91 lines
2.0 KiB
C++
91 lines
2.0 KiB
C++
// SPDX-License-Identifier: GPL-2.0-or-later
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// Copyright The Music Player Daemon Project
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#include "ApeLoader.hxx"
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#include "input/InputStream.hxx"
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#include "util/PackedLittleEndian.hxx"
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#include "util/SpanCast.hxx"
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#include <cassert>
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#include <cstdint>
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#include <cstring>
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#include <memory>
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struct ApeFooter {
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unsigned char id[8];
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uint32_t version;
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uint32_t length;
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uint32_t count;
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unsigned char flags[4];
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unsigned char reserved[8];
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};
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bool
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tag_ape_scan(InputStream &is, const ApeTagCallback& callback)
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try {
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std::unique_lock lock{is.mutex};
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if (!is.KnownSize() || !is.CheapSeeking())
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return false;
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/* determine if file has an apeV2 tag */
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ApeFooter footer;
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is.Seek(lock, is.GetSize() - sizeof(footer));
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is.ReadFull(lock, ReferenceAsWritableBytes(footer));
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if (memcmp(footer.id, "APETAGEX", sizeof(footer.id)) != 0 ||
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FromLE32(footer.version) != 2000)
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return false;
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/* find beginning of ape tag */
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size_t remaining = FromLE32(footer.length);
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if (remaining <= sizeof(footer) + 10 ||
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/* refuse to load more than one megabyte of tag data */
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remaining > 1024 * 1024)
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return false;
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is.Seek(lock, is.GetSize() - remaining);
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/* read tag into buffer */
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remaining -= sizeof(footer);
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assert(remaining > 10);
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auto buffer = std::make_unique_for_overwrite<std::byte[]>(remaining);
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is.ReadFull(lock, {buffer.get(), remaining});
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/* read tags */
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unsigned n = FromLE32(footer.count);
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const char *p = (const char *)buffer.get();
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while (n-- && remaining > 10) {
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size_t size = *(const PackedLE32 *)p;
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p += 4;
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remaining -= 4;
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unsigned long flags = *(const PackedLE32 *)p;
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p += 4;
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remaining -= 4;
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/* get the key */
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const char *key = p;
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const char *key_end = (const char *)std::memchr(p, '\0', remaining);
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if (key_end == nullptr)
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break;
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p = key_end + 1;
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remaining -= p - key;
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/* get the value */
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if (remaining < size)
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break;
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if (!callback(flags, key, {p, size}))
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break;
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p += size;
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remaining -= size;
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}
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return true;
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} catch (...) {
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return false;
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}
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