From 8794b4cacd06cef44861ea4cebb80a73169585ce Mon Sep 17 00:00:00 2001 From: Phil Rosenberg Date: Mon, 23 Feb 2015 21:44:01 +0000 Subject: [PATCH] Created a basic random number generator seeded from system entropy for use in creating memory map files in the wxWidgets driver to avoid name clashes for multiple instances --- drivers/wxwidgets_dev.cpp | 69 +++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 66 insertions(+), 3 deletions(-) diff --git a/drivers/wxwidgets_dev.cpp b/drivers/wxwidgets_dev.cpp index f5671d8..051cde3 100644 --- a/drivers/wxwidgets_dev.cpp +++ b/drivers/wxwidgets_dev.cpp @@ -23,6 +23,16 @@ #define DEBUG #define NEED_PLDEBUG +//headers needed for Rand +#ifdef WIN32 +//this include must occur before any other include of stdlib.h +//due to the #define _CRT_RAND_S +#define _CRT_RAND_S +#include +#else +#include +#endif + //plplot headers #include "plDevs.h" #include "wxwidgets.h" // includes wx/wx.h @@ -87,6 +97,59 @@ private: }; //-------------------------------------------------------------------------- +// class Rand +// This is a simple random number generator class, created soley so that +// random numbers can be generated in this file without "contaminating" the +// global series of random numbers with a new seed. +// It uses an algorithm that apparently used to be used in gcc rand() +// provided under GNU LGPL v2.1. +//--------------------------------------------------------------------------- +class Rand +{ +public: + Rand() + { +#ifdef WIN32 + rand_s( &m_seed ); +#else + std::fstream fin( "/dev/random", std::ios::in ); + fin.read( (char*)(&m_seed), sizeof( m_seed); + fin.close(); +#endif + } + Rand( unsigned int seed ) + { + m_seed = seed; + } + unsigned int operator()() + { + unsigned int next = m_seed; + int result; + + next *= 1103515245; + next += 12345; + result = (unsigned int) (next / max) % 2048; + + next *= 1103515245; + next += 12345; + result <<= 10; + result ^= (unsigned int) (next / max) % 1024; + + next *= 1103515245; + next += 12345; + result <<= 10; + result ^= (unsigned int) (next / max) % 1024; + + m_seed = next; + + return result; + } + static const unsigned int max = 65536; +private: + unsigned int m_seed; +}; + +//-------------------------------------------------------------------------- // wxPLDevice::wxPLDevice( void ) // // Constructor of the standard wxWidgets device based on the wxPLDevBase @@ -1066,13 +1129,13 @@ void wxPLDevice::SetupMemoryMap() int nTries = 0; char mapName[PLPLOT_MAX_PATH]; char mutexName[PLPLOT_MAX_PATH]; + static Rand randomGenerator; // make this static so that rapid repeat calls don't use the same seed while ( nTries < 10 ) { for ( int i = 0; i < strlen( m_mfo ); ++i ) { - if ( m_mfo[i] == '?' ) //this is reall a poor imitation of a random number generator. - mapName[i] = 'A' + (int) ( 26. * plrandd() ); //Using C++11 generators would be better, but are not supported - //on some enterpise linux systems at the moment + if ( m_mfo[i] == '?' ) + mapName[i] = 'A' + (char) ( randomGenerator() % 26 ); else mapName[i] = m_mfo[i]; } -- 1.7.9