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//
// Created by barkerm on 9/09/15.
//
#include <errno.h>
#include <stddef.h>
#include <math.h>
#include "hdr_encoding.h"
#include "hdr_tests.h"
int zig_zag_encode_i64(uint8_t* buffer, int64_t signed_value)
{
int64_t value = signed_value;
value = (value << 1) ^ (value >> 63);
int bytesWritten = 0;
if (value >> 7 == 0)
{
buffer[0] = (uint8_t) value;
bytesWritten = 1;
}
else
{
buffer[0] = (uint8_t) ((value & 0x7F) | 0x80);
if (value >> 14 == 0)
{
buffer[1] = (uint8_t) (value >> 7);
bytesWritten = 2;
}
else
{
buffer[1] = (uint8_t) ((value >> 7 | 0x80));
if (value >> 21 == 0)
{
buffer[2] = (uint8_t) (value >> 14);
bytesWritten = 3;
}
else
{
buffer[2] = (uint8_t) (value >> 14 | 0x80);
if (value >> 28 == 0)
{
buffer[3] = (uint8_t) (value >> 21);
bytesWritten = 4;
}
else
{
buffer[3] = (uint8_t) (value >> 21 | 0x80);
if (value >> 35 == 0)
{
buffer[4] = (uint8_t) (value >> 28);
bytesWritten = 5;
}
else
{
buffer[4] = (uint8_t) (value >> 28 | 0x80);
if (value >> 42 == 0)
{
buffer[5] = (uint8_t) (value >> 35);
bytesWritten = 6;
}
else
{
buffer[5] = (uint8_t) (value >> 35 | 0x80);
if (value >> 49 == 0)
{
buffer[6] = (uint8_t) (value >> 42);
bytesWritten = 7;
}
else
{
buffer[6] = (uint8_t) (value >> 42 | 0x80);
if (value >> 56 == 0)
{
buffer[7] = (uint8_t) (value >> 49);
bytesWritten = 8;
}
else
{
buffer[7] = (uint8_t) (value >> 49 | 0x80);
buffer[8] = (uint8_t) (value >> 56);
bytesWritten = 9;
}
}
}
}
}
}
}
}
return bytesWritten;
}
int zig_zag_decode_i64(const uint8_t* buffer, int64_t* retVal)
{
uint64_t v = buffer[0];
uint64_t value = v & 0x7F;
int bytesRead = 1;
if ((v & 0x80) != 0)
{
bytesRead = 2;
v = buffer[1];
value |= (v & 0x7F) << 7;
if ((v & 0x80) != 0)
{
bytesRead = 3;
v = buffer[2];
value |= (v & 0x7F) << 14;
if ((v & 0x80) != 0)
{
bytesRead = 4;
v = buffer[3];
value |= (v & 0x7F) << 21;
if ((v & 0x80) != 0)
{
bytesRead = 5;
v = buffer[4];
value |= (v & 0x7F) << 28;
if ((v & 0x80) != 0)
{
bytesRead = 6;
v = buffer[5];
value |= (v & 0x7F) << 35;
if ((v & 0x80) != 0)
{
bytesRead = 7;
v = buffer[6];
value |= (v & 0x7F) << 42;
if ((v & 0x80) != 0)
{
bytesRead = 8;
v = buffer[7];
value |= (v & 0x7F) << 49;
if ((v & 0x80) != 0)
{
bytesRead = 9;
v = buffer[8];
value |= v << 56;
}
}
}
}
}
}
}
}
value = (value >> 1) ^ (-(value & 1));
*retVal = (int64_t) value;
return bytesRead;
}
static const char base64_table[] =
{
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/', '\0'
};
static char get_base_64(uint32_t _24_bit_value, int shift)
{
uint32_t _6_bit_value = 0x3F & (_24_bit_value >> shift);
return base64_table[_6_bit_value];
}
static int from_base_64(int c)
{
if ('A' <= c && c <= 'Z')
{
return c - 'A';
}
else if ('a' <= c && c <= 'z')
{
return (c - 'a') + 26;
}
else if ('0' <= c && c <= '9')
{
return (c - '0') + 52;
}
else if ('+' == c)
{
return 62;
}
else if ('/' == c)
{
return 63;
}
else if ('=' == c)
{
return 0;
}
return EINVAL;
}
size_t hdr_base64_encoded_len(size_t decoded_size)
{
return (size_t) (ceil(decoded_size / 3.0) * 4.0);
}
size_t hdr_base64_decoded_len(size_t encoded_size)
{
return (encoded_size / 4) * 3;
}
static void hdr_base64_encode_block_pad(const uint8_t* input, char* output, size_t pad)
{
uint32_t _24_bit_value = 0;
switch (pad)
{
case 2:
_24_bit_value = (input[0] << 16) + (input[1] << 8);
output[0] = get_base_64(_24_bit_value, 18);
output[1] = get_base_64(_24_bit_value, 12);
output[2] = get_base_64(_24_bit_value, 6);
output[3] = '=';
break;
case 1:
_24_bit_value = (input[0] << 16);
output[0] = get_base_64(_24_bit_value, 18);
output[1] = get_base_64(_24_bit_value, 12);
output[2] = '=';
output[3] = '=';
break;
default:
// No-op
break;
}
}
/**
* Assumes that there is 3 input bytes and 4 output chars.
*/
void hdr_base64_encode_block(const uint8_t* input, char* output)
{
uint32_t _24_bit_value = (input[0] << 16) + (input[1] << 8) + (input[2]);
output[0] = get_base_64(_24_bit_value, 18);
output[1] = get_base_64(_24_bit_value, 12);
output[2] = get_base_64(_24_bit_value, 6);
output[3] = get_base_64(_24_bit_value, 0);
}
int hdr_base64_encode(
const uint8_t* input, size_t input_len, char* output, size_t output_len)
{
if (hdr_base64_encoded_len(input_len) != output_len)
{
return EINVAL;
}
size_t i = 0;
size_t j = 0;
for (; input_len - i >= 3 && j < output_len; i += 3, j += 4)
{
hdr_base64_encode_block(&input[i], &output[j]);
}
size_t remaining = input_len - i;
hdr_base64_encode_block_pad(&input[i], &output[j], remaining);
return 0;
}
/**
* Assumes that there is 4 input chars available and 3 output chars.
*/
void hdr_base64_decode_block(const char* input, uint8_t* output)
{
uint32_t _24_bit_value = 0;
_24_bit_value |= from_base_64(input[0]) << 18;
_24_bit_value |= from_base_64(input[1]) << 12;
_24_bit_value |= from_base_64(input[2]) << 6;
_24_bit_value |= from_base_64(input[3]);
output[0] = (uint8_t) ((_24_bit_value >> 16) & 0xFF);
output[1] = (uint8_t) ((_24_bit_value >> 8) & 0xFF);
output[2] = (uint8_t) ((_24_bit_value) & 0xFF);
}
int hdr_base64_decode(
const char* input, size_t input_len, uint8_t* output, size_t output_len)
{
size_t i, j;
if (input_len < 4 ||
(input_len & 3) != 0 ||
(input_len / 4) * 3 != output_len)
{
return EINVAL;
}
for (i = 0, j = 0; i < input_len; i += 4, j += 3)
{
hdr_base64_decode_block(&input[i], &output[j]);
}
return 0;
}
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