/*
 * jcapistd.c
 *
 * Copyright (C) 1994-1995, 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 application interface code for the compression half
 * of the JPEG library.  These are the "standard" API routines that are
 * used in the normal full-compression case.  They are not used by a
 * transcoding-only application.  Note that if an application links in
 * jpeg_start_compress, it will end up linking in the entire compressor.
 * We thus must separate this file from jcapimin.c to avoid linking the
 * whole compression library into a transcoder.
 */

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


/*
 * Compression initialization.
 * Before calling this, all parameters and a data destination must be set up.
 *
 * We require a write_all_tables parameter as a failsafe check when writing
 * multiple datastreams from the same compression object.  Since prior runs
 * will have left all the tables marked sent_table=TRUE, a subsequent run
 * would emit an abbreviated stream (no tables) by default.  This may be what
 * is wanted, but for safety's sake it should not be the default behavior:
 * programmers should have to make a deliberate choice to emit abbreviated
 * images.  Therefore the documentation and examples should encourage people
 * to pass write_all_tables=TRUE; then it will take active thought to do the
 * wrong thing.
 */

GLOBAL void
jpeg_start_compress( j_compress_ptr cinfo, boolean write_all_tables ) {
    if ( cinfo->global_state != CSTATE_START ) {
        ERREXIT1( cinfo, JERR_BAD_STATE, cinfo->global_state );
    }

    if ( write_all_tables ) {
        jpeg_suppress_tables( cinfo, FALSE );
    }                                   /* mark all tables to be written */

    /* (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 */
    jinit_compress_master( cinfo );
    /* Set up for the first pass */
    ( *cinfo->master->prepare_for_pass )( cinfo );
    /* Ready for application to drive first pass through jpeg_write_scanlines
     * or jpeg_write_raw_data.
     */
    cinfo->next_scanline = 0;
    cinfo->global_state = ( cinfo->raw_data_in ? CSTATE_RAW_OK : CSTATE_SCANNING );
}


/*
 * Write some scanlines of data to the JPEG compressor.
 *
 * The return value will be the number of lines actually written.
 * This should be less than the supplied num_lines only in case that
 * the data destination module has requested suspension of the compressor,
 * or if more than image_height scanlines are passed in.
 *
 * Note: we warn about excess calls to jpeg_write_scanlines() since
 * this likely signals an application programmer error.  However,
 * excess scanlines passed in the last valid call are *silently* ignored,
 * so that the application need not adjust num_lines for end-of-image
 * when using a multiple-scanline buffer.
 */

GLOBAL JDIMENSION
jpeg_write_scanlines( j_compress_ptr cinfo, JSAMPARRAY scanlines,
                      JDIMENSION num_lines ) {
    JDIMENSION row_ctr, rows_left;

    if ( cinfo->global_state != CSTATE_SCANNING ) {
        ERREXIT1( cinfo, JERR_BAD_STATE, cinfo->global_state );
    }
    if ( cinfo->next_scanline >= cinfo->image_height ) {
        WARNMS( cinfo, JWRN_TOO_MUCH_DATA );
    }

    /* Call progress monitor hook if present */
    if ( cinfo->progress != NULL ) {
        cinfo->progress->pass_counter = (long) cinfo->next_scanline;
        cinfo->progress->pass_limit = (long) cinfo->image_height;
        ( *cinfo->progress->progress_monitor )( (j_common_ptr) cinfo );
    }

    /* Give master control module another chance if this is first call to
     * jpeg_write_scanlines.  This lets output of the frame/scan headers be
     * delayed so that application can write COM, etc, markers between
     * jpeg_start_compress and jpeg_write_scanlines.
     */
    if ( cinfo->master->call_pass_startup ) {
        ( *cinfo->master->pass_startup )( cinfo );
    }

    /* Ignore any extra scanlines at bottom of image. */
    rows_left = cinfo->image_height - cinfo->next_scanline;
    if ( num_lines > rows_left ) {
        num_lines = rows_left;
    }

    row_ctr = 0;
    ( *cinfo->main->process_data )( cinfo, scanlines, &row_ctr, num_lines );
    cinfo->next_scanline += row_ctr;
    return row_ctr;
}


/*
 * Alternate entry point to write raw data.
 * Processes exactly one iMCU row per call, unless suspended.
 */

GLOBAL JDIMENSION
jpeg_write_raw_data( j_compress_ptr cinfo, JSAMPIMAGE data,
                     JDIMENSION num_lines ) {
    JDIMENSION lines_per_iMCU_row;

    if ( cinfo->global_state != CSTATE_RAW_OK ) {
        ERREXIT1( cinfo, JERR_BAD_STATE, cinfo->global_state );
    }
    if ( cinfo->next_scanline >= cinfo->image_height ) {
        WARNMS( cinfo, JWRN_TOO_MUCH_DATA );
        return 0;
    }

    /* Call progress monitor hook if present */
    if ( cinfo->progress != NULL ) {
        cinfo->progress->pass_counter = (long) cinfo->next_scanline;
        cinfo->progress->pass_limit = (long) cinfo->image_height;
        ( *cinfo->progress->progress_monitor )( (j_common_ptr) cinfo );
    }

    /* Give master control module another chance if this is first call to
     * jpeg_write_raw_data.  This lets output of the frame/scan headers be
     * delayed so that application can write COM, etc, markers between
     * jpeg_start_compress and jpeg_write_raw_data.
     */
    if ( cinfo->master->call_pass_startup ) {
        ( *cinfo->master->pass_startup )( cinfo );
    }

    /* Verify that at least one iMCU row has been passed. */
    lines_per_iMCU_row = cinfo->max_v_samp_factor * DCTSIZE;
    if ( num_lines < lines_per_iMCU_row ) {
        ERREXIT( cinfo, JERR_BUFFER_SIZE );
    }

    /* Directly compress the row. */
    if ( !( *cinfo->coef->compress_data )( cinfo, data ) ) {
        /* If compressor did not consume the whole row, suspend processing. */
        return 0;
    }

    /* OK, we processed one iMCU row. */
    cinfo->next_scanline += lines_per_iMCU_row;
    return lines_per_iMCU_row;
}