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 /*

  * jcapistd.c

  *

  * Copyright (C) 1994-1996, 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;

 }