decoder_file_stream&);
78 jpeg_decoder_file_stream& operator =(const jpeg_decoder_file_stream&);
79
80 FILE* m_pFile;
81 bool m_eof_flag, m_error_flag;
82
83 public:
84 jpeg_decoder_file_stream();
85 virtual ~jpeg_decoder_file_stream();
86
87 bool open(const char* Pfilename);
88 void close();
89
90 virtual int read(uint8* pBuf, int max_bytes_to_read, bool* pEOF_flag);
91 };
92
93 // Memory stream class.
94 class jpeg_decoder_mem_stream : public jpeg_decoder_stream
95 {
96 const uint8* m_pSrc_data;
97 uint m_ofs, m_size;
98
99 public:
100 jpeg_decoder_mem_stream() : m_pSrc_data(NULL), m_ofs(0), m_size(0) { }
101 jpeg_decoder_mem_stream(const uint8* pSrc_data, uint size) : m_pSrc_data(pSrc_data), m_ofs(0), m_size(size) { }
102
103 virtual ~jpeg_decoder_mem_stream() { }
104
105 bool open(const uint8* pSrc_data, uint size);
106 void close() { m_pSrc_data = NULL; m_ofs = 0; m_size = 0; }
107
108 virtual int read(uint8* pBuf, int max_bytes_to_read, bool* pEOF_flag);
109 };
110
111 // Loads JPEG file from a jpeg_decoder_stream.
112 unsigned char* decompress_jpeg_image_from_stream(jpeg_decoder_stream* pStream, int* width, int* height, int* actual_comps, int req_comps, uint32_t flags = 0);
113
114 enum
115 {
116 JPGD_IN_BUF_SIZE = 8192, JPGD_MAX_BLOCKS_PER_MCU = 10, JPGD_MAX_HUFF_TABLES = 8, JPGD_MAX_QUANT_TABLES = 4,
117 JPGD_MAX_COMPONENTS = 4, JPGD_MAX_COMPS_IN_SCAN = 4, JPGD_MAX_BLOCKS_PER_ROW = 16384, JPGD_MAX_HEIGHT = 32768, JPGD_MAX_WIDTH = 32768
118 };
119
120 typedef int16 jpgd_quant_t;
121 typedef int16 jpgd_block_t;
122
123 class jpeg_decoder
124 {
125 public:
126 enum
127 {
128 cFlagLinearChromaFiltering = 1
129 };
130
131 // Call get_error_code() after constructing to determine if the stream is valid or not. You may call the get_width(), get_height(), etc.
132 // methods after the constructor is called. You may then either destruct the object, or begin decoding the image by calling begin_decoding(), then decode() on each scanline.
133 jpeg_decoder(jpeg_decoder_stream* pStream, uint32_t flags = cFlagLinearChromaFiltering);
134
135 ~jpeg_decoder();
136
137 // Call this method after constructing the object to begin decompression.
138 // If JPGD_SUCCESS is returned you may then call decode() on each scanline.
139
140 int begin_decoding();
141
142 // Returns the next scan line.
143 // For grayscale images, pScan_line will point to a buffer containing 8-bit pixels (get_bytes_per_pixel() will return 1).
144 // Otherwise, it will always point to a buffer containing 32-bit RGBA pixels (A will always be 255, and get_bytes_per_pixel() will return 4).
145 // Returns JPGD_SUCCESS if a scan line has been returned.
146 // Returns JPGD_DONE if all scan lines have been returned.
147 // Returns JPGD_FAILED if an error occurred. Call get_error_code() for a more info.
148 int decode(const void** pScan_line, uint* pScan_line_len);
149
150 inline jpgd_status get_error_code() const { return m_error_code; }
151
152 inline int get_width() const { return m_image_x_size; }
153 inline int get_height() const { return m_image_y_size; }
154
155 inline int get_num_components() const { return m_comps_in_frame; }
156
157 inline int get_bytes_per_pixel() const { return m_dest_bytes_per_pixel; }
158 inline int get_bytes_per_scan_line() const { return m_image_x_size * get_bytes_per_pixel(); }
159
160 // Returns the total number of bytes actually consumed by the decoder (which should equal the actual size of the JPEG file).
161 inline int get_total_bytes_read() const { return m_total_bytes_read; }
162
163 private:
164 jpeg_decoder(const jpeg_decoder&);
165 jpeg_decoder& operator =(const jpeg_decoder&);
166
167 typedef void (*pDecode_block_func)(jpeg_decoder*, int, int, int);
168
169 struct huff_tables
170 {
171 bool ac_table;
172 uint look_up[256];
173 uint look_up2[256];
174 uint8 code_size[JPGD_HUFF_CODE_SIZE_MAX_LENGTH];
175 uint tree[JPGD_HUFF_TREE_MAX_LENGTH];
176 };
177
178 struct coeff_buf
179 {
180 uint8* pData;
181 int block_num_x, block_num_y;
182 int block_len_x, block_len_y;
183 int block_size;
184 };
185
186 struct mem_block
187 {
188 mem_block* m_pNext;
189 size_t m_used_count;
190 size_t m_size;
191 char m_data[1];
192 };
193
194 jmp_buf m_jmp_state;
195 uint32_t m_flags;
196 mem_block* m_pMem_blocks;
197 int m_image_x_size;
198 int m_image_y_size;
199 jpeg_decoder_stream* m_pStream;
200
201 int m_progressive_flag;
202
203 uint8 m_huff_ac[JPGD_MAX_HUFF_TABLES];
204 uint8* m_huff_num[JPGD_MAX_HUFF_TABLES]; // pointer to number of Huffman codes per bit size
205 uint8* m_huff_val[JPGD_MAX_HUFF_TABLES]; // pointer to Huffman codes per bit size
206 jpgd_quant_t* m_quant[JPGD_MAX_QUANT_TABLES]; // pointer to quantization tables
207 int m_scan_type; // Gray, Yh1v1, Yh1v2, Yh2v1, Yh2v2 (CMYK111, CMYK4114 no longer supported)
208 int m_comps_in_frame; // # of components in frame
209 int m_comp_h_samp[JPGD_MAX_COMPONENTS]; // component's horizontal sampling factor
210 int m_comp_v_samp[JPGD_MAX_COMPONENTS]; // component's vertical sampling factor
211 int m_comp_quant[JPGD_MAX_COMPONENTS]; // component's quantization table selector
212 int m_comp_ident[JPGD_MAX_COMPONENTS]; // component's ID
213 int m_comp_h_blocks[JPGD_MAX_COMPONENTS];
214 int m_comp_v_blocks[JPGD_MAX_COMPONENTS];
215 int m_comps_in_scan; // # of components in scan
216 int m_comp_list[JPGD_MAX_COMPS_IN_SCAN]; // components in this scan
217 int m_comp_dc_tab[JPGD_MAX_COMPONENTS]; // component's DC Huffman coding table selector
218 int m_comp_ac_tab[JPGD_MAX_COMPONENTS]; // component's AC Huffman coding table selector
219 int m_spectral_start; // spectral selection start
220 int m_spectral_end; // spectral selection end
221 int m_successive_low; // successive approximation low
222 int m_successive_high; // successive approximation high
223 int m_max_mcu_x_size; // MCU's max. X size in pixels
224 int m_max_mcu_y_size; // MCU's max. Y size in pixels
225 int m_blocks_per_mcu;
226 int m_max_blocks_per_row;
227 int m_mcus_per_row, m_mcus_per_col;
228 int m_mcu_org[JPGD_MAX_BLOCKS_PER_MCU];
229 int m_total_lines_left; // total # lines left in image
230 int m_mcu_lines_left; // total # lines left in this MCU
231 int m_num_buffered_scanlines;
232 int m_real_dest_bytes_per_scan_line;
233 int m_dest_bytes_per_scan_line; // rounded up
234 int m_dest_bytes_per_pixel; // 4 (RGB) or 1 (Y)
235 huff_tables* m_pHuff_tabs[JPGD_MAX_HUFF_TABLES];
236 coeff_buf* m_dc_coeffs[JPGD_MAX_COMPONENTS];
237 coeff_buf* m_ac_coeffs[JPGD_MAX_COMPONENTS];
238 int m_eob_run;
239 int m_block_y_mcu[JPGD_MAX_COMPONENTS];
240 uint8* m_pIn_buf_ofs;
241 int m_in_buf_left;
242 int m_tem_flag;
243
244 uint8 m_in_buf_pad_start[64];
245 uint8 m_in_buf[JPGD_IN_BUF_SIZE + 128];
246 uint8 m_in_buf_pad_end[64];
247
248 int m_bits_left;
249 uint m_bit_buf;
250 int m_restart_interval;
251 int m_restarts_left;
252 int m_next_restart_num;
253 int m_max_mcus_per_row;
254 int m_max_blocks_per_mcu;
255
256 int m_max_mcus_per_col;
257 uint m_last_dc_val[JPGD_MAX_COMPONENTS];
258 jpgd_block_t* m_pMCU_coefficients;
259 int m_mcu_block_max_zag[JPGD_MAX_BLOCKS_PER_MCU];
260 uint8* m_pSample_buf;
261 uint8* m_pSample_buf_prev;
262 int m_crr[256];
263 int m_cbb[256];
264 int m_crg[256];
265 int m_cbg[256];
266 uint8* m_pScan_line_0;
267 uint8* m_pScan_line_1;
268 jpgd_status m_error_code;
269 int m_total_bytes_read;
270
271 bool m_ready_flag;
272 bool m_eof_flag;
273 bool m_sample_buf_prev_valid;
274
275 inline int check_sample_buf_ofs(int ofs) const { assert(ofs >= 0); assert(ofs < m_max_blocks_per_row * 64); return ofs; }
276 void free_all_blocks();
277 JPGD_NORETURN void stop_decoding(jpgd_status status);
278 void* alloc(size_t n, bool zero = false);
279 void word_clear(void* p, uint16 c, uint n);
280 void prep_in_buffer();
281 void read_dht_marker();
282 void read_dqt_marker();
283 void read_sof_marker();
284 void skip_variable_marker();
285 void read_dri_marker();
286 void read_sos_marker();
287 int next_marker();
288 int process_markers();
289 void locate_soi_marker();
290 void locate_sof_marker();
291 int locate_sos_marker();
292 void init(jpeg_decoder_stream* pStream, uint32_t flags);
293 void create_look_ups();
294 void fix_in_buffer();
295 void transform_mcu(int mcu_row);
296 coeff_buf* coeff_buf_open(int block_num_x, int block_num_y, int block_len_x, int block_len_y);
297 inline jpgd_block_t* coeff_buf_getp(coeff_buf* cb, int block_x, int block_y);
298 void load_next_row();
299 void decode_next_row();
300 void make_huff_table(int index, huff_tables* pH);
301 void check_quant_tables();
302 void check_huff_tables();
303 bool calc_mcu_block_order();
304 int init_scan();
305 void init_frame();
306 void process_restart();
307 void decode_scan(pDecode_block_func decode_block_func);
308 void init_progressive();
309 void init_sequential();
310 void decode_start();
311 void decode_init(jpeg_decoder_stream* pStream, uint32_t flags);
312 void H2V2Convert();
313 uint32_t H2V2ConvertFiltered();
314 void H2V1Convert();
315 void H2V1ConvertFiltered();
316 void H1V2Convert();
317 void H1V2ConvertFiltered();
318 void H1V1Convert();
319 void gray_convert();
320 void find_eoi();
321 inline uint get_char();
322 inline uint get_char(bool* pPadding_flag);
323 inline void stuff_char(uint8 q);
324 inline uint8 get_octet();
325 inline uint get_bits(int num_bits);
326 inline uint get_bits_no_markers(int numbits);
327 inline int huff_decode(huff_tables* pH);
328 inline int huff_decode(huff_tables* pH, int& extrabits);
329
330 // Clamps a value between 0-255.
331 static inline uint8 clamp(int i)
332 {
333 if (static_cast<uint>(i) > 255)
334 i = (((~i) >> 31) & 0xFF);
335 return static_cast<uint8>(i);
336 }
337 int decode_next_mcu_row();
338
339 static void decode_block_dc_first(jpeg_decoder* pD, int component_id, int block_x, int block_y);
340 static void decode_block_dc_refine(jpeg_decoder* pD, int component_id, int block_x, int block_y);
341 static void decode_block_ac_first(jpeg_decoder* pD, int component_id, int block_x, int block_y);
342 static void decode_block_ac_refine(jpeg_decoder* pD, int component_id, int block_x, int block_y);
343 };
344
345} // namespace jpgd
346
347#endif // JPEG_DECODER_H
348