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
174
175
176
177
178
use std::io::{Read, Write};
use crate::{
common::traits::private::Sealed,
v0::{
raw::VariableLengthEnum,
traits::{ReadFrom, WriteTo},
},
};
use super::error::{MetadataHeaderReadError, MetadataHeaderWriteError};
/// Header for the metadata section of a FEF file.
pub struct MetadataHeader {
/// Number of records in the metadata
record_count: usize,
/// Total number of bytes all the records take. If zero, record_count == 0.
byte_size: usize,
}
impl Sealed for MetadataHeader {}
impl<R: ?Sized + Read> ReadFrom<R> for MetadataHeader {
type ReadError = MetadataHeaderReadError;
/// Reads a metadata header from a reader.
///
/// # Example
///
/// Reading a non-empty metadata header:
/// ```rust
/// # use fef::v0::metadata::MetadataHeader;
/// # use fef::v0::config::DEFAULT_CONFIG;
/// # use fef::v0::traits::ReadFrom;
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// let data: Vec<u8> = vec![
/// 0x02, // 2 records
/// 0x10, // takes 16 bytes
/// 0x01, 0x02, 0x01, b'F', // record 1 - formula name "F"
/// 0x02, 0x03, 0x01, 0x01, b'x', // record 2 - variable name "x"
/// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 // padding
/// ];
/// let mut reader = &mut data.as_slice();
/// let header = MetadataHeader::read_from(&mut reader, &DEFAULT_CONFIG)?;
/// assert_eq!(header.record_count(), 2);
/// assert_eq!(header.byte_size(), 16);
///
/// # let record1 = fef::v0::metadata::MetadataRecord::read_from(&mut reader, &DEFAULT_CONFIG)?;
/// # let record2 = fef::v0::metadata::MetadataRecord::read_from(&mut reader, &DEFAULT_CONFIG)?;
/// # assert_eq!(record1, fef::v0::metadata::MetadataRecord::Name(fef::v0::metadata::NameMetadataRecordObj::new("F".to_string())));
/// # assert_eq!(record2, fef::v0::metadata::MetadataRecord::VariableName(fef::v0::metadata::VariableNameMetadataRecordObj::new("x".to_string(), fef::v0::raw::VariableLengthEnum::from(1))));
///
/// # Ok(())
/// # }
/// ```
///
/// Reading an empty metadata header:
/// ```rust
/// # use fef::v0::metadata::MetadataHeader;
/// # use fef::v0::config::DEFAULT_CONFIG;
/// # use fef::v0::traits::ReadFrom;
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// let data: Vec<u8> = vec![
/// 0x00, // 0 records
/// ];
/// let mut reader = &mut data.as_slice();
/// let header = MetadataHeader::read_from(&mut reader, &DEFAULT_CONFIG)?;
/// assert_eq!(header.record_count(), 0);
/// assert_eq!(header.byte_size(), 0);
/// # Ok(())
/// # }
/// ```
fn read_from<C: ?Sized + crate::v0::config::Config>(
reader: &mut R,
configuration: &C,
) -> Result<Self, Self::ReadError> {
let record_count: usize = VariableLengthEnum::read_from(reader, configuration)
.map_err(|err| MetadataHeaderReadError::RecordCountError(err))?
.try_into()
.map_err(|err| MetadataHeaderReadError::RecordCountError(err))?;
if record_count == 0 {
return Ok(MetadataHeader {
byte_size: 0,
record_count: 0,
});
};
let byte_size: usize = VariableLengthEnum::read_from(reader, configuration)
.map_err(|err| MetadataHeaderReadError::ByteLengthError(err))?
.try_into()
.map_err(|err| MetadataHeaderReadError::ByteLengthError(err))?;
Ok(MetadataHeader {
record_count: record_count,
byte_size: byte_size,
})
}
}
impl<W: ?Sized + Write> WriteTo<W> for MetadataHeader {
type WriteError = MetadataHeaderWriteError;
/// Writes the metadata header to a writer.
///
/// # Example
///
/// Writing a non-empty metadata header:
/// ```rust
/// # use fef::v0::metadata::MetadataHeader;
/// # use fef::v0::config::DEFAULT_CONFIG;
/// # use fef::v0::traits::WriteTo;
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// let header = MetadataHeader::new(2, 16);
/// let mut writer: Vec<u8> = Vec::new();
/// header.write_to(&mut writer, &DEFAULT_CONFIG)?;
/// assert_eq!(writer, vec![0x02, 0x10]);
/// # Ok(())
/// # }
/// ```
///
/// Writing an empty metadata header:
/// ```rust
/// # use fef::v0::metadata::MetadataHeader;
/// # use fef::v0::config::DEFAULT_CONFIG;
/// # use fef::v0::traits::WriteTo;
/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
/// let header = MetadataHeader::new(0, 0);
/// let mut writer: Vec<u8> = Vec::new();
/// header.write_to(&mut writer, &DEFAULT_CONFIG)?;
/// assert_eq!(writer, vec![0x00]);
/// # Ok(())
/// # }
/// ```
fn write_to<C: ?Sized + crate::v0::config::Config>(
&self,
writer: &mut W,
configuration: &C,
) -> Result<(), Self::WriteError> {
VariableLengthEnum::from(self.record_count as usize)
.write_to(writer, configuration)
.map_err(|err| MetadataHeaderWriteError::RecordCountError(err))?;
if self.record_count != 0 {
VariableLengthEnum::from(self.byte_size as usize)
.write_to(writer, configuration)
.map_err(|err| MetadataHeaderWriteError::ByteLengthError(err))?;
}
Ok(())
}
}
impl MetadataHeader {
/// Returns the number of records in the metadata.
pub fn record_count(&self) -> usize {
self.record_count
}
/// Returns the number of bytes the metadata section takes including padding bytes at the end.
pub fn byte_size(&self) -> usize {
self.byte_size
}
/// Creates a new metadata header from the given record count and byte size.
///
/// # Example
///
/// ```rust
/// # use fef::v0::metadata::MetadataHeader;
/// let header = MetadataHeader::new(10, 100);
///
/// assert_eq!(header.record_count(), 10);
/// assert_eq!(header.byte_size(), 100);
/// ```
pub fn new(record_count: usize, byte_size: usize) -> Self {
MetadataHeader {
record_count,
byte_size,
}
}
}