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/*
* Hex Encoding and Decoding
* (C) 2010 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/hex.h>
#include <botan/mem_ops.h>
#include <stdexcept>
namespace Botan {
void hex_encode(char output[],
const byte input[],
size_t input_length,
bool uppercase)
{
static const byte BIN_TO_HEX_UPPER[16] = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F' };
static const byte BIN_TO_HEX_LOWER[16] = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'a', 'b', 'c', 'd', 'e', 'f' };
const byte* tbl = uppercase ? BIN_TO_HEX_UPPER : BIN_TO_HEX_LOWER;
for(size_t i = 0; i != input_length; ++i)
{
byte x = input[i];
output[2*i ] = tbl[(x >> 4) & 0x0F];
output[2*i+1] = tbl[(x ) & 0x0F];
}
}
std::string hex_encode(const byte input[],
size_t input_length,
bool uppercase)
{
std::string output(2 * input_length, 0);
if(input_length)
hex_encode(&output[0], input, input_length, uppercase);
return output;
}
size_t hex_decode(byte output[],
const char input[],
size_t input_length,
size_t& input_consumed,
bool ignore_ws)
{
/*
* Mapping of hex characters to either their binary equivalent
* or to an error code.
* If valid hex (0-9 A-F a-f), the value.
* If whitespace, then 0x80
* Otherwise 0xFF
* Warning: this table assumes ASCII character encodings
*/
static const byte HEX_TO_BIN[256] = {
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80,
0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x01,
0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x0A, 0x0B, 0x0C,
0x0D, 0x0E, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
byte* out_ptr = output;
bool top_nibble = true;
clear_mem(output, input_length / 2);
for(size_t i = 0; i != input_length; ++i)
{
const byte bin = HEX_TO_BIN[static_cast<byte>(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 std::invalid_argument(
std::string("hex_decode: invalid hex character '") +
bad_char + "'");
}
*out_ptr |= bin << (top_nibble*4);
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 byte 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(byte 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 std::invalid_argument("hex_decode: input did not have full bytes");
return written;
}
size_t hex_decode(byte output[],
const std::string& input,
bool ignore_ws)
{
return hex_decode(output, &input[0], input.length(), ignore_ws);
}
secure_vector<byte> hex_decode(const char input[],
size_t input_length,
bool ignore_ws)
{
secure_vector<byte> bin(1 + input_length / 2);
size_t written = hex_decode(&bin[0],
input,
input_length,
ignore_ws);
bin.resize(written);
return bin;
}
secure_vector<byte> hex_decode(const std::string& input,
bool ignore_ws)
{
return hex_decode(&input[0], input.size(), ignore_ws);
}
}
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