/*

cencoder.c - c source to a base64 encoding algorithm implementation

This is part of the libb64 project, and has been placed in the public domain.

For details, see http://sourceforge.net/projects/libb64

*/

#include "b64/cencode.h"

void base64_init_encodestate(base64_encodestate* state_in)

{

	state_in->step = step_A;

	state_in->result = 0;

	state_in->stepcount = 0;

}

char base64_encode_value(char value_in)

{

	static const char* encoding = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

	if (value_in > 63) return '=';

	return encoding[(int)value_in];

}

int base64_encode_block(const char* plaintext_in, int length_in, char* code_out, base64_encodestate* state_in)

{

	const char* plainchar = plaintext_in;

	const char* const plaintextend = plaintext_in + length_in;

	char* codechar = code_out;

	char result;

	char fragment;

	result = state_in->result;

	switch (state_in->step)

	{

		while (1)

		{

	case step_A:

			if (plainchar == plaintextend)

			{

				state_in->result = result;

				state_in->step = step_A;

				return (int)(codechar - code_out);

			}

			fragment = *plainchar++;

			result = (fragment & 0x0fc) >> 2;

			*codechar++ = base64_encode_value(result);

			result = (fragment & 0x003) << 4;

	case step_B:

			if (plainchar == plaintextend)

			{

				state_in->result = result;

				state_in->step = step_B;

				return (int)(codechar - code_out);

			}

			fragment = *plainchar++;

			result |= (fragment & 0x0f0) >> 4;

			*codechar++ = base64_encode_value(result);

			result = (fragment & 0x00f) << 2;

	case step_C:

			if (plainchar == plaintextend)

			{

				state_in->result = result;

				state_in->step = step_C;

				return (int)(codechar - code_out);

			}

			fragment = *plainchar++;

			result |= (fragment & 0x0c0) >> 6;

			*codechar++ = base64_encode_value(result);

			result  = (fragment & 0x03f) >> 0;

			*codechar++ = base64_encode_value(result);

			++(state_in->stepcount);

		}

	}

	/* control should not reach here */

	return (int)(codechar - code_out);

}

int base64_encode_blockend(char* code_out, base64_encodestate* state_in)

{

	char* codechar = code_out;

	switch (state_in->step)

	{

	case step_B:

		*codechar++ = base64_encode_value(state_in->result);

		*codechar++ = '=';

		*codechar++ = '=';

		break;

	case step_C:

		*codechar++ = base64_encode_value(state_in->result);

		*codechar++ = '=';

		break;

	case step_A:

		break;

	}

	*codechar++ = '\n';

	return (int)(codechar - code_out);

}