jcdctmgr.c~

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/*
 * jcdctmgr.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 the forward-DCT management logic.
 * This code selects a particular DCT implementation to be used,
 * and it performs related housekeeping chores including coefficient
 * quantization.
 */

/*
 ************************************************
 *
 * $Log: jcdctmgr.c,v $
 * Revision 1.1  2000/05/18 15:40:50  jliang
 * Initial revision
 *
 *
 *
 *
 ************************************************
 */

/*
**********************************************************************
*
* Modification History:
* Date       Programmer   Description
* --------   ----------   --------------------------------------------
* 05/18/00   Jie          Modified jinit_forward_dct
* 06/28/00   Jie          Added support for lossless compression: 
*                              No quantization is used, and perfect reconstruction is thus guaranteed by lifting.
***********************************************************************
*/

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
#include "jdct.h"		/* Private declarations for DCT subsystem */

/******************************
 Defined in cjpeg, Jie 062800
*****************************/
extern boolean   lossless_codec;

int first_blk = 1;

/* Private subobject for this module */

typedef struct {
  struct jpeg_forward_dct pub;	/* public fields */

  /* Pointer to the DCT routine actually in use */
  forward_DCT_method_ptr do_dct;

  /* The actual post-DCT divisors --- not identical to the quant table
   * entries, because of scaling (especially for an unnormalized DCT).
   * Each table is given in normal array order.
   */
  DCTELEM * divisors[NUM_QUANT_TBLS];

#ifdef DCT_FLOAT_SUPPORTED
  /* Same as above for the floating-point case. */
  float_DCT_method_ptr do_float_dct;
  FAST_FLOAT * float_divisors[NUM_QUANT_TBLS];
#endif
} my_fdct_controller;

typedef my_fdct_controller * my_fdct_ptr;


/*
 * Initialize for a processing pass.
 * Verify that all referenced Q-tables are present, and set up
 * the divisor table for each one.
 * In the current implementation, DCT of all components is done during
 * the first pass, even if only some components will be output in the
 * first scan.  Hence all components should be examined here.
 */

METHODDEF(void)
start_pass_fdctmgr (j_compress_ptr cinfo)
{
  my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct;
  int ci, qtblno, i;
  jpeg_component_info *compptr;
  JQUANT_TBL * qtbl;
  DCTELEM * dtbl;

  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
       ci++, compptr++) {
    qtblno = compptr->quant_tbl_no;
    /* Make sure specified quantization table is present */
    if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
	cinfo->quant_tbl_ptrs[qtblno] == NULL)
      ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
    qtbl = cinfo->quant_tbl_ptrs[qtblno];
    /* Compute divisors for this quant table */
    /* We may do this more than once for same table, but it's not a big deal */
    switch (cinfo->dct_method) {
#ifdef DCT_ISLOW_SUPPORTED
    case JDCT_ISLOW:
      /* For LL&M IDCT method, divisors are equal to raw quantization
       * coefficients multiplied by 8 (to counteract scaling).
       */
      if (fdct->divisors[qtblno] == NULL) {
	fdct->divisors[qtblno] = (DCTELEM *)
	  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				      DCTSIZE2 * SIZEOF(DCTELEM));
      }
      dtbl = fdct->divisors[qtblno];
      for (i = 0; i < DCTSIZE2; i++) {
	dtbl[i] = ((DCTELEM) qtbl->quantval[i]) << 3;
      }
      break;
#endif
#ifdef DCT_IFAST_SUPPORTED
    case JDCT_IFAST:
      {
	/* For AA&N IDCT method, divisors are equal to quantization
	 * coefficients scaled by scalefactor[row]*scalefactor[col], where
	 *   scalefactor[0] = 1
	 *   scalefactor[k] = cos(k*PI/16) * sqrt(2)    for k=1..7
	 * We apply a further scale factor of 8.
	 */
#define CONST_BITS 14
	static const INT16 aanscales[DCTSIZE2] = {
	  /* precomputed values scaled up by 14 bits */
	  16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
	  22725, 31521, 29692, 26722, 22725, 17855, 12299,  6270,
	  21407, 29692, 27969, 25172, 21407, 16819, 11585,  5906,
	  19266, 26722, 25172, 22654, 19266, 15137, 10426,  5315,
	  16384, 22725, 21407, 19266, 16384, 12873,  8867,  4520,
	  12873, 17855, 16819, 15137, 12873, 10114,  6967,  3552,
	   8867, 12299, 11585, 10426,  8867,  6967,  4799,  2446,
	   4520,  6270,  5906,  5315,  4520,  3552,  2446,  1247
	};
	SHIFT_TEMPS

	if (fdct->divisors[qtblno] == NULL) {
	  fdct->divisors[qtblno] = (DCTELEM *)
	    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
					DCTSIZE2 * SIZEOF(DCTELEM));
	}
	dtbl = fdct->divisors[qtblno];
	for (i = 0; i < DCTSIZE2; i++) {
	  dtbl[i] = (DCTELEM)
	    DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
				  (INT32) aanscales[i]),
		    CONST_BITS-3);
	}
      }
      break;
#endif
#ifdef DCT_FLOAT_SUPPORTED
    case JDCT_FLOAT:
      {
	/* For float AA&N IDCT method, divisors are equal to quantization
	 * coefficients scaled by scalefactor[row]*scalefactor[col], where
	 *   scalefactor[0] = 1
	 *   scalefactor[k] = cos(k*PI/16) * sqrt(2)    for k=1..7
	 * We apply a further scale factor of 8.
	 * What's actually stored is 1/divisor so that the inner loop can
	 * use a multiplication rather than a division.
	 */
	FAST_FLOAT * fdtbl;
	int row, col;
	static const double aanscalefactor[DCTSIZE] = {
	  1.0, 1.387039845, 1.306562965, 1.175875602,
	  1.0, 0.785694958, 0.541196100, 0.275899379
	};

	if (fdct->float_divisors[qtblno] == NULL) {
	  fdct->float_divisors[qtblno] = (FAST_FLOAT *)
	    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
					DCTSIZE2 * SIZEOF(FAST_FLOAT));
	}
	fdtbl = fdct->float_divisors[qtblno];
	i = 0;
	for (row = 0; row < DCTSIZE; row++) {
	  for (col = 0; col < DCTSIZE; col++) {
	    fdtbl[i] = (FAST_FLOAT)
	      (1.0 / (((double) qtbl->quantval[i] *
		       aanscalefactor[row] * aanscalefactor[col] * 8.0)));
	    i++;
	  }
	}
      }
      break;
#endif

	  /* Jie 05/18/00 */
#ifdef DCT_BIN_A1_SUPPORTED   
    case JDCT_BIN_A1:
      {
		int row, col;
		/* bin_a1 forward 2D transform result * scale[i] *scale[j] / 4 = True DCT.
		   Hence the modified Q table is: (Q0 / scale[i] / scale[j] * 4). */
		static const double bin_a1_scalefactor[DCTSIZE] = {
	 	  0.707106781, 1.019591158, 1.0823922, 1.202689774,
	 	  1.414213562, 0.831469612, 0.923879532, 0.98078528
		};
	
		if (!lossless_codec) {
		  /* skip quantization if lossless is specified. */

		  if (fdct->divisors[qtblno] == NULL) {
			fdct->divisors[qtblno] = (DCTELEM *)
			  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				      DCTSIZE2 * SIZEOF(DCTELEM));
		  }
		  dtbl = fdct->divisors[qtblno];
		  i = 0;

		  for (row = 0; row < DCTSIZE; row++) {
			for (col = 0; col < DCTSIZE; col++) {
			  dtbl[i] = (DCTELEM) ( (double) qtbl->quantval[i] / bin_a1_scalefactor[row] / bin_a1_scalefactor[col] * 4 + 0.5);
			  i++;
			}
		  }

		}
      }
      break;
#endif

#ifdef DCT_BIN_B1_SUPPORTED
    case JDCT_BIN_B1:
   {	
	 int row, col;
#define B1_CONST_BITS 13
	 /* max number in scalign is 2, so scale 13 bits, instead of 14 */
	static const double bin_b1_scalefactor[DCTSIZE] = {
	  0.707106781, 1.019591158, 1.0823922, 1.202689774,
	  1.414213562, 0.831469612, 0.923879532, 0.98078528
 	};

	if (TRUE != lossless_codec) {
    /* skip quantization if lossless is specified. */


	  if (fdct->divisors[qtblno] == NULL) {
		fdct->divisors[qtblno] = (DCTELEM *)
		  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
					DCTSIZE2 * SIZEOF(DCTELEM));
	  }
	  dtbl = fdct->divisors[qtblno];
	  i = 0;
	  for (row = 0; row < DCTSIZE; row++) {
		for ( col = 0; col < DCTSIZE; col++) {
		  dtbl[i] = (DCTELEM) (qtbl->quantval[i] / bin_b1_scalefactor[row] / bin_b1_scalefactor[col] * 4 + 0.5);
		  i++;
		}
	  }
	}

  }
  break;
#endif

#ifdef DCT_BIN_C1_SUPPORTED
    case JDCT_BIN_C1:
      {
		int row, col;
		/* bin_a1 forward 2D transform result * scale[i] *scale[j] / 4 = True DCT.
		   Hence the modified Q table is: (Q0 / scale[i] / scale[j] * 4). */
		static const double bin_c1_scalefactor[DCTSIZE] = {
	 	  0.707106781, 1.019591158, 1.0823922, 1.202689774,
	 	  1.414213562, 0.831469612, 0.923879532, 0.98078528
		};
	
		if (!lossless_codec) {
		  /* skip quantization if lossless is specified. */

		  if (fdct->divisors[qtblno] == NULL) {
			fdct->divisors[qtblno] = (DCTELEM *)
			  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				      DCTSIZE2 * SIZEOF(DCTELEM));
		  }
		  dtbl = fdct->divisors[qtblno];
		  i = 0;

		  for (row = 0; row < DCTSIZE; row++) {
			for (col = 0; col < DCTSIZE; col++) {
			  dtbl[i] = (DCTELEM) ( (double) qtbl->quantval[i] / bin_c1_scalefactor[row] / bin_c1_scalefactor[col] * 4 + 0.5);
			  i++;
			}
		  }

		}
      }
      break;
#endif

#ifdef DCT_BIN_L1_SUPPORTED
    case JDCT_BIN_L1:
      {
		int row, col;
		static const double bin_l1_scalefactor[DCTSIZE] = {
		  0.35355339, 0.35355339, 0.5411961, 0.5,
		  0.70710678, 0.5,        0.4619398, 0.70710678
		};
	
		if (!lossless_codec) {
		  /* skip quantization if lossless is specified. */

		  if (fdct->divisors[qtblno] == NULL) {
			fdct->divisors[qtblno] = (DCTELEM *)
			  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				      DCTSIZE2 * SIZEOF(DCTELEM));
		  }
		  dtbl = fdct->divisors[qtblno];
		  i = 0;

		  for (row = 0; row < DCTSIZE; row++) {
			for (col = 0; col < DCTSIZE; col++) {
			  dtbl[i] = (DCTELEM) ( (double) qtbl->quantval[i] / bin_l1_scalefactor[row] / bin_l1_scalefactor[col] + 0.5);
			  i++;
			}
		  }

		}
      }
      break;
#endif

    default:
      ERREXIT(cinfo, JERR_NOT_COMPILED);
      break;
    }
  }
}