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/*
* Hex Encoding and Decoding
* (C) 2010,2020 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/hex.h>
#include <botan/mem_ops.h>
#include <botan/exceptn.h>
#include <botan/internal/ct_utils.h>
namespace Botan {
namespace {
char hex_encode_nibble(uint8_t n, bool uppercase)
{
BOTAN_DEBUG_ASSERT(n <= 15);
const auto in_09 = CT::Mask<uint8_t>::is_lt(n, 10);
const char c_09 = n + '0';
const char c_af = n + (uppercase ? 'A' : 'a') - 10;
return in_09.select(c_09, c_af);
}
}
void hex_encode(char output[],
const uint8_t input[],
size_t input_length,
bool uppercase)
{
for(size_t i = 0; i != input_length; ++i)
{
const uint8_t n0 = (input[i] >> 4) & 0xF;
const uint8_t n1 = (input[i] ) & 0xF;
output[2*i ] = hex_encode_nibble(n0, uppercase);
output[2*i+1] = hex_encode_nibble(n1, uppercase);
}
}
std::string hex_encode(const uint8_t input[],
size_t input_length,
bool uppercase)
{
std::string output(2 * input_length, 0);
if(input_length)
hex_encode(&output.front(), input, input_length, uppercase);
return output;
}
namespace {
uint8_t hex_char_to_bin(char input)
{
const uint8_t c = static_cast<uint8_t>(input);
const auto is_alpha_upper = CT::Mask<uint8_t>::is_within_range(c, uint8_t('A'), uint8_t('F'));
const auto is_alpha_lower = CT::Mask<uint8_t>::is_within_range(c, uint8_t('a'), uint8_t('f'));
const auto is_decimal = CT::Mask<uint8_t>::is_within_range(c, uint8_t('0'), uint8_t('9'));
const auto is_whitespace = CT::Mask<uint8_t>::is_any_of(c, {
uint8_t(' '), uint8_t('\t'), uint8_t('\n'), uint8_t('\r')
});
const uint8_t c_upper = c - uint8_t('A') + 10;
const uint8_t c_lower = c - uint8_t('a') + 10;
const uint8_t c_decim = c - uint8_t('0');
uint8_t ret = 0xFF; // default value
ret = is_alpha_upper.select(c_upper, ret);
ret = is_alpha_lower.select(c_lower, ret);
ret = is_decimal.select(c_decim, ret);
ret = is_whitespace.select(0x80, ret);
return ret;
}
}
size_t hex_decode(uint8_t output[],
const char input[],
size_t input_length,
size_t& input_consumed,
bool ignore_ws)
{
uint8_t* out_ptr = output;
bool top_nibble = true;
clear_mem(output, input_length / 2);
for(size_t i = 0; i != input_length; ++i)
{
const uint8_t bin = hex_char_to_bin(input[i]);
if(bin >= 0x10)
{
if(bin == 0x80 && ignore_ws)
continue;
std::string bad_char(1, input[i]);
if(bad_char == "\t")
bad_char = "\\t";
else if(bad_char == "\n")
bad_char = "\\n";
throw Invalid_Argument(
std::string("hex_decode: invalid hex character '") +
bad_char + "'");
}
if(top_nibble)
*out_ptr |= bin << 4;
else
*out_ptr |= bin;
top_nibble = !top_nibble;
if(top_nibble)
++out_ptr;
}
input_consumed = input_length;
size_t written = (out_ptr - output);
/*
* We only got half of a uint8_t at the end; zap the half-written
* output and mark it as unread
*/
if(!top_nibble)
{
*out_ptr = 0;
input_consumed -= 1;
}
return written;
}
size_t hex_decode(uint8_t output[],
const char input[],
size_t input_length,
bool ignore_ws)
{
size_t consumed = 0;
size_t written = hex_decode(output, input, input_length,
consumed, ignore_ws);
if(consumed != input_length)
throw Invalid_Argument("hex_decode: input did not have full bytes");
return written;
}
size_t hex_decode(uint8_t output[],
const std::string& input,
bool ignore_ws)
{
return hex_decode(output, input.data(), input.length(), ignore_ws);
}
secure_vector<uint8_t> hex_decode_locked(const char input[],
size_t input_length,
bool ignore_ws)
{
secure_vector<uint8_t> bin(1 + input_length / 2);
size_t written = hex_decode(bin.data(),
input,
input_length,
ignore_ws);
bin.resize(written);
return bin;
}
secure_vector<uint8_t> hex_decode_locked(const std::string& input,
bool ignore_ws)
{
return hex_decode_locked(input.data(), input.size(), ignore_ws);
}
std::vector<uint8_t> hex_decode(const char input[],
size_t input_length,
bool ignore_ws)
{
std::vector<uint8_t> bin(1 + input_length / 2);
size_t written = hex_decode(bin.data(),
input,
input_length,
ignore_ws);
bin.resize(written);
return bin;
}
std::vector<uint8_t> hex_decode(const std::string& input,
bool ignore_ws)
{
return hex_decode(input.data(), input.size(), ignore_ws);
}
}