/*
 * jctrans.c
 *
 * Copyright (C) 1995, 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 contains library routines for transcoding compression,
 * that is, writing raw DCT coefficient arrays to an output JPEG file.
 * The routines in jcapimin.c will also be needed by a transcoder.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"


/* Forward declarations */
LOCAL void transencode_master_selection
JPP( ( j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays ) );
LOCAL void transencode_coef_controller
JPP( ( j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays ) );


/*
 * Compression initialization for writing raw-coefficient data.
 * Before calling this, all parameters and a data destination must be set up.
 * Call jpeg_finish_compress() to actually write the data.
 *
 * The number of passed virtual arrays must match cinfo->num_components.
 * Note that the virtual arrays need not be filled or even realized at
 * the time write_coefficients is called; indeed, if the virtual arrays
 * were requested from this compression object's memory manager, they
 * typically will be realized during this routine and filled afterwards.
 */

GLOBAL void
jpeg_write_coefficients( j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays ) {
	if ( cinfo->global_state != CSTATE_START ) {
		ERREXIT1( cinfo, JERR_BAD_STATE, cinfo->global_state );
	}
	/* Mark all tables to be written */
	jpeg_suppress_tables( cinfo, FALSE );
	/* (Re)initialize error mgr and destination modules */
	( *cinfo->err->reset_error_mgr )( (j_common_ptr) cinfo );
	( *cinfo->dest->init_destination )( cinfo );
	/* Perform master selection of active modules */
	transencode_master_selection( cinfo, coef_arrays );
	/* Wait for jpeg_finish_compress() call */
	cinfo->next_scanline = 0; /* so jpeg_write_marker works */
	cinfo->global_state = CSTATE_WRCOEFS;
}


/*
 * Initialize the compression object with default parameters,
 * then copy from the source object all parameters needed for lossless
 * transcoding.  Parameters that can be varied without loss (such as
 * scan script and Huffman optimization) are left in their default states.
 */

GLOBAL void
jpeg_copy_critical_parameters( j_decompress_ptr srcinfo,
							   j_compress_ptr dstinfo ) {
	JQUANT_TBL ** qtblptr;
	jpeg_component_info *incomp, *outcomp;
	JQUANT_TBL *c_quant, *slot_quant;
	int tblno, ci, coefi;

	/* Safety check to ensure start_compress not called yet. */
	if ( dstinfo->global_state != CSTATE_START ) {
		ERREXIT1( dstinfo, JERR_BAD_STATE, dstinfo->global_state );
	}
	/* Copy fundamental image dimensions */
	dstinfo->image_width = srcinfo->image_width;
	dstinfo->image_height = srcinfo->image_height;
	dstinfo->input_components = srcinfo->num_components;
	dstinfo->in_color_space = srcinfo->jpeg_color_space;
	/* Initialize all parameters to default values */
	jpeg_set_defaults( dstinfo );
	/* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.
	 * Fix it to get the right header markers for the image colorspace.
	 */
	jpeg_set_colorspace( dstinfo, srcinfo->jpeg_color_space );
	dstinfo->data_precision = srcinfo->data_precision;
	dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;
	/* Copy the source's quantization tables. */
	for ( tblno = 0; tblno < NUM_QUANT_TBLS; tblno++ ) {
		if ( srcinfo->quant_tbl_ptrs[tblno] != NULL ) {
			qtblptr = &dstinfo->quant_tbl_ptrs[tblno];
			if ( *qtblptr == NULL ) {
				*qtblptr = jpeg_alloc_quant_table( (j_common_ptr) dstinfo );
			}
			MEMCOPY( ( *qtblptr )->quantval,
					 srcinfo->quant_tbl_ptrs[tblno]->quantval,
					 SIZEOF( ( *qtblptr )->quantval ) );
			( *qtblptr )->sent_table = FALSE;
		}
	}
	/* Copy the source's per-component info.
	 * Note we assume jpeg_set_defaults has allocated the dest comp_info array.
	 */
	dstinfo->num_components = srcinfo->num_components;
	if ( dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS ) {
		ERREXIT2( dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,
				  MAX_COMPONENTS );
	}
	for ( ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;
		  ci < dstinfo->num_components; ci++, incomp++, outcomp++ ) {
		outcomp->component_id = incomp->component_id;
		outcomp->h_samp_factor = incomp->h_samp_factor;
		outcomp->v_samp_factor = incomp->v_samp_factor;
		outcomp->quant_tbl_no = incomp->quant_tbl_no;
		/* Make sure saved quantization table for component matches the qtable
		 * slot.  If not, the input file re-used this qtable slot.
		 * IJG encoder currently cannot duplicate this.
		 */
		tblno = outcomp->quant_tbl_no;
		if ( tblno < 0 || tblno >= NUM_QUANT_TBLS ||
			 srcinfo->quant_tbl_ptrs[tblno] == NULL ) {
			ERREXIT1( dstinfo, JERR_NO_QUANT_TABLE, tblno );
		}
		slot_quant = srcinfo->quant_tbl_ptrs[tblno];
		c_quant = incomp->quant_table;
		if ( c_quant != NULL ) {
			for ( coefi = 0; coefi < DCTSIZE2; coefi++ ) {
				if ( c_quant->quantval[coefi] != slot_quant->quantval[coefi] ) {
					ERREXIT1( dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno );
				}
			}
		}
		/* Note: we do not copy the source's Huffman table assignments;
		 * instead we rely on jpeg_set_colorspace to have made a suitable choice.
		 */
	}
}


/*
 * Master selection of compression modules for transcoding.
 * This substitutes for jcinit.c's initialization of the full compressor.
 */

LOCAL void
transencode_master_selection( j_compress_ptr cinfo,
							  jvirt_barray_ptr * coef_arrays ) {
	/* Although we don't actually use input_components for transcoding,
	 * jcmaster.c's initial_setup will complain if input_components is 0.
	 */
	cinfo->input_components = 1;
	/* Initialize master control (includes parameter checking/processing) */
	jinit_c_master_control( cinfo, TRUE /* transcode only */ );

	/* Entropy encoding: either Huffman or arithmetic coding. */
	if ( cinfo->arith_code ) {
		ERREXIT( cinfo, JERR_ARITH_NOTIMPL );
	} else {
		if ( cinfo->progressive_mode ) {
#ifdef C_PROGRESSIVE_SUPPORTED
			jinit_phuff_encoder( cinfo );
#else
			ERREXIT( cinfo, JERR_NOT_COMPILED );
#endif
		} else {
			jinit_huff_encoder( cinfo );
		}
	}

	/* We need a special coefficient buffer controller. */
	transencode_coef_controller( cinfo, coef_arrays );

	jinit_marker_writer( cinfo );

	/* We can now tell the memory manager to allocate virtual arrays. */
	( *cinfo->mem->realize_virt_arrays )( (j_common_ptr) cinfo );

	/* Write the datastream header (SOI) immediately.
	 * Frame and scan headers are postponed till later.
	 * This lets application insert special markers after the SOI.
	 */
	( *cinfo->marker->write_file_header )( cinfo );
}


/*
 * The rest of this file is a special implementation of the coefficient
 * buffer controller.  This is similar to jccoefct.c, but it handles only
 * output from presupplied virtual arrays.  Furthermore, we generate any
 * dummy padding blocks on-the-fly rather than expecting them to be present
 * in the arrays.
 */

/* Private buffer controller object */

typedef struct {
	struct jpeg_c_coef_controller pub; /* public fields */

	JDIMENSION iMCU_row_num; /* iMCU row # within image */
	JDIMENSION mcu_ctr;     /* counts MCUs processed in current row */
	int MCU_vert_offset;    /* counts MCU rows within iMCU row */
	int MCU_rows_per_iMCU_row;  /* number of such rows needed */

	/* Virtual block array for each component. */
	jvirt_barray_ptr * whole_image;

	/* Workspace for constructing dummy blocks at right/bottom edges. */
	JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];
} my_coef_controller;

typedef my_coef_controller * my_coef_ptr;


LOCAL void
start_iMCU_row( j_compress_ptr cinfo ) {
/* Reset within-iMCU-row counters for a new row */
	my_coef_ptr coef = (my_coef_ptr) cinfo->coef;

	/* In an interleaved scan, an MCU row is the same as an iMCU row.
	 * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.
	 * But at the bottom of the image, process only what's left.
	 */
	if ( cinfo->comps_in_scan > 1 ) {
		coef->MCU_rows_per_iMCU_row = 1;
	} else {
		if ( coef->iMCU_row_num < ( cinfo->total_iMCU_rows - 1 ) ) {
			coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;
		} else {
			coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;
		}
	}

	coef->mcu_ctr = 0;
	coef->MCU_vert_offset = 0;
}


/*
 * Initialize for a processing pass.
 */

METHODDEF void
start_pass_coef( j_compress_ptr cinfo, J_BUF_MODE pass_mode ) {
	my_coef_ptr coef = (my_coef_ptr) cinfo->coef;

	if ( pass_mode != JBUF_CRANK_DEST ) {
		ERREXIT( cinfo, JERR_BAD_BUFFER_MODE );
	}

	coef->iMCU_row_num = 0;
	start_iMCU_row( cinfo );
}


/*
 * Process some data.
 * We process the equivalent of one fully interleaved MCU row ("iMCU" row)
 * per call, ie, v_samp_factor block rows for each component in the scan.
 * The data is obtained from the virtual arrays and fed to the entropy coder.
 * Returns TRUE if the iMCU row is completed, FALSE if suspended.
 *
 * NB: input_buf is ignored; it is likely to be a NULL pointer.
 */

METHODDEF boolean
compress_output( j_compress_ptr cinfo, JSAMPIMAGE input_buf ) {
	my_coef_ptr coef = (my_coef_ptr) cinfo->coef;
	JDIMENSION MCU_col_num; /* index of current MCU within row */
	JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;
	JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;
	int blkn, ci, xindex, yindex, yoffset, blockcnt;
	JDIMENSION start_col;
	JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];
	JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];
	JBLOCKROW buffer_ptr;
	jpeg_component_info *compptr;

	/* Align the virtual buffers for the components used in this scan. */
	for ( ci = 0; ci < cinfo->comps_in_scan; ci++ ) {
		compptr = cinfo->cur_comp_info[ci];
		buffer[ci] = ( *cinfo->mem->access_virt_barray )
				  ( (j_common_ptr) cinfo, coef->whole_image[compptr->component_index],
				  coef->iMCU_row_num * compptr->v_samp_factor,
				  (JDIMENSION) compptr->v_samp_factor, FALSE );
	}

	/* Loop to process one whole iMCU row */
	for ( yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;
		  yoffset++ ) {
		for ( MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;
			  MCU_col_num++ ) {
			/* Construct list of pointers to DCT blocks belonging to this MCU */
			blkn = 0;   /* index of current DCT block within MCU */
			for ( ci = 0; ci < cinfo->comps_in_scan; ci++ ) {
				compptr = cinfo->cur_comp_info[ci];
				start_col = MCU_col_num * compptr->MCU_width;
				blockcnt = ( MCU_col_num < last_MCU_col ) ? compptr->MCU_width
						   : compptr->last_col_width;
				for ( yindex = 0; yindex < compptr->MCU_height; yindex++ ) {
					if ( coef->iMCU_row_num < last_iMCU_row ||
						 yindex + yoffset < compptr->last_row_height ) {
						/* Fill in pointers to real blocks in this row */
						buffer_ptr = buffer[ci][yindex + yoffset] + start_col;
						for ( xindex = 0; xindex < blockcnt; xindex++ )
							MCU_buffer[blkn++] = buffer_ptr++;
					} else {
						/* At bottom of image, need a whole row of dummy blocks */
						xindex = 0;
					}
					/* Fill in any dummy blocks needed in this row.
					 * Dummy blocks are filled in the same way as in jccoefct.c:
					 * all zeroes in the AC entries, DC entries equal to previous
					 * block's DC value.  The init routine has already zeroed the
					 * AC entries, so we need only set the DC entries correctly.
					 */
					for (; xindex < compptr->MCU_width; xindex++ ) {
						MCU_buffer[blkn] = coef->dummy_buffer[blkn];
						MCU_buffer[blkn][0][0] = MCU_buffer[blkn - 1][0][0];
						blkn++;
					}
				}
			}
			/* Try to write the MCU. */
			if ( !( *cinfo->entropy->encode_mcu )( cinfo, MCU_buffer ) ) {
				/* Suspension forced; update state counters and exit */
				coef->MCU_vert_offset = yoffset;
				coef->mcu_ctr = MCU_col_num;
				return FALSE;
			}
		}
		/* Completed an MCU row, but perhaps not an iMCU row */
		coef->mcu_ctr = 0;
	}
	/* Completed the iMCU row, advance counters for next one */
	coef->iMCU_row_num++;
	start_iMCU_row( cinfo );
	return TRUE;
}


/*
 * Initialize coefficient buffer controller.
 *
 * Each passed coefficient array must be the right size for that
 * coefficient: width_in_blocks wide and height_in_blocks high,
 * with unitheight at least v_samp_factor.
 */

LOCAL void
transencode_coef_controller( j_compress_ptr cinfo,
							 jvirt_barray_ptr * coef_arrays ) {
	my_coef_ptr coef;
	JBLOCKROW buffer;
	int i;

	coef = (my_coef_ptr)
				( *cinfo->mem->alloc_small ) ( (j_common_ptr) cinfo, JPOOL_IMAGE,
											   SIZEOF( my_coef_controller ) );
	cinfo->coef = (struct jpeg_c_coef_controller *) coef;
	coef->pub.start_pass = start_pass_coef;
	coef->pub.compress_data = compress_output;

	/* Save pointer to virtual arrays */
	coef->whole_image = coef_arrays;

	/* Allocate and pre-zero space for dummy DCT blocks. */
	buffer = (JBLOCKROW)
				( *cinfo->mem->alloc_large ) ( (j_common_ptr) cinfo, JPOOL_IMAGE,
											   C_MAX_BLOCKS_IN_MCU * SIZEOF( JBLOCK ) );
	jzero_far( (void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF( JBLOCK ) );
	for ( i = 0; i < C_MAX_BLOCKS_IN_MCU; i++ ) {
		coef->dummy_buffer[i] = buffer + i;
	}
}
