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+/*
+ * jdct.h
+ *
+ * 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 include file contains common declarations for the forward and
+ * inverse DCT modules. These declarations are private to the DCT managers
+ * (jcdctmgr.c, jddctmgr.c) and the individual DCT algorithms.
+ * The individual DCT algorithms are kept in separate files to ease
+ * machine-dependent tuning (e.g., assembly coding).
+ */
+
+
+/*
+ * A forward DCT routine is given a pointer to an input sample array and
+ * a pointer to a work area of type DCTELEM[]; the DCT is to be performed
+ * in-place in that buffer. Type DCTELEM is int for 8-bit samples, INT32
+ * for 12-bit samples. (NOTE: Floating-point DCT implementations use an
+ * array of type FAST_FLOAT, instead.)
+ * The input data is to be fetched from the sample array starting at a
+ * specified column. (Any row offset needed will be applied to the array
+ * pointer before it is passed to the FDCT code.)
+ * Note that the number of samples fetched by the FDCT routine is
+ * DCT_h_scaled_size * DCT_v_scaled_size.
+ * The DCT outputs are returned scaled up by a factor of 8; they therefore
+ * have a range of +-8K for 8-bit data, +-128K for 12-bit data. This
+ * convention improves accuracy in integer implementations and saves some
+ * work in floating-point ones.
+ * Quantization of the output coefficients is done by jcdctmgr.c.
+ */
+
+#if BITS_IN_JSAMPLE == 8
+typedef int DCTELEM; /* 16 or 32 bits is fine */
+#else
+typedef INT32 DCTELEM; /* must have 32 bits */
+#endif
+
+typedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data,
+ JSAMPARRAY sample_data,
+ JDIMENSION start_col));
+typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data,
+ JSAMPARRAY sample_data,
+ JDIMENSION start_col));
+
+
+/*
+ * An inverse DCT routine is given a pointer to the input JBLOCK and a pointer
+ * to an output sample array. The routine must dequantize the input data as
+ * well as perform the IDCT; for dequantization, it uses the multiplier table
+ * pointed to by compptr->dct_table. The output data is to be placed into the
+ * sample array starting at a specified column. (Any row offset needed will
+ * be applied to the array pointer before it is passed to the IDCT code.)
+ * Note that the number of samples emitted by the IDCT routine is
+ * DCT_h_scaled_size * DCT_v_scaled_size.
+ */
+
+/* typedef inverse_DCT_method_ptr is declared in jpegint.h */
+
+/*
+ * Each IDCT routine has its own ideas about the best dct_table element type.
+ */
+
+typedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */
+#if BITS_IN_JSAMPLE == 8
+typedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */
+#define IFAST_SCALE_BITS 2 /* fractional bits in scale factors */
+#else
+typedef INT32 IFAST_MULT_TYPE; /* need 32 bits for scaled quantizers */
+#define IFAST_SCALE_BITS 13 /* fractional bits in scale factors */
+#endif
+typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */
+
+
+/*
+ * Each IDCT routine is responsible for range-limiting its results and
+ * converting them to unsigned form (0..MAXJSAMPLE). The raw outputs could
+ * be quite far out of range if the input data is corrupt, so a bulletproof
+ * range-limiting step is required. We use a mask-and-table-lookup method
+ * to do the combined operations quickly. See the comments with
+ * prepare_range_limit_table (in jdmaster.c) for more info.
+ */
+
+#define IDCT_range_limit(cinfo) ((cinfo)->sample_range_limit + CENTERJSAMPLE)
+
+#define RANGE_MASK (MAXJSAMPLE * 4 + 3) /* 2 bits wider than legal samples */
+
+
+/* Short forms of external names for systems with brain-damaged linkers. */
+
+#ifdef NEED_SHORT_EXTERNAL_NAMES
+#define jpeg_fdct_islow jFDislow
+#define jpeg_fdct_ifast jFDifast
+#define jpeg_fdct_float jFDfloat
+#define jpeg_fdct_7x7 jFD7x7
+#define jpeg_fdct_6x6 jFD6x6
+#define jpeg_fdct_5x5 jFD5x5
+#define jpeg_fdct_4x4 jFD4x4
+#define jpeg_fdct_3x3 jFD3x3
+#define jpeg_fdct_2x2 jFD2x2
+#define jpeg_fdct_1x1 jFD1x1
+#define jpeg_fdct_9x9 jFD9x9
+#define jpeg_fdct_10x10 jFD10x10
+#define jpeg_fdct_11x11 jFD11x11
+#define jpeg_fdct_12x12 jFD12x12
+#define jpeg_fdct_13x13 jFD13x13
+#define jpeg_fdct_14x14 jFD14x14
+#define jpeg_fdct_15x15 jFD15x15
+#define jpeg_fdct_16x16 jFD16x16
+#define jpeg_fdct_16x8 jFD16x8
+#define jpeg_fdct_14x7 jFD14x7
+#define jpeg_fdct_12x6 jFD12x6
+#define jpeg_fdct_10x5 jFD10x5
+#define jpeg_fdct_8x4 jFD8x4
+#define jpeg_fdct_6x3 jFD6x3
+#define jpeg_fdct_4x2 jFD4x2
+#define jpeg_fdct_2x1 jFD2x1
+#define jpeg_fdct_8x16 jFD8x16
+#define jpeg_fdct_7x14 jFD7x14
+#define jpeg_fdct_6x12 jFD6x12
+#define jpeg_fdct_5x10 jFD5x10
+#define jpeg_fdct_4x8 jFD4x8
+#define jpeg_fdct_3x6 jFD3x6
+#define jpeg_fdct_2x4 jFD2x4
+#define jpeg_fdct_1x2 jFD1x2
+#define jpeg_idct_islow jRDislow
+#define jpeg_idct_ifast jRDifast
+#define jpeg_idct_float jRDfloat
+#define jpeg_idct_7x7 jRD7x7
+#define jpeg_idct_6x6 jRD6x6
+#define jpeg_idct_5x5 jRD5x5
+#define jpeg_idct_4x4 jRD4x4
+#define jpeg_idct_3x3 jRD3x3
+#define jpeg_idct_2x2 jRD2x2
+#define jpeg_idct_1x1 jRD1x1
+#define jpeg_idct_9x9 jRD9x9
+#define jpeg_idct_10x10 jRD10x10
+#define jpeg_idct_11x11 jRD11x11
+#define jpeg_idct_12x12 jRD12x12
+#define jpeg_idct_13x13 jRD13x13
+#define jpeg_idct_14x14 jRD14x14
+#define jpeg_idct_15x15 jRD15x15
+#define jpeg_idct_16x16 jRD16x16
+#define jpeg_idct_16x8 jRD16x8
+#define jpeg_idct_14x7 jRD14x7
+#define jpeg_idct_12x6 jRD12x6
+#define jpeg_idct_10x5 jRD10x5
+#define jpeg_idct_8x4 jRD8x4
+#define jpeg_idct_6x3 jRD6x3
+#define jpeg_idct_4x2 jRD4x2
+#define jpeg_idct_2x1 jRD2x1
+#define jpeg_idct_8x16 jRD8x16
+#define jpeg_idct_7x14 jRD7x14
+#define jpeg_idct_6x12 jRD6x12
+#define jpeg_idct_5x10 jRD5x10
+#define jpeg_idct_4x8 jRD4x8
+#define jpeg_idct_3x6 jRD3x8
+#define jpeg_idct_2x4 jRD2x4
+#define jpeg_idct_1x2 jRD1x2
+#endif /* NEED_SHORT_EXTERNAL_NAMES */
+
+/* Extern declarations for the forward and inverse DCT routines. */
+
+EXTERN(void) jpeg_fdct_islow
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_ifast
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_float
+ JPP((FAST_FLOAT * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_7x7
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_6x6
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_5x5
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_4x4
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_3x3
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_2x2
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_1x1
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_9x9
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_10x10
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_11x11
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_12x12
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_13x13
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_14x14
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_15x15
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_16x16
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_16x8
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_14x7
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_12x6
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_10x5
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_8x4
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_6x3
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_4x2
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_2x1
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_8x16
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_7x14
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_6x12
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_5x10
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_4x8
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_3x6
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_2x4
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+EXTERN(void) jpeg_fdct_1x2
+ JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
+
+EXTERN(void) jpeg_idct_islow
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_ifast
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_float
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_7x7
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_6x6
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_5x5
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_4x4
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_3x3
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_2x2
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_1x1
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_9x9
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_10x10
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_11x11
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_12x12
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_13x13
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_14x14
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_15x15
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_16x16
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_16x8
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_14x7
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_12x6
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_10x5
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_8x4
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_6x3
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_4x2
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_2x1
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_8x16
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_7x14
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_6x12
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_5x10
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_4x8
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_3x6
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_2x4
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+EXTERN(void) jpeg_idct_1x2
+ JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
+ JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
+
+
+/*
+ * Macros for handling fixed-point arithmetic; these are used by many
+ * but not all of the DCT/IDCT modules.
+ *
+ * All values are expected to be of type INT32.
+ * Fractional constants are scaled left by CONST_BITS bits.
+ * CONST_BITS is defined within each module using these macros,
+ * and may differ from one module to the next.
+ */
+
+#define ONE ((INT32) 1)
+#define CONST_SCALE (ONE << CONST_BITS)
+
+/* Convert a positive real constant to an integer scaled by CONST_SCALE.
+ * Caution: some C compilers fail to reduce "FIX(constant)" at compile time,
+ * thus causing a lot of useless floating-point operations at run time.
+ */
+
+#define FIX(x) ((INT32) ((x) * CONST_SCALE + 0.5))
+
+/* Descale and correctly round an INT32 value that's scaled by N bits.
+ * We assume RIGHT_SHIFT rounds towards minus infinity, so adding
+ * the fudge factor is correct for either sign of X.
+ */
+
+#define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n)
+
+/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
+ * This macro is used only when the two inputs will actually be no more than
+ * 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a
+ * full 32x32 multiply. This provides a useful speedup on many machines.
+ * Unfortunately there is no way to specify a 16x16->32 multiply portably
+ * in C, but some C compilers will do the right thing if you provide the
+ * correct combination of casts.
+ */
+
+#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
+#define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT16) (const)))
+#endif
+#ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */
+#define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT32) (const)))
+#endif
+
+#ifndef MULTIPLY16C16 /* default definition */
+#define MULTIPLY16C16(var,const) ((var) * (const))
+#endif
+
+/* Same except both inputs are variables. */
+
+#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
+#define MULTIPLY16V16(var1,var2) (((INT16) (var1)) * ((INT16) (var2)))
+#endif
+
+#ifndef MULTIPLY16V16 /* default definition */
+#define MULTIPLY16V16(var1,var2) ((var1) * (var2))
+#endif
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