--- /dev/null
+/*
+ * 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.
+ *
+ * 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.
+ */
+
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+#include "jdct.h" /* Private declarations for DCT subsystem */
+
+
+/* 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[MAX_COMPONENTS];
+
+#ifdef DCT_FLOAT_SUPPORTED
+ /* Same as above for the floating-point case. */
+ float_DCT_method_ptr do_float_dct[MAX_COMPONENTS];
+#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.
+ */
+#ifdef DCT_ISLOW_SUPPORTED
+#define PROVIDE_ISLOW_TABLES
+#else
+#ifdef DCT_SCALING_SUPPORTED
+#define PROVIDE_ISLOW_TABLES
+#endif
+#endif
+
+
+/*
+ * Perform forward DCT on one or more blocks of a component.
+ *
+ * The input samples are taken from the sample_data[] array starting at
+ * position start_row/start_col, and moving to the right for any additional
+ * blocks. The quantized coefficients are returned in coef_blocks[].
+ */
+
+METHODDEF(void)
+forward_DCT (j_compress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY sample_data, JBLOCKROW coef_blocks,
+ JDIMENSION start_row, JDIMENSION start_col,
+ JDIMENSION num_blocks)
+/* This version is used for integer DCT implementations. */
+{
+ /* 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 = (DCTELEM *) compptr->dct_table;
+ DCTELEM workspace[DCTSIZE2]; /* work area for FDCT subroutine */
+ JDIMENSION bi;
+
+ sample_data += start_row; /* fold in the vertical offset once */
+
+ for (bi = 0; bi < num_blocks; bi++, start_col += compptr->DCT_h_scaled_size) {
+ /* Perform the DCT */
+ (*do_dct) (workspace, sample_data, start_col);
+
+ /* Quantize/descale the coefficients, and store into coef_blocks[] */
+ { register DCTELEM temp, qval;
+ register int i;
+ register JCOEFPTR output_ptr = coef_blocks[bi];
+
+ for (i = 0; i < DCTSIZE2; i++) {
+ qval = divisors[i];
+ temp = workspace[i];
+ /* Divide the coefficient value by qval, ensuring proper rounding.
+ * Since C does not specify the direction of rounding for negative
+ * quotients, we have to force the dividend positive for portability.
+ *
+ * In most files, at least half of the output values will be zero
+ * (at default quantization settings, more like three-quarters...)
+ * so we should ensure that this case is fast. On many machines,
+ * a comparison is enough cheaper than a divide to make a special test
+ * a win. Since both inputs will be nonnegative, we need only test
+ * for a < b to discover whether a/b is 0.
+ * If your machine's division is fast enough, define FAST_DIVIDE.
+ */
+#ifdef FAST_DIVIDE
+#define DIVIDE_BY(a,b) a /= b
+#else
+#define DIVIDE_BY(a,b) if (a >= b) a /= b; else a = 0
+#endif
+ if (temp < 0) {
+ temp = -temp;
+ temp += qval>>1; /* for rounding */
+ DIVIDE_BY(temp, qval);
+ temp = -temp;
+ } else {
+ temp += qval>>1; /* for rounding */
+ DIVIDE_BY(temp, qval);
+ }
+ output_ptr[i] = (JCOEF) temp;
+ }
+ }
+ }
+}
+
+
+#ifdef DCT_FLOAT_SUPPORTED
+
+METHODDEF(void)
+forward_DCT_float (j_compress_ptr cinfo, jpeg_component_info * compptr,
+ JSAMPARRAY sample_data, JBLOCKROW coef_blocks,
+ JDIMENSION start_row, JDIMENSION start_col,
+ JDIMENSION num_blocks)
+/* This version is used for floating-point DCT implementations. */
+{
+ /* 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 = (FAST_FLOAT *) compptr->dct_table;
+ FAST_FLOAT workspace[DCTSIZE2]; /* work area for FDCT subroutine */
+ JDIMENSION bi;
+
+ sample_data += start_row; /* fold in the vertical offset once */
+
+ for (bi = 0; bi < num_blocks; bi++, start_col += compptr->DCT_h_scaled_size) {
+ /* Perform the DCT */
+ (*do_dct) (workspace, sample_data, start_col);
+
+ /* Quantize/descale the coefficients, and store into coef_blocks[] */
+ { register FAST_FLOAT temp;
+ register int i;
+ register JCOEFPTR output_ptr = coef_blocks[bi];
+
+ for (i = 0; i < DCTSIZE2; i++) {
+ /* Apply the quantization and scaling factor */
+ temp = workspace[i] * divisors[i];
+ /* Round to nearest integer.
+ * Since C does not specify the direction of rounding for negative
+ * quotients, we have to force the dividend positive for portability.
+ * The maximum coefficient size is +-16K (for 12-bit data), so this
+ * code should work for either 16-bit or 32-bit ints.
+ */
+ output_ptr[i] = (JCOEF) ((int) (temp + (FAST_FLOAT) 16384.5) - 16384);
+ }
+ }
+ }
+}
+
+#endif /* DCT_FLOAT_SUPPORTED */
+
+
+/*
+ * 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;
+ int method = 0;
+ JQUANT_TBL * qtbl;
+ DCTELEM * dtbl;
+
+ for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
+ ci++, compptr++) {
+ /* Select the proper DCT routine for this component's scaling */
+ switch ((compptr->DCT_h_scaled_size << 8) + compptr->DCT_v_scaled_size) {
+#ifdef DCT_SCALING_SUPPORTED
+ case ((1 << 8) + 1):
+ fdct->do_dct[ci] = jpeg_fdct_1x1;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((2 << 8) + 2):
+ fdct->do_dct[ci] = jpeg_fdct_2x2;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((3 << 8) + 3):
+ fdct->do_dct[ci] = jpeg_fdct_3x3;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((4 << 8) + 4):
+ fdct->do_dct[ci] = jpeg_fdct_4x4;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((5 << 8) + 5):
+ fdct->do_dct[ci] = jpeg_fdct_5x5;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((6 << 8) + 6):
+ fdct->do_dct[ci] = jpeg_fdct_6x6;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((7 << 8) + 7):
+ fdct->do_dct[ci] = jpeg_fdct_7x7;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((9 << 8) + 9):
+ fdct->do_dct[ci] = jpeg_fdct_9x9;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((10 << 8) + 10):
+ fdct->do_dct[ci] = jpeg_fdct_10x10;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((11 << 8) + 11):
+ fdct->do_dct[ci] = jpeg_fdct_11x11;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((12 << 8) + 12):
+ fdct->do_dct[ci] = jpeg_fdct_12x12;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((13 << 8) + 13):
+ fdct->do_dct[ci] = jpeg_fdct_13x13;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((14 << 8) + 14):
+ fdct->do_dct[ci] = jpeg_fdct_14x14;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((15 << 8) + 15):
+ fdct->do_dct[ci] = jpeg_fdct_15x15;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((16 << 8) + 16):
+ fdct->do_dct[ci] = jpeg_fdct_16x16;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((16 << 8) + 8):
+ fdct->do_dct[ci] = jpeg_fdct_16x8;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((14 << 8) + 7):
+ fdct->do_dct[ci] = jpeg_fdct_14x7;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((12 << 8) + 6):
+ fdct->do_dct[ci] = jpeg_fdct_12x6;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((10 << 8) + 5):
+ fdct->do_dct[ci] = jpeg_fdct_10x5;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((8 << 8) + 4):
+ fdct->do_dct[ci] = jpeg_fdct_8x4;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((6 << 8) + 3):
+ fdct->do_dct[ci] = jpeg_fdct_6x3;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((4 << 8) + 2):
+ fdct->do_dct[ci] = jpeg_fdct_4x2;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((2 << 8) + 1):
+ fdct->do_dct[ci] = jpeg_fdct_2x1;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((8 << 8) + 16):
+ fdct->do_dct[ci] = jpeg_fdct_8x16;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((7 << 8) + 14):
+ fdct->do_dct[ci] = jpeg_fdct_7x14;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((6 << 8) + 12):
+ fdct->do_dct[ci] = jpeg_fdct_6x12;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((5 << 8) + 10):
+ fdct->do_dct[ci] = jpeg_fdct_5x10;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((4 << 8) + 8):
+ fdct->do_dct[ci] = jpeg_fdct_4x8;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((3 << 8) + 6):
+ fdct->do_dct[ci] = jpeg_fdct_3x6;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((2 << 8) + 4):
+ fdct->do_dct[ci] = jpeg_fdct_2x4;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+ case ((1 << 8) + 2):
+ fdct->do_dct[ci] = jpeg_fdct_1x2;
+ method = JDCT_ISLOW; /* jfdctint uses islow-style table */
+ break;
+#endif
+ case ((DCTSIZE << 8) + DCTSIZE):
+ switch (cinfo->dct_method) {
+#ifdef DCT_ISLOW_SUPPORTED
+ case JDCT_ISLOW:
+ fdct->do_dct[ci] = jpeg_fdct_islow;
+ method = JDCT_ISLOW;
+ break;
+#endif
+#ifdef DCT_IFAST_SUPPORTED
+ case JDCT_IFAST:
+ fdct->do_dct[ci] = jpeg_fdct_ifast;
+ method = JDCT_IFAST;
+ break;
+#endif
+#ifdef DCT_FLOAT_SUPPORTED
+ case JDCT_FLOAT:
+ fdct->do_float_dct[ci] = jpeg_fdct_float;
+ method = JDCT_FLOAT;
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+ break;
+ }
+ break;
+ default:
+ ERREXIT2(cinfo, JERR_BAD_DCTSIZE,
+ compptr->DCT_h_scaled_size, compptr->DCT_v_scaled_size);
+ break;
+ }
+ 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];
+ /* 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).
+ */
+ dtbl = (DCTELEM *) compptr->dct_table;
+ for (i = 0; i < DCTSIZE2; i++) {
+ dtbl[i] =
+ ((DCTELEM) qtbl->quantval[i]) << (compptr->component_needed ? 4 : 3);
+ }
+ fdct->pub.forward_DCT[ci] = forward_DCT;
+ 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
+
+ dtbl = (DCTELEM *) compptr->dct_table;
+ for (i = 0; i < DCTSIZE2; i++) {
+ dtbl[i] = (DCTELEM)
+ DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
+ (INT32) aanscales[i]),
+ compptr->component_needed ? CONST_BITS-4 : CONST_BITS-3);
+ }
+ }
+ fdct->pub.forward_DCT[ci] = forward_DCT;
+ 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 = (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
+ };
+
+ 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] *
+ (compptr->component_needed ? 16.0 : 8.0)));
+ i++;
+ }
+ }
+ }
+ fdct->pub.forward_DCT[ci] = forward_DCT_float;
+ break;
+#endif
+ default:
+ ERREXIT(cinfo, JERR_NOT_COMPILED);
+ break;
+ }
+ }
+}
+
+
+/*
+ * Initialize FDCT manager.
+ */
+
+GLOBAL(void)
+jinit_forward_dct (j_compress_ptr cinfo)
+{
+ my_fdct_ptr fdct;
+ 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 = &fdct->pub;
+ fdct->pub.start_pass = start_pass_fdctmgr;
+
+ 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));
+ }
+}
Ecere Software / sdk / blobdiff