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/*
* Copyright 2003-2019 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_OPUS_READER_HXX
#define MPD_OPUS_READER_HXX
#include "util/StringView.hxx"
#include <algorithm>
#include <stdint.h>
#include <string.h>
class OpusReader {
const uint8_t *p, *const end;
public:
OpusReader(const void *_p, size_t size)
:p((const uint8_t *)_p), end(p + size) {}
bool Skip(size_t length) {
p += length;
return p <= end;
}
const void *Read(size_t length) {
const uint8_t *result = p;
return Skip(length)
? result
: nullptr;
}
bool Expect(const void *value, size_t length) {
const void *data = Read(length);
return data != nullptr && memcmp(value, data, length) == 0;
}
bool ReadByte(uint8_t &value_r) {
if (p >= end)
return false;
value_r = *p++;
return true;
}
bool ReadShort(uint16_t &value_r) {
const uint8_t *value = (const uint8_t *)Read(sizeof(value_r));
if (value == nullptr)
return false;
value_r = value[0] | (value[1] << 8);
return true;
}
bool ReadWord(uint32_t &value_r) {
const uint8_t *value = (const uint8_t *)Read(sizeof(value_r));
if (value == nullptr)
return false;
value_r = value[0] | (value[1] << 8)
| (value[2] << 16) | (value[3] << 24);
return true;
}
bool SkipString() {
uint32_t length;
return ReadWord(length) && Skip(length);
}
StringView ReadString() {
uint32_t length;
if (!ReadWord(length))
return nullptr;
const char *src = (const char *)Read(length);
if (src == nullptr)
return nullptr;
return {src, length};
}
};
#endif
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