async_mp4/
header.rs

1
2use uuid::Uuid;
3use crate::bytes_read::{Mp4Readable, ReadMp4};
4use crate::bytes_write::{Mp4Writable, WriteMp4};
5use crate::error::MP4Error;
6use crate::id::BoxId;
7use crate::r#type::BoxType;
8use crate::size::BoxSize;
9use crate::size::BoxSize::Known;
10use crate::size::BoxSize::Unknown;
11use async_trait::async_trait;
12
13#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
14pub struct BoxHeader {
15    pub size: BoxSize,
16    pub id: BoxType
17}
18
19impl BoxHeader {
20
21    pub fn from_id_and_inner_size(id: BoxType, inner_size: usize) -> Self {
22        Self {
23            size: BoxSize::from_size_without_self(inner_size + id.byte_size()),
24            id
25        }
26    }
27
28    pub fn size_minus_self(&self) -> BoxSize {
29        match self.size {
30            Known(size) => Known(self.byte_size() - size),
31            Unknown => Unknown
32        }
33    }
34
35}
36
37#[async_trait]
38impl Mp4Readable for BoxHeader {
39    async fn read<R: ReadMp4>(reader: &mut R) -> Result<Self, MP4Error> {
40        let size: u32 = reader.read().await?;
41        let id = BoxId::read(reader).await?;
42        let size = match size {
43            0 => Unknown,
44            1 =>  {
45                let size: u64 = reader.read().await?;
46                Known(size as _)
47            }
48            _ => Known(size as _)
49        };
50        let id = if id == b"uuid" {
51            BoxType::UUID(reader.read().await?)
52        } else {
53            BoxType::Id(id)
54        };
55        Ok(Self {
56            size, id
57        })
58    }
59}
60
61impl Mp4Writable for BoxHeader {
62    fn byte_size(&self) -> usize {
63        self.size.byte_size() + self.id.byte_size()
64    }
65
66
67    fn write<W: WriteMp4>(&self, writer: &mut W) -> Result<usize, MP4Error> {
68        let (id, uuid) = match self.id {
69            BoxType::Id(id) => (id, None),
70            BoxType::UUID(uuid) => (BoxId(*b"uuid"), Some(uuid))
71        };
72        let (size, big_size) = match self.size {
73            Known(size) => {
74                if cfg!(target_pointer_width = "64") {
75                    if size > u32::MAX as usize {
76                        (1, Some(size as u64))
77                    } else {
78                        (size as u32, None)
79                    }
80                } else {
81                    (size as u32, None)
82                }
83            }
84            Unknown => (0, None)
85        };
86        let mut count = 0;
87        count += size.write(writer)?;
88        count += id.write(writer)?;
89        count += big_size.write(writer)?;
90        count += uuid.write(writer)?;
91        Ok(count)
92    }
93}
94
95#[async_trait]
96impl Mp4Readable for Uuid {
97    async fn read<R: ReadMp4>(reader: &mut R) -> Result<Self, MP4Error> {
98        Ok(Uuid::from_bytes(reader.read().await?))
99    }
100}
101
102impl Mp4Writable for Uuid {
103    fn byte_size(&self) -> usize {
104        self.as_bytes().byte_size()
105    }
106
107    fn write<W: WriteMp4>(&self, writer: &mut W) -> Result<usize, MP4Error> {
108        self.as_bytes().write(writer)
109    }
110}
async_mp4/header.rs

async_mp4/
header.rs
