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webrtc/src//d39ce8d45bc9bcfaef2b3d39bb24d04fa962cfe8/./rtc_base/base64.cc
blob: 6add993fa104106d27f48c0827aa6563832d1054 [file]
//*********************************************************************
//* 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/base64.h"
#include <string.h>
#include <assert.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(const std::string& 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) {
assert(nullptr != 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) {
assert(nullptr != result);
assert(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;
assert(0 != parse_flags);
assert(0 != pad_flags);
assert(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