jcmaster.c

EVM板JPEG实现,Texas Instruments TMS320C54x EVM JPEG

/*
 * jcmaster.c
 *
 * Copyright (C) 1991, 1992, 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 the main control for the JPEG compressor.
 * The system-dependent (user interface) code should call jpeg_compress()
 * after doing appropriate setup of the compress_info_struct parameter.
 */

/* This program was changed considerably.  This program calls the necessary
   functions to do the compression.  It also assumes that the output file
   is to be of JFIF format.  Christopher Chang, Summer 1993.
*/

#include "jinclude.h"

METHODDEF void
c_per_scan_method_selection (compress_info_ptr cinfo)
/* Central point for per-scan method selection */
{
  /* Edge expansion */
  jselexpand(cinfo);
  /* Downsampling of pixels */
  jseldownsample(cinfo);
  /* MCU extraction */
  jselcmcu(cinfo);
}

METHODDEF void
c_ui_method_selection(compress_info_ptr cinfo)
{
	/* gray scale - not the same as the original */
/*    if(cinfo->in_color_space == CS_GRAYSCALE)
	  j_monochrome_default(cinfo); */
	jselwjfif(cinfo);       /* assume that output should be JFIF format */
}

LOCAL void
c_initial_method_selection (compress_info_ptr cinfo)
/* Central point for initial method selection */
{
  /* Input image reading method selection is already done. */
  /* So is output file header formatting (both are done by user interface). */

  /* Gamma and color space conversion */
  jselccolor(cinfo);
  /* Entropy encoding: either Huffman or arithmetic coding. */
/* #ifdef C_ARITH_CODING_SUPPORTED
  jselcarithmetic(cinfo);
#else */
  cinfo->arith_code = FALSE;    /* force Huffman mode */
/* #endif */
  jselchuffman(cinfo);
  /* Pipeline control */
  jselcpipeline(cinfo);
  /* Overall control (that's me!) */
  cinfo->methods->c_per_scan_method_selection = c_per_scan_method_selection;
}

LOCAL void
initial_setup (compress_info_ptr cinfo)
/* Do computations that are needed before initial method selection */
{
  short ci;
  jpeg_component_info *compptr;

  /* Compute maximum sampling factors; check factor validity */
  cinfo->max_h_samp_factor = 1;
  cinfo->max_v_samp_factor = 1;
  for (ci = 0; ci < cinfo->num_components; ci++) {
	compptr = &cinfo->comp_info[ci];
/*  if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR ||
	compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR)
	  ERREXIT(cinfo->emethods, "Bogus sampling factors"); */
	cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor,
					compptr->h_samp_factor);
	cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor,
					compptr->v_samp_factor);
}

  /* Compute logical downsampled dimensions of components */
  for (ci = 0; ci < cinfo->num_components; ci++) {
	compptr = &cinfo->comp_info[ci];
	compptr->true_comp_width = (cinfo->image_width * compptr->h_samp_factor
				+ cinfo->max_h_samp_factor - 1)
				/ cinfo->max_h_samp_factor;
	compptr->true_comp_height = (cinfo->image_height * compptr->v_samp_factor
				 + cinfo->max_v_samp_factor - 1)
				 / cinfo->max_v_samp_factor;
  }
}

/*
 * This is the main entry point to the JPEG compressor.
 */

GLOBAL void
jpeg_compress (compress_info_ptr cinfo)
{
  int sft;
  send_command(SND);
  receive_command();
  sft = receive_data();    /* check to see first character in file */
  jselrgif(cinfo);      /* but assume that input is GIF anyways */
  /* Init pass counts to 0 --- total_passes is adjusted in method selection */
  cinfo->total_passes = 0;
  cinfo->completed_passes = 0;

  /* Read the input file header: determine image size & component count.
	* NOTE: the user interface must have initialized the input_init method
	* pointer (eg, by calling jselrppm) before calling me.
	* The other file reading methods (get_input_row etc.) were probably
	* set at the same time, but could be set up by input_init itself,
	* or by c_ui_method_selection.
	*/
  (*cinfo->methods->input_init) (cinfo);

  /* Give UI a chance to adjust compression parameters and select */
  /* output file format based on results of input_init. */
  (*cinfo->methods->c_ui_method_selection) (cinfo);

  /* Now select methods for compression steps. */
  initial_setup(cinfo);
  c_initial_method_selection(cinfo);

  /* Initialize the output file & other modules as needed */
  /* (entropy_encoder is inited by pipeline controller) */

  (*cinfo->methods->colorin_init) (cinfo);
  (*cinfo->methods->write_file_header) (cinfo);

  /* And let the pipeline controller do the rest. */
  (*cinfo->methods->c_pipeline_controller) (cinfo);

  /* Finish output file, release working storage, etc */
  (*cinfo->methods->write_file_trailer) (cinfo);
  (*cinfo->methods->colorin_term) (cinfo);
  (*cinfo->methods->input_term) (cinfo);

  (*cinfo->emethods->free_all) ();
  send_command(DONE);  /* tell host we are done! */
  /* My, that was easy, wasn't it? */
}

void main(void)
{
		compress_info_ptr tinfo;
		struct Compress_info_struct cinfo;
		struct Compress_methods_struct c_methods;
		struct External_methods_struct e_methods;
      init_54();                   /* initialize EVM                     */
      initialize();                /* initialize communications          */
      tinfo = &cinfo;  /* establish space in memory for pointer, tinfo   */
		tinfo->methods = &c_methods;
		tinfo->emethods = &e_methods;
		jselerror(tinfo->emethods);  /* initialize tinfo with error checks */
      jselmemmgr(tinfo->emethods); /* initialize tinfo with memory       */
		tinfo->methods->c_ui_method_selection = c_ui_method_selection;

		#ifdef NEED_SIGNAL_CATCHER
			emethods = tinfo->emethods;
		#endif

		j_c_defaults(tinfo,75,FALSE);
		jpeg_compress(tinfo);        /* primary control function */
}