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Copy pathDecoderAPI.cxx
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114 lines (91 loc) · 2.21 KB
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// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright The Music Player Daemon Project
#include "DecoderAPI.hxx"
#include "input/InputStream.hxx"
#include "util/IntOverflow.hxx"
#include "Log.hxx"
#include <cassert>
size_t
decoder_read(DecoderClient *client,
InputStream &is,
std::span<std::byte> dest) noexcept
{
/* XXX don't allow client==nullptr */
if (client != nullptr)
return client->Read(is, dest);
try {
return is.LockRead(dest);
} catch (...) {
LogError(std::current_exception());
return 0;
}
}
size_t
decoder_read_much(DecoderClient *client, InputStream &is,
std::span<std::byte> dest) noexcept
{
size_t total = 0;
while (!dest.empty() && !is.LockIsEOF()) {
size_t nbytes = decoder_read(client, is, dest);
if (nbytes == 0)
return false;
dest = dest.subspan(nbytes);
total += nbytes;
}
return total;
}
bool
decoder_read_full(DecoderClient *client, InputStream &is,
std::span<std::byte> dest) noexcept
{
while (!dest.empty()) {
size_t nbytes = decoder_read(client, is, dest);
if (nbytes == 0)
return false;
dest = dest.subspan(nbytes);
}
return true;
}
bool
decoder_skip(DecoderClient *client, InputStream &is, offset_type delta) noexcept
{
if (delta > 1024 && is.IsSeekable() &&
(delta > 1024 * 1024 || is.CheapSeeking())) {
offset_type new_offset;
if (AddOverflow(is.GetOffset(), delta, new_offset))
return false;
return decoder_seek(client, is, new_offset);
}
if (delta > 4 * 1024 * 1024)
/* skipping that much would be too expensive */
return false;
while (delta > 0) {
std::byte buffer[1024];
std::span<std::byte> dest{buffer};
if (delta < dest.size())
dest = dest.first(delta);
size_t nbytes = decoder_read(client, is, dest);
if (nbytes == 0)
return false;
delta -= nbytes;
}
return true;
}
bool
decoder_seek(DecoderClient *client, InputStream &is, offset_type new_offset) noexcept
{
if (is.IsSeekable()) {
if (client != nullptr)
return client->Seek(is, new_offset);
try {
is.LockSeek(new_offset);
return true;
} catch (...) {
LogError(std::current_exception());
return false;
}
}
if (is.GetOffset() > new_offset)
return false;
return decoder_skip(client, is, new_offset - is.GetOffset());
}