1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151

use super::*;

const DLRR_REPORT_LENGTH: u16 = 12;

/// DLRRReport encodes a single report inside a DLRRReportBlock.
#[derive(Debug, Default, PartialEq, Eq, Clone)]
pub struct DLRRReport {
    pub ssrc: u32,
    pub last_rr: u32,
    pub dlrr: u32,
}

impl fmt::Display for DLRRReport {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{self:?}")
    }
}

/// DLRRReportBlock encodes a DLRR Report Block as described in
/// RFC 3611 section 4.5.
///
///  0                   1                   2                   3
///  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/// |     BT=5      |   reserved    |         block length          |
/// +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
/// |                 SSRC_1 (ssrc of first receiver)               | sub-
/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
/// |                         last RR (LRR)                         |   1
/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/// |                   delay since last RR (DLRR)                  |
/// +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
/// |                 SSRC_2 (ssrc of second receiver)              | sub-
/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
/// :                               ...                             :   2
/// +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
#[derive(Debug, Default, PartialEq, Eq, Clone)]
pub struct DLRRReportBlock {
    pub reports: Vec<DLRRReport>,
}

impl fmt::Display for DLRRReportBlock {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{self:?}")
    }
}

impl DLRRReportBlock {
    pub fn xr_header(&self) -> XRHeader {
        XRHeader {
            block_type: BlockType::DLRR,
            type_specific: 0,
            block_length: (self.raw_size() / 4 - 1) as u16,
        }
    }
}

impl Packet for DLRRReportBlock {
    fn header(&self) -> Header {
        Header::default()
    }

    /// destination_ssrc returns an array of ssrc values that this report block refers to.
    fn destination_ssrc(&self) -> Vec<u32> {
        let mut ssrc = Vec::with_capacity(self.reports.len());
        for r in &self.reports {
            ssrc.push(r.ssrc);
        }
        ssrc
    }

    fn raw_size(&self) -> usize {
        XR_HEADER_LENGTH + self.reports.len() * 4 * 3
    }

    fn as_any(&self) -> &(dyn Any + Send + Sync) {
        self
    }
    fn equal(&self, other: &(dyn Packet + Send + Sync)) -> bool {
        other
            .as_any()
            .downcast_ref::<DLRRReportBlock>()
            .map_or(false, |a| self == a)
    }
    fn cloned(&self) -> Box<dyn Packet + Send + Sync> {
        Box::new(self.clone())
    }
}

impl MarshalSize for DLRRReportBlock {
    fn marshal_size(&self) -> usize {
        self.raw_size()
    }
}

impl Marshal for DLRRReportBlock {
    /// marshal_to encodes the DLRRReportBlock in binary
    fn marshal_to(&self, mut buf: &mut [u8]) -> Result<usize> {
        if buf.remaining_mut() < self.marshal_size() {
            return Err(error::Error::BufferTooShort.into());
        }

        let h = self.xr_header();
        let n = h.marshal_to(buf)?;
        buf = &mut buf[n..];

        for rep in &self.reports {
            buf.put_u32(rep.ssrc);
            buf.put_u32(rep.last_rr);
            buf.put_u32(rep.dlrr);
        }

        Ok(self.marshal_size())
    }
}

impl Unmarshal for DLRRReportBlock {
    /// Unmarshal decodes the DLRRReportBlock from binary
    fn unmarshal<B>(raw_packet: &mut B) -> Result<Self>
    where
        Self: Sized,
        B: Buf,
    {
        if raw_packet.remaining() < XR_HEADER_LENGTH {
            return Err(error::Error::PacketTooShort.into());
        }

        let xr_header = XRHeader::unmarshal(raw_packet)?;
        let block_length = xr_header.block_length * 4;
        if block_length % DLRR_REPORT_LENGTH != 0 || raw_packet.remaining() < block_length as usize
        {
            return Err(error::Error::PacketTooShort.into());
        }

        let mut offset = 0;
        let mut reports = vec![];
        while offset < block_length {
            let ssrc = raw_packet.get_u32();
            let last_rr = raw_packet.get_u32();
            let dlrr = raw_packet.get_u32();
            reports.push(DLRRReport {
                ssrc,
                last_rr,
                dlrr,
            });
            offset += DLRR_REPORT_LENGTH;
        }

        Ok(DLRRReportBlock { reports })
    }
}