demboyz/external/cbase64-1.1/include/cbase64/cbase64.h

245 lines
7.2 KiB
C
Raw Normal View History

2015-07-10 02:52:06 +02:00
/* cbase64 - public domain base64 encoder/decoder
Do this:
#define CBASE64_IMPLEMENTATION
before you include this file in *one* C or C++ file to create the implementation.
// i.e. it should look like this:
#include ...
#include ...
#include ...
#define CBASE64_IMPLEMENTATION
#include "cbase64.h"
*/
#ifndef CBASE64_H
#define CBASE64_H
#ifdef __cplusplus
extern "C" {
#endif
typedef enum
{
step_A, step_B, step_C, step_D
} cbase64_step;
typedef struct
{
cbase64_step step;
unsigned char result;
} cbase64_encodestate;
typedef struct
{
cbase64_step step;
char result;
} cbase64_decodestate;
void cbase64_init_encodestate(cbase64_encodestate* state_in);
void cbase64_init_decodestate(cbase64_decodestate* state_in);
unsigned int cbase64_calc_encoded_length(unsigned int length_in);
unsigned int cbase64_calc_decoded_length(const char* code_in, unsigned int length_in);
unsigned int cbase64_encode_block(const unsigned char* data_in, unsigned int length_in,
char* code_out, cbase64_encodestate* state_in);
unsigned int cbase64_decode_block(const char* code_in, unsigned int length_in,
unsigned char* data_out, cbase64_decodestate* state_in);
unsigned int cbase64_encode_blockend(char* code_out, cbase64_encodestate* state_in);
#ifdef __cplusplus
}
#endif
#endif // CBASE64_H
#ifdef CBASE64_IMPLEMENTATION
char cbase64__encode_value(unsigned char value_in)
{
static const char* encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
return encoding[(int)value_in];
}
char cbase64__decode_value(char value_in)
{
static const char decoding[] = {62,-1,-1,-1,63,52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-2,-1,-1,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,-1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51};
static const char decoding_size = sizeof(decoding);
value_in -= 43;
if (value_in < 0 || value_in >= decoding_size) return -1;
return decoding[(int)value_in];
}
void cbase64_init_encodestate(cbase64_encodestate* state_in)
{
state_in->step = step_A;
state_in->result = '\0';
}
void cbase64_init_decodestate(cbase64_decodestate* state_in)
{
state_in->step = step_A;
state_in->result = '\0';
}
unsigned int cbase64_calc_encoded_length(unsigned int length_in)
{
return 4 * (length_in / 3) + ((length_in % 3 != 0) ? 4 : 0);
}
unsigned int cbase64_calc_decoded_length(const char* code_in, unsigned int length_in)
{
if (length_in == 0 || ((length_in & 3) != 0))
{
return 0;
}
const char secondlast = code_in[length_in - 2];
const char last = code_in[length_in - 1];
return 3 * (length_in / 4) - (secondlast == '=') - (last == '=');
}
unsigned int cbase64_encode_block(const unsigned char* data_in, unsigned int length_in,
char* code_out, cbase64_encodestate* state_in)
{
const unsigned char* datachar = data_in;
const unsigned char* const datatextend = data_in + length_in;
char* codechar = code_out;
unsigned char result = state_in->result;
unsigned char fragment;
switch (state_in->step)
{
while (1)
{
case step_A:
if (datachar == datatextend)
{
state_in->step = step_A;
state_in->result = result;
return codechar - code_out;
}
fragment = *datachar++;
result = (fragment & 0x0fc) >> 2;
*codechar++ = cbase64__encode_value(result);
result = (fragment & 0x003) << 4;
case step_B:
if (datachar == datatextend)
{
state_in->step = step_B;
state_in->result = result;
return codechar - code_out;
}
fragment = *datachar++;
result |= (fragment & 0x0f0) >> 4;
*codechar++ = cbase64__encode_value(result);
result = (fragment & 0x00f) << 2;
case step_C:
if (datachar == datatextend)
{
state_in->step = step_C;
state_in->result = result;
return codechar - code_out;
}
fragment = *datachar++;
result |= (fragment & 0x0c0) >> 6;
*codechar++ = cbase64__encode_value(result);
result = (fragment & 0x03f) >> 0;
*codechar++ = cbase64__encode_value(result);
}
}
// control should not reach here
return codechar - code_out;
}
unsigned int cbase64_decode_block(const char* code_in, unsigned int length_in,
unsigned char* data_out, cbase64_decodestate* state_in)
{
const char* codechar = code_in;
const char* const codeend = code_in + length_in;
unsigned char* datachar = data_out;
char fragment;
2015-07-13 04:50:55 +02:00
char overwrite = state_in->result;
2015-07-10 02:52:06 +02:00
switch (state_in->step)
{
while (1)
{
case step_A:
do {
if (codechar == codeend)
{
state_in->step = step_A;
2015-07-13 04:50:55 +02:00
state_in->result = overwrite;
2015-07-10 02:52:06 +02:00
return datachar - data_out;
}
fragment = cbase64__decode_value(*codechar++);
} while (fragment < 0);
2015-07-13 04:50:55 +02:00
*datachar = (fragment & 0x03f) << 2;
2015-07-10 02:52:06 +02:00
case step_B:
do {
if (codechar == codeend)
{
state_in->step = step_B;
2015-07-13 04:50:55 +02:00
state_in->result = overwrite;
2015-07-10 02:52:06 +02:00
return datachar - data_out;
}
fragment = cbase64__decode_value(*codechar++);
} while (fragment < 0);
*datachar++ |= (fragment & 0x030) >> 4;
2015-07-13 04:50:55 +02:00
overwrite = (fragment & 0x00f) << 4;
2015-07-10 02:52:06 +02:00
case step_C:
do {
if (codechar == codeend)
{
state_in->step = step_C;
2015-07-13 04:50:55 +02:00
state_in->result = overwrite;
2015-07-10 02:52:06 +02:00
return datachar - data_out;
}
fragment = cbase64__decode_value(*codechar++);
} while (fragment < 0);
2015-07-13 04:50:55 +02:00
*datachar++ = overwrite | (fragment & 0x03c) >> 2;
overwrite = (fragment & 0x003) << 6;
2015-07-10 02:52:06 +02:00
case step_D:
do {
if (codechar == codeend)
{
state_in->step = step_D;
2015-07-13 04:50:55 +02:00
state_in->result = overwrite;
2015-07-10 02:52:06 +02:00
return datachar - data_out;
}
fragment = cbase64__decode_value(*codechar++);
} while (fragment < 0);
2015-07-13 04:50:55 +02:00
*datachar++ = overwrite | (fragment & 0x03f);
2015-07-10 02:52:06 +02:00
}
}
// control should not reach here
return datachar - data_out;
}
unsigned int cbase64_encode_blockend(char* code_out, cbase64_encodestate* state_in)
{
char* codechar = code_out;
switch (state_in->step)
{
case step_B:
*codechar++ = cbase64__encode_value(state_in->result);
*codechar++ = '=';
*codechar++ = '=';
break;
case step_C:
*codechar++ = cbase64__encode_value(state_in->result);
*codechar++ = '=';
break;
case step_A:
break;
}
return codechar - code_out;
}
#endif // CBASE64_IMPLEMENTATION