From 9e6e4962f2346a3fbd96ab3e6c331858ef6ec0d1 Mon Sep 17 00:00:00 2001
From: Felix Kaaman <tmtu@tmtu.ee>
Date: Thu, 7 Jan 2021 20:32:49 +0100
Subject: Initial commit

---
 src/boxes/trun.rs | 179 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 179 insertions(+)
 create mode 100644 src/boxes/trun.rs

(limited to 'src/boxes/trun.rs')

diff --git a/src/boxes/trun.rs b/src/boxes/trun.rs
new file mode 100644
index 0000000..f093a41
--- /dev/null
+++ b/src/boxes/trun.rs
@@ -0,0 +1,179 @@
+use byteorder::{BigEndian, WriteBytesExt};
+use four_cc::FourCC;
+
+use bytes::{BufMut, BytesMut};
+
+use std::mem::size_of;
+
+use crate::{FullBoxHeader, Mp4Box, Mp4BoxError};
+
+bitflags::bitflags! {
+    pub struct TrackFragmentRunFlags: u32 {
+        const DATA_OFFSET_PRESENT = 0x00000001;
+        const FIRST_SAMPLE_FLAGS_PRESENT = 0x00000004;
+        const SAMPLE_DURATION_PRESENT = 0x00000100;
+        const SAMPLE_SIZE_PRESENT = 0x00000200;
+        const SAMPLE_FLAGS_PRESENT = 0x00000400;
+        const SAMPLE_COMPOSITION_TIME_OFFSET_PRESENT = 0x00000800;
+    }
+}
+
+pub struct TrackFragmentSample {
+    pub duration: Option<u32>,
+    pub size: Option<u32>,
+    pub flags: Option<u32>,
+    pub composition_time_offset: Option<i32>,
+}
+
+pub struct TrackFragmentRunBox {
+    pub data_offset: Option<i32>,
+    pub first_sample_flags: Option<u32>,
+    pub samples: Vec<TrackFragmentSample>,
+}
+
+impl TrackFragmentRunBox {
+    fn sample_size(&self, flags: TrackFragmentRunFlags) -> u64 {
+        let mut sample_size = 0;
+
+        if flags.contains(TrackFragmentRunFlags::SAMPLE_DURATION_PRESENT) {
+            sample_size += 4; // sample_duration
+        }
+
+        if flags.contains(TrackFragmentRunFlags::SAMPLE_SIZE_PRESENT) {
+            sample_size += 4; // sample_size
+        }
+
+        if flags.contains(TrackFragmentRunFlags::SAMPLE_FLAGS_PRESENT) {
+            sample_size += 4; // sample_flags
+        }
+
+        if flags.contains(TrackFragmentRunFlags::SAMPLE_COMPOSITION_TIME_OFFSET_PRESENT) {
+            sample_size += 4; // sample_composition_time_offset
+        }
+
+        sample_size
+    }
+
+    fn flags_from_fields(&self) -> TrackFragmentRunFlags {
+        let mut flags = TrackFragmentRunFlags::empty();
+
+        if self.data_offset.is_some() {
+            flags.insert(TrackFragmentRunFlags::DATA_OFFSET_PRESENT);
+        }
+
+        if self.first_sample_flags.is_some() {
+            flags.insert(TrackFragmentRunFlags::FIRST_SAMPLE_FLAGS_PRESENT);
+        }
+
+        if let Some(sample) = self.samples.get(0) {
+            if sample.duration.is_some() {
+                flags.insert(TrackFragmentRunFlags::SAMPLE_DURATION_PRESENT);
+            }
+
+            if sample.size.is_some() {
+                flags.insert(TrackFragmentRunFlags::SAMPLE_SIZE_PRESENT);
+            }
+
+            if sample.flags.is_some() {
+                flags.insert(TrackFragmentRunFlags::SAMPLE_FLAGS_PRESENT);
+            }
+
+            if sample.composition_time_offset.is_some() {
+                flags.insert(TrackFragmentRunFlags::SAMPLE_COMPOSITION_TIME_OFFSET_PRESENT);
+            }
+        }
+
+        flags
+    }
+}
+
+impl Mp4Box for TrackFragmentRunBox {
+    const NAME: FourCC = FourCC(*b"trun");
+
+    fn get_full_box_header(&self) -> Option<FullBoxHeader> {
+        Some(FullBoxHeader::new(0, self.flags_from_fields().bits()))
+    }
+
+    fn content_size(&self) -> u64 {
+        let flags = self.flags_from_fields();
+
+        let mut size = 0;
+
+        size += size_of::<u32>() as u64; // sample_count
+
+        if flags.contains(TrackFragmentRunFlags::DATA_OFFSET_PRESENT) {
+            size += size_of::<i32>() as u64; // data_offset
+        }
+
+        if flags.contains(TrackFragmentRunFlags::FIRST_SAMPLE_FLAGS_PRESENT) {
+            size += size_of::<u32>() as u64; // first_sample_flags
+        }
+
+        size += self.sample_size(flags) * self.samples.len() as u64;
+
+        size
+    }
+
+    fn write_box_contents(&self, writer: &mut BytesMut) -> Result<(), Mp4BoxError> {
+        let mut v = Vec::new();
+
+        v.write_u32::<BigEndian>(self.samples.len() as u32)?; // TODO: check for truncation
+
+        if let Some(data_offset) = self.data_offset {
+            v.write_i32::<BigEndian>(data_offset)?;
+        }
+
+        if let Some(first_sample_flags) = self.first_sample_flags {
+            v.write_u32::<BigEndian>(first_sample_flags)?;
+        }
+
+        let flags = self.flags_from_fields();
+        for sample in &self.samples {
+            ensure_sample_fields_present(&sample, flags);
+
+            if let Some(duration) = sample.duration {
+                v.write_u32::<BigEndian>(duration)?;
+            }
+
+            if let Some(size) = sample.size {
+                v.write_u32::<BigEndian>(size)?;
+            }
+
+            if let Some(flags) = sample.flags {
+                v.write_u32::<BigEndian>(flags)?;
+            }
+
+            if let Some(composition_time_offset) = sample.composition_time_offset {
+                v.write_i32::<BigEndian>(composition_time_offset)?;
+            }
+        }
+
+        assert_eq!(v.len() as u64, self.content_size());
+
+        writer.put_slice(&v);
+
+        Ok(())
+    }
+}
+
+fn ensure_sample_fields_present(sample: &TrackFragmentSample, flags: TrackFragmentRunFlags) {
+    let duration_should_be_present = flags.contains(TrackFragmentRunFlags::SAMPLE_DURATION_PRESENT);
+    let size_should_be_present = flags.contains(TrackFragmentRunFlags::SAMPLE_SIZE_PRESENT);
+    let flags_should_be_present = flags.contains(TrackFragmentRunFlags::SAMPLE_FLAGS_PRESENT);
+    let composition_time_offset_should_be_present =
+        flags.contains(TrackFragmentRunFlags::SAMPLE_COMPOSITION_TIME_OFFSET_PRESENT);
+
+    let duration_is_present = sample.duration.is_some();
+    let size_is_present = sample.size.is_some();
+    let flags_is_present = sample.flags.is_some();
+    let composition_time_offset_is_present = sample.composition_time_offset.is_some();
+
+    // TODO: return error
+    assert_eq!(duration_should_be_present, duration_is_present);
+    assert_eq!(size_should_be_present, size_is_present);
+    assert_eq!(flags_should_be_present, flags_is_present);
+    assert_eq!(
+        composition_time_offset_should_be_present,
+        composition_time_offset_is_present
+    );
+}
-- 
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