1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 /** 17 ************************************************************************ 18 * @file M4PSW_Trace.c 19 * @brief Trace function for trace macros 20 * @note This file gives the implementation of the trace function used 21 * in the trace instrumentation macros 22 ************************************************************************ 23 */ 24 25 #include <stdio.h> /*for printf */ 26 #include <stdarg.h> /* ANSI C macros and defs for variable args */ 27 #include <stdlib.h> 28 #include <string.h> 29 #include <time.h> 30 31 #include "M4OSA_Types.h" 32 #include "M4OSA_Error.h" 33 #include "M4OSA_Memory.h" 34 #include "M4OSA_Mutex.h" 35 /** 36 ************************************************************************ 37 * @fn M4OSA_ERR M4OSA_randInit() 38 * @brief this function initialize the number generator 39 * this function must be called once before any call to M4OSA_rand() 40 * need the stdlib and time libraries 41 * @note 42 * @param 43 * @return M4NO_ERROR 44 ************************************************************************ 45 */ 46 47 M4OSA_ERR M4OSA_randInit() 48 { 49 int i; 50 51 srand(time(NULL)); 52 53 /* Windows' rand is rotten, the first generated value after the init 54 above is not random enough, so let's shake things a little... */ 55 56 for (i=0; i<100; i++) rand(); 57 58 return M4NO_ERROR; 59 } 60 /** 61 ************************************************************************ 62 * @fn M4OSA_ERR M4OSA_rand(M4OSA_Int32* out_value, M4OSA_UInt32 max_value) 63 * @brief This function gives a random number between 1 and max_value 64 * (inclusive) with approximately equal probability, and 65 * returns this number in out_value. For instance, a max_value 66 * of 6 will simulate a fair 6-sided dice roll. 67 * @note 68 * @param out_value (OUT): on return, points to random result 69 * @param max_value (IN): max expected value 70 * @return M4NO_ERROR 71 ************************************************************************ 72 */ 73 74 M4OSA_ERR M4OSA_rand(M4OSA_Int32* out_value, M4OSA_UInt32 max_value) 75 { 76 if( (out_value == M4OSA_NULL) || (max_value < 1) ) 77 { 78 return M4ERR_PARAMETER; 79 } 80 81 (*out_value) = rand(); 82 /* notice this algorithm will only work for max_values such that the multiplication 83 won't overflow, which means that max_value typically shouldn't go over the range of 84 an Int16. */ 85 (*out_value) = (((*out_value) * max_value) / ((M4OSA_UInt32)RAND_MAX + 1)) + 1; 86 87 return M4NO_ERROR; 88 } 89 90 91
