1 /*===========================================================================* 2 * dct.h * 3 * * 4 * DCT procedures * 5 * * 6 *===========================================================================*/ 7 8 /* 9 * Copyright (c) 1995 The Regents of the University of California. 10 * All rights reserved. 11 * 12 * Permission to use, copy, modify, and distribute this software and its 13 * documentation for any purpose, without fee, and without written agreement is 14 * hereby granted, provided that the above copyright notice and the following 15 * two paragraphs appear in all copies of this software. 16 * 17 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR 18 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT 19 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF 20 * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 21 * 22 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, 23 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 24 * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS 25 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO 26 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. 27 */ 28 29 30 #ifndef DCT_INCLUDED 31 #define DCT_INCLUDED 32 33 34 #include "ansi.h" 35 36 37 38 #define DCTSIZE 8 /* you really don't want to change this */ 39 #define DCTSIZE_SQ 64 /* you really don't want to change this */ 40 41 #define DCTSIZE2 DCTSIZE*DCTSIZE 42 typedef short DCTELEM; 43 typedef DCTELEM DCTBLOCK[DCTSIZE2]; 44 typedef DCTELEM DCTBLOCK_2D[DCTSIZE][DCTSIZE]; 45 46 47 /* 48 * from mfwddct.c: 49 */ 50 extern void mp_fwd_dct_block2 _ANSI_ARGS_((DCTBLOCK_2D src, DCTBLOCK_2D dest)); 51 52 /* jrevdct.c */ 53 extern void init_pre_idct _ANSI_ARGS_((void )); 54 extern void mpeg_jrevdct _ANSI_ARGS_((DCTBLOCK data )); 55 56 57 /* We assume that right shift corresponds to signed division by 2 with 58 * rounding towards minus infinity. This is correct for typical "arithmetic 59 * shift" instructions that shift in copies of the sign bit. But some 60 * C compilers implement >> with an unsigned shift. For these machines you 61 * must define RIGHT_SHIFT_IS_UNSIGNED. 62 * RIGHT_SHIFT provides a proper signed right shift of an int32 quantity. 63 * It is only applied with constant shift counts. SHIFT_TEMPS must be 64 * included in the variables of any routine using RIGHT_SHIFT. 65 */ 66 67 #ifdef RIGHT_SHIFT_IS_UNSIGNED 68 #define SHIFT_TEMPS int32 shift_temp; 69 #define RIGHT_SHIFT(x,shft) \ 70 ((shift_temp = (x)) < 0 ? \ 71 (shift_temp >> (shft)) | ((~((int32) 0)) << (32-(shft))) : \ 72 (shift_temp >> (shft))) 73 #else 74 #define SHIFT_TEMPS 75 #define RIGHT_SHIFT(x,shft) ((x) >> (shft)) 76 #endif 77 78 79 #endif /* DCT_INCLUDED */ 80