mozjpeg/jpegint.h

/*
 * jpegint.h
 *
 * Copyright (C) 1991-1994, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README 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 */
	JBUF_CRANK_SOURCE,	/* Run source subobject, no output expected */
	/* 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 */
} J_BUF_MODE;

/* Values of global_state field */
#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 DSTATE_START	200	/* after create_decompress */
#define DSTATE_INHEADER	201	/* read_header initialized but not done */
#define DSTATE_READY	202	/* read_header done, found image */
#define DSTATE_SCANNING	203	/* start_decompress done, read_scanlines OK */
#define DSTATE_RAW_OK	204	/* start_decompress done, read_raw_data OK */
#define DSTATE_STOPPING	205	/* done reading data, looking for EOI */


/* Declarations for compression modules */

/* Master control module */
struct jpeg_comp_master {
  JMETHOD(void, prepare_for_pass, (j_compress_ptr cinfo));
  JMETHOD(void, pass_startup, (j_compress_ptr cinfo));
  JMETHOD(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 {
  JMETHOD(void, start_pass, (j_compress_ptr cinfo, J_BUF_MODE pass_mode));
  JMETHOD(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 {
  JMETHOD(void, start_pass, (j_compress_ptr cinfo, J_BUF_MODE pass_mode));
  JMETHOD(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 {
  JMETHOD(void, start_pass, (j_compress_ptr cinfo, J_BUF_MODE pass_mode));
  JMETHOD(void, compress_data, (j_compress_ptr cinfo,
				JSAMPIMAGE input_buf,
				JDIMENSION *in_mcu_ctr));
};

/* Colorspace conversion */
struct jpeg_color_converter {
  JMETHOD(void, start_pass, (j_compress_ptr cinfo));
  JMETHOD(void, color_convert, (j_compress_ptr cinfo,
				JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
				JDIMENSION output_row, int num_rows));
};

/* Downsampling */
struct jpeg_downsampler {
  JMETHOD(void, start_pass, (j_compress_ptr cinfo));
  JMETHOD(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 {
  JMETHOD(void, start_pass, (j_compress_ptr cinfo));
  /* perhaps this should be an array??? */
  JMETHOD(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 {
  JMETHOD(void, start_pass, (j_compress_ptr cinfo, boolean gather_statistics));
  JMETHOD(boolean, encode_mcu, (j_compress_ptr cinfo, JBLOCKROW *MCU_data));
  JMETHOD(void, finish_pass, (j_compress_ptr cinfo));
};

/* Marker writing */
struct jpeg_marker_writer {
  /* write_any_marker is exported for use by applications */
  /* Probably only COM and APPn markers should be written */
  JMETHOD(void, write_any_marker, (j_compress_ptr cinfo, int marker,
				   const JOCTET *dataptr, unsigned int datalen));
  JMETHOD(void, write_file_header, (j_compress_ptr cinfo));
  JMETHOD(void, write_frame_header, (j_compress_ptr cinfo));
  JMETHOD(void, write_scan_header, (j_compress_ptr cinfo));
  JMETHOD(void, write_file_trailer, (j_compress_ptr cinfo));
  JMETHOD(void, write_tables_only, (j_compress_ptr cinfo));
};


/* Declarations for decompression modules */

/* Master control module */
struct jpeg_decomp_master {
  JMETHOD(void, prepare_for_pass, (j_decompress_ptr cinfo));
  JMETHOD(void, finish_pass, (j_decompress_ptr cinfo));

  /* State variables made visible to other modules */
  boolean is_last_pass;		/* True during last pass */
  boolean eoi_processed;	/* True if EOI marker already read */
};

/* Main buffer control (downsampled-data buffer) */
struct jpeg_d_main_controller {
  JMETHOD(void, start_pass, (j_decompress_ptr cinfo, J_BUF_MODE pass_mode));
  JMETHOD(void, process_data, (j_decompress_ptr cinfo,
			       JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
			       JDIMENSION out_rows_avail));
  /* During input-only passes, output_buf and out_rows_avail are ignored.
   * out_row_ctr is incremented towards the limit num_chunks.
   */
  JDIMENSION num_chunks;	/* number of chunks to be processed in pass */
};

/* Coefficient buffer control */
struct jpeg_d_coef_controller {
  JMETHOD(void, start_pass, (j_decompress_ptr cinfo, J_BUF_MODE pass_mode));
  JMETHOD(boolean, decompress_data, (j_decompress_ptr cinfo,
				     JSAMPIMAGE output_buf));
};

/* Decompression postprocessing (color quantization buffer control) */
struct jpeg_d_post_controller {
  JMETHOD(void, start_pass, (j_decompress_ptr cinfo, J_BUF_MODE pass_mode));
  JMETHOD(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 {
  JMETHOD(void, reset_marker_reader, (j_decompress_ptr cinfo));
  /* Read markers until SOS or EOI.
   * Returns same codes as are defined for jpeg_read_header,
   * but HEADER_OK and HEADER_TABLES_ONLY merely indicate which marker type
   * stopped the scan --- further validation is needed to declare file OK.
   */
  JMETHOD(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;
  /* Application-overridable marker processing methods */
  jpeg_marker_parser_method process_COM;
  jpeg_marker_parser_method process_APPn[16];

  /* 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 {
  JMETHOD(void, start_pass, (j_decompress_ptr cinfo));
  JMETHOD(boolean, decode_mcu, (j_decompress_ptr cinfo,
				JBLOCKROW *MCU_data));
};

/* Inverse DCT (also performs dequantization) */
typedef JMETHOD(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 {
  JMETHOD(void, start_input_pass, (j_decompress_ptr cinfo));
  JMETHOD(void, start_output_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 {
  JMETHOD(void, start_pass, (j_decompress_ptr cinfo));
  JMETHOD(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 {
  JMETHOD(void, start_pass, (j_decompress_ptr cinfo));
  JMETHOD(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 {
  JMETHOD(void, start_pass, (j_decompress_ptr cinfo, boolean is_pre_scan));
  JMETHOD(void, color_quantize, (j_decompress_ptr cinfo,
				 JSAMPARRAY input_buf, JSAMPARRAY output_buf,
				 int num_rows));
  JMETHOD(void, finish_pass, (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
 * must define RIGHT_SHIFT_IS_UNSIGNED.
 * RIGHT_SHIFT provides a proper signed right shift of an INT32 quantity.
 * It is only applied with constant shift counts.  SHIFT_TEMPS must be
 * included in the variables of any routine using RIGHT_SHIFT.
 */

#ifdef RIGHT_SHIFT_IS_UNSIGNED
#define SHIFT_TEMPS	INT32 shift_temp;
#define RIGHT_SHIFT(x,shft)  \
	((shift_temp = (x)) < 0 ? \
	 (shift_temp >> (shft)) | ((~((INT32) 0)) << (32-(shft))) : \
	 (shift_temp >> (shft)))
#else
#define SHIFT_TEMPS
#define RIGHT_SHIFT(x,shft)	((x) >> (shft))
#endif


/* Short forms of external names for systems with brain-damaged linkers. */

#ifdef NEED_SHORT_EXTERNAL_NAMES
#define jinit_master_compress	jICMaster
#define jinit_c_main_controller	jICMainC
#define jinit_c_prep_controller	jICPrepC
#define jinit_c_coef_controller	jICCoefC
#define jinit_color_converter	jICColor
#define jinit_downsampler	jIDownsampler
#define jinit_forward_dct	jIFDCT
#define jinit_huff_encoder	jIHEncoder
#define jinit_marker_writer	jIMWriter
#define jinit_master_decompress	jIDMaster
#define jinit_d_main_controller	jIDMainC
#define jinit_d_coef_controller	jIDCoefC
#define jinit_d_post_controller	jIDPostC
#define jinit_marker_reader	jIMReader
#define jinit_huff_decoder	jIHDecoder
#define jinit_inverse_dct	jIIDCT
#define jinit_upsampler		jIUpsampler
#define jinit_color_deconverter	jIDColor
#define jinit_1pass_quantizer	jI1Quant
#define jinit_2pass_quantizer	jI2Quant
#define jinit_merged_upsampler	jIMUpsampler
#define jinit_memory_mgr	jIMemMgr
#define jdiv_round_up		jDivRound
#define jround_up		jRound
#define jcopy_sample_rows	jCopySamples
#define jcopy_block_row		jCopyBlocks
#define jzero_far		jZeroFar
#endif /* NEED_SHORT_EXTERNAL_NAMES */


/* Compression module initialization routines */
EXTERN void jinit_master_compress JPP((j_compress_ptr cinfo));
EXTERN void jinit_c_main_controller JPP((j_compress_ptr cinfo,
					 boolean need_full_buffer));
EXTERN void jinit_c_prep_controller JPP((j_compress_ptr cinfo,
					 boolean need_full_buffer));
EXTERN void jinit_c_coef_controller JPP((j_compress_ptr cinfo,
					 boolean need_full_buffer));
EXTERN void jinit_color_converter JPP((j_compress_ptr cinfo));
EXTERN void jinit_downsampler JPP((j_compress_ptr cinfo));
EXTERN void jinit_forward_dct JPP((j_compress_ptr cinfo));
EXTERN void jinit_huff_encoder JPP((j_compress_ptr cinfo));
EXTERN void jinit_marker_writer JPP((j_compress_ptr cinfo));
/* Decompression module initialization routines */
EXTERN void jinit_master_decompress JPP((j_decompress_ptr cinfo));
EXTERN void jinit_d_main_controller JPP((j_decompress_ptr cinfo,
					 boolean need_full_buffer));
EXTERN void jinit_d_coef_controller JPP((j_decompress_ptr cinfo,
					 boolean need_full_buffer));
EXTERN void jinit_d_post_controller JPP((j_decompress_ptr cinfo,
					 boolean need_full_buffer));
EXTERN void jinit_marker_reader JPP((j_decompress_ptr cinfo));
EXTERN void jinit_huff_decoder JPP((j_decompress_ptr cinfo));
EXTERN void jinit_inverse_dct JPP((j_decompress_ptr cinfo));
EXTERN void jinit_upsampler JPP((j_decompress_ptr cinfo));
EXTERN void jinit_color_deconverter JPP((j_decompress_ptr cinfo));
EXTERN void jinit_1pass_quantizer JPP((j_decompress_ptr cinfo));
EXTERN void jinit_2pass_quantizer JPP((j_decompress_ptr cinfo));
EXTERN void jinit_merged_upsampler JPP((j_decompress_ptr cinfo));
/* Memory manager initialization */
EXTERN void jinit_memory_mgr JPP((j_common_ptr cinfo));

/* Utility routines in jutils.c */
EXTERN long jdiv_round_up JPP((long a, long b));
EXTERN long jround_up JPP((long a, long b));
EXTERN void jcopy_sample_rows JPP((JSAMPARRAY input_array, int source_row,
				   JSAMPARRAY output_array, int dest_row,
				   int num_rows, JDIMENSION num_cols));
EXTERN void jcopy_block_row JPP((JBLOCKROW input_row, JBLOCKROW output_row,
				 JDIMENSION num_blocks));
EXTERN void jzero_far JPP((void FAR * target, size_t bytestozero));


/* Suppress undefined-structure complaints if necessary. */

#ifdef INCOMPLETE_TYPES_BROKEN
#ifndef AM_MEMORY_MANAGER	/* only jmemmgr.c defines these */
struct jvirt_sarray_control { long dummy; };
struct jvirt_barray_control { long dummy; };
#endif
#endif /* INCOMPLETE_TYPES_BROKEN */