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/* Copyright (C) 2002-2003 RealVNC Ltd. All Rights Reserved.
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
#include <rdr/RandomStream.h>
#include <rdr/Exception.h>
#include <time.h>
#include <stdlib.h>
#ifndef WIN32
#include <unistd.h>
#include <errno.h>
#else
#define getpid() GetCurrentProcessId()
#endif
using namespace rdr;
const int DEFAULT_BUF_LEN = 256;
unsigned int RandomStream::seed;
RandomStream::RandomStream()
: offset(0)
{
ptr = end = start = new U8[DEFAULT_BUF_LEN];
#ifdef WIN32
provider = 0;
if (!CryptAcquireContext(&provider, 0, 0, PROV_RSA_FULL, 0)) {
if (GetLastError() == NTE_BAD_KEYSET) {
if (!CryptAcquireContext(&provider, 0, 0, PROV_RSA_FULL, CRYPT_NEWKEYSET)) {
fprintf(stderr, "RandomStream: unable to create keyset\n");
provider = 0;
}
} else {
fprintf(stderr, "RandomStream: unable to acquire context\n");
provider = 0;
}
}
if (!provider) {
#else
fp = fopen("/dev/urandom", "r");
if (!fp)
fp = fopen("/dev/random", "r");
if (!fp) {
#endif
fprintf(stderr,"RandomStream: warning: no OS supplied random source - using rand()\n");
seed += (unsigned int) time(0) + getpid() + getpid() * 987654 + rand();
srand(seed);
}
}
RandomStream::~RandomStream() {
delete [] start;
#ifdef WIN32
if (provider) {
CryptReleaseContext(provider, 0);
}
#else
if (fp) fclose(fp);
#endif
}
int RandomStream::pos() {
return offset + ptr - start;
}
int RandomStream::overrun(int itemSize, int nItems, bool wait) {
if (itemSize > DEFAULT_BUF_LEN)
throw Exception("RandomStream overrun: max itemSize exceeded");
if (end - ptr != 0)
memmove(start, ptr, end - ptr);
end -= ptr - start;
offset += ptr - start;
ptr = start;
int length = start + DEFAULT_BUF_LEN - end;
#ifdef WIN32
if (provider) {
if (!CryptGenRandom(provider, length, (U8*)end))
throw rdr::SystemException("unable to CryptGenRandom", GetLastError());
end += length;
#else
if (fp) {
int n = fread((U8*)end, length, 1, fp);
if (n != 1)
throw rdr::SystemException("reading /dev/urandom or /dev/random failed",
errno);
end += length;
#endif
} else {
for (int i=0; i<length; i++)
*(U8*)end++ = (int) (256.0*rand()/(RAND_MAX+1.0));
}
if (itemSize * nItems > end - ptr)
nItems = (end - ptr) / itemSize;
return nItems;
}
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