minetest-world-manager/src/minetest_world_manager_base64.c

/*
minetest_world_manager_base64.c

This is an altered source version.
This is not the original source code written by René Nyffenegger.

Copyright (C) 2016 YuGiOhJCJ
Copyright (C) 2004-2008 René Nyffenegger

This source code is provided 'as-is', without any express or implied
warranty. In no event will the author be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this source code must not be misrepresented; you must not
   claim that you wrote the original source code. If you use this source code
   in a product, an acknowledgment in the product documentation would be
   appreciated but is not required.

2. Altered source versions must be plainly marked as such, and must not be
   misrepresented as being the original source code.

3. This notice may not be removed or altered from any source distribution.

YuGiOhJCJ <yugiohjcj@1s.fr>
René Nyffenegger <rene.nyffenegger@adp-gmbh.ch>
*/
#include <ctype.h> /* for isalnum */
#include <stdlib.h> /* for NULL */
#include <string.h> /* for strlen */
#include "minetest_world_manager_base64.h" /* for minetest_world_manager_base64_encode */
#include "minetest_world_manager_print.h" /* for minetest_world_manager_print_error */
static const char *minetest_world_manager_base64_chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static int minetest_world_manager_base64_is_base64(unsigned char c);
static int minetest_world_manager_base64_is_base64(unsigned char c)
{
	return (isalnum(c) || (c == '+') || (c == '/'));
}
char *minetest_world_manager_base64_decode(const char *encoded_string, size_t *ret_size)
{
	int in_len = strlen(encoded_string);
	int i = 0;
	int j = 0;
	int in_ = 0;
	unsigned char char_array_4[4], char_array_3[3];
	char *ret = NULL;
	*ret_size = 0;
	while(in_len-- && (encoded_string[in_] != '=') && minetest_world_manager_base64_is_base64(encoded_string[in_]))
	{
		char_array_4[i++] = encoded_string[in_]; in_++;
		if(i ==4)
		{
			for(i = 0; i <4; i++)
			{
				char *character = strchr(minetest_world_manager_base64_chars, char_array_4[i]);
				if(character == NULL)
				{
					minetest_world_manager_print_error(__FILE__, __LINE__, "Unable to get the character for the base64 decoded value.");
					return NULL;
				}
				char_array_4[i] = character - minetest_world_manager_base64_chars;
			}
			char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
			char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
			char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
			for(i = 0; (i < 3); i++)
			{
				(*ret_size)++;
				ret = realloc(ret, sizeof(char) * (*ret_size + 1));
				if(ret == NULL)
				{
					minetest_world_manager_print_error(__FILE__, __LINE__, "Unable to allocate memory for the base64 decoded value.");
					return NULL;
				}
				ret[*ret_size - 1] = char_array_3[i];
			}
			i = 0;
		}
	}
	if(i)
	{
		for(j = i; j <4; j++)
			char_array_4[j] = 0;
		for(j = 0; j <4; j++)
		{
			char *character = strchr(minetest_world_manager_base64_chars, char_array_4[j]);
			if(character == NULL)
			{
				minetest_world_manager_print_error(__FILE__, __LINE__, "Unable to get the character for the base64 decoded value.");
				return NULL;
			}
			char_array_4[j] = character - minetest_world_manager_base64_chars;
		}
		char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
		char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
		char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
		for(j = 0; (j < i - 1); j++)
		{
			(*ret_size)++;
			ret = realloc(ret, sizeof(char) * (*ret_size + 1));
			if(ret == NULL)
			{
				minetest_world_manager_print_error(__FILE__, __LINE__, "Unable to allocate memory for the base64 decoded value.");
				return NULL;
			}
			ret[*ret_size - 1] = char_array_3[j];
		}
	}
	if(ret != NULL)
		ret[*ret_size] = '\0';
	return ret;
}
char *minetest_world_manager_base64_encode(unsigned char const *bytes_to_encode, unsigned int in_len)
{
	char *ret = NULL;
	int ret_size = 0;
	int i = 0;
	int j = 0;
	unsigned char char_array_3[3];
	unsigned char char_array_4[4];
	while(in_len--)
	{
		char_array_3[i++] = *(bytes_to_encode++);
		if(i == 3)
		{
			char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
			char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
			char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
			char_array_4[3] = char_array_3[2] & 0x3f;
			for(i = 0; (i <4) ; i++)
			{
				ret_size++;
				ret = realloc(ret, sizeof(char) * (ret_size + 1));
				if(ret == NULL)
				{
					minetest_world_manager_print_error(__FILE__, __LINE__, "Unable to allocate memory for the base64 encoded value.");
					return NULL;
				}
				ret[ret_size - 1] = minetest_world_manager_base64_chars[char_array_4[i]];
			}
			i = 0;
		}
	}
	if(i)
	{
		for(j = i; j < 3; j++)
			char_array_3[j] = '\0';
		char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
		char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
		char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
		char_array_4[3] = char_array_3[2] & 0x3f;
		for(j = 0; (j < i + 1); j++)
		{
			ret_size++;
			ret = realloc(ret, sizeof(char) * (ret_size + 1));
			if(ret == NULL)
			{
				minetest_world_manager_print_error(__FILE__, __LINE__, "Unable to allocate memory for the base64 encoded value.");
				return NULL;
			}
			ret[ret_size - 1] = minetest_world_manager_base64_chars[char_array_4[j]];
		}
	}
	if(ret != NULL)
		ret[ret_size] = '\0';
	return ret;
}