/*
 * Copyleft (c) 1999, 2016
 * -----------------------------------------------------------------------
 * Author   : scz <scz@nsfocus.com>
 * Compile  : For *nix
 *          : gcc -Wall -pipe -O3 -s -o hexout hexout.c
 *          :
 *          : strip hexout or gcc -s
 *          : mcs -d hexout (only for Solaris)
 *          :
 * Compile  : For x86/EWindows XP SP1 & VC 7.1
 *          : cl hexout.c /Fehexout.exe /nologo /Os /GB /Gz /Gs65536 /W3 /WX /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /link /RELEASE
 *          :
 * Create   : 2005-03-31 16:04
 * Modify   : 2006-11-30 11:56
 * -----------------------------------------------------------------------
 * The only thing they can't take from us are our minds. !H
 */

#if 0

这个程序是为了配合nc快速测试一些协议相关的东西，没有更多其它意义，因为看到
TK在用类似工具，下手写一个备用。

Windows

> hexout "\xd\xa\x0\0\x9\x7scz\x" | xxd -g 1
0000000: 0d 0a 00 5c 30 09 07 73 63 7a 5c 78              ...\0..scz\x

Linux

$ ./hexout "\xd\xa\x0\0\x9\x7scz\x" | xxd -g 1
0000000: 0d 0a 00 5c 30 09 07 73 63 7a 5c 78              ...\0..scz\x

Solaris

$ ./hexout "\xd\xa\x0\0\x9\x7scz\x" | od -Ax -tx1
0000000 0d 0a 00 5c 30 09 07 73 63 7a 5c 78

#endif

/************************************************************************
 *                                                                      *
 *                               Head File                              *
 *                                                                      *
 ************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>

#if !defined(WIN32)
#include <unistd.h>
#else
#include <io.h>
#endif

/************************************************************************
 *                                                                      *
 *                               Macro                                  *
 *                                                                      *
 ************************************************************************/

#if defined(WIN32)

#pragma comment( linker, "/INCREMENTAL:NO"      )
#pragma comment( linker, "/merge:.rdata=.text"  )
#pragma comment( linker, "/subsystem:console"   )

#define write   _write
#define fileno  _fileno

#endif

/************************************************************************
 *                                                                      *
 *                            Function Prototype                        *
 *                                                                      *
 ************************************************************************/

static unsigned int dosomething
(
    unsigned char  *in,
    unsigned char  *out
);
static void         reverse
(
    unsigned char  *in,
    unsigned int    insize,
    unsigned char  *out
);

/************************************************************************
 *                                                                      *
 *                            Static Global Var                         *
 *                                                                      *
 ************************************************************************/

/************************************************************************/

/*
 * 2005-05-11 09:42
 *
 * 处理\\、\xH、\xHH、\r、\n、\t、\0这几种情形
 */
static unsigned int dosomething
(
    unsigned char  *in,
    unsigned char  *out
)
{
    unsigned int    i, j;
    unsigned char   str[3];

    for ( i = 0, j = 0; '\0' != in[i]; i++, j++ )
    {
        if ( '\\' != in[i] )
        {
            out[j]  = in[i];
        }
        else
        {
            switch ( in[i+1] )
            {
            case '\\':
                /*
                 * 出现了两个\
                 */
                out[j]  = '\\';
                i++;
                break;
            case 'r':
                /*
                 * 出现了\r
                 */
                out[j]  = '\r';
                i++;
                break;
            case 'n':
                /*
                 * 出现了\n
                 */
                out[j]  = '\n';
                i++;
                break;
            case 't':
                /*
                 * 出现了\t
                 */
                out[j]  = '\t';
                i++;
                break;
            case '0':
                /*
                 * 出现了\0
                 */
                out[j]  = '\0';
                i++;
                break;
            case 'x':
                /*
                 * 出现了\x
                 */
                str[1]  =
                str[2]  = '\0';
                if ( ( in[i+2] >= '0' && in[i+2] <= '9' ) || ( in[i+2] >= 'a' && in[i+2] <= 'f' ) || ( in[i+2] >= 'A' && in[i+2] <= 'F' ) )
                {
                    i      += 2;
                    str[0]  = in[i];
                    if ( ( in[i+1] >= '0' && in[i+1] <= '9' ) || ( in[i+1] >= 'a' && in[i+1] <= 'f' ) || ( in[i+1] >= 'A' && in[i+1] <= 'F' ) )
                    {
                        i++;
                        str[1]  = in[i];
                    }
                    /*
                     * 按16进制串处理
                     */
                    out[j]  = ( unsigned char )strtoul( str, NULL, 16 );
                }
                else
                {
                    out[j]  = in[i];
                }
                break;
            case '\0':
                /*
                 * 最后一个\
                 */
            default:
                /*
                 * 无需转义
                 */
                out[j]  = in[i];
                break;
            }  /* end of switch */
        }
    }  /* end of for */
    return( j );
}  /* end of dosomething */

/*
 * 2006-11-30 13:47 scz
 *
 * in、out可以重叠，insize必须大于0
 */
static void reverse
(
    unsigned char  *in,
    unsigned int    insize,
    unsigned char  *out
)
{
    unsigned int    i,
                    j;

    memmove( out, in, insize );
    for ( i = 0, j = insize - 1; i < j; i++, j-- )
    {
        out[i] ^= out[j];
        out[j] ^= out[i];
        out[i] ^= out[j];
    }  /* end of for */
    return;
}  /* end of reverse */

#if !defined(WIN32)
int main ( int argc, char * argv[] )
#else
int __cdecl main ( int argc, char * argv[] )
#endif
{
    int             ret = EXIT_FAILURE;
    unsigned int    i;

    if ( argc <= 1 )
    {
        fprintf
        (
            stderr,
            "Usage: %s <string> [r]\n",
            argv[0]
        );
        goto main_exit;
    }
#if defined(WIN32)
    /*
     * 对于Windows平台有这个问题，不这样设置的话，向标准输出输出0x0A时会被
     * 转换成0x0D 0x0A。
     */
    _setmode( fileno( stdout ), _O_BINARY );
#endif
    i   = dosomething( argv[1], argv[1] );
    if ( argc >= 3 )
    {
        if ( 'r' == argv[2][0] || 'R' == argv[2][0] )
        {
            reverse( argv[1], i, argv[1] );
        }
    }
    write( fileno( stdout ), argv[1], i );
    ret = EXIT_SUCCESS;

main_exit:

    return( ret );
}  /* end of main */

/************************************************************************/