forked from bartvdbraak/blender
102 lines
1.9 KiB
C
102 lines
1.9 KiB
C
/*
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* Random number generator module. Defines a simple API to allocate, use and
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* destroy a generator of randomness. Relies on platform-specific APIs.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "v_randgen.h"
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#if defined _WIN32
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/* This is a fall-back to the old style of simply using rand(). It should
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* be replaced by something using the proper Win32 cryptography APIs.
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* The CryptAcquireContext() and CryptGenRandom() calls sound interesting.
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*
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* FIXME: Replace ASAP.
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*/
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VRandGen * v_randgen_new(void)
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{
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return (VRandGen *) 1; /* Anything that isn't NULL. */
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}
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void v_randgen_get(VRandGen *gen, void *bytes, size_t num)
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{
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if(gen != NULL && bytes != NULL)
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{
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unsigned char *put = bytes, *get;
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size_t i;
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int x;
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while(num > 0)
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{
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x = rand();
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get = (unsigned char *) &x;
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for(i = 0; i < sizeof x && num > 0; i++, num--)
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*put++ = *get++;
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}
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}
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}
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void v_randgen_destroy(VRandGen *gen)
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{
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/* Nothing to do here. */
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}
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#else
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/* On non-Win32 platforms (which is Linux and Darwin, at the moment), we
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* read random data from a file, which is assumed to be one of the kernel's
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* virtual files.
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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struct VRandGen {
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int fd;
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};
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#define SOURCE "/dev/urandom" /* Name of file to read random bits from. */
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VRandGen * v_randgen_new(void)
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{
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VRandGen *gen;
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if((gen = malloc(sizeof *gen)) != NULL)
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{
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gen->fd = open(SOURCE, O_RDONLY);
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if(gen->fd < 0)
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{
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fprintf(stderr, __FILE__ ": Couldn't open " SOURCE " for reading\n");
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free(gen);
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gen = NULL;
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}
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}
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return gen;
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}
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void v_randgen_get(VRandGen *gen, void *bytes, size_t num)
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{
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if(gen != NULL && bytes != NULL)
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{
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if(read(gen->fd, bytes, num) != (int) num)
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fprintf(stderr, __FILE__ ": Failed to read %u bytes of random data from " SOURCE "\n", (unsigned int) num);
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}
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}
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void v_randgen_destroy(VRandGen *gen)
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{
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if(gen != NULL)
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{
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close(gen->fd);
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free(gen);
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}
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}
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#endif
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