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 /*

  * jdapistd.c

  *

  * This file was part of the Independent JPEG Group's software:

  * Copyright (C) 1994-1996, Thomas G. Lane.

  * libjpeg-turbo Modifications:

  * Copyright (C) 2010, D. R. Commander.

  * For conditions of distribution and use, see the accompanying README file.

  *

  * This file contains application interface code for the decompression half

  * of the JPEG library.  These are the "standard" API routines that are

  * used in the normal full-decompression case.  They are not used by a

  * transcoding-only application.  Note that if an application links in

  * jpeg_start_decompress, it will end up linking in the entire decompressor.

  * We thus must separate this file from jdapimin.c to avoid linking the

  * whole decompression library into a transcoder.

  */

 #define JPEG_INTERNALS

 #include "jinclude.h"

 #include "jpeglib.h"

 #include "jpegcomp.h"

 /* Forward declarations */

 LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo));

 /*

  * Decompression initialization.

  * jpeg_read_header must be completed before calling this.

  *

  * If a multipass operating mode was selected, this will do all but the

  * last pass, and thus may take a great deal of time.

  *

  * Returns FALSE if suspended.  The return value need be inspected only if

  * a suspending data source is used.

  */

 GLOBAL(boolean)

 jpeg_start_decompress (j_decompress_ptr cinfo)

 {

   if (cinfo->global_state == DSTATE_READY) {

     /* First call: initialize master control, select active modules */

     jinit_master_decompress(cinfo);

     if (cinfo->buffered_image) {

       /* No more work here; expecting jpeg_start_output next */

       cinfo->global_state = DSTATE_BUFIMAGE;

       return TRUE;

     }

     cinfo->global_state = DSTATE_PRELOAD;

   }

   if (cinfo->global_state == DSTATE_PRELOAD) {

     /* If file has multiple scans, absorb them all into the coef buffer */

     if (cinfo->inputctl->has_multiple_scans) {

 #ifdef D_MULTISCAN_FILES_SUPPORTED

       for (;;) {

 	int retcode;

 	/* Call progress monitor hook if present */

 	if (cinfo->progress != NULL)

 	  (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);

 	/* Absorb some more input */

 	retcode = (*cinfo->inputctl->consume_input) (cinfo);

 	if (retcode == JPEG_SUSPENDED)

 	  return FALSE;

 	if (retcode == JPEG_REACHED_EOI)

 	  break;

 	/* Advance progress counter if appropriate */

 	if (cinfo->progress != NULL &&

 	    (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) {

 	  if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) {

 	    /* jdmaster underestimated number of scans; ratchet up one scan */

 	    cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows;

 	  }

 	}

       }

 #else

       ERREXIT(cinfo, JERR_NOT_COMPILED);

 #endif /* D_MULTISCAN_FILES_SUPPORTED */

     }

     cinfo->output_scan_number = cinfo->input_scan_number;

   } else if (cinfo->global_state != DSTATE_PRESCAN)

     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

   /* Perform any dummy output passes, and set up for the final pass */

   return output_pass_setup(cinfo);

 }

 /*

  * Set up for an output pass, and perform any dummy pass(es) needed.

  * Common subroutine for jpeg_start_decompress and jpeg_start_output.

  * Entry: global_state = DSTATE_PRESCAN only if previously suspended.

  * Exit: If done, returns TRUE and sets global_state for proper output mode.

  *       If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN.

  */

 LOCAL(boolean)

 output_pass_setup (j_decompress_ptr cinfo)

 {

   if (cinfo->global_state != DSTATE_PRESCAN) {

     /* First call: do pass setup */

     (*cinfo->master->prepare_for_output_pass) (cinfo);

     cinfo->output_scanline = 0;

     cinfo->global_state = DSTATE_PRESCAN;

   }

   /* Loop over any required dummy passes */

   while (cinfo->master->is_dummy_pass) {

 #ifdef QUANT_2PASS_SUPPORTED

     /* Crank through the dummy pass */

     while (cinfo->output_scanline < cinfo->output_height) {

       JDIMENSION last_scanline;

       /* Call progress monitor hook if present */

       if (cinfo->progress != NULL) {

 	cinfo->progress->pass_counter = (long) cinfo->output_scanline;

 	cinfo->progress->pass_limit = (long) cinfo->output_height;

 	(*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);

       }

       /* Process some data */

       last_scanline = cinfo->output_scanline;

       (*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL,

 				    &cinfo->output_scanline, (JDIMENSION) 0);

       if (cinfo->output_scanline == last_scanline)

 	return FALSE;		/* No progress made, must suspend */

     }

     /* Finish up dummy pass, and set up for another one */

     (*cinfo->master->finish_output_pass) (cinfo);

     (*cinfo->master->prepare_for_output_pass) (cinfo);

     cinfo->output_scanline = 0;

 #else

     ERREXIT(cinfo, JERR_NOT_COMPILED);

 #endif /* QUANT_2PASS_SUPPORTED */

   }

   /* Ready for application to drive output pass through

    * jpeg_read_scanlines or jpeg_read_raw_data.

    */

   cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING;

   return TRUE;

 }

 /*

  * Read some scanlines of data from the JPEG decompressor.

  *

  * The return value will be the number of lines actually read.

  * This may be less than the number requested in several cases,

  * including bottom of image, data source suspension, and operating

  * modes that emit multiple scanlines at a time.

  *

  * Note: we warn about excess calls to jpeg_read_scanlines() since

  * this likely signals an application programmer error.  However,

  * an oversize buffer (max_lines > scanlines remaining) is not an error.

  */

 GLOBAL(JDIMENSION)

 jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines,

 		     JDIMENSION max_lines)

 {

   JDIMENSION row_ctr;

   if (cinfo->global_state != DSTATE_SCANNING)

     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

   if (cinfo->output_scanline >= cinfo->output_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->output_scanline;

     cinfo->progress->pass_limit = (long) cinfo->output_height;

     (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);

   }

   /* Process some data */

   row_ctr = 0;

   (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines);

   cinfo->output_scanline += row_ctr;

   return row_ctr;

 }

 /*

  * Alternate entry point to read raw data.

  * Processes exactly one iMCU row per call, unless suspended.

  */

 GLOBAL(JDIMENSION)

 jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data,

 		    JDIMENSION max_lines)

 {

   JDIMENSION lines_per_iMCU_row;

   if (cinfo->global_state != DSTATE_RAW_OK)

     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

   if (cinfo->output_scanline >= cinfo->output_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->output_scanline;

     cinfo->progress->pass_limit = (long) cinfo->output_height;

     (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo);

   }

   /* Verify that at least one iMCU row can be returned. */

   lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->_min_DCT_scaled_size;

   if (max_lines < lines_per_iMCU_row)

     ERREXIT(cinfo, JERR_BUFFER_SIZE);

   /* Decompress directly into user's buffer. */

   if (! (*cinfo->coef->decompress_data) (cinfo, data))

     return 0;			/* suspension forced, can do nothing more */

   /* OK, we processed one iMCU row. */

   cinfo->output_scanline += lines_per_iMCU_row;

   return lines_per_iMCU_row;

 }

 /* Additional entry points for buffered-image mode. */

 #ifdef D_MULTISCAN_FILES_SUPPORTED

 /*

  * Initialize for an output pass in buffered-image mode.

  */

 GLOBAL(boolean)

 jpeg_start_output (j_decompress_ptr cinfo, int scan_number)

 {

   if (cinfo->global_state != DSTATE_BUFIMAGE &&

       cinfo->global_state != DSTATE_PRESCAN)

     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

   /* Limit scan number to valid range */

   if (scan_number <= 0)

     scan_number = 1;

   if (cinfo->inputctl->eoi_reached &&

       scan_number > cinfo->input_scan_number)

     scan_number = cinfo->input_scan_number;

   cinfo->output_scan_number = scan_number;

   /* Perform any dummy output passes, and set up for the real pass */

   return output_pass_setup(cinfo);

 }

 /*

  * Finish up after an output pass in buffered-image mode.

  *

  * Returns FALSE if suspended.  The return value need be inspected only if

  * a suspending data source is used.

  */

 GLOBAL(boolean)

 jpeg_finish_output (j_decompress_ptr cinfo)

 {

   if ((cinfo->global_state == DSTATE_SCANNING ||

        cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) {

     /* Terminate this pass. */

     /* We do not require the whole pass to have been completed. */

     (*cinfo->master->finish_output_pass) (cinfo);

     cinfo->global_state = DSTATE_BUFPOST;

   } else if (cinfo->global_state != DSTATE_BUFPOST) {

     /* BUFPOST = repeat call after a suspension, anything else is error */

     ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

   }

   /* Read markers looking for SOS or EOI */

   while (cinfo->input_scan_number <= cinfo->output_scan_number &&

 	 ! cinfo->inputctl->eoi_reached) {

     if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED)

       return FALSE;		/* Suspend, come back later */

   }

   cinfo->global_state = DSTATE_BUFIMAGE;

   return TRUE;

 }

 #endif /* D_MULTISCAN_FILES_SUPPORTED */