95 lines
2.9 KiB
C
95 lines
2.9 KiB
C
// midi for embedded chips,
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// Copyright 2010 Alex Norman
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//
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// This file is part of avr-midi.
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//
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// avr-midi is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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//(at your option) any later version.
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//
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// avr-midi is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with avr-midi. If not, see <http://www.gnu.org/licenses/>.
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#ifndef SYSEX_TOOLS_H
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#define SYSEX_TOOLS_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <inttypes.h>
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/**
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* @file
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* @brief Sysex utility functions
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*
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* These functions are for converting data to and from a "midi-safe" format,
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* which can be use to send data with sysex messages. Sysex messages may only
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* contain data where the to bit is not set.
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*
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* An "encoded" midi message is one that contains all of the data from its
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* original state, but does not have any of the top bits set.
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*
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* Every 7 bytes of decoded data is converted into 8 bytes of encoded data and
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* visa-versa. If you'd like to operate on small segments, make sure that you
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* encode in 7 byte increments and decode in 8 byte increments.
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*
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*/
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/** @defgroup sysex_tools Sysex utility functions
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* @{
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*/
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/**
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* @brief Compute the length of a message after it is encoded.
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*
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* @param decoded_length The length, in bytes, of the message to encode.
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*
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* @return The length, in bytes, of the message after encodeing.
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*/
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uint16_t sysex_encoded_length(uint16_t decoded_length);
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/**
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* @brief Compute the length of a message after it is decoded.
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*
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* @param encoded_length The length, in bytes, of the encoded message.
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*
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* @return The length, in bytes, of the message after it is decoded.
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*/
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uint16_t sysex_decoded_length(uint16_t encoded_length);
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/**
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* @brief Encode data so that it can be transmitted safely in a sysex message.
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*
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* @param encoded The output data buffer, must be at least sysex_encoded_length(length) bytes long.
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* @param source The input buffer of data to be encoded.
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* @param length The number of bytes from the input buffer to encode.
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*
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* @return number of bytes encoded.
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*/
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uint16_t sysex_encode(uint8_t *encoded, const uint8_t *source, uint16_t length);
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/**
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* @brief Decode encoded data.
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*
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* @param decoded The output data buffer, must be at least sysex_decoded_length(length) bytes long.
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* @param source The input buffer of data to be decoded.
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* @param length The number of bytes from the input buffer to decode.
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*
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* @return number of bytes decoded.
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*/
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uint16_t sysex_decode(uint8_t *decoded, const uint8_t *source, uint16_t length);
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/**@}*/
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#ifdef __cplusplus
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}
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#endif
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#endif
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