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/* $Id$ */

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/** @file endian_check.cpp

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 * This pretty simple file checks if the system is LITTLE_ENDIAN or BIG_ENDIAN

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 *  it does that by putting a 1 and a 0 in an array, and read it out as one

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 *  number. If it is 1, it is LITTLE_ENDIAN, if it is 256, it is BIG_ENDIAN

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 *

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 * After that it outputs the contents of an include files (endian.h)

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 *  that says or TTD_LITTLE_ENDIAN, or TTD_BIG_ENDIAN. Makefile takes

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 *  care of the real writing to the file. */

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#include <stdio.h>

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#include <string.h>

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/** Supported endian types */

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enum Endian {

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	ENDIAN_LITTLE, ///< little endian

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	ENDIAN_BIG     ///< big endian

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};

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/**

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 * Shortcut to printf("#define TTD_ENDIAN TTD_*_ENDIAN")

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 * @param endian endian type to define

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 */

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static inline void printf_endian(Endian endian)

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{

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	printf("#define TTD_ENDIAN %s\n", endian == ENDIAN_LITTLE ? "TTD_LITTLE_ENDIAN" : "TTD_BIG_ENDIAN");

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}

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/**

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 * Main call of the endian_check program

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 * @param argc argument count

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 * @param argv arguments themselves

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 * @return exit code

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 */

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int main (int argc, char *argv[])

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{

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	unsigned char endian_test[2] = { 1, 0 };

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	int force_BE = 0, force_LE = 0, force_PREPROCESSOR = 0;

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	if (argc > 1 && strcmp(argv[1], "BE") == 0) force_BE = 1;

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	if (argc > 1 && strcmp(argv[1], "LE") == 0) force_LE = 1;

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	if (argc > 1 && strcmp(argv[1], "PREPROCESSOR") == 0) force_PREPROCESSOR = 1;

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	printf("#ifndef ENDIAN_H\n#define ENDIAN_H\n");

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	if (force_LE == 1) {

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		printf_endian(ENDIAN_LITTLE);

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	} else if (force_BE == 1) {

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		printf_endian(ENDIAN_BIG);

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	} else if (force_PREPROCESSOR == 1) {

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		/* Support for universal binaries on OSX

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		 * Universal binaries supports both PPC and x86

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		 * If a compiler for OSX gets this setting, it will always pick the correct endian and no test is needed

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		 */

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		printf("#ifdef __BIG_ENDIAN__\n");

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		printf_endian(ENDIAN_BIG);

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		printf("#else\n");

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		printf_endian(ENDIAN_LITTLE);

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		printf("#endif\n");

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	} else if (*(short*)endian_test == 1 ) {

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		printf_endian(ENDIAN_LITTLE);

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	} else {

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		printf_endian(ENDIAN_BIG);

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	}

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	printf("#endif\n");

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	return 0;

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}