jpeglib.h 48 KB

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  1. /*
  2. * jpeglib.h
  3. *
  4. * Copyright (C) 1991-1998, Thomas G. Lane.
  5. * Modified 2002-2020 by Guido Vollbeding.
  6. * This file is part of the Independent JPEG Group's software.
  7. * For conditions of distribution and use, see the accompanying README file.
  8. *
  9. * This file defines the application interface for the JPEG library.
  10. * Most applications using the library need only include this file,
  11. * and perhaps jerror.h if they want to know the exact error codes.
  12. */
  13. #ifndef JPEGLIB_H
  14. #define JPEGLIB_H
  15. /*
  16. * First we include the configuration files that record how this
  17. * installation of the JPEG library is set up. jconfig.h can be
  18. * generated automatically for many systems. jmorecfg.h contains
  19. * manual configuration options that most people need not worry about.
  20. */
  21. #ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */
  22. #include "jconfig.h" /* widely used configuration options */
  23. #endif
  24. #include "jmorecfg.h" /* seldom changed options */
  25. #ifdef __cplusplus
  26. #ifndef DONT_USE_EXTERN_C
  27. extern "C" {
  28. #endif
  29. #endif
  30. /* Version IDs for the JPEG library.
  31. * Might be useful for tests like "#if JPEG_LIB_VERSION >= 90".
  32. */
  33. #define JPEG_LIB_VERSION 90 /* Compatibility version 9.0 */
  34. #define JPEG_LIB_VERSION_MAJOR 9
  35. #define JPEG_LIB_VERSION_MINOR 5
  36. /* Various constants determining the sizes of things.
  37. * All of these are specified by the JPEG standard,
  38. * so don't change them if you want to be compatible.
  39. */
  40. #define DCTSIZE 8 /* The basic DCT block is 8x8 coefficients */
  41. #define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
  42. #define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */
  43. #define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */
  44. #define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */
  45. #define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */
  46. #define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */
  47. /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
  48. * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
  49. * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
  50. * to handle it. We even let you do this from the jconfig.h file. However,
  51. * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
  52. * sometimes emits noncompliant files doesn't mean you should too.
  53. */
  54. #define C_MAX_BLOCKS_IN_MCU 10 /* compressor's limit on blocks per MCU */
  55. #ifndef D_MAX_BLOCKS_IN_MCU
  56. #define D_MAX_BLOCKS_IN_MCU 10 /* decompressor's limit on blocks per MCU */
  57. #endif
  58. /* Data structures for images (arrays of samples and of DCT coefficients).
  59. * On 80x86 machines, the image arrays are too big for near pointers,
  60. * but the pointer arrays can fit in near memory.
  61. */
  62. typedef JSAMPLE FAR *JSAMPROW; /* ptr to one image row of pixel samples. */
  63. typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */
  64. typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
  65. typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */
  66. typedef JBLOCK FAR *JBLOCKROW; /* pointer to one row of coefficient blocks */
  67. typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */
  68. typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */
  69. typedef JCOEF FAR *JCOEFPTR; /* useful in a couple of places */
  70. /* Types for JPEG compression parameters and working tables. */
  71. /* DCT coefficient quantization tables. */
  72. typedef struct {
  73. /* This array gives the coefficient quantizers in natural array order
  74. * (not the zigzag order in which they are stored in a JPEG DQT marker).
  75. * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
  76. */
  77. UINT16 quantval[DCTSIZE2]; /* quantization step for each coefficient */
  78. /* This field is used only during compression. It's initialized FALSE when
  79. * the table is created, and set TRUE when it's been output to the file.
  80. * You could suppress output of a table by setting this to TRUE.
  81. * (See jpeg_suppress_tables for an example.)
  82. */
  83. boolean sent_table; /* TRUE when table has been output */
  84. } JQUANT_TBL;
  85. /* Huffman coding tables. */
  86. typedef struct {
  87. /* These two fields directly represent the contents of a JPEG DHT marker */
  88. UINT8 bits[17]; /* bits[k] = # of symbols with codes of */
  89. /* length k bits; bits[0] is unused */
  90. UINT8 huffval[256]; /* The symbols, in order of incr code length */
  91. /* This field is used only during compression. It's initialized FALSE when
  92. * the table is created, and set TRUE when it's been output to the file.
  93. * You could suppress output of a table by setting this to TRUE.
  94. * (See jpeg_suppress_tables for an example.)
  95. */
  96. boolean sent_table; /* TRUE when table has been output */
  97. } JHUFF_TBL;
  98. /* Basic info about one component (color channel). */
  99. typedef struct {
  100. /* These values are fixed over the whole image. */
  101. /* For compression, they must be supplied by parameter setup; */
  102. /* for decompression, they are read from the SOF marker. */
  103. int component_id; /* identifier for this component (0..255) */
  104. int component_index; /* its index in SOF or cinfo->comp_info[] */
  105. int h_samp_factor; /* horizontal sampling factor (1..4) */
  106. int v_samp_factor; /* vertical sampling factor (1..4) */
  107. int quant_tbl_no; /* quantization table selector (0..3) */
  108. /* These values may vary between scans. */
  109. /* For compression, they must be supplied by parameter setup; */
  110. /* for decompression, they are read from the SOS marker. */
  111. /* The decompressor output side may not use these variables. */
  112. int dc_tbl_no; /* DC entropy table selector (0..3) */
  113. int ac_tbl_no; /* AC entropy table selector (0..3) */
  114. /* Remaining fields should be treated as private by applications. */
  115. /* These values are computed during compression or decompression startup: */
  116. /* Component's size in DCT blocks.
  117. * Any dummy blocks added to complete an MCU are not counted; therefore
  118. * these values do not depend on whether a scan is interleaved or not.
  119. */
  120. JDIMENSION width_in_blocks;
  121. JDIMENSION height_in_blocks;
  122. /* Size of a DCT block in samples,
  123. * reflecting any scaling we choose to apply during the DCT step.
  124. * Values from 1 to 16 are supported.
  125. * Note that different components may receive different DCT scalings.
  126. */
  127. int DCT_h_scaled_size;
  128. int DCT_v_scaled_size;
  129. /* The downsampled dimensions are the component's actual, unpadded number
  130. * of samples at the main buffer (preprocessing/compression interface);
  131. * DCT scaling is included, so
  132. * downsampled_width =
  133. * ceil(image_width * Hi/Hmax * DCT_h_scaled_size/block_size)
  134. * and similarly for height.
  135. */
  136. JDIMENSION downsampled_width; /* actual width in samples */
  137. JDIMENSION downsampled_height; /* actual height in samples */
  138. /* For decompression, in cases where some of the components will be
  139. * ignored (eg grayscale output from YCbCr image), we can skip most
  140. * computations for the unused components.
  141. * For compression, some of the components will need further quantization
  142. * scale by factor of 2 after DCT (eg BG_YCC output from normal RGB input).
  143. * The field is first set TRUE for decompression, FALSE for compression
  144. * in initial_setup, and then adapted in color conversion setup.
  145. */
  146. boolean component_needed;
  147. /* These values are computed before starting a scan of the component. */
  148. /* The decompressor output side may not use these variables. */
  149. int MCU_width; /* number of blocks per MCU, horizontally */
  150. int MCU_height; /* number of blocks per MCU, vertically */
  151. int MCU_blocks; /* MCU_width * MCU_height */
  152. int MCU_sample_width; /* MCU width in samples: MCU_width * DCT_h_scaled_size */
  153. int last_col_width; /* # of non-dummy blocks across in last MCU */
  154. int last_row_height; /* # of non-dummy blocks down in last MCU */
  155. /* Saved quantization table for component; NULL if none yet saved.
  156. * See jdinput.c comments about the need for this information.
  157. * This field is currently used only for decompression.
  158. */
  159. JQUANT_TBL * quant_table;
  160. /* Private per-component storage for DCT or IDCT subsystem. */
  161. void * dct_table;
  162. } jpeg_component_info;
  163. /* The script for encoding a multiple-scan file is an array of these: */
  164. typedef struct {
  165. int comps_in_scan; /* number of components encoded in this scan */
  166. int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
  167. int Ss, Se; /* progressive JPEG spectral selection parms */
  168. int Ah, Al; /* progressive JPEG successive approx. parms */
  169. } jpeg_scan_info;
  170. /* The decompressor can save APPn and COM markers in a list of these: */
  171. typedef struct jpeg_marker_struct FAR * jpeg_saved_marker_ptr;
  172. struct jpeg_marker_struct {
  173. jpeg_saved_marker_ptr next; /* next in list, or NULL */
  174. UINT8 marker; /* marker code: JPEG_COM, or JPEG_APP0+n */
  175. unsigned int original_length; /* # bytes of data in the file */
  176. unsigned int data_length; /* # bytes of data saved at data[] */
  177. JOCTET FAR * data; /* the data contained in the marker */
  178. /* the marker length word is not counted in data_length or original_length */
  179. };
  180. /* Known color spaces. */
  181. typedef enum {
  182. JCS_UNKNOWN, /* error/unspecified */
  183. JCS_GRAYSCALE, /* monochrome */
  184. JCS_RGB, /* red/green/blue, standard RGB (sRGB) */
  185. JCS_YCbCr, /* Y/Cb/Cr (also known as YUV), standard YCC */
  186. JCS_CMYK, /* C/M/Y/K */
  187. JCS_YCCK, /* Y/Cb/Cr/K */
  188. JCS_BG_RGB, /* big gamut red/green/blue, bg-sRGB */
  189. JCS_BG_YCC /* big gamut Y/Cb/Cr, bg-sYCC */
  190. } J_COLOR_SPACE;
  191. /* Supported color transforms. */
  192. typedef enum {
  193. JCT_NONE = 0,
  194. JCT_SUBTRACT_GREEN = 1
  195. } J_COLOR_TRANSFORM;
  196. /* DCT/IDCT algorithm options. */
  197. typedef enum {
  198. JDCT_ISLOW, /* slow but accurate integer algorithm */
  199. JDCT_IFAST, /* faster, less accurate integer method */
  200. JDCT_FLOAT /* floating-point: accurate, fast on fast HW */
  201. } J_DCT_METHOD;
  202. #ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */
  203. #define JDCT_DEFAULT JDCT_ISLOW
  204. #endif
  205. #ifndef JDCT_FASTEST /* may be overridden in jconfig.h */
  206. #define JDCT_FASTEST JDCT_IFAST
  207. #endif
  208. /* Dithering options for decompression. */
  209. typedef enum {
  210. JDITHER_NONE, /* no dithering */
  211. JDITHER_ORDERED, /* simple ordered dither */
  212. JDITHER_FS /* Floyd-Steinberg error diffusion dither */
  213. } J_DITHER_MODE;
  214. /* Common fields between JPEG compression and decompression master structs. */
  215. #define jpeg_common_fields \
  216. struct jpeg_error_mgr * err; /* Error handler module */\
  217. struct jpeg_memory_mgr * mem; /* Memory manager module */\
  218. struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\
  219. void * client_data; /* Available for use by application */\
  220. boolean is_decompressor; /* So common code can tell which is which */\
  221. int global_state /* For checking call sequence validity */
  222. /* Routines that are to be used by both halves of the library are declared
  223. * to receive a pointer to this structure. There are no actual instances of
  224. * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
  225. */
  226. struct jpeg_common_struct {
  227. jpeg_common_fields; /* Fields common to both master struct types */
  228. /* Additional fields follow in an actual jpeg_compress_struct or
  229. * jpeg_decompress_struct. All three structs must agree on these
  230. * initial fields! (This would be a lot cleaner in C++.)
  231. */
  232. };
  233. typedef struct jpeg_common_struct * j_common_ptr;
  234. typedef struct jpeg_compress_struct * j_compress_ptr;
  235. typedef struct jpeg_decompress_struct * j_decompress_ptr;
  236. /* Master record for a compression instance */
  237. struct jpeg_compress_struct {
  238. jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */
  239. /* Destination for compressed data */
  240. struct jpeg_destination_mgr * dest;
  241. /* Description of source image --- these fields must be filled in by
  242. * outer application before starting compression. in_color_space must
  243. * be correct before you can even call jpeg_set_defaults().
  244. */
  245. JDIMENSION image_width; /* input image width */
  246. JDIMENSION image_height; /* input image height */
  247. int input_components; /* # of color components in input image */
  248. J_COLOR_SPACE in_color_space; /* colorspace of input image */
  249. double input_gamma; /* image gamma of input image */
  250. /* Compression parameters --- these fields must be set before calling
  251. * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to
  252. * initialize everything to reasonable defaults, then changing anything
  253. * the application specifically wants to change. That way you won't get
  254. * burnt when new parameters are added. Also note that there are several
  255. * helper routines to simplify changing parameters.
  256. */
  257. unsigned int scale_num, scale_denom; /* fraction by which to scale image */
  258. JDIMENSION jpeg_width; /* scaled JPEG image width */
  259. JDIMENSION jpeg_height; /* scaled JPEG image height */
  260. /* Dimensions of actual JPEG image that will be written to file,
  261. * derived from input dimensions by scaling factors above.
  262. * These fields are computed by jpeg_start_compress().
  263. * You can also use jpeg_calc_jpeg_dimensions() to determine these values
  264. * in advance of calling jpeg_start_compress().
  265. */
  266. int data_precision; /* bits of precision in image data */
  267. int num_components; /* # of color components in JPEG image */
  268. J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
  269. jpeg_component_info * comp_info;
  270. /* comp_info[i] describes component that appears i'th in SOF */
  271. JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
  272. int q_scale_factor[NUM_QUANT_TBLS];
  273. /* ptrs to coefficient quantization tables, or NULL if not defined,
  274. * and corresponding scale factors (percentage, initialized 100).
  275. */
  276. JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
  277. JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
  278. /* ptrs to Huffman coding tables, or NULL if not defined */
  279. UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
  280. UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
  281. UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
  282. int num_scans; /* # of entries in scan_info array */
  283. const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */
  284. /* The default value of scan_info is NULL, which causes a single-scan
  285. * sequential JPEG file to be emitted. To create a multi-scan file,
  286. * set num_scans and scan_info to point to an array of scan definitions.
  287. */
  288. boolean raw_data_in; /* TRUE=caller supplies downsampled data */
  289. boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
  290. boolean optimize_coding; /* TRUE=optimize entropy encoding parms */
  291. boolean CCIR601_sampling; /* TRUE=first samples are cosited */
  292. boolean do_fancy_downsampling; /* TRUE=apply fancy downsampling */
  293. int smoothing_factor; /* 1..100, or 0 for no input smoothing */
  294. J_DCT_METHOD dct_method; /* DCT algorithm selector */
  295. /* The restart interval can be specified in absolute MCUs by setting
  296. * restart_interval, or in MCU rows by setting restart_in_rows
  297. * (in which case the correct restart_interval will be figured
  298. * for each scan).
  299. */
  300. unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
  301. int restart_in_rows; /* if > 0, MCU rows per restart interval */
  302. /* Parameters controlling emission of special markers. */
  303. boolean write_JFIF_header; /* should a JFIF marker be written? */
  304. UINT8 JFIF_major_version; /* What to write for the JFIF version number */
  305. UINT8 JFIF_minor_version;
  306. /* These three values are not used by the JPEG code, merely copied */
  307. /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */
  308. /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */
  309. /* ratio is defined by X_density/Y_density even when density_unit=0. */
  310. UINT8 density_unit; /* JFIF code for pixel size units */
  311. UINT16 X_density; /* Horizontal pixel density */
  312. UINT16 Y_density; /* Vertical pixel density */
  313. boolean write_Adobe_marker; /* should an Adobe marker be written? */
  314. J_COLOR_TRANSFORM color_transform;
  315. /* Color transform identifier, writes LSE marker if nonzero */
  316. /* State variable: index of next scanline to be written to
  317. * jpeg_write_scanlines(). Application may use this to control its
  318. * processing loop, e.g., "while (next_scanline < image_height)".
  319. */
  320. JDIMENSION next_scanline; /* 0 .. image_height-1 */
  321. /* Remaining fields are known throughout compressor, but generally
  322. * should not be touched by a surrounding application.
  323. */
  324. /*
  325. * These fields are computed during compression startup
  326. */
  327. boolean progressive_mode; /* TRUE if scan script uses progressive mode */
  328. int max_h_samp_factor; /* largest h_samp_factor */
  329. int max_v_samp_factor; /* largest v_samp_factor */
  330. int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */
  331. int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */
  332. JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to coef ctlr */
  333. /* The coefficient controller receives data in units of MCU rows as defined
  334. * for fully interleaved scans (whether the JPEG file is interleaved or not).
  335. * There are v_samp_factor * DCT_v_scaled_size sample rows of each component
  336. * in an "iMCU" (interleaved MCU) row.
  337. */
  338. /*
  339. * These fields are valid during any one scan.
  340. * They describe the components and MCUs actually appearing in the scan.
  341. */
  342. int comps_in_scan; /* # of JPEG components in this scan */
  343. jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
  344. /* *cur_comp_info[i] describes component that appears i'th in SOS */
  345. JDIMENSION MCUs_per_row; /* # of MCUs across the image */
  346. JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
  347. int blocks_in_MCU; /* # of DCT blocks per MCU */
  348. int MCU_membership[C_MAX_BLOCKS_IN_MCU];
  349. /* MCU_membership[i] is index in cur_comp_info of component owning */
  350. /* i'th block in an MCU */
  351. int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
  352. int block_size; /* the basic DCT block size: 1..16 */
  353. const int * natural_order; /* natural-order position array */
  354. int lim_Se; /* min( Se, DCTSIZE2-1 ) */
  355. /*
  356. * Links to compression subobjects (methods and private variables of modules)
  357. */
  358. struct jpeg_comp_master * master;
  359. struct jpeg_c_main_controller * main;
  360. struct jpeg_c_prep_controller * prep;
  361. struct jpeg_c_coef_controller * coef;
  362. struct jpeg_marker_writer * marker;
  363. struct jpeg_color_converter * cconvert;
  364. struct jpeg_downsampler * downsample;
  365. struct jpeg_forward_dct * fdct;
  366. struct jpeg_entropy_encoder * entropy;
  367. jpeg_scan_info * script_space; /* workspace for jpeg_simple_progression */
  368. int script_space_size;
  369. };
  370. /* Master record for a decompression instance */
  371. struct jpeg_decompress_struct {
  372. jpeg_common_fields; /* Fields shared with jpeg_compress_struct */
  373. /* Source of compressed data */
  374. struct jpeg_source_mgr * src;
  375. /* Basic description of image --- filled in by jpeg_read_header(). */
  376. /* Application may inspect these values to decide how to process image. */
  377. JDIMENSION image_width; /* nominal image width (from SOF marker) */
  378. JDIMENSION image_height; /* nominal image height */
  379. int num_components; /* # of color components in JPEG image */
  380. J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
  381. /* Decompression processing parameters --- these fields must be set before
  382. * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes
  383. * them to default values.
  384. */
  385. J_COLOR_SPACE out_color_space; /* colorspace for output */
  386. unsigned int scale_num, scale_denom; /* fraction by which to scale image */
  387. double output_gamma; /* image gamma wanted in output */
  388. boolean buffered_image; /* TRUE=multiple output passes */
  389. boolean raw_data_out; /* TRUE=downsampled data wanted */
  390. J_DCT_METHOD dct_method; /* IDCT algorithm selector */
  391. boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */
  392. boolean do_block_smoothing; /* TRUE=apply interblock smoothing */
  393. boolean quantize_colors; /* TRUE=colormapped output wanted */
  394. /* the following are ignored if not quantize_colors: */
  395. J_DITHER_MODE dither_mode; /* type of color dithering to use */
  396. boolean two_pass_quantize; /* TRUE=use two-pass color quantization */
  397. int desired_number_of_colors; /* max # colors to use in created colormap */
  398. /* these are significant only in buffered-image mode: */
  399. boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */
  400. boolean enable_external_quant;/* enable future use of external colormap */
  401. boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */
  402. /* Description of actual output image that will be returned to application.
  403. * These fields are computed by jpeg_start_decompress().
  404. * You can also use jpeg_calc_output_dimensions() to determine these values
  405. * in advance of calling jpeg_start_decompress().
  406. */
  407. JDIMENSION output_width; /* scaled image width */
  408. JDIMENSION output_height; /* scaled image height */
  409. int out_color_components; /* # of color components in out_color_space */
  410. int output_components; /* # of color components returned */
  411. /* output_components is 1 (a colormap index) when quantizing colors;
  412. * otherwise it equals out_color_components.
  413. */
  414. int rec_outbuf_height; /* min recommended height of scanline buffer */
  415. /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
  416. * high, space and time will be wasted due to unnecessary data copying.
  417. * Usually rec_outbuf_height will be 1 or 2, at most 4.
  418. */
  419. /* When quantizing colors, the output colormap is described by these fields.
  420. * The application can supply a colormap by setting colormap non-NULL before
  421. * calling jpeg_start_decompress; otherwise a colormap is created during
  422. * jpeg_start_decompress or jpeg_start_output.
  423. * The map has out_color_components rows and actual_number_of_colors columns.
  424. */
  425. int actual_number_of_colors; /* number of entries in use */
  426. JSAMPARRAY colormap; /* The color map as a 2-D pixel array */
  427. /* State variables: these variables indicate the progress of decompression.
  428. * The application may examine these but must not modify them.
  429. */
  430. /* Row index of next scanline to be read from jpeg_read_scanlines().
  431. * Application may use this to control its processing loop, e.g.,
  432. * "while (output_scanline < output_height)".
  433. */
  434. JDIMENSION output_scanline; /* 0 .. output_height-1 */
  435. /* Current input scan number and number of iMCU rows completed in scan.
  436. * These indicate the progress of the decompressor input side.
  437. */
  438. int input_scan_number; /* Number of SOS markers seen so far */
  439. JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */
  440. /* The "output scan number" is the notional scan being displayed by the
  441. * output side. The decompressor will not allow output scan/row number
  442. * to get ahead of input scan/row, but it can fall arbitrarily far behind.
  443. */
  444. int output_scan_number; /* Nominal scan number being displayed */
  445. JDIMENSION output_iMCU_row; /* Number of iMCU rows read */
  446. /* Current progression status. coef_bits[c][i] indicates the precision
  447. * with which component c's DCT coefficient i (in zigzag order) is known.
  448. * It is -1 when no data has yet been received, otherwise it is the point
  449. * transform (shift) value for the most recent scan of the coefficient
  450. * (thus, 0 at completion of the progression).
  451. * This pointer is NULL when reading a non-progressive file.
  452. */
  453. int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */
  454. /* Internal JPEG parameters --- the application usually need not look at
  455. * these fields. Note that the decompressor output side may not use
  456. * any parameters that can change between scans.
  457. */
  458. /* Quantization and Huffman tables are carried forward across input
  459. * datastreams when processing abbreviated JPEG datastreams.
  460. */
  461. JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
  462. /* ptrs to coefficient quantization tables, or NULL if not defined */
  463. JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
  464. JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
  465. /* ptrs to Huffman coding tables, or NULL if not defined */
  466. /* These parameters are never carried across datastreams, since they
  467. * are given in SOF/SOS markers or defined to be reset by SOI.
  468. */
  469. int data_precision; /* bits of precision in image data */
  470. jpeg_component_info * comp_info;
  471. /* comp_info[i] describes component that appears i'th in SOF */
  472. boolean is_baseline; /* TRUE if Baseline SOF0 encountered */
  473. boolean progressive_mode; /* TRUE if SOFn specifies progressive mode */
  474. boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
  475. UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
  476. UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
  477. UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
  478. unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
  479. /* These fields record data obtained from optional markers recognized by
  480. * the JPEG library.
  481. */
  482. boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */
  483. /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
  484. UINT8 JFIF_major_version; /* JFIF version number */
  485. UINT8 JFIF_minor_version;
  486. UINT8 density_unit; /* JFIF code for pixel size units */
  487. UINT16 X_density; /* Horizontal pixel density */
  488. UINT16 Y_density; /* Vertical pixel density */
  489. boolean saw_Adobe_marker; /* TRUE iff an Adobe APP14 marker was found */
  490. UINT8 Adobe_transform; /* Color transform code from Adobe marker */
  491. J_COLOR_TRANSFORM color_transform;
  492. /* Color transform identifier derived from LSE marker, otherwise zero */
  493. boolean CCIR601_sampling; /* TRUE=first samples are cosited */
  494. /* Aside from the specific data retained from APPn markers known to the
  495. * library, the uninterpreted contents of any or all APPn and COM markers
  496. * can be saved in a list for examination by the application.
  497. */
  498. jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */
  499. /* Remaining fields are known throughout decompressor, but generally
  500. * should not be touched by a surrounding application.
  501. */
  502. /*
  503. * These fields are computed during decompression startup
  504. */
  505. int max_h_samp_factor; /* largest h_samp_factor */
  506. int max_v_samp_factor; /* largest v_samp_factor */
  507. int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */
  508. int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */
  509. JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */
  510. /* The coefficient controller's input and output progress is measured in
  511. * units of "iMCU" (interleaved MCU) rows. These are the same as MCU rows
  512. * in fully interleaved JPEG scans, but are used whether the scan is
  513. * interleaved or not. We define an iMCU row as v_samp_factor DCT block
  514. * rows of each component. Therefore, the IDCT output contains
  515. * v_samp_factor * DCT_v_scaled_size sample rows of a component per iMCU row.
  516. */
  517. JSAMPLE * sample_range_limit; /* table for fast range-limiting */
  518. /*
  519. * These fields are valid during any one scan.
  520. * They describe the components and MCUs actually appearing in the scan.
  521. * Note that the decompressor output side must not use these fields.
  522. */
  523. int comps_in_scan; /* # of JPEG components in this scan */
  524. jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
  525. /* *cur_comp_info[i] describes component that appears i'th in SOS */
  526. JDIMENSION MCUs_per_row; /* # of MCUs across the image */
  527. JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
  528. int blocks_in_MCU; /* # of DCT blocks per MCU */
  529. int MCU_membership[D_MAX_BLOCKS_IN_MCU];
  530. /* MCU_membership[i] is index in cur_comp_info of component owning */
  531. /* i'th block in an MCU */
  532. int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
  533. /* These fields are derived from Se of first SOS marker.
  534. */
  535. int block_size; /* the basic DCT block size: 1..16 */
  536. const int * natural_order; /* natural-order position array for entropy decode */
  537. int lim_Se; /* min( Se, DCTSIZE2-1 ) for entropy decode */
  538. /* This field is shared between entropy decoder and marker parser.
  539. * It is either zero or the code of a JPEG marker that has been
  540. * read from the data source, but has not yet been processed.
  541. */
  542. int unread_marker;
  543. /*
  544. * Links to decompression subobjects (methods, private variables of modules)
  545. */
  546. struct jpeg_decomp_master * master;
  547. struct jpeg_d_main_controller * main;
  548. struct jpeg_d_coef_controller * coef;
  549. struct jpeg_d_post_controller * post;
  550. struct jpeg_input_controller * inputctl;
  551. struct jpeg_marker_reader * marker;
  552. struct jpeg_entropy_decoder * entropy;
  553. struct jpeg_inverse_dct * idct;
  554. struct jpeg_upsampler * upsample;
  555. struct jpeg_color_deconverter * cconvert;
  556. struct jpeg_color_quantizer * cquantize;
  557. };
  558. /* "Object" declarations for JPEG modules that may be supplied or called
  559. * directly by the surrounding application.
  560. * As with all objects in the JPEG library, these structs only define the
  561. * publicly visible methods and state variables of a module. Additional
  562. * private fields may exist after the public ones.
  563. */
  564. /* Error handler object */
  565. struct jpeg_error_mgr {
  566. /* Error exit handler: does not return to caller */
  567. JMETHOD(noreturn_t, error_exit, (j_common_ptr cinfo));
  568. /* Conditionally emit a trace or warning message */
  569. JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
  570. /* Routine that actually outputs a trace or error message */
  571. JMETHOD(void, output_message, (j_common_ptr cinfo));
  572. /* Format a message string for the most recent JPEG error or message */
  573. JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
  574. #define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */
  575. /* Reset error state variables at start of a new image */
  576. JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
  577. /* The message ID code and any parameters are saved here.
  578. * A message can have one string parameter or up to 8 int parameters.
  579. */
  580. int msg_code;
  581. #define JMSG_STR_PARM_MAX 80
  582. union {
  583. int i[8];
  584. char s[JMSG_STR_PARM_MAX];
  585. } msg_parm;
  586. /* Standard state variables for error facility */
  587. int trace_level; /* max msg_level that will be displayed */
  588. /* For recoverable corrupt-data errors, we emit a warning message,
  589. * but keep going unless emit_message chooses to abort. emit_message
  590. * should count warnings in num_warnings. The surrounding application
  591. * can check for bad data by seeing if num_warnings is nonzero at the
  592. * end of processing.
  593. */
  594. long num_warnings; /* number of corrupt-data warnings */
  595. /* These fields point to the table(s) of error message strings.
  596. * An application can change the table pointer to switch to a different
  597. * message list (typically, to change the language in which errors are
  598. * reported). Some applications may wish to add additional error codes
  599. * that will be handled by the JPEG library error mechanism; the second
  600. * table pointer is used for this purpose.
  601. *
  602. * First table includes all errors generated by JPEG library itself.
  603. * Error code 0 is reserved for a "no such error string" message.
  604. */
  605. const char * const * jpeg_message_table; /* Library errors */
  606. int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */
  607. /* Second table can be added by application (see cjpeg/djpeg for example).
  608. * It contains strings numbered first_addon_message..last_addon_message.
  609. */
  610. const char * const * addon_message_table; /* Non-library errors */
  611. int first_addon_message; /* code for first string in addon table */
  612. int last_addon_message; /* code for last string in addon table */
  613. };
  614. /* Progress monitor object */
  615. struct jpeg_progress_mgr {
  616. JMETHOD(void, progress_monitor, (j_common_ptr cinfo));
  617. long pass_counter; /* work units completed in this pass */
  618. long pass_limit; /* total number of work units in this pass */
  619. int completed_passes; /* passes completed so far */
  620. int total_passes; /* total number of passes expected */
  621. };
  622. /* Data destination object for compression */
  623. struct jpeg_destination_mgr {
  624. JOCTET * next_output_byte; /* => next byte to write in buffer */
  625. size_t free_in_buffer; /* # of byte spaces remaining in buffer */
  626. JMETHOD(void, init_destination, (j_compress_ptr cinfo));
  627. JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
  628. JMETHOD(void, term_destination, (j_compress_ptr cinfo));
  629. };
  630. /* Data source object for decompression */
  631. struct jpeg_source_mgr {
  632. const JOCTET * next_input_byte; /* => next byte to read from buffer */
  633. size_t bytes_in_buffer; /* # of bytes remaining in buffer */
  634. JMETHOD(void, init_source, (j_decompress_ptr cinfo));
  635. JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
  636. JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
  637. JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
  638. JMETHOD(void, term_source, (j_decompress_ptr cinfo));
  639. };
  640. /* Memory manager object.
  641. * Allocates "small" objects (a few K total), "large" objects (tens of K),
  642. * and "really big" objects (virtual arrays with backing store if needed).
  643. * The memory manager does not allow individual objects to be freed; rather,
  644. * each created object is assigned to a pool, and whole pools can be freed
  645. * at once. This is faster and more convenient than remembering exactly what
  646. * to free, especially where malloc()/free() are not too speedy.
  647. * NB: alloc routines never return NULL. They exit to error_exit if not
  648. * successful.
  649. */
  650. #define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */
  651. #define JPOOL_IMAGE 1 /* lasts until done with image/datastream */
  652. #define JPOOL_NUMPOOLS 2
  653. typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
  654. typedef struct jvirt_barray_control * jvirt_barray_ptr;
  655. struct jpeg_memory_mgr {
  656. /* Method pointers */
  657. JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
  658. size_t sizeofobject));
  659. JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
  660. size_t sizeofobject));
  661. JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
  662. JDIMENSION samplesperrow,
  663. JDIMENSION numrows));
  664. JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
  665. JDIMENSION blocksperrow,
  666. JDIMENSION numrows));
  667. JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
  668. int pool_id,
  669. boolean pre_zero,
  670. JDIMENSION samplesperrow,
  671. JDIMENSION numrows,
  672. JDIMENSION maxaccess));
  673. JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
  674. int pool_id,
  675. boolean pre_zero,
  676. JDIMENSION blocksperrow,
  677. JDIMENSION numrows,
  678. JDIMENSION maxaccess));
  679. JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
  680. JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
  681. jvirt_sarray_ptr ptr,
  682. JDIMENSION start_row,
  683. JDIMENSION num_rows,
  684. boolean writable));
  685. JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
  686. jvirt_barray_ptr ptr,
  687. JDIMENSION start_row,
  688. JDIMENSION num_rows,
  689. boolean writable));
  690. JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
  691. JMETHOD(void, self_destruct, (j_common_ptr cinfo));
  692. /* Limit on memory allocation for this JPEG object. (Note that this is
  693. * merely advisory, not a guaranteed maximum; it only affects the space
  694. * used for virtual-array buffers.) May be changed by outer application
  695. * after creating the JPEG object.
  696. */
  697. long max_memory_to_use;
  698. /* Maximum allocation request accepted by alloc_large. */
  699. long max_alloc_chunk;
  700. };
  701. /* Routine signature for application-supplied marker processing methods.
  702. * Need not pass marker code since it is stored in cinfo->unread_marker.
  703. */
  704. typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
  705. /* Declarations for routines called by application.
  706. * The JPP macro hides prototype parameters from compilers that can't cope.
  707. * Note JPP requires double parentheses.
  708. */
  709. #ifdef HAVE_PROTOTYPES
  710. #define JPP(arglist) arglist
  711. #else
  712. #define JPP(arglist) ()
  713. #endif
  714. /* Short forms of external names for systems with brain-damaged linkers.
  715. * We shorten external names to be unique in the first six letters, which
  716. * is good enough for all known systems.
  717. * (If your compiler itself needs names to be unique in less than 15
  718. * characters, you are out of luck. Get a better compiler.)
  719. */
  720. #ifdef NEED_SHORT_EXTERNAL_NAMES
  721. #define jpeg_std_error jStdError
  722. #define jpeg_CreateCompress jCreaCompress
  723. #define jpeg_CreateDecompress jCreaDecompress
  724. #define jpeg_destroy_compress jDestCompress
  725. #define jpeg_destroy_decompress jDestDecompress
  726. #define jpeg_stdio_dest jStdDest
  727. #define jpeg_stdio_src jStdSrc
  728. #define jpeg_mem_dest jMemDest
  729. #define jpeg_mem_src jMemSrc
  730. #define jpeg_set_defaults jSetDefaults
  731. #define jpeg_set_colorspace jSetColorspace
  732. #define jpeg_default_colorspace jDefColorspace
  733. #define jpeg_set_quality jSetQuality
  734. #define jpeg_set_linear_quality jSetLQuality
  735. #define jpeg_default_qtables jDefQTables
  736. #define jpeg_add_quant_table jAddQuantTable
  737. #define jpeg_quality_scaling jQualityScaling
  738. #define jpeg_simple_progression jSimProgress
  739. #define jpeg_suppress_tables jSuppressTables
  740. #define jpeg_alloc_quant_table jAlcQTable
  741. #define jpeg_alloc_huff_table jAlcHTable
  742. #define jpeg_std_huff_table jStdHTable
  743. #define jpeg_start_compress jStrtCompress
  744. #define jpeg_write_scanlines jWrtScanlines
  745. #define jpeg_finish_compress jFinCompress
  746. #define jpeg_calc_jpeg_dimensions jCjpegDimensions
  747. #define jpeg_write_raw_data jWrtRawData
  748. #define jpeg_write_marker jWrtMarker
  749. #define jpeg_write_m_header jWrtMHeader
  750. #define jpeg_write_m_byte jWrtMByte
  751. #define jpeg_write_tables jWrtTables
  752. #define jpeg_read_header jReadHeader
  753. #define jpeg_start_decompress jStrtDecompress
  754. #define jpeg_read_scanlines jReadScanlines
  755. #define jpeg_finish_decompress jFinDecompress
  756. #define jpeg_read_raw_data jReadRawData
  757. #define jpeg_has_multiple_scans jHasMultScn
  758. #define jpeg_start_output jStrtOutput
  759. #define jpeg_finish_output jFinOutput
  760. #define jpeg_input_complete jInComplete
  761. #define jpeg_new_colormap jNewCMap
  762. #define jpeg_consume_input jConsumeInput
  763. #define jpeg_core_output_dimensions jCoreDimensions
  764. #define jpeg_calc_output_dimensions jCalcDimensions
  765. #define jpeg_save_markers jSaveMarkers
  766. #define jpeg_set_marker_processor jSetMarker
  767. #define jpeg_read_coefficients jReadCoefs
  768. #define jpeg_write_coefficients jWrtCoefs
  769. #define jpeg_copy_critical_parameters jCopyCrit
  770. #define jpeg_abort_compress jAbrtCompress
  771. #define jpeg_abort_decompress jAbrtDecompress
  772. #define jpeg_abort jAbort
  773. #define jpeg_destroy jDestroy
  774. #define jpeg_resync_to_restart jResyncRestart
  775. #endif /* NEED_SHORT_EXTERNAL_NAMES */
  776. /* Default error-management setup */
  777. EXTERN(struct jpeg_error_mgr *) jpeg_std_error
  778. JPP((struct jpeg_error_mgr * err));
  779. /* Initialization of JPEG compression objects.
  780. * jpeg_create_compress() and jpeg_create_decompress() are the exported
  781. * names that applications should call. These expand to calls on
  782. * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
  783. * passed for version mismatch checking.
  784. * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
  785. */
  786. #define jpeg_create_compress(cinfo) \
  787. jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
  788. (size_t) sizeof(struct jpeg_compress_struct))
  789. #define jpeg_create_decompress(cinfo) \
  790. jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
  791. (size_t) sizeof(struct jpeg_decompress_struct))
  792. EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo,
  793. int version, size_t structsize));
  794. EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo,
  795. int version, size_t structsize));
  796. /* Destruction of JPEG compression objects */
  797. EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo));
  798. EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
  799. /* Standard data source and destination managers: stdio streams. */
  800. /* Caller is responsible for opening the file before and closing after. */
  801. EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
  802. EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile));
  803. /* Data source and destination managers: memory buffers. */
  804. EXTERN(void) jpeg_mem_dest JPP((j_compress_ptr cinfo,
  805. unsigned char ** outbuffer,
  806. size_t * outsize));
  807. EXTERN(void) jpeg_mem_src JPP((j_decompress_ptr cinfo,
  808. const unsigned char * inbuffer,
  809. size_t insize));
  810. /* Default parameter setup for compression */
  811. EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo));
  812. /* Compression parameter setup aids */
  813. EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo,
  814. J_COLOR_SPACE colorspace));
  815. EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo));
  816. EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
  817. boolean force_baseline));
  818. EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
  819. int scale_factor,
  820. boolean force_baseline));
  821. EXTERN(void) jpeg_default_qtables JPP((j_compress_ptr cinfo,
  822. boolean force_baseline));
  823. EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
  824. const unsigned int *basic_table,
  825. int scale_factor,
  826. boolean force_baseline));
  827. EXTERN(int) jpeg_quality_scaling JPP((int quality));
  828. EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo));
  829. EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo,
  830. boolean suppress));
  831. EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
  832. EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
  833. EXTERN(JHUFF_TBL *) jpeg_std_huff_table JPP((j_common_ptr cinfo,
  834. boolean isDC, int tblno));
  835. /* Main entry points for compression */
  836. EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo,
  837. boolean write_all_tables));
  838. EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo,
  839. JSAMPARRAY scanlines,
  840. JDIMENSION num_lines));
  841. EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo));
  842. /* Precalculate JPEG dimensions for current compression parameters. */
  843. EXTERN(void) jpeg_calc_jpeg_dimensions JPP((j_compress_ptr cinfo));
  844. /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
  845. EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo,
  846. JSAMPIMAGE data,
  847. JDIMENSION num_lines));
  848. /* Write a special marker. See libjpeg.txt concerning safe usage. */
  849. EXTERN(void) jpeg_write_marker
  850. JPP((j_compress_ptr cinfo, int marker,
  851. const JOCTET * dataptr, unsigned int datalen));
  852. /* Same, but piecemeal. */
  853. EXTERN(void) jpeg_write_m_header
  854. JPP((j_compress_ptr cinfo, int marker, unsigned int datalen));
  855. EXTERN(void) jpeg_write_m_byte
  856. JPP((j_compress_ptr cinfo, int val));
  857. /* Alternate compression function: just write an abbreviated table file */
  858. EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo));
  859. /* Decompression startup: read start of JPEG datastream to see what's there */
  860. EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo,
  861. boolean require_image));
  862. /* Return value is one of: */
  863. #define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */
  864. #define JPEG_HEADER_OK 1 /* Found valid image datastream */
  865. #define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
  866. /* If you pass require_image = TRUE (normal case), you need not check for
  867. * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
  868. * JPEG_SUSPENDED is only possible if you use a data source module that can
  869. * give a suspension return (the stdio source module doesn't).
  870. */
  871. /* Main entry points for decompression */
  872. EXTERN(boolean) jpeg_start_decompress JPP((j_decompress_ptr cinfo));
  873. EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
  874. JSAMPARRAY scanlines,
  875. JDIMENSION max_lines));
  876. EXTERN(boolean) jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
  877. /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
  878. EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
  879. JSAMPIMAGE data,
  880. JDIMENSION max_lines));
  881. /* Additional entry points for buffered-image mode. */
  882. EXTERN(boolean) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
  883. EXTERN(boolean) jpeg_start_output JPP((j_decompress_ptr cinfo,
  884. int scan_number));
  885. EXTERN(boolean) jpeg_finish_output JPP((j_decompress_ptr cinfo));
  886. EXTERN(boolean) jpeg_input_complete JPP((j_decompress_ptr cinfo));
  887. EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo));
  888. EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo));
  889. /* Return value is one of: */
  890. /* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */
  891. #define JPEG_REACHED_SOS 1 /* Reached start of new scan */
  892. #define JPEG_REACHED_EOI 2 /* Reached end of image */
  893. #define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */
  894. #define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */
  895. /* Precalculate output dimensions for current decompression parameters. */
  896. EXTERN(void) jpeg_core_output_dimensions JPP((j_decompress_ptr cinfo));
  897. EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
  898. /* Control saving of COM and APPn markers into marker_list. */
  899. EXTERN(void) jpeg_save_markers
  900. JPP((j_decompress_ptr cinfo, int marker_code,
  901. unsigned int length_limit));
  902. /* Install a special processing method for COM or APPn markers. */
  903. EXTERN(void) jpeg_set_marker_processor
  904. JPP((j_decompress_ptr cinfo, int marker_code,
  905. jpeg_marker_parser_method routine));
  906. /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
  907. EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
  908. EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo,
  909. jvirt_barray_ptr * coef_arrays));
  910. EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
  911. j_compress_ptr dstinfo));
  912. /* If you choose to abort compression or decompression before completing
  913. * jpeg_finish_(de)compress, then you need to clean up to release memory,
  914. * temporary files, etc. You can just call jpeg_destroy_(de)compress
  915. * if you're done with the JPEG object, but if you want to clean it up and
  916. * reuse it, call this:
  917. */
  918. EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo));
  919. EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
  920. /* Generic versions of jpeg_abort and jpeg_destroy that work on either
  921. * flavor of JPEG object. These may be more convenient in some places.
  922. */
  923. EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo));
  924. EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo));
  925. /* Default restart-marker-resync procedure for use by data source modules */
  926. EXTERN(boolean) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
  927. int desired));
  928. /* These marker codes are exported since applications and data source modules
  929. * are likely to want to use them.
  930. */
  931. #define JPEG_RST0 0xD0 /* RST0 marker code */
  932. #define JPEG_EOI 0xD9 /* EOI marker code */
  933. #define JPEG_APP0 0xE0 /* APP0 marker code */
  934. #define JPEG_COM 0xFE /* COM marker code */
  935. /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
  936. * for structure definitions that are never filled in, keep it quiet by
  937. * supplying dummy definitions for the various substructures.
  938. */
  939. #ifdef INCOMPLETE_TYPES_BROKEN
  940. #ifndef JPEG_INTERNALS /* will be defined in jpegint.h */
  941. struct jvirt_sarray_control { long dummy; };
  942. struct jvirt_barray_control { long dummy; };
  943. struct jpeg_comp_master { long dummy; };
  944. struct jpeg_c_main_controller { long dummy; };
  945. struct jpeg_c_prep_controller { long dummy; };
  946. struct jpeg_c_coef_controller { long dummy; };
  947. struct jpeg_marker_writer { long dummy; };
  948. struct jpeg_color_converter { long dummy; };
  949. struct jpeg_downsampler { long dummy; };
  950. struct jpeg_forward_dct { long dummy; };
  951. struct jpeg_entropy_encoder { long dummy; };
  952. struct jpeg_decomp_master { long dummy; };
  953. struct jpeg_d_main_controller { long dummy; };
  954. struct jpeg_d_coef_controller { long dummy; };
  955. struct jpeg_d_post_controller { long dummy; };
  956. struct jpeg_input_controller { long dummy; };
  957. struct jpeg_marker_reader { long dummy; };
  958. struct jpeg_entropy_decoder { long dummy; };
  959. struct jpeg_inverse_dct { long dummy; };
  960. struct jpeg_upsampler { long dummy; };
  961. struct jpeg_color_deconverter { long dummy; };
  962. struct jpeg_color_quantizer { long dummy; };
  963. #endif /* JPEG_INTERNALS */
  964. #endif /* INCOMPLETE_TYPES_BROKEN */
  965. /*
  966. * The JPEG library modules define JPEG_INTERNALS before including this file.
  967. * The internal structure declarations are read only when that is true.
  968. * Applications using the library should not include jpegint.h, but may wish
  969. * to include jerror.h.
  970. */
  971. #ifdef JPEG_INTERNALS
  972. #include "jpegint.h" /* fetch private declarations */
  973. #include "jerror.h" /* fetch error codes too */
  974. #endif
  975. #ifdef __cplusplus
  976. #ifndef DONT_USE_EXTERN_C
  977. }
  978. #endif
  979. #endif
  980. #endif /* JPEGLIB_H */