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374 | // Copyright (C) 2024 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#include <config.h>
#include <exceptions/exceptions.h>
#include <exceptions/isc_assert.h>
#include <util/encode/encode.h>
#include <iostream><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <stdint.h><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <stdexcept><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <string><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <cstring><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
#include <vector><--- Include file: not found. Please note: Cppcheck does not need standard library headers to get proper results.
using namespace std;
namespace isc {
namespace util {
namespace encode {
BaseNEncoder::BaseNEncoder(const std::string& algorithm,
const char* digit_set,
const std::vector<uint8_t>& bits_table,
size_t bits_per_digit,
size_t digits_per_group,
const char pad_char,
size_t max_pad,
bool case_sensitive)
: algorithm_(algorithm),
digit_set_(digit_set),
bits_table_(bits_table),
bits_per_digit_(bits_per_digit),
digits_per_group_(digits_per_group),
pad_char_(pad_char),
max_pad_(max_pad),
case_sensitive_(case_sensitive),
max_bits_to_digit_(strlen(digit_set) - 1),
max_digit_to_bits_(bits_table_.size() - 1) {
}
char
BaseNEncoder::bitsToDigit(uint8_t bits) {
if (bits > max_bits_to_digit_) {
isc_throw(BadValue, "Digit bits : "
<< static_cast<uint16_t>(bits) << " invalid for " << algorithm_);
}
return (digit_set_[bits]);
}
uint8_t
BaseNEncoder::digitToBits(uint8_t digit) {
if (digit > max_digit_to_bits_) {
isc_throw(BadValue, "Digit exceeds look up table: "
<< static_cast<uint16_t>(digit) << " for " << algorithm_);
}
return (bits_table_[digit]);
}
std::string
BaseNEncoder::encode(const std::vector<uint8_t>& input) {
std::string encoded_output;
if (input.empty()) {
return (encoded_output);
}
// Iterate over the input bytes as a bit stream. We add input bits
// to a digit set index value until we have enough (bits_per_digit). We
// look up a digit in the digit set add it to the encoded output and start over
// on the next index value. When we have exhausted the bits in the current
// byte, get the next byte from input and continue. In other words, we pull bits
// from the left side of the input bit stream and push them into the right side of
// the index value. Each time we have done bits_per_digit bits we look up
// the digit and start the index value over.
int digit_idx = 0; // Digit index we are currently constructing.
size_t cnt = 0; // How many bits we have in the current digit idx
int cur_byte = 0; // Current input byte.
uint8_t cur_bit_mask = 0x0; // Bitmask of the current bit in the current byte.
auto bytes = input.begin(); // Start with the first byte.
while (1) {
// If the current bitmask is zero, it's time for the next input byte.
if (!cur_bit_mask) {
if (bytes == input.end()) {
break;
}
// Grab the next byte.
cur_byte = *bytes;
// Start at the bitmask at the left-most bit.
cur_bit_mask = 0x80;
// Bump the iterator.
++bytes;
}
// Do we need more bits in this digit index?
if (cnt < bits_per_digit_) {
// Yes, so shift the index over to make room for the next bit.
digit_idx <<= 1;
} else {
// No, the index is complete, lookup its digit and add it to the
// output. Start over for the next index.
encoded_output.push_back(bitsToDigit(digit_idx));
digit_idx = 0;
cnt = 0;
}
// If the current bit in the current byte is set,
// set the right-most digit index bit to 1 (otherwise
// its left as zero).
if (cur_byte & cur_bit_mask) {
digit_idx |= 1;
}
// Shift the cur_bit mask to select the next input bit and
// bump the number of bits in the current index.
cur_bit_mask >>= 1;
++cnt;
}
// We've exhausted the input bits but have bits in the
// digit index. This means the remaining bits in our
// last index are zeros (pad bits). Shift "in" the
// required number of bits and add the corresponding
// digit.
digit_idx <<= (bits_per_digit_ - cnt);
encoded_output.push_back(bitsToDigit(digit_idx));
// Add padding as needed.
if (digits_per_group_) {
auto rem = encoded_output.size() % digits_per_group_;
if (rem) {
auto need = digits_per_group_ - rem;
while (need--) {
encoded_output.push_back(pad_char_);
}
}
}
return (encoded_output);
}
void
BaseNEncoder::decode(const std::string& encoded_str, std::vector<uint8_t>& output) {
// Mechanics are essentially the same as encode(). We iterate over the encoded
// string's digits, discarding whitespaces. We lookup the digit's binary value
// in the lookup table, keeping only binary value's right-most, bits_per_digit bits.
// The remaining bits are then shifted out from the left of binary value into the
// right of the currently accumulating output byte until the byte is complete
// (8 bits) or the value's bits are exhausted. Completed bytes are added to the
// output buffer. We continue building bytes until we've exhausted the encoded
// string.
output.clear();
size_t dig_cnt = 0; // Tracks how many encoded digits we see.
size_t pad_cnt = 0; // Tracks how many pad characters we see.
size_t shift_bits = 8 - bits_per_digit_; // Number of unused bits in digit data values.
uint8_t cur_byte = 0; // Current output byte.
size_t cur_bit_cnt = 0; // How man bits we have added to the current byte.
for (const auto enc_digit : encoded_str) {
// If it's a pad char, count it and go on.
if (pad_char_ && enc_digit == pad_char_) {
pad_cnt++;
continue;
}
// Translate the encoded digit to its binary bits.
uint8_t dig_bits = digitToBits(enc_digit);
// Skip whitespace. The choice of 0xee to signify white-space was arbitrary.
if (dig_bits == 0xee) {
continue;
}
// Error on invalid characters.
if (dig_bits == 0xff) {
isc_throw(isc::BadValue, "attempt to decode a value not in "
<< algorithm_ << " char set" << ": " << encoded_str);
}
// Error if pad characters occur in the middle.
if (pad_cnt) {
isc_throw(isc::BadValue, "pad mixed with digits in "
<< algorithm_ << ": " << encoded_str);
}
// Bump the valid character count.
dig_cnt++;
// Shift off the unused bits.
dig_bits <<= shift_bits;
// Add digit's decoded bits to current byte.
for (size_t i = 0; i < bits_per_digit_; ++i) {
if (cur_bit_cnt < 8) {
// Shift contents over one to make room for next bit.
cur_byte <<= 1;
} else {
// Add the completed byte to the output.
output.push_back(cur_byte);
cur_byte = 0;
cur_bit_cnt = 0;
}
// Add the next bit if its set.
if (dig_bits & 0x80) {
cur_byte |= 1;
}
// Shift the decoded bits over.
dig_bits <<= 1;
// Update the current byte bit count.
++cur_bit_cnt;
}
}
if (cur_bit_cnt == 8) {
// Whole one left to add.
output.push_back(cur_byte);
} else if (cur_bit_cnt && cur_byte) {
// Left over bits that are not zero.
isc_throw(BadValue, "non-zero bits left over " << encoded_str);
}
if (pad_char_) {
// Check for too many pad characters.
if (pad_cnt > max_pad_) {
isc_throw(isc::BadValue, "too many pad characters for "
<< algorithm_ << ": " << encoded_str);
}
// Check for an invalid number of pad bits.
// Calculate the number of pad bits corresponding to the pad
// characters. In general, the pad bits consist of all-zero
// trailing bits of the last encoded character plus the zero bits
// represented by each pad character.
// 1st pad 2nd pad 3rd pad...
// +++===== ======= ===... (+: from encoded chars, =: from pad chars)
// 0000...0 0......0 000...
// 0 7 8 15 16.... (bits)
// The number of bits for the '==...' part is padchars * BitsPerChunk.
// So the total number of pad bits is the smallest multiple of 8
// that is >= padchars * BitsPerChunk.
// (Below, note the common idiom of the bitwise AND with ~0x7. It clears the
// lowest three bits, so has the effect of rounding the result down to the
// nearest multiple of 8)
const size_t padbits = ((pad_cnt * bits_per_digit_) + 7) & ~0x7;
if (padbits > bits_per_digit_ * (pad_cnt + 1)) {
isc_throw(isc::BadValue, "Invalid padding for "
<< algorithm_ << ": " << encoded_str);
}
}
// Check for an invalid total of encoded characters.
if ((pad_cnt + dig_cnt) % digits_per_group_) {
isc_throw (isc::BadValue, "Incomplete input for "
<< algorithm_ << ": " << encoded_str);
}
}
const char* Base64Encoder::DIGIT_SET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789"
"+/";
const std::vector<uint8_t> Base64Encoder::BITS_TABLE = {
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xee,0xee,0xee,0xee,0xee,0xff,0xff, // 00-0f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 10-1f
0xee,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,62,0xff,0xff,0xff,63, // 20-2f
52,53,54,55,56,57,58,59,60,61,0xff,0xff,0xff, 0,0xff,0xff, // 30-3f
0xff, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14, // 40-4f
15,16,17,18,19,20,21,22,23,24,25,0xff,0xff,0xff,0xff,0xff, // 50-5f
0xff,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40, // 60-6f
41,42,43,44,45,46,47,48,49,50,51,0xff,0xff,0xff,0xff,0xff, // 70-7f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 80-8f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 90-9f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // a0-af
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // b0-bf
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // c0-cf
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // d0-df
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // e0-ef
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff // f0-ff,
};
const char* Base32HexEncoder::DIGIT_SET = "0123456789ABCDEFGHIJKLMNOPQRSTUV";
const std::vector<uint8_t> Base32HexEncoder::BITS_TABLE = {
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xee,0xee,0xee,0xee,0xee,0xff,0xff, // 00-0f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 10-1f
0xee,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 20-2f
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,0xff,0xff,0xff,0xff,0xff,0xff, // 30-3f
0xff,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24, // 40-4f
25,26,27,28,29,30,31,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 50-5f
0xff,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24, // 60-6f
25,26,27,28,29,30,31,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 70-7f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 80-8f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 90-9f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // a0-af
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // b0-bf
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // c0-cf
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // d0-df
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // e0-ef
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff // f0-ff
};
const char* Base16Encoder::DIGIT_SET = "0123456789ABCDEF";
const std::vector<uint8_t> Base16Encoder::BITS_TABLE = {
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xee,0xee,0xee,0xee,0xee,0xff,0xff, // 00-0f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 10-1f
0xee,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 20-2f
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,0xff,0xff,0xff,0xff,0xff,0xff, // 30-3f
0xff,10,11,12,13,14,15,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 40-4f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 50-5f
0xff,10,11,12,13,14,15,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 60-6f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 70-7f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 80-8f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // 90-9f
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // a0-af
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // b0-bf
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // c0-cf
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // d0-df
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff, // e0-ef
0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff // f0-ff
};
string
encodeBase64(const vector<uint8_t>& binary) {
static Base64Encoder encoder;
return (encoder.encode(binary));
}
void
decodeBase64 (const std::string& encoded_str, std::vector<uint8_t>& output) {
static Base64Encoder encoder;
encoder.decode(encoded_str, output);
}
string
encodeBase32Hex(const vector<uint8_t>& binary) {
static Base32HexEncoder encoder;
return (encoder.encode(binary));
}
void
decodeBase32Hex(const std::string& encoded_str, std::vector<uint8_t>& output) {
static Base32HexEncoder encoder;
encoder.decode(encoded_str, output);
}
string
encodeHex(const vector<uint8_t>& binary) {
static Base16Encoder encoder;
return (encoder.encode(binary));
}
void
decodeHex(const string& encoded_str, vector<uint8_t>& output) {
static Base16Encoder encoder;
encoder.decode(encoded_str, output);
}
} // namespace encode
} // namespace util
} // namespace isc
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