base64.c (5558B)
1 /* 2 * Copyright (c) 2006 Ryan Martell. (rdm4@martellventures.com) 3 * 4 * This file is part of FFmpeg. 5 * 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21 /** 22 * @file 23 * @brief Base64 encode/decode 24 * @author Ryan Martell <rdm4@martellventures.com> (with lots of Michael) 25 */ 26 27 #include <limits.h> 28 #include <stddef.h> 29 30 #include "base64.h" 31 #include "error.h" 32 #include "intreadwrite.h" 33 34 /* ---------------- private code */ 35 static const uint8_t map2[256] = 36 { 37 0xfe, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 38 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 39 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 40 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 41 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 42 0xff, 0xff, 0xff, 43 44 0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36, 45 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff, 46 0xff, 0xff, 0xfe, 0xff, 0xff, 0xff, 0x00, 0x01, 47 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 48 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 49 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 50 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b, 51 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, 52 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 53 0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 54 55 0xff, 0xff, 0xff, 0xff, 0xff, 56 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 57 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 58 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 59 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 60 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 61 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 62 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 63 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 64 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 65 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 66 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 67 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 68 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 69 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 70 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 71 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 72 }; 73 74 #define BASE64_DEC_STEP(i) do { \ 75 bits = map2[in[i]]; \ 76 if (bits & 0x80) \ 77 goto out ## i; \ 78 v = i ? (v << 6) + bits : bits; \ 79 } while(0) 80 81 int av_base64_decode(uint8_t *out, const char *in_str, int out_size) 82 { 83 uint8_t *dst = out; 84 uint8_t *end; 85 // no sign extension 86 const uint8_t *in = in_str; 87 unsigned bits = 0xff; 88 unsigned v; 89 90 if (!out) 91 goto validity_check; 92 93 end = out + out_size; 94 while (end - dst > 3) { 95 BASE64_DEC_STEP(0); 96 BASE64_DEC_STEP(1); 97 BASE64_DEC_STEP(2); 98 BASE64_DEC_STEP(3); 99 // Using AV_WB32 directly confuses compiler 100 v = av_be2ne32(v << 8); 101 AV_WN32(dst, v); 102 dst += 3; 103 in += 4; 104 } 105 if (end - dst) { 106 BASE64_DEC_STEP(0); 107 BASE64_DEC_STEP(1); 108 BASE64_DEC_STEP(2); 109 BASE64_DEC_STEP(3); 110 *dst++ = v >> 16; 111 if (end - dst) 112 *dst++ = v >> 8; 113 if (end - dst) 114 *dst++ = v; 115 in += 4; 116 } 117 validity_check: 118 while (1) { 119 BASE64_DEC_STEP(0); 120 in++; 121 BASE64_DEC_STEP(0); 122 in++; 123 BASE64_DEC_STEP(0); 124 in++; 125 BASE64_DEC_STEP(0); 126 in++; 127 } 128 129 out3: 130 if (end - dst) 131 *dst++ = v >> 10; 132 v <<= 2; 133 out2: 134 if (end - dst) 135 *dst++ = v >> 4; 136 out1: 137 out0: 138 return bits & 1 ? AVERROR_INVALIDDATA : out ? dst - out : 0; 139 } 140 141 /***************************************************************************** 142 * b64_encode: Stolen from VLC's http.c. 143 * Simplified by Michael. 144 * Fixed edge cases and made it work from data (vs. strings) by Ryan. 145 *****************************************************************************/ 146 147 char *av_base64_encode(char *out, int out_size, const uint8_t *in, int in_size) 148 { 149 static const char b64[] = 150 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 151 char *ret, *dst; 152 unsigned i_bits = 0; 153 int i_shift = 0; 154 int bytes_remaining = in_size; 155 156 if (in_size >= UINT_MAX / 4 || 157 out_size < AV_BASE64_SIZE(in_size)) 158 return NULL; 159 ret = dst = out; 160 while (bytes_remaining > 3) { 161 i_bits = AV_RB32(in); 162 in += 3; bytes_remaining -= 3; 163 *dst++ = b64[ i_bits>>26 ]; 164 *dst++ = b64[(i_bits>>20) & 0x3F]; 165 *dst++ = b64[(i_bits>>14) & 0x3F]; 166 *dst++ = b64[(i_bits>>8 ) & 0x3F]; 167 } 168 i_bits = 0; 169 while (bytes_remaining) { 170 i_bits = (i_bits << 8) + *in++; 171 bytes_remaining--; 172 i_shift += 8; 173 } 174 while (i_shift > 0) { 175 *dst++ = b64[(i_bits << 6 >> i_shift) & 0x3f]; 176 i_shift -= 6; 177 } 178 while ((dst - ret) & 3) 179 *dst++ = '='; 180 *dst = '\0'; 181 182 return ret; 183 }