base64.c 4.79 KB
Newer Older
1 2 3
/*
 * Copyright (c) 2006 Ryan Martell. (rdm4@martellventures.com)
 *
4
 * This file is part of Libav.
5
 *
6
 * Libav is free software; you can redistribute it and/or
7 8 9 10
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
11
 * Libav is distributed in the hope that it will be useful,
12 13 14 15 16
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
17
 * License along with Libav; if not, write to the Free Software
18 19 20 21
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
22
 * @file
23
 * @brief Base64 encode/decode
24 25 26 27 28 29 30
 * @author Ryan Martell <rdm4@martellventures.com> (with lots of Michael)
 */

#include "common.h"
#include "base64.h"

/* ---------------- private code */
31
static const uint8_t map2[] =
32 33 34 35 36 37 38 39 40 41 42 43 44
{
    0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
    0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x01,
    0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
    0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
    0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
    0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
    0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
    0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33
};

45
int av_base64_decode(uint8_t *out, const char *in, int out_size)
46 47 48 49 50 51 52
{
    int i, v;
    uint8_t *dst = out;

    v = 0;
    for (i = 0; in[i] && in[i] != '='; i++) {
        unsigned int index= in[i]-43;
53
        if (index>=FF_ARRAY_ELEMS(map2) || map2[index] == 0xff)
54 55 56
            return -1;
        v = (v << 6) + map2[index];
        if (i & 3) {
57
            if (dst - out < out_size) {
58 59 60 61 62
                *dst++ = v >> (6 - 2 * (i & 3));
            }
        }
    }

63
    return dst - out;
64 65 66
}

/*****************************************************************************
67 68 69
* b64_encode: Stolen from VLC's http.c.
* Simplified by Michael.
* Fixed edge cases and made it work from data (vs. strings) by Ryan.
70 71
*****************************************************************************/

72
char *av_base64_encode(char *out, int out_size, const uint8_t *in, int in_size)
73 74 75 76 77 78
{
    static const char b64[] =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    char *ret, *dst;
    unsigned i_bits = 0;
    int i_shift = 0;
79
    int bytes_remaining = in_size;
80

81
    if (in_size >= UINT_MAX / 4 ||
Howard Chu's avatar
Howard Chu committed
82
        out_size < AV_BASE64_SIZE(in_size))
83
        return NULL;
84
    ret = dst = out;
85
    while (bytes_remaining) {
86
        i_bits = (i_bits << 8) + *in++;
87 88
        bytes_remaining--;
        i_shift += 8;
89

90 91 92 93 94 95 96
        do {
            *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f];
            i_shift -= 6;
        } while (i_shift > 6 || (bytes_remaining == 0 && i_shift > 0));
    }
    while ((dst - ret) & 3)
        *dst++ = '=';
97 98 99 100
    *dst = '\0';

    return ret;
}
101 102 103 104 105 106 107 108

#ifdef TEST

#undef printf

#define MAX_DATA_SIZE    1024
#define MAX_ENCODED_SIZE 2048

109 110
static int test_encode_decode(const uint8_t *data, unsigned int data_size,
                              const char *encoded_ref)
111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164
{
    char  encoded[MAX_ENCODED_SIZE];
    uint8_t data2[MAX_DATA_SIZE];
    int data2_size, max_data2_size = MAX_DATA_SIZE;

    if (!av_base64_encode(encoded, MAX_ENCODED_SIZE, data, data_size)) {
        printf("Failed: cannot encode the input data\n");
        return 1;
    }
    if (encoded_ref && strcmp(encoded, encoded_ref)) {
        printf("Failed: encoded string differs from reference\n"
               "Encoded:\n%s\nReference:\n%s\n", encoded, encoded_ref);
        return 1;
    }

    if ((data2_size = av_base64_decode(data2, encoded, max_data2_size)) < 0) {
        printf("Failed: cannot decode the encoded string\n"
               "Encoded:\n%s\n", encoded);
        return 1;
    }
    if (memcmp(data2, data, data_size)) {
        printf("Failed: encoded/decoded data differs from original data\n");
        return 1;
    }

    printf("Passed!\n");
    return 0;
}

int main(void)
{
    int i, error_count = 0;
    struct test {
        const uint8_t *data;
        const char *encoded_ref;
    } tests[] = {
        { "",        ""},
        { "1",       "MQ=="},
        { "22",      "MjI="},
        { "333",     "MzMz"},
        { "4444",    "NDQ0NA=="},
        { "55555",   "NTU1NTU="},
        { "666666",  "NjY2NjY2"},
        { "abc:def", "YWJjOmRlZg=="},
    };

    printf("Encoding/decoding tests\n");
    for (i = 0; i < FF_ARRAY_ELEMS(tests); i++)
        error_count += test_encode_decode(tests[i].data, strlen(tests[i].data), tests[i].encoded_ref);

    return error_count;
}

#endif