/*
 * jctrans.c
 *
 * This file was part of the Independent JPEG Group's software:
 * Copyright (C) 1995-1998, Thomas G. Lane.
 * Modified 2000-2009 by Guido Vollbeding.
 * It was modified by The libjpeg-turbo Project to include only code relevant
 * to libjpeg-turbo.
 * For conditions of distribution and use, see the accompanying README.ijg
 * 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
		(j_compress_ptr cinfo, jvirt_barray_ptr *coef_arrays);

LOCAL(void) transencode_coef_controller
		(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;
#if JPEG_LIB_VERSION >= 70
	dstinfo->jpeg_width = srcinfo->output_width;
	dstinfo->jpeg_height = srcinfo->output_height;
	dstinfo->min_DCT_h_scaled_size = srcinfo->min_DCT_h_scaled_size;
	dstinfo->min_DCT_v_scaled_size = srcinfo->min_DCT_v_scaled_size;
#endif
	/* 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.
		 */
	}
	/* Also copy JFIF version and resolution information, if available.
	 * Strictly speaking this isn't "critical" info, but it's nearly
	 * always appropriate to copy it if available.  In particular,
	 * if the application chooses to copy JFIF 1.02 extension markers from
	 * the source file, we need to copy the version to make sure we don't
	 * emit a file that has 1.02 extensions but a claimed version of 1.01.
	 * We will *not*, however, copy version info from mislabeled "2.01" files.
	 */
	if (srcinfo->saw_JFIF_marker) {
		if (srcinfo->JFIF_major_version == 1) {
			dstinfo->JFIF_major_version = srcinfo->JFIF_major_version;
			dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version;
		}
		dstinfo->density_unit = srcinfo->density_unit;
		dstinfo->X_density = srcinfo->X_density;
		dstinfo->Y_density = srcinfo->Y_density;
	}
}


/*
 * 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) {
#ifdef C_ARITH_CODING_SUPPORTED
		jinit_arith_encoder(cinfo);
#else
		ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
#endif
	} 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, JFIF) 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 *) buffer, C_MAX_BLOCKS_IN_MCU * sizeof(JBLOCK));
	for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {
		coef->dummy_buffer[i] = buffer + i;
	}
}
