//  * 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;
}