From 60f147290241faf389694afbd4f87938cd6aca4f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?kleines=20Filmr=C3=B6llchen?= <filmroellchen@serenityos.org>
Date: Wed, 5 Jul 2023 00:03:52 +0200
Subject: [PATCH] LibAudio: Store all available data in the FLAC frame header

This will make it possible to write the header back out.
---
 Userland/Libraries/LibAudio/FlacLoader.cpp | 12 +++++++-----
 Userland/Libraries/LibAudio/FlacTypes.h    | 11 ++++++++++-
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/Userland/Libraries/LibAudio/FlacLoader.cpp b/Userland/Libraries/LibAudio/FlacLoader.cpp
index 8d23a8d1a5..a84c8e1343 100644
--- a/Userland/Libraries/LibAudio/FlacLoader.cpp
+++ b/Userland/Libraries/LibAudio/FlacLoader.cpp
@@ -440,11 +440,13 @@ LoaderSamples FlacLoaderPlugin::next_frame()
     dbgln_if(AFLACLOADER_DEBUG, "Frame: {} samples, {}bit {}Hz, channeltype {:x}, {} number {}, header checksum {:02x}{}", sample_count, bit_depth, frame_sample_rate, channel_type_num, blocking_strategy ? "sample" : "frame", m_current_sample_or_frame, specified_header_checksum, specified_header_checksum != calculated_header_checksum ? " (checksum error)"sv : ""sv);
 
     m_current_frame = FlacFrameHeader {
-        sample_count,
-        frame_sample_rate,
-        channel_type,
-        bit_depth,
-        specified_checksum,
+        .sample_rate = frame_sample_rate,
+        .sample_count = static_cast<u16>(sample_count),
+        .sample_or_frame_index = static_cast<u32>(m_current_sample_or_frame),
+        .blocking_strategy = static_cast<BlockingStrategy>(blocking_strategy),
+        .channels = channel_type,
+        .bit_depth = bit_depth,
+        .checksum = specified_header_checksum,
     };
 
     u8 subframe_count = frame_channel_type_to_channel_count(channel_type);
diff --git a/Userland/Libraries/LibAudio/FlacTypes.h b/Userland/Libraries/LibAudio/FlacTypes.h
index 8b5d4d7eb8..e2333a7310 100644
--- a/Userland/Libraries/LibAudio/FlacTypes.h
+++ b/Userland/Libraries/LibAudio/FlacTypes.h
@@ -86,10 +86,19 @@ struct FlacRawMetadataBlock {
     ByteBuffer data;
 };
 
+enum class BlockingStrategy : u8 {
+    Fixed = 0,
+    Variable = 1,
+};
+
 // 11.22. FRAME_HEADER
 struct FlacFrameHeader {
-    u32 sample_count;
     u32 sample_rate;
+    // Referred to as “block size” in the specification.
+    u16 sample_count;
+    // If blocking strategy is fixed, this encodes the frame index instead of the sample index.
+    u32 sample_or_frame_index;
+    BlockingStrategy blocking_strategy;
     FlacFrameChannelType channels;
     u8 bit_depth;
     u8 checksum;