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