mocari 0.2.0

A pure Rust Live2D/Cubism-compatible runtime
Documentation 
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
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173

use crate::{Error, Result};

use super::{Endianness, Moc3SectionOffsets};

pub(super) fn read_i32_section(
    bytes: &[u8],
    offsets: &Moc3SectionOffsets,
    slot: usize,
    count: usize,
    endianness: Endianness,
) -> Result<Vec<i32>> {
    read_section(bytes, offsets, slot, count, 4, |bytes, offset| {
        let raw = [
            bytes[offset],
            bytes[offset + 1],
            bytes[offset + 2],
            bytes[offset + 3],
        ];
        match endianness {
            Endianness::Little => i32::from_le_bytes(raw),
            Endianness::Big => i32::from_be_bytes(raw),
        }
    })
}

pub(super) fn read_i32_section_or_default(
    bytes: &[u8],
    offsets: &Moc3SectionOffsets,
    slot: usize,
    count: usize,
    endianness: Endianness,
    default: i32,
) -> Result<Vec<i32>> {
    match offsets.section_offset(slot) {
        Some(0) | None => Ok(vec![default; count]),
        Some(_) => read_i32_section(bytes, offsets, slot, count, endianness),
    }
}

pub(super) fn read_i16_section(
    bytes: &[u8],
    offsets: &Moc3SectionOffsets,
    slot: usize,
    count: usize,
    endianness: Endianness,
) -> Result<Vec<i16>> {
    read_section(bytes, offsets, slot, count, 2, |bytes, offset| {
        let raw = [bytes[offset], bytes[offset + 1]];
        match endianness {
            Endianness::Little => i16::from_le_bytes(raw),
            Endianness::Big => i16::from_be_bytes(raw),
        }
    })
}

pub(super) fn read_u16_section(
    bytes: &[u8],
    offsets: &Moc3SectionOffsets,
    slot: usize,
    count: usize,
    endianness: Endianness,
) -> Result<Vec<u16>> {
    read_section(bytes, offsets, slot, count, 2, |bytes, offset| {
        let raw = [bytes[offset], bytes[offset + 1]];
        match endianness {
            Endianness::Little => u16::from_le_bytes(raw),
            Endianness::Big => u16::from_be_bytes(raw),
        }
    })
}

pub(super) fn read_f32_section(
    bytes: &[u8],
    offsets: &Moc3SectionOffsets,
    slot: usize,
    count: usize,
    endianness: Endianness,
) -> Result<Vec<f32>> {
    read_section(bytes, offsets, slot, count, 4, |bytes, offset| {
        let raw = [
            bytes[offset],
            bytes[offset + 1],
            bytes[offset + 2],
            bytes[offset + 3],
        ];
        match endianness {
            Endianness::Little => f32::from_le_bytes(raw),
            Endianness::Big => f32::from_be_bytes(raw),
        }
    })
}

pub(super) fn read_f32_section_or_default(
    bytes: &[u8],
    offsets: &Moc3SectionOffsets,
    slot: usize,
    count: usize,
    endianness: Endianness,
    default: f32,
) -> Result<Vec<f32>> {
    match offsets.section_offset(slot) {
        Some(0) | None => Ok(vec![default; count]),
        Some(_) => read_f32_section(bytes, offsets, slot, count, endianness),
    }
}

pub(super) fn read_u8_section(
    bytes: &[u8],
    offsets: &Moc3SectionOffsets,
    slot: usize,
    count: usize,
) -> Result<Vec<u8>> {
    read_section(bytes, offsets, slot, count, 1, |bytes, offset| {
        bytes[offset]
    })
}

pub(super) fn read_bool_section(
    bytes: &[u8],
    offsets: &Moc3SectionOffsets,
    slot: usize,
    count: usize,
    endianness: Endianness,
) -> Result<Vec<bool>> {
    read_i32_section(bytes, offsets, slot, count, endianness)
        .map(|values| values.into_iter().map(|value| value == 1).collect())
}

pub(super) fn read_section<T>(
    bytes: &[u8],
    offsets: &Moc3SectionOffsets,
    slot: usize,
    count: usize,
    element_size: usize,
    read: impl Fn(&[u8], usize) -> T,
) -> Result<Vec<T>> {
    if count == 0 {
        return Ok(Vec::new());
    }

    let offset = offsets
        .section_offset(slot)
        .ok_or_else(|| invalid_moc3(format!("section slot {slot} is outside offset table")))?;
    if offset == 0 {
        return Err(invalid_moc3(format!("section slot {slot} has no offset")));
    }

    let offset = usize::try_from(offset)
        .map_err(|_| invalid_moc3(format!("section slot {slot} offset is too large")))?;
    let byte_len = count
        .checked_mul(element_size)
        .ok_or_else(|| invalid_moc3(format!("section slot {slot} size overflows")))?;
    if bytes.len().saturating_sub(offset) < byte_len {
        return Err(invalid_moc3(format!("section slot {slot} is incomplete")));
    }

    let mut values = Vec::with_capacity(count);
    for index in 0..count {
        values.push(read(bytes, offset + index * element_size));
    }

    Ok(values)
}

pub(super) fn to_usize(value: u32, name: &'static str) -> Result<usize> {
    usize::try_from(value).map_err(|_| invalid_moc3(format!("{name} is too large")))
}

pub(super) fn invalid_moc3(message: impl Into<String>) -> Error {
    Error::InvalidMoc3 {
        message: message.into(),
    }
}