/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#ifndef GUAC_COMMON_SSH_BUFFER_H
#define GUAC_COMMON_SSH_BUFFER_H

#include "config.h"

#include <openssl/bn.h>
#include <stdint.h>

/**
 * Writes the given byte to the given buffer, advancing the buffer pointer by
 * one byte.
 *
 * @param buffer
 *     The buffer to write to.
 *
 * @param value
 *     The value to write.
 */
void guac_common_ssh_buffer_write_byte(char** buffer, uint8_t value);

/**
 * Writes the given integer to the given buffer, advancing the buffer pointer
 * four bytes.
 *
 * @param buffer
 *     The buffer to write to.
 *
 * @param value
 *     The value to write.
 */
void guac_common_ssh_buffer_write_uint32(char** buffer, uint32_t value);

/**
 * Writes the given string and its length to the given buffer, advancing the
 * buffer pointer by the size of the length (four bytes) and the size of the
 * string.
 *
 * @param buffer
 *     The buffer to write to.
 *
 * @param string
 *     The string value to write.
 *
 * @param length
 *     The length of the string to write, in bytes.
 */
void guac_common_ssh_buffer_write_string(char** buffer, const char* string,
        int length);

/**
 * Writes the given BIGNUM the given buffer, advancing the buffer pointer by
 * the size of the length (four bytes) and the size of the BIGNUM.
 *
 * @param buffer
 *     The buffer to write to.
 *
 * @param value
 *     The value to write.
 */
void guac_common_ssh_buffer_write_bignum(char** buffer, BIGNUM* value);

/**
 * Writes the given data the given buffer, advancing the buffer pointer by the
 * given length.
 *
 * @param data
 *     The arbitrary data to write.
 *
 * @param length
 *     The length of data to write, in bytes.
 */
void guac_common_ssh_buffer_write_data(char** buffer, const char* data, int length);

/**
 * Reads a single byte from the given buffer, advancing the buffer by one byte.
 *
 * @param buffer
 *     The buffer to read from.
 *
 * @return
 *     The value read from the buffer.
 */
uint8_t guac_common_ssh_buffer_read_byte(char** buffer);

/**
 * Reads an integer from the given buffer, advancing the buffer by four bytes.
 *
 * @param buffer
 *     The buffer to read from.
 *
 * @return
 *     The value read from the buffer.
 */
uint32_t guac_common_ssh_buffer_read_uint32(char** buffer);

/**
 * Reads a string and its length from the given buffer, advancing the buffer
 * by the size of the length (four bytes) and the size of the string, and
 * returning a pointer to the buffer. The length of the string is stored in
 * the given int.
 *
 * @param buffer
 *     The buffer to read from.
 *
 * @param length
 *     A pointer to an integer into which the length of the read string will
 *     be stored.
 *
 * @return
 *     A pointer to the value within the buffer.
 */
char* guac_common_ssh_buffer_read_string(char** buffer, int* length);

#endif