1 /* 2 * Copyright (c) 1999-2000 Image Power, Inc. and the University of 3 * British Columbia. 4 * Copyright (c) 2001-2002 Michael David Adams. 5 * All rights reserved. 6 */ 7 8 /* __START_OF_JASPER_LICENSE__ 9 * 10 * JasPer License Version 2.0 11 * 12 * Copyright (c) 2001-2006 Michael David Adams 13 * Copyright (c) 1999-2000 Image Power, Inc. 14 * Copyright (c) 1999-2000 The University of British Columbia 15 * 16 * All rights reserved. 17 * 18 * Permission is hereby granted, free of charge, to any person (the 19 * "User") obtaining a copy of this software and associated documentation 20 * files (the "Software"), to deal in the Software without restriction, 21 * including without limitation the rights to use, copy, modify, merge, 22 * publish, distribute, and/or sell copies of the Software, and to permit 23 * persons to whom the Software is furnished to do so, subject to the 24 * following conditions: 25 * 26 * 1. The above copyright notices and this permission notice (which 27 * includes the disclaimer below) shall be included in all copies or 28 * substantial portions of the Software. 29 * 30 * 2. The name of a copyright holder shall not be used to endorse or 31 * promote products derived from the Software without specific prior 32 * written permission. 33 * 34 * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS 35 * LICENSE. NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER 36 * THIS DISCLAIMER. THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 37 * "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING 38 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 39 * PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN NO 40 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL 41 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING 42 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, 43 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION 44 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. NO ASSURANCES ARE 45 * PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE 46 * THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY. 47 * EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS 48 * BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL 49 * PROPERTY RIGHTS OR OTHERWISE. AS A CONDITION TO EXERCISING THE RIGHTS 50 * GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE 51 * ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY. THE SOFTWARE 52 * IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL 53 * SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES, 54 * AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL 55 * SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH 56 * THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH, 57 * PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH 58 * RISK ACTIVITIES"). THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY 59 * EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES. 60 * 61 * __END_OF_JASPER_LICENSE__ 62 */ 63 64 /* 65 * Math Library 66 * 67 * $Id: jpc_math.c,v 1.2 2008-05-26 09:40:52 vp153 Exp $ 68 */ 69 70 /******************************************************************************\ 71 * Includes 72 \******************************************************************************/ 73 74 #include <assert.h> 75 #include <stdio.h> 76 #include <string.h> 77 #include <math.h> 78 #include <stdlib.h> 79 #include <stdarg.h> 80 81 #include "jpc_math.h" 82 83 /******************************************************************************\ 84 * Miscellaneous Functions 85 \******************************************************************************/ 86 87 /* Calculate the integer quantity floor(log2(x)), where x is a positive 88 integer. */ 89 int jpc_floorlog2(int x) 90 { 91 int y; 92 93 /* The argument must be positive. */ 94 assert(x > 0); 95 96 y = 0; 97 while (x > 1) { 98 x >>= 1; 99 ++y; 100 } 101 return y; 102 } 103 104 /* Calculate the bit position of the first leading one in a nonnegative 105 integer. */ 106 /* This function is the basically the same as ceillog2(x), except that the 107 allowable range for x is slightly different. */ 108 int jpc_firstone(int x) 109 { 110 int n; 111 112 /* The argument must be nonnegative. */ 113 assert(x >= 0); 114 115 n = -1; 116 while (x > 0) { 117 x >>= 1; 118 ++n; 119 } 120 return n; 121 } 122
