mpd/src/lib/chromaprint/Context.hxx

/*
 * Copyright 2018-2019 Max Kellermann <max.kellermann@gmail.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the
 * distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef CHROMAPRINT_HXX
#define CHROMAPRINT_HXX

#include "util/ScopeExit.hxx"

#include <chromaprint.h>

#include <span>
#include <stdexcept>
#include <string>

namespace Chromaprint {

class Context {
	ChromaprintContext *const ctx;

public:
	Context() noexcept
		:ctx(chromaprint_new(CHROMAPRINT_ALGORITHM_DEFAULT)) {}

	~Context() noexcept {
		chromaprint_free(ctx);
	}

	Context(const Context &) = delete;
	Context &operator=(const Context &) = delete;

	void Start(unsigned sample_rate, unsigned num_channels) {
		if (chromaprint_start(ctx, sample_rate, num_channels) != 1)
			throw std::runtime_error("chromaprint_start() failed");
	}

	void Feed(std::span<const int16_t> src) {
		if (chromaprint_feed(ctx, src.data(), src.size()) != 1)
			throw std::runtime_error("chromaprint_feed() failed");
	}

	void Finish() {
		if (chromaprint_finish(ctx) != 1)
			throw std::runtime_error("chromaprint_finish() failed");
	}

	std::string GetFingerprint() const {
		char *fingerprint;
		if (chromaprint_get_fingerprint(ctx, &fingerprint) != 1)
			throw std::runtime_error("chromaprint_get_fingerprint() failed");

		AtScopeExit(fingerprint) { chromaprint_dealloc(fingerprint); };
		return fingerprint;
	}
};

} //namespace Chromaprint

#endif