jdk

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/*
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 * reserved comment block
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 * DO NOT REMOVE OR ALTER!
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 */
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/*
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 * jcapistd.c
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 *
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 * Copyright (C) 1994-1996, Thomas G. Lane.
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 * This file is part of the Independent JPEG Group's software.
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 * For conditions of distribution and use, see the accompanying README file.
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 *
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 * This file contains application interface code for the compression half
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 * of the JPEG library.  These are the "standard" API routines that are
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 * used in the normal full-compression case.  They are not used by a
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 * transcoding-only application.  Note that if an application links in
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 * jpeg_start_compress, it will end up linking in the entire compressor.
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 * We thus must separate this file from jcapimin.c to avoid linking the
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 * whole compression library into a transcoder.
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 */
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#define JPEG_INTERNALS
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#include "jinclude.h"
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#include "jpeglib.h"
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/*
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 * Compression initialization.
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 * Before calling this, all parameters and a data destination must be set up.
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 *
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 * We require a write_all_tables parameter as a failsafe check when writing
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 * multiple datastreams from the same compression object.  Since prior runs
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 * will have left all the tables marked sent_table=TRUE, a subsequent run
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 * would emit an abbreviated stream (no tables) by default.  This may be what
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 * is wanted, but for safety's sake it should not be the default behavior:
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 * programmers should have to make a deliberate choice to emit abbreviated
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 * images.  Therefore the documentation and examples should encourage people
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 * to pass write_all_tables=TRUE; then it will take active thought to do the
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 * wrong thing.
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 */
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GLOBAL(void)
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jpeg_start_compress (j_compress_ptr cinfo, boolean write_all_tables)
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{
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  if (cinfo->global_state != CSTATE_START)
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    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
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  if (write_all_tables)
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    jpeg_suppress_tables(cinfo, FALSE); /* mark all tables to be written */
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  /* (Re)initialize error mgr and destination modules */
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  (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);
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  (*cinfo->dest->init_destination) (cinfo);
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  /* Perform master selection of active modules */
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  jinit_compress_master(cinfo);
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  /* Set up for the first pass */
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  (*cinfo->master->prepare_for_pass) (cinfo);
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  /* Ready for application to drive first pass through jpeg_write_scanlines
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   * or jpeg_write_raw_data.
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   */
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  cinfo->next_scanline = 0;
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  cinfo->global_state = (cinfo->raw_data_in ? CSTATE_RAW_OK : CSTATE_SCANNING);
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}
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/*
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 * Write some scanlines of data to the JPEG compressor.
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 *
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 * The return value will be the number of lines actually written.
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 * This should be less than the supplied num_lines only in case that
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 * the data destination module has requested suspension of the compressor,
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 * or if more than image_height scanlines are passed in.
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 *
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 * Note: we warn about excess calls to jpeg_write_scanlines() since
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 * this likely signals an application programmer error.  However,
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 * excess scanlines passed in the last valid call are *silently* ignored,
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 * so that the application need not adjust num_lines for end-of-image
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 * when using a multiple-scanline buffer.
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 */
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GLOBAL(JDIMENSION)
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jpeg_write_scanlines (j_compress_ptr cinfo, JSAMPARRAY scanlines,
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                      JDIMENSION num_lines)
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{
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  JDIMENSION row_ctr, rows_left;
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  if (cinfo->global_state != CSTATE_SCANNING)
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    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
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  if (cinfo->next_scanline >= cinfo->image_height)
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    WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
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  /* Call progress monitor hook if present */
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  if (cinfo->progress != NULL) {
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    cinfo->progress->pass_counter = (long) cinfo->next_scanline;
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    cinfo->progress->pass_limit = (long) cinfo->image_height;
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    (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
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  }
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  /* Give master control module another chance if this is first call to
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   * jpeg_write_scanlines.  This lets output of the frame/scan headers be
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   * delayed so that application can write COM, etc, markers between
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   * jpeg_start_compress and jpeg_write_scanlines.
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   */
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  if (cinfo->master->call_pass_startup)
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    (*cinfo->master->pass_startup) (cinfo);
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  /* Ignore any extra scanlines at bottom of image. */
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  rows_left = cinfo->image_height - cinfo->next_scanline;
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  if (num_lines > rows_left)
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    num_lines = rows_left;
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  row_ctr = 0;
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  (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, num_lines);
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  cinfo->next_scanline += row_ctr;
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  return row_ctr;
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}
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/*
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 * Alternate entry point to write raw data.
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 * Processes exactly one iMCU row per call, unless suspended.
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 */
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GLOBAL(JDIMENSION)
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jpeg_write_raw_data (j_compress_ptr cinfo, JSAMPIMAGE data,
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                     JDIMENSION num_lines)
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{
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  JDIMENSION lines_per_iMCU_row;
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  if (cinfo->global_state != CSTATE_RAW_OK)
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    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
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  if (cinfo->next_scanline >= cinfo->image_height) {
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    WARNMS(cinfo, JWRN_TOO_MUCH_DATA);
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    return 0;
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  }
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  /* Call progress monitor hook if present */
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  if (cinfo->progress != NULL) {
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    cinfo->progress->pass_counter = (long) cinfo->next_scanline;
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    cinfo->progress->pass_limit = (long) cinfo->image_height;
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    (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);
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  }
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  /* Give master control module another chance if this is first call to
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   * jpeg_write_raw_data.  This lets output of the frame/scan headers be
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   * delayed so that application can write COM, etc, markers between
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   * jpeg_start_compress and jpeg_write_raw_data.
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   */
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  if (cinfo->master->call_pass_startup)
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    (*cinfo->master->pass_startup) (cinfo);
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  /* Verify that at least one iMCU row has been passed. */
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  lines_per_iMCU_row = cinfo->max_v_samp_factor * DCTSIZE;
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  if (num_lines < lines_per_iMCU_row)
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    ERREXIT(cinfo, JERR_BUFFER_SIZE);
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  /* Directly compress the row. */
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  if (! (*cinfo->coef->compress_data) (cinfo, data)) {
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    /* If compressor did not consume the whole row, suspend processing. */
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    return 0;
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  }
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  /* OK, we processed one iMCU row. */
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  cinfo->next_scanline += lines_per_iMCU_row;
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  return lines_per_iMCU_row;
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}
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