* jcdctmgr.c
*
* Copyright (C) 1994-1996, Thomas G. Lane.
+ * Modified 2003-2013 by Guido Vollbeding.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
/* Pointer to the DCT routine actually in use */
forward_DCT_method_ptr do_dct[MAX_COMPONENTS];
- /* 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[MAX_COMPONENTS];
- FAST_FLOAT * float_divisors[NUM_QUANT_TBLS];
#endif
} my_fdct_controller;
typedef my_fdct_controller * my_fdct_ptr;
+/* The allocated post-DCT divisor tables -- big enough for any
+ * supported variant and not identical to the quant table entries,
+ * because of scaling (especially for an unnormalized DCT) --
+ * are pointed to by dct_table in the per-component comp_info
+ * structures. Each table is given in normal array order.
+ */
+
+typedef union {
+ DCTELEM int_array[DCTSIZE2];
+#ifdef DCT_FLOAT_SUPPORTED
+ FAST_FLOAT float_array[DCTSIZE2];
+#endif
+} divisor_table;
+
+
/* The current scaled-DCT routines require ISLOW-style divisor tables,
* so be sure to compile that code if either ISLOW or SCALING is requested.
*/
/* This routine is heavily used, so it's worth coding it tightly. */
my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct;
forward_DCT_method_ptr do_dct = fdct->do_dct[compptr->component_index];
- DCTELEM * divisors = fdct->divisors[compptr->quant_tbl_no];
+ DCTELEM * divisors = (DCTELEM *) compptr->dct_table;
DCTELEM workspace[DCTSIZE2]; /* work area for FDCT subroutine */
JDIMENSION bi;
/* This routine is heavily used, so it's worth coding it tightly. */
my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct;
float_DCT_method_ptr do_dct = fdct->do_float_dct[compptr->component_index];
- FAST_FLOAT * divisors = fdct->float_divisors[compptr->quant_tbl_no];
+ FAST_FLOAT * divisors = (FAST_FLOAT *) compptr->dct_table;
FAST_FLOAT workspace[DCTSIZE2]; /* work area for FDCT subroutine */
JDIMENSION bi;
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 */
+ /* Create divisor table from quant table */
switch (method) {
#ifdef PROVIDE_ISLOW_TABLES
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];
+ dtbl = (DCTELEM *) compptr->dct_table;
for (i = 0; i < DCTSIZE2; i++) {
- dtbl[i] = ((DCTELEM) qtbl->quantval[i]) << 3;
+ dtbl[i] =
+ ((DCTELEM) qtbl->quantval[i]) << (compptr->component_needed ? 4 : 3);
}
fdct->pub.forward_DCT[ci] = forward_DCT;
break;
};
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];
+ dtbl = (DCTELEM *) compptr->dct_table;
for (i = 0; i < DCTSIZE2; i++) {
dtbl[i] = (DCTELEM)
DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
(INT32) aanscales[i]),
- CONST_BITS-3);
+ compptr->component_needed ? CONST_BITS-4 : CONST_BITS-3);
}
}
fdct->pub.forward_DCT[ci] = forward_DCT;
* What's actually stored is 1/divisor so that the inner loop can
* use a multiplication rather than a division.
*/
- FAST_FLOAT * fdtbl;
+ FAST_FLOAT * fdtbl = (FAST_FLOAT *) compptr->dct_table;
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)));
+ (1.0 / ((double) qtbl->quantval[i] *
+ aanscalefactor[row] * aanscalefactor[col] *
+ (compptr->component_needed ? 16.0 : 8.0)));
i++;
}
}
jinit_forward_dct (j_compress_ptr cinfo)
{
my_fdct_ptr fdct;
- int i;
+ int ci;
+ jpeg_component_info *compptr;
fdct = (my_fdct_ptr)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
SIZEOF(my_fdct_controller));
- cinfo->fdct = (struct jpeg_forward_dct *) fdct;
+ cinfo->fdct = &fdct->pub;
fdct->pub.start_pass = start_pass_fdctmgr;
- /* Mark divisor tables unallocated */
- for (i = 0; i < NUM_QUANT_TBLS; i++) {
- fdct->divisors[i] = NULL;
-#ifdef DCT_FLOAT_SUPPORTED
- fdct->float_divisors[i] = NULL;
-#endif
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Allocate a divisor table for each component */
+ compptr->dct_table =
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ SIZEOF(divisor_table));
}
}
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