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* jpegint.h
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1991-1997, Thomas G. Lane.
* Modified 1997-2009 by Guido Vollbeding.
* libjpeg-turbo Modifications:
* Copyright (C) 2015-2016, D. R. Commander.
* Copyright (C) 2015, Google, Inc.
* For conditions of distribution and use, see the accompanying README.ijg
* file.
* This file provides common declarations for the various JPEG modules.
* These declarations are considered internal to the JPEG library; most
* applications using the library shouldn't need to include this file.
/* Declarations for both compression & decompression */
typedef enum { /* Operating modes for buffer controllers */
JBUF_PASS_THRU, /* Plain stripwise operation */
/* Remaining modes require a full-image buffer to have been created */
JBUF_SAVE_SOURCE, /* Run source subobject only, save output */
JBUF_CRANK_DEST, /* Run dest subobject only, using saved data */
JBUF_SAVE_AND_PASS /* Run both subobjects, save output */
/* Values of global_state field (jdapi.c has some dependencies on ordering!) */
#define CSTATE_START 100 /* after create_compress */
#define CSTATE_SCANNING 101 /* start_compress done, write_scanlines OK */
#define CSTATE_RAW_OK 102 /* start_compress done, write_raw_data OK */
#define CSTATE_WRCOEFS 103 /* jpeg_write_coefficients done */
#define DSTATE_START 200 /* after create_decompress */
#define DSTATE_INHEADER 201 /* reading header markers, no SOS yet */
#define DSTATE_READY 202 /* found SOS, ready for start_decompress */
#define DSTATE_PRELOAD 203 /* reading multiscan file in start_decompress*/
#define DSTATE_PRESCAN 204 /* performing dummy pass for 2-pass quant */
#define DSTATE_SCANNING 205 /* start_decompress done, read_scanlines OK */
#define DSTATE_RAW_OK 206 /* start_decompress done, read_raw_data OK */
#define DSTATE_BUFIMAGE 207 /* expecting jpeg_start_output */
#define DSTATE_BUFPOST 208 /* looking for SOS/EOI in jpeg_finish_output */
#define DSTATE_RDCOEFS 209 /* reading file in jpeg_read_coefficients */
#define DSTATE_STOPPING 210 /* looking for EOI in jpeg_finish_decompress */
/* JLONG must hold at least signed 32-bit values. */
typedef long JLONG;
* Left shift macro that handles a negative operand without causing any
* sanitizer warnings
#define LEFT_SHIFT(a, b) ((JLONG)((unsigned long)(a) << (b)))
/* Declarations for compression modules */
/* Master control module */
struct jpeg_comp_master {
void (*prepare_for_pass) (j_compress_ptr cinfo);
void (*pass_startup) (j_compress_ptr cinfo);
void (*finish_pass) (j_compress_ptr cinfo);
/* State variables made visible to other modules */
boolean call_pass_startup; /* True if pass_startup must be called */
boolean is_last_pass; /* True during last pass */
/* Main buffer control (downsampled-data buffer) */
struct jpeg_c_main_controller {
void (*start_pass) (j_compress_ptr cinfo, J_BUF_MODE pass_mode);
void (*process_data) (j_compress_ptr cinfo, JSAMPARRAY input_buf,
JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail);
/* Compression preprocessing (downsampling input buffer control) */
struct jpeg_c_prep_controller {
void (*start_pass) (j_compress_ptr cinfo, J_BUF_MODE pass_mode);
void (*pre_process_data) (j_compress_ptr cinfo, JSAMPARRAY input_buf,
JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail,
JSAMPIMAGE output_buf,
JDIMENSION *out_row_group_ctr,
JDIMENSION out_row_groups_avail);
/* Coefficient buffer control */
struct jpeg_c_coef_controller {
void (*start_pass) (j_compress_ptr cinfo, J_BUF_MODE pass_mode);
boolean (*compress_data) (j_compress_ptr cinfo, JSAMPIMAGE input_buf);
/* Colorspace conversion */
struct jpeg_color_converter {
void (*start_pass) (j_compress_ptr cinfo);
void (*color_convert) (j_compress_ptr cinfo, JSAMPARRAY input_buf,
JSAMPIMAGE output_buf, JDIMENSION output_row,
int num_rows);
/* Downsampling */
struct jpeg_downsampler {
void (*start_pass) (j_compress_ptr cinfo);
void (*downsample) (j_compress_ptr cinfo, JSAMPIMAGE input_buf,
JDIMENSION in_row_index, JSAMPIMAGE output_buf,
JDIMENSION out_row_group_index);
boolean need_context_rows; /* TRUE if need rows above & below */
/* Forward DCT (also controls coefficient quantization) */
struct jpeg_forward_dct {
void (*start_pass) (j_compress_ptr cinfo);
/* perhaps this should be an array??? */
void (*forward_DCT) (j_compress_ptr cinfo, jpeg_component_info *compptr,
JSAMPARRAY sample_data, JBLOCKROW coef_blocks,
JDIMENSION start_row, JDIMENSION start_col,
JDIMENSION num_blocks);
/* Entropy encoding */
struct jpeg_entropy_encoder {
void (*start_pass) (j_compress_ptr cinfo, boolean gather_statistics);
boolean (*encode_mcu) (j_compress_ptr cinfo, JBLOCKROW *MCU_data);
void (*finish_pass) (j_compress_ptr cinfo);
/* Marker writing */
struct jpeg_marker_writer {
void (*write_file_header) (j_compress_ptr cinfo);
void (*write_frame_header) (j_compress_ptr cinfo);
void (*write_scan_header) (j_compress_ptr cinfo);
void (*write_file_trailer) (j_compress_ptr cinfo);
void (*write_tables_only) (j_compress_ptr cinfo);
/* These routines are exported to allow insertion of extra markers */
/* Probably only COM and APPn markers should be written this way */
void (*write_marker_header) (j_compress_ptr cinfo, int marker,
unsigned int datalen);
void (*write_marker_byte) (j_compress_ptr cinfo, int val);
/* Declarations for decompression modules */
/* Master control module */
struct jpeg_decomp_master {
void (*prepare_for_output_pass) (j_decompress_ptr cinfo);
void (*finish_output_pass) (j_decompress_ptr cinfo);
/* State variables made visible to other modules */
boolean is_dummy_pass; /* True during 1st pass for 2-pass quant */
/* Partial decompression variables */
JDIMENSION first_iMCU_col;
boolean jinit_upsampler_no_alloc;
/* Input control module */
struct jpeg_input_controller {
int (*consume_input) (j_decompress_ptr cinfo);
void (*reset_input_controller) (j_decompress_ptr cinfo);
void (*start_input_pass) (j_decompress_ptr cinfo);
void (*finish_input_pass) (j_decompress_ptr cinfo);
/* State variables made visible to other modules */
boolean has_multiple_scans; /* True if file has multiple scans */
boolean eoi_reached; /* True when EOI has been consumed */
/* Main buffer control (downsampled-data buffer) */
struct jpeg_d_main_controller {
void (*start_pass) (j_decompress_ptr cinfo, J_BUF_MODE pass_mode);
void (*process_data) (j_decompress_ptr cinfo, JSAMPARRAY output_buf,
JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail);
/* Coefficient buffer control */
struct jpeg_d_coef_controller {
void (*start_input_pass) (j_decompress_ptr cinfo);
int (*consume_data) (j_decompress_ptr cinfo);
void (*start_output_pass) (j_decompress_ptr cinfo);
int (*decompress_data) (j_decompress_ptr cinfo, JSAMPIMAGE output_buf);
/* Pointer to array of coefficient virtual arrays, or NULL if none */
jvirt_barray_ptr *coef_arrays;
/* Decompression postprocessing (color quantization buffer control) */
struct jpeg_d_post_controller {
void (*start_pass) (j_decompress_ptr cinfo, J_BUF_MODE pass_mode);
void (*post_process_data) (j_decompress_ptr cinfo, JSAMPIMAGE input_buf,
JDIMENSION *in_row_group_ctr,
JDIMENSION in_row_groups_avail,
JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
JDIMENSION out_rows_avail);
/* Marker reading & parsing */
struct jpeg_marker_reader {
void (*reset_marker_reader) (j_decompress_ptr cinfo);
/* Read markers until SOS or EOI.
* Returns same codes as are defined for jpeg_consume_input:
int (*read_markers) (j_decompress_ptr cinfo);
/* Read a restart marker --- exported for use by entropy decoder only */
jpeg_marker_parser_method read_restart_marker;
/* State of marker reader --- nominally internal, but applications
* supplying COM or APPn handlers might like to know the state.
boolean saw_SOI; /* found SOI? */
boolean saw_SOF; /* found SOF? */
int next_restart_num; /* next restart number expected (0-7) */
unsigned int discarded_bytes; /* # of bytes skipped looking for a marker */
/* Entropy decoding */
struct jpeg_entropy_decoder {
void (*start_pass) (j_decompress_ptr cinfo);
boolean (*decode_mcu) (j_decompress_ptr cinfo, JBLOCKROW *MCU_data);
/* This is here to share code between baseline and progressive decoders; */
/* other modules probably should not use it */
boolean insufficient_data; /* set TRUE after emitting warning */
/* Inverse DCT (also performs dequantization) */
typedef void (*inverse_DCT_method_ptr) (j_decompress_ptr cinfo,
jpeg_component_info *compptr,
JCOEFPTR coef_block,
JSAMPARRAY output_buf,
JDIMENSION output_col);
struct jpeg_inverse_dct {
void (*start_pass) (j_decompress_ptr cinfo);
/* It is useful to allow each component to have a separate IDCT method. */
inverse_DCT_method_ptr inverse_DCT[MAX_COMPONENTS];
/* Upsampling (note that upsampler must also call color converter) */
struct jpeg_upsampler {
void (*start_pass) (j_decompress_ptr cinfo);
void (*upsample) (j_decompress_ptr cinfo, JSAMPIMAGE input_buf,
JDIMENSION *in_row_group_ctr,
JDIMENSION in_row_groups_avail, JSAMPARRAY output_buf,
JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail);
boolean need_context_rows; /* TRUE if need rows above & below */
/* Colorspace conversion */
struct jpeg_color_deconverter {
void (*start_pass) (j_decompress_ptr cinfo);
void (*color_convert) (j_decompress_ptr cinfo, JSAMPIMAGE input_buf,
JDIMENSION input_row, JSAMPARRAY output_buf,
int num_rows);
/* Color quantization or color precision reduction */
struct jpeg_color_quantizer {
void (*start_pass) (j_decompress_ptr cinfo, boolean is_pre_scan);
void (*color_quantize) (j_decompress_ptr cinfo, JSAMPARRAY input_buf,
JSAMPARRAY output_buf, int num_rows);
void (*finish_pass) (j_decompress_ptr cinfo);
void (*new_color_map) (j_decompress_ptr cinfo);
/* Miscellaneous useful macros */
#undef MAX
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#undef MIN
#define MIN(a, b) ((a) < (b) ? (a) : (b))
/* We assume that right shift corresponds to signed division by 2 with
* rounding towards minus infinity. This is correct for typical "arithmetic
* shift" instructions that shift in copies of the sign bit. But some
* C compilers implement >> with an unsigned shift. For these machines you
* RIGHT_SHIFT provides a proper signed right shift of a JLONG quantity.
* It is only applied with constant shift counts. SHIFT_TEMPS must be
* included in the variables of any routine using RIGHT_SHIFT.
#define SHIFT_TEMPS JLONG shift_temp;
#define RIGHT_SHIFT(x, shft) \
((shift_temp = (x)) < 0 ? \
(shift_temp >> (shft)) | ((~((JLONG)0)) << (32 - (shft))) : \
(shift_temp >> (shft)))
#define RIGHT_SHIFT(x, shft) ((x) >> (shft))
/* Compression module initialization routines */
EXTERN(void) jinit_compress_master(j_compress_ptr cinfo);
EXTERN(void) jinit_c_master_control(j_compress_ptr cinfo,
boolean transcode_only);
EXTERN(void) jinit_c_main_controller(j_compress_ptr cinfo,
boolean need_full_buffer);
EXTERN(void) jinit_c_prep_controller(j_compress_ptr cinfo,
boolean need_full_buffer);
EXTERN(void) jinit_c_coef_controller(j_compress_ptr cinfo,
boolean need_full_buffer);
EXTERN(void) jinit_color_converter(j_compress_ptr cinfo);
EXTERN(void) jinit_downsampler(j_compress_ptr cinfo);
EXTERN(void) jinit_forward_dct(j_compress_ptr cinfo);
EXTERN(void) jinit_huff_encoder(j_compress_ptr cinfo);
EXTERN(void) jinit_phuff_encoder(j_compress_ptr cinfo);
EXTERN(void) jinit_arith_encoder(j_compress_ptr cinfo);
EXTERN(void) jinit_marker_writer(j_compress_ptr cinfo);
/* Decompression module initialization routines */
EXTERN(void) jinit_master_decompress(j_decompress_ptr cinfo);
EXTERN(void) jinit_d_main_controller(j_decompress_ptr cinfo,
boolean need_full_buffer);
EXTERN(void) jinit_d_coef_controller(j_decompress_ptr cinfo,
boolean need_full_buffer);
EXTERN(void) jinit_d_post_controller(j_decompress_ptr cinfo,
boolean need_full_buffer);
EXTERN(void) jinit_input_controller(j_decompress_ptr cinfo);
EXTERN(void) jinit_marker_reader(j_decompress_ptr cinfo);
EXTERN(void) jinit_huff_decoder(j_decompress_ptr cinfo);
EXTERN(void) jinit_phuff_decoder(j_decompress_ptr cinfo);
EXTERN(void) jinit_arith_decoder(j_decompress_ptr cinfo);
EXTERN(void) jinit_inverse_dct(j_decompress_ptr cinfo);
EXTERN(void) jinit_upsampler(j_decompress_ptr cinfo);
EXTERN(void) jinit_color_deconverter(j_decompress_ptr cinfo);
EXTERN(void) jinit_1pass_quantizer(j_decompress_ptr cinfo);
EXTERN(void) jinit_2pass_quantizer(j_decompress_ptr cinfo);
EXTERN(void) jinit_merged_upsampler(j_decompress_ptr cinfo);
/* Memory manager initialization */
EXTERN(void) jinit_memory_mgr(j_common_ptr cinfo);
/* Utility routines in jutils.c */
EXTERN(long) jdiv_round_up(long a, long b);
EXTERN(long) jround_up(long a, long b);
EXTERN(void) jcopy_sample_rows(JSAMPARRAY input_array, int source_row,
JSAMPARRAY output_array, int dest_row,
int num_rows, JDIMENSION num_cols);
EXTERN(void) jcopy_block_row(JBLOCKROW input_row, JBLOCKROW output_row,
JDIMENSION num_blocks);
EXTERN(void) jzero_far(void *target, size_t bytestozero);
/* Constant tables in jutils.c */
#if 0 /* This table is not actually needed in v6a */
extern const int jpeg_zigzag_order[]; /* natural coef order to zigzag order */
extern const int jpeg_natural_order[]; /* zigzag coef order to natural order */
/* Arithmetic coding probability estimation tables in jaricom.c */
extern const JLONG jpeg_aritab[];
/* Suppress undefined-structure complaints if necessary. */
#ifndef AM_MEMORY_MANAGER /* only jmemmgr.c defines these */
struct jvirt_sarray_control { long dummy; };
struct jvirt_barray_control { long dummy; };