/*
 * 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;
    }
}