source: libcf/trunk/src/cf_codec.c@ 165

/**
 * \file cf_codec.c
 *
 * \author myusgun <myusgun@gmail.com>
 *
 * \brief 데이터 변환 구현
 */
#include "cf_codec.h"
#include "cf_type.h"
#include "cf_error.h"

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

#define BASE64_PADDING_CHAR_INDEX   64

#define ASSERT_ARGS(x)  \
    if ((x))            \
        return CF_ERROR_CODEC_INVALID_ARGS

/**
 * hex-encode
 *
 * \return 성공 시, CF_OK; 실패 시, 오류 코드
 *
 * \param bin   바이너리 데이터
 * \param len   바이너리 데이터의 길이
 * \param hex   16진수 문자열을 저장할 주소
 *
 * \remarks
 * hex는 할당된 메모리이며, 크기는 '\0'를 제외하고 len * 2
 */
int
CF_Codec_Hex_Encode (const cf_byte  * bin,
                     const size_t   len,
                     char           * hex)
{
    const cf_byte   * src = bin;
    char            * dst = hex;

    const static char   hexenc[] = {
        '0', '1', '2', '3', '4', '5', '6', '7',
        '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
    };

    ASSERT_ARGS (bin == NULL);
    ASSERT_ARGS (hex == NULL);

    for ( ; *src ; src++)
    {
        *dst++ = hexenc[((*src) >> 4) & 0x0f];
        *dst++ = hexenc[((*src)     ) & 0x0f];
    }
    *dst = '\0';

    return CF_OK;
}

/**
 * hex-decode
 *
 * \return 성공 시, CF_OK; 실패 시, 오류 코드
 *
 * \param hex   16진수 문자열
 * \param bin   바이너리 데이터를 저장할 주소
 * \param len   바이너리 데이터의 길이를 저장할 주소
 *
 * \remarks
 * bin는 할당된 메모리이며, 크기는 strlen (hex) / 2
 */
int
CF_Codec_Hex_Decode (const char * hex,
                     cf_byte    * bin,
                     size_t     * len)
{
    size_t      length = 0; /* absolutely even-number */

    const char  * src = hex;
    cf_byte     * dst = bin;
    char        buf = 0;
    cf_byte     val = 0;
    cf_byte     asciiHex = 0;

    const static cf_byte hexdec[] = {
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /*  00 -  07 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /*  08 -  15 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /*  16 -  23 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /*  24 -  31 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /*  32 -  39 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /*  40 -  47 */
         '0', '0', '0', '0', '0', '0', '0', '0',    /*  48 -  55 */
         '0', '0',0x00,0x00,0x00,0x00,0x00,0x00,    /*  56 -  63 */
        0x00, 'A', 'A', 'A', 'A', 'A', 'A',0x00,    /*  64 -  71 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /*  71 -  79 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /*  80 -  87 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /*  88 -  95 */
        0x00, 'a', 'a', 'a', 'a', 'a', 'a',0x00,    /*  96 - 103 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /* 104 - 111 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,    /* 112 - 119 */
        0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00     /* 120 - 127 */
    };

    ASSERT_ARGS (hex == NULL);
    ASSERT_ARGS (bin == NULL);
    ASSERT_ARGS (len == NULL);

    for ( ; hexdec[(int)*src] && *src ; src++, length++);

    if (*src)
        return CF_ERROR_CODEC_NOT_HEXSTRING;

    for (src = hex ; *src ; )
    {
        val = 0;    /* init/re-init docoding-buffer */

        /* decode one character */
#define DECODE_HEX(x)                   \
        do {                            \
        buf = *(x);                     \
        val = (cf_byte)(val << 4);      \
        asciiHex = hexdec[(int)buf];    \
        \
        val |=  (cf_byte)               \
                (buf - asciiHex + (asciiHex == '0' ? 0 : 10));  \
        } while (0)

        /* decode one byte by decode two character */
        DECODE_HEX (src++);
        DECODE_HEX (src++);

        *dst++ = val;
    }
    *len = length / 2;

    return CF_OK;
}

/**
 * Base64-encode
 *
 * \return 성공 시, CF_OK; 실패 시, 오류 코드
 *
 * \param bin       바이너리 데이터
 * \param len       바이너리 데이터 길이
 * \param base64    base64 문자열을 저장할 주소
 *
 * \remarks
 * base64는 할당된 메모리이며, 크기는 '\0'를 제외하고 ((len + 2) / 3) * 4
 */
int
CF_Codec_Base64_Encode (const cf_byte   * bin,
                        const size_t    len,
                        char            * base64)
{
    const cf_byte   * src = bin;
    char            * dst = base64;

    const static char base64enc[] = {
        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', /* 00 - 07 */
        'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', /* 08 - 15 */
        'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', /* 16 - 23 */
        'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', /* 24 - 31 */
        'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', /* 32 - 39 */
        'o', 'p', 'q', 'r', 's', 't', 'u', 'v', /* 40 - 47 */
        'w', 'x', 'y', 'z', '0', '1', '2', '3', /* 48 - 55 */
        '4', '5', '6', '7', '8', '9', '+', '/', /* 56 - 63 */
        '='                                     /* padding */
    };

    ASSERT_ARGS (src == NULL);
    ASSERT_ARGS (dst == NULL);

#define SEXTUPLE_E_1(__x)   (((__x[0]) >> 2) & 0x3f)
#define SEXTUPLE_E_2(__x)   (((__x[0]) << 4) & 0x30)
#define SEXTUPLE_E_3(__x)   (((__x[1]) >> 4) & 0x0f)
#define SEXTUPLE_E_4(__x)   (((__x[1]) << 2) & 0x3c)
#define SEXTUPLE_E_5(__x)   (((__x[2]) >> 6) & 0x03)
#define SEXTUPLE_E_6(__x)   (((__x[2])     ) & 0x3f)

    for ( ; (size_t)(src - bin) < len - 2 ; src += 3)
    {
        *dst++ = base64enc[SEXTUPLE_E_1 (src)];
        *dst++ = base64enc[SEXTUPLE_E_2 (src) | SEXTUPLE_E_3 (src)];
        *dst++ = base64enc[SEXTUPLE_E_4 (src) | SEXTUPLE_E_5 (src)];
        *dst++ = base64enc[SEXTUPLE_E_6 (src)];
    }

    if ((size_t)(src - bin) < len)
    {
        *dst++ = base64enc[SEXTUPLE_E_1 (src)];

        if ((size_t) (src - bin) == len - 1)
        {
            *dst++ = base64enc[SEXTUPLE_E_2 (src)];
            *dst++ = base64enc[BASE64_PADDING_CHAR_INDEX];
        }
        else
        {
            *dst++ = base64enc[SEXTUPLE_E_2 (src) | SEXTUPLE_E_3 (src)];
            *dst++ = base64enc[SEXTUPLE_E_4 (src)];
        }

        *dst++ = base64enc[BASE64_PADDING_CHAR_INDEX];
    }
    *dst = '\0';

    return CF_OK;
}

/**
 * Base64-decode
 *
 * \return 성공 시, CF_OK; 실패 시, 오류 코드
 *
 * \param base64    base64 문자열
 * \param bin       바이너리 데이터를 저장할 주소
 * \param len       바이너리 데이터의 길이를 저장할 주소
 *
 * \remarks
 * base64는 할당된 메모리이며, 크기는 (strlen (base64)) / 4 * 3
 */
int
CF_Codec_Base64_Decode (const char  * base64,
                        cf_byte     * bin,
                        size_t      * len)
{
    const char  * src = base64;
    cf_byte     * dst = bin;
    size_t      remain = 0;
    size_t      binlen = 0;

    const static cf_byte base64dec[] = {
        0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,    /*  00 -  07 */
        0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,    /*  08 -  15 */
        0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,    /*  16 -  23 */
        0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,    /*  24 -  31 */
        0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,    /*  32 -  39 */
        0xff,0xff,0xff,  62,0xff,0xff,0xff,  63,    /*  40 -  47 */
          52,  53,  54,  55,  56,  57,  58,  59,    /*  48 -  55 */
          60,  61,0xff,0xff,0xff,  64,0xff,0xff,    /*  56 -  63 */
        0xff,   0,   1,   2,   3,   4,   5,   6,    /*  64 -  71 */
           7,   8,   9,  10,  11,  12,  13,  14,    /*  71 -  79 */
          15,  16,  17,  18,  19,  20,  21,  22,    /*  80 -  87 */
          23,  24,  25,0xff,0xff,0xff,0xff,0xff,    /*  88 -  95 */
        0xff,  26,  27,  28,  29,  30,  31,  32,    /*  96 - 103 */
          33,  34,  35,  36,  37,  38,  39,  40,    /* 104 - 111 */
          41,  42,  43,  44,  45,  46,  47,  48,    /* 112 - 119 */
          49,  50,  51,0xff,0xff,0xff,0xff,0xff     /* 120 - 127 */
    };

    ASSERT_ARGS (src == NULL);
    ASSERT_ARGS (dst == NULL);
    ASSERT_ARGS (len == NULL);

    while (base64dec[(int)*src] < BASE64_PADDING_CHAR_INDEX) src++;

    if (*src == 0xff)
        return CF_ERROR_CODEC_NOT_BASE64;

    remain = (size_t)(src - base64);
    binlen = ((remain + 2/* max padding length */) / 4) * 3;

#define SEXTUPLE_D_1(src)   (base64dec[(int)src[0]] << 2)
#define SEXTUPLE_D_2(src)   (base64dec[(int)src[1]] >> 4)
#define SEXTUPLE_D_3(src)   (base64dec[(int)src[1]] << 4)
#define SEXTUPLE_D_4(src)   (base64dec[(int)src[2]] >> 2)
#define SEXTUPLE_D_5(src)   (base64dec[(int)src[2]] << 6)
#define SEXTUPLE_D_6(src)   (base64dec[(int)src[3]]     )

    for (src = base64 ; remain > 4 ; remain -= 4, src += 4)
    {
        *dst++ = (cf_byte)(SEXTUPLE_D_1 (src) | SEXTUPLE_D_2 (src));
        *dst++ = (cf_byte)(SEXTUPLE_D_3 (src) | SEXTUPLE_D_4 (src));
        *dst++ = (cf_byte)(SEXTUPLE_D_5 (src) | SEXTUPLE_D_6 (src));
    }

    if (remain > 1)
        *dst++ = (cf_byte)(SEXTUPLE_D_1 (src) | SEXTUPLE_D_2 (src));
    if (remain > 2)
        *dst++ = (cf_byte)(SEXTUPLE_D_3 (src) | SEXTUPLE_D_4 (src));
    if (remain > 3)
        *dst++ = (cf_byte)(SEXTUPLE_D_5 (src) | SEXTUPLE_D_6 (src));

    *len = binlen - (4 - remain);

    return CF_OK;
}