// Minimal changes introduced, for which:
// Copyright(c) 2006 to 2019 ZettaScale Technology and others
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
// v. 1.0 which is available at
// http://www.eclipse.org/org/documents/edl-v10.php.
//
// SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause

// Copyright (C) 1999, 2002 Aladdin Enterprises.  All rights reserved.
//
// This software is provided 'as-is', without any express or implied
// warranty.  In no event will the authors 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 software must not be misrepresented; you must not
//    claim that you wrote the original software. If you use this software
//    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 software.
// 3. This notice may not be removed or altered from any source distribution.
//
// L. Peter Deutsch
// ghost@aladdin.com

// $Id: md5.h,v 1.4 2002/04/13 19:20:28 lpd Exp $
// Independent implementation of MD5 (RFC 1321).
//
// This code implements the MD5 Algorithm defined in RFC 1321, whose
// text is available at
//       http://www.ietf.org/rfc/rfc1321.txt
// The code is derived from the text of the RFC, including the test suite
// (section A.5) but excluding the rest of Appendix A.  It does not include
// any code or documentation that is identified in the RFC as being
// copyrighted.
//
// The original and principal author of md5.h is L. Peter Deutsch
// <ghost@aladdin.com>.  Other authors are noted in the change history
// that follows (in reverse chronological order):
//
// 2002-04-13 lpd Removed support for non-ANSI compilers; removed
//       references to Ghostscript; clarified derivation from RFC 1321;
//       now handles byte order either statically or dynamically.
// 1999-11-04 lpd Edited comments slightly for automatic TOC extraction.
// 1999-10-18 lpd Fixed typo in header comment (ansi2knr rather than md5);
//       added conditionalization for C++ compilation from Martin
//       Purschke <purschke@bnl.gov>.
// 1999-05-03 lpd Original version.

#ifndef DDSRT_MD5_H
#define DDSRT_MD5_H

#include <stddef.h>
#include "dds/export.h"

/** @file md5.h
 * The MD5 hash (a 128-bit hash, still suitable for detecting unintentional corruption,
 * but no longer to be used where a cryptographic hash is needed)
 * 
 * This package supports both compile-time and run-time determination of CPU
 * byte order.  If ARCH_IS_BIG_ENDIAN is defined as 0, the code will be
 * compiled to run only on little-endian CPUs; if ARCH_IS_BIG_ENDIAN is
 * defined as non-zero, the code will be compiled to run only on big-endian
 * CPUs; if ARCH_IS_BIG_ENDIAN is not defined, the code will be compiled to
 * run on either big- or little-endian CPUs, but will run slightly less
 * efficiently on either one than if ARCH_IS_BIG_ENDIAN is defined.
 */

typedef unsigned char ddsrt_md5_byte_t; /* 8-bit byte */
typedef unsigned int ddsrt_md5_word_t; /* 32-bit word */

/** @brief The state object for the MD5 Algorithm. */
typedef struct ddsrt_md5_state_s {
    ddsrt_md5_word_t count[2];        /* message length in bits, lsw first */
    ddsrt_md5_word_t abcd[4];         /* digest buffer */
    ddsrt_md5_byte_t buf[64];         /* accumulate block */
} ddsrt_md5_state_t;

#ifdef __cplusplus
extern "C"
{
#endif

/**
 * @brief Initialize the @ref ddsrt_md5_state_s
 * 
 * @param[out] pms the state object to initialize
 */
DDS_EXPORT void ddsrt_md5_init(ddsrt_md5_state_t *pms);

/**
 * @brief Add bytes to the message
 * 
 * @param[in,out] pms the state object
 * @param[in] data pointer to data from which to compute the hash
 * @param[in] nbytes size of the data in bytes
 */
DDS_EXPORT void ddsrt_md5_append(ddsrt_md5_state_t *pms, const ddsrt_md5_byte_t *data, unsigned nbytes);

/**
 * @brief Finish the message and return the hash
 * 
 * @param[in,out] pms the state object
 * @param[out] digest the 128-bit hash
 */
DDS_EXPORT void ddsrt_md5_finish(ddsrt_md5_state_t *pms, ddsrt_md5_byte_t digest[16]);

#ifdef __cplusplus
}  /* end extern "C" */
#endif

#endif /* DDSRT_MD5_H */
