| |
| //********************************************************************* |
| //* Base64 - a simple base64 encoder and decoder. |
| //* |
| //* Copyright (c) 1999, Bob Withers - bwit@pobox.com |
| //* |
| //* This code may be freely used for any purpose, either personal |
| //* or commercial, provided the authors copyright notice remains |
| //* intact. |
| //* |
| //* Enhancements by Stanley Yamane: |
| //* o reverse lookup table for the decode function |
| //* o reserve string buffer space in advance |
| //* |
| //********************************************************************* |
| |
| #include "rtc_base/third_party/base64/base64.h" |
| |
| #include <string.h> |
| |
| #include "absl/strings/string_view.h" |
| #include "rtc_base/checks.h" |
| |
| using std::vector; |
| |
| namespace rtc { |
| |
| static const char kPad = '='; |
| static const unsigned char pd = 0xFD; // Padding |
| static const unsigned char sp = 0xFE; // Whitespace |
| static const unsigned char il = 0xFF; // Illegal base64 character |
| |
| const char Base64::Base64Table[] = |
| // 0000000000111111111122222222223333333333444444444455555555556666 |
| // 0123456789012345678901234567890123456789012345678901234567890123 |
| "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
| |
| // Decode Table gives the index of any valid base64 character in the |
| // Base64 table |
| // 65 == A, 97 == a, 48 == 0, 43 == +, 47 == / |
| |
| const unsigned char Base64::DecodeTable[] = { |
| // 0 1 2 3 4 5 6 7 8 9 |
| il, il, il, il, il, il, il, il, il, sp, // 0 - 9 |
| sp, sp, sp, sp, il, il, il, il, il, il, // 10 - 19 |
| il, il, il, il, il, il, il, il, il, il, // 20 - 29 |
| il, il, sp, il, il, il, il, il, il, il, // 30 - 39 |
| il, il, il, 62, il, il, il, 63, 52, 53, // 40 - 49 |
| 54, 55, 56, 57, 58, 59, 60, 61, il, il, // 50 - 59 |
| il, pd, il, il, il, 0, 1, 2, 3, 4, // 60 - 69 |
| 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, // 70 - 79 |
| 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, // 80 - 89 |
| 25, il, il, il, il, il, il, 26, 27, 28, // 90 - 99 |
| 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // 100 - 109 |
| 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, // 110 - 119 |
| 49, 50, 51, il, il, il, il, il, il, il, // 120 - 129 |
| il, il, il, il, il, il, il, il, il, il, // 130 - 139 |
| il, il, il, il, il, il, il, il, il, il, // 140 - 149 |
| il, il, il, il, il, il, il, il, il, il, // 150 - 159 |
| il, il, il, il, il, il, il, il, il, il, // 160 - 169 |
| il, il, il, il, il, il, il, il, il, il, // 170 - 179 |
| il, il, il, il, il, il, il, il, il, il, // 180 - 189 |
| il, il, il, il, il, il, il, il, il, il, // 190 - 199 |
| il, il, il, il, il, il, il, il, il, il, // 200 - 209 |
| il, il, il, il, il, il, il, il, il, il, // 210 - 219 |
| il, il, il, il, il, il, il, il, il, il, // 220 - 229 |
| il, il, il, il, il, il, il, il, il, il, // 230 - 239 |
| il, il, il, il, il, il, il, il, il, il, // 240 - 249 |
| il, il, il, il, il, il // 250 - 255 |
| }; |
| |
| bool Base64::IsBase64Char(char ch) { |
| return (('A' <= ch) && (ch <= 'Z')) || (('a' <= ch) && (ch <= 'z')) || |
| (('0' <= ch) && (ch <= '9')) || (ch == '+') || (ch == '/'); |
| } |
| |
| bool Base64::GetNextBase64Char(char ch, char* next_ch) { |
| if (next_ch == nullptr) { |
| return false; |
| } |
| const char* p = strchr(Base64Table, ch); |
| if (!p) |
| return false; |
| ++p; |
| *next_ch = (*p) ? *p : Base64Table[0]; |
| return true; |
| } |
| |
| bool Base64::IsBase64Encoded(absl::string_view str) { |
| for (size_t i = 0; i < str.size(); ++i) { |
| if (!IsBase64Char(str.at(i))) |
| return false; |
| } |
| return true; |
| } |
| |
| void Base64::EncodeFromArray(const void* data, |
| size_t len, |
| std::string* result) { |
| RTC_DCHECK(result); |
| result->clear(); |
| result->resize(((len + 2) / 3) * 4); |
| const unsigned char* byte_data = static_cast<const unsigned char*>(data); |
| |
| unsigned char c; |
| size_t i = 0; |
| size_t dest_ix = 0; |
| while (i < len) { |
| c = (byte_data[i] >> 2) & 0x3f; |
| (*result)[dest_ix++] = Base64Table[c]; |
| |
| c = (byte_data[i] << 4) & 0x3f; |
| if (++i < len) { |
| c |= (byte_data[i] >> 4) & 0x0f; |
| } |
| (*result)[dest_ix++] = Base64Table[c]; |
| |
| if (i < len) { |
| c = (byte_data[i] << 2) & 0x3f; |
| if (++i < len) { |
| c |= (byte_data[i] >> 6) & 0x03; |
| } |
| (*result)[dest_ix++] = Base64Table[c]; |
| } else { |
| (*result)[dest_ix++] = kPad; |
| } |
| |
| if (i < len) { |
| c = byte_data[i] & 0x3f; |
| (*result)[dest_ix++] = Base64Table[c]; |
| ++i; |
| } else { |
| (*result)[dest_ix++] = kPad; |
| } |
| } |
| } |
| |
| size_t Base64::GetNextQuantum(DecodeFlags parse_flags, |
| bool illegal_pads, |
| const char* data, |
| size_t len, |
| size_t* dpos, |
| unsigned char qbuf[4], |
| bool* padded) { |
| size_t byte_len = 0, pad_len = 0, pad_start = 0; |
| for (; (byte_len < 4) && (*dpos < len); ++*dpos) { |
| qbuf[byte_len] = DecodeTable[static_cast<unsigned char>(data[*dpos])]; |
| if ((il == qbuf[byte_len]) || (illegal_pads && (pd == qbuf[byte_len]))) { |
| if (parse_flags != DO_PARSE_ANY) |
| break; |
| // Ignore illegal characters |
| } else if (sp == qbuf[byte_len]) { |
| if (parse_flags == DO_PARSE_STRICT) |
| break; |
| // Ignore spaces |
| } else if (pd == qbuf[byte_len]) { |
| if (byte_len < 2) { |
| if (parse_flags != DO_PARSE_ANY) |
| break; |
| // Ignore unexpected padding |
| } else if (byte_len + pad_len >= 4) { |
| if (parse_flags != DO_PARSE_ANY) |
| break; |
| // Ignore extra pads |
| } else { |
| if (1 == ++pad_len) { |
| pad_start = *dpos; |
| } |
| } |
| } else { |
| if (pad_len > 0) { |
| if (parse_flags != DO_PARSE_ANY) |
| break; |
| // Ignore pads which are followed by data |
| pad_len = 0; |
| } |
| ++byte_len; |
| } |
| } |
| for (size_t i = byte_len; i < 4; ++i) { |
| qbuf[i] = 0; |
| } |
| if (4 == byte_len + pad_len) { |
| *padded = true; |
| } else { |
| *padded = false; |
| if (pad_len) { |
| // Roll back illegal padding |
| *dpos = pad_start; |
| } |
| } |
| return byte_len; |
| } |
| |
| bool Base64::DecodeFromArray(const char* data, |
| size_t len, |
| DecodeFlags flags, |
| std::string* result, |
| size_t* data_used) { |
| return DecodeFromArrayTemplate<std::string>(data, len, flags, result, |
| data_used); |
| } |
| |
| bool Base64::DecodeFromArray(const char* data, |
| size_t len, |
| DecodeFlags flags, |
| vector<char>* result, |
| size_t* data_used) { |
| return DecodeFromArrayTemplate<vector<char>>(data, len, flags, result, |
| data_used); |
| } |
| |
| bool Base64::DecodeFromArray(const char* data, |
| size_t len, |
| DecodeFlags flags, |
| vector<uint8_t>* result, |
| size_t* data_used) { |
| return DecodeFromArrayTemplate<vector<uint8_t>>(data, len, flags, result, |
| data_used); |
| } |
| |
| template <typename T> |
| bool Base64::DecodeFromArrayTemplate(const char* data, |
| size_t len, |
| DecodeFlags flags, |
| T* result, |
| size_t* data_used) { |
| RTC_DCHECK(result); |
| RTC_DCHECK_LE(flags, (DO_PARSE_MASK | DO_PAD_MASK | DO_TERM_MASK)); |
| |
| const DecodeFlags parse_flags = flags & DO_PARSE_MASK; |
| const DecodeFlags pad_flags = flags & DO_PAD_MASK; |
| const DecodeFlags term_flags = flags & DO_TERM_MASK; |
| RTC_DCHECK_NE(0, parse_flags); |
| RTC_DCHECK_NE(0, pad_flags); |
| RTC_DCHECK_NE(0, term_flags); |
| |
| result->clear(); |
| result->reserve(len); |
| |
| size_t dpos = 0; |
| bool success = true, padded; |
| unsigned char c, qbuf[4]; |
| while (dpos < len) { |
| size_t qlen = GetNextQuantum(parse_flags, (DO_PAD_NO == pad_flags), data, |
| len, &dpos, qbuf, &padded); |
| c = (qbuf[0] << 2) | ((qbuf[1] >> 4) & 0x3); |
| if (qlen >= 2) { |
| result->push_back(c); |
| c = ((qbuf[1] << 4) & 0xf0) | ((qbuf[2] >> 2) & 0xf); |
| if (qlen >= 3) { |
| result->push_back(c); |
| c = ((qbuf[2] << 6) & 0xc0) | qbuf[3]; |
| if (qlen >= 4) { |
| result->push_back(c); |
| c = 0; |
| } |
| } |
| } |
| if (qlen < 4) { |
| if ((DO_TERM_ANY != term_flags) && (0 != c)) { |
| success = false; // unused bits |
| } |
| if ((DO_PAD_YES == pad_flags) && !padded) { |
| success = false; // expected padding |
| } |
| break; |
| } |
| } |
| if ((DO_TERM_BUFFER == term_flags) && (dpos != len)) { |
| success = false; // unused chars |
| } |
| if (data_used) { |
| *data_used = dpos; |
| } |
| return success; |
| } |
| |
| } // namespace rtc |
