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//*********************************************************************
//* 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 "webrtc/base/base64.h"
#include <string.h>
#include "webrtc/base/common.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 == NULL) {
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(NULL != 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);
}
template<typename T>
bool Base64::DecodeFromArrayTemplate(const char* data, size_t len,
DecodeFlags flags, T* result,
size_t* data_used)
{
ASSERT(NULL != 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
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