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/*
* Copyright (c) 2021, Hunter Salyer <thefalsehonesty@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include "MatroskaDocument.h"
#include <AK/Debug.h>
#include <AK/Math.h>
#include <AK/NonnullOwnPtrVector.h>
#include <AK/Optional.h>
#include <AK/OwnPtr.h>
namespace Video {
class MatroskaReader {
public:
MatroskaReader(u8 const* data, size_t size)
: m_streamer(data, size)
{
}
static OwnPtr<MatroskaDocument> parse_matroska_from_file(StringView const& path);
static OwnPtr<MatroskaDocument> parse_matroska_from_data(u8 const*, size_t);
OwnPtr<MatroskaDocument> parse();
private:
class Streamer {
public:
Streamer(u8 const* data, size_t size)
: m_data_ptr(data)
, m_size_remaining(size)
{
}
u8 const* data() { return m_data_ptr; }
char const* data_as_chars() { return reinterpret_cast<char const*>(m_data_ptr); }
u8 read_octet()
{
VERIFY(m_size_remaining >= 1);
m_size_remaining--;
m_octets_read.last()++;
return *(m_data_ptr++);
}
i16 read_i16()
{
return (read_octet() << 8) | read_octet();
}
size_t octets_read() { return m_octets_read.last(); }
void push_octets_read() { m_octets_read.append(0); }
void pop_octets_read()
{
auto popped = m_octets_read.take_last();
if (!m_octets_read.is_empty())
m_octets_read.last() += popped;
}
Optional<u64> read_variable_size_integer(bool mask_length = true)
{
dbgln_if(MATROSKA_TRACE_DEBUG, "Reading from offset {:p}", m_data_ptr);
auto length_descriptor = read_octet();
dbgln_if(MATROSKA_TRACE_DEBUG, "Reading VINT, first byte is {:#02x}", length_descriptor);
if (length_descriptor == 0)
return {};
size_t length = 0;
while (length < 8) {
if (length_descriptor & (1u << (8 - length)))
break;
length++;
}
dbgln_if(MATROSKA_TRACE_DEBUG, "Reading VINT of total length {}", length);
if (length > 8)
return {};
u64 result;
if (mask_length)
result = length_descriptor & ~(1u << (8 - length));
else
result = length_descriptor;
dbgln_if(MATROSKA_TRACE_DEBUG, "Beginning of VINT is {:#02x}", result);
for (size_t i = 1; i < length; i++) {
if (!has_octet()) {
dbgln_if(MATROSKA_TRACE_DEBUG, "Ran out of stream data");
return {};
}
u8 next_octet = read_octet();
dbgln_if(MATROSKA_TRACE_DEBUG, "Read octet of {:#02x}", next_octet);
result = (result << 8u) | next_octet;
dbgln_if(MATROSKA_TRACE_DEBUG, "New result is {:#010x}", result);
}
return result;
}
Optional<i64> read_variable_sized_signed_integer()
{
auto length_descriptor = read_octet();
if (length_descriptor == 0)
return {};
size_t length = 0;
while (length < 8) {
if (length_descriptor & (1u << (8 - length)))
break;
length++;
}
if (length > 8)
return {};
i64 result = length_descriptor & ~(1u << (8 - length));
for (size_t i = 1; i < length; i++) {
if (!has_octet()) {
return {};
}
u8 next_octet = read_octet();
result = (result << 8u) | next_octet;
}
result -= AK::exp2<i64>(length * 7 - 1) - 1;
return result;
}
void drop_octets(size_t num_octets)
{
VERIFY(m_size_remaining >= num_octets);
m_size_remaining -= num_octets;
m_octets_read.last() += num_octets;
m_data_ptr += num_octets;
}
bool at_end() const { return !m_size_remaining; }
bool has_octet() const { return m_size_remaining >= 1; }
size_t remaining() const { return m_size_remaining; }
void set_remaining(size_t remaining) { m_size_remaining = remaining; }
private:
u8 const* m_data_ptr { nullptr };
size_t m_size_remaining { 0 };
Vector<size_t> m_octets_read { 0 };
};
bool parse_master_element(StringView const& element_name, Function<bool(u64 element_id)> element_consumer);
Optional<EBMLHeader> parse_ebml_header();
bool parse_segment_elements(MatroskaDocument&);
OwnPtr<SegmentInformation> parse_information();
bool parse_tracks(MatroskaDocument&);
OwnPtr<TrackEntry> parse_track_entry();
Optional<TrackEntry::VideoTrack> parse_video_track_information();
Optional<TrackEntry::AudioTrack> parse_audio_track_information();
OwnPtr<Cluster> parse_cluster();
OwnPtr<Block> parse_simple_block();
Optional<String> read_string_element();
Optional<u64> read_u64_element();
bool read_unknown_element();
Streamer m_streamer;
};
}
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