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/**
* \file os_uuid.c
* \brief Create a new UUID.
* \author Copyright (c) 2002-2012 Jason Perkins and the Premake project
*/
#include "premake.h"
#if PLATFORM_WINDOWS
#include <objbase.h>
#endif
/*
* Pull off the four lowest bytes of a value and add them to my array,
* without the help of the determinately sized C99 data types that
* are not yet universally supported.
*/
static void add(unsigned char* bytes, int offset, unsigned long value)
{
int i;
for (i = 0; i < 4; ++i)
{
bytes[offset++] = (unsigned char)(value & 0xff);
value >>= 8;
}
}
int os_uuid(lua_State* L)
{
char uuid[38];
unsigned char bytes[16];
/* If a name argument is supplied, build the UUID from that. For speed we
* are using a simple DBJ2 hashing function; if this isn't sufficient we
* can switch to a full RFC 4122 §4.3 implementation later. */
const char* name = luaL_optstring(L, 1, NULL);
if (name != NULL)
{
add(bytes, 0, do_hash(name, 0));
add(bytes, 4, do_hash(name, 'L'));
add(bytes, 8, do_hash(name, 'u'));
add(bytes, 12, do_hash(name, 'a'));
}
/* If no name is supplied, try to build one properly */
else
{
#if PLATFORM_WINDOWS
CoCreateGuid((GUID*)bytes);
#elif PLATFORM_OS2
int i;
for (i = 0; i < 16; i++)
bytes[i] = (unsigned char)gethrtime();
#else
int result;
/* not sure how to get a UUID here, so I fake it */
FILE* rnd = fopen("/dev/urandom", "rb");
result = fread(bytes, 16, 1, rnd);
fclose(rnd);
if (!result)
{
return 0;
}
#endif
}
sprintf(uuid, "%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
bytes[0], bytes[1], bytes[2], bytes[3],
bytes[4], bytes[5],
bytes[6], bytes[7],
bytes[8], bytes[9],
bytes[10], bytes[11], bytes[12], bytes[13], bytes[14], bytes[15]);
lua_pushstring(L, uuid);
return 1;
}
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