/*

* jctrans.c

*

* Copyright (C) 1995-1998, Thomas G. Lane.

* Modified 2000-2011 by Guido Vollbeding.

* 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;

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;

/* 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)

{

/* 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)

jinit_arith_encoder(cinfo);

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));

FMEMZERO((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;

}

}