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
|
const std = @import("std");
const Self = @This();
pub const Component = packed struct(u24) {
identifier: u8,
horizontal_sampling_factor: u4,
vertical_sampling_factor: u4,
quantization_table_destination_selector: u8,
};
index: usize,
sample_precision: u8,
number_of_lines: u16,
samples_per_line: u16,
components: []Component,
pub fn read(
gpa: std.mem.Allocator,
index: usize,
reader: *std.Io.Reader,
) !Self {
var self: Self = undefined;
self.index = index;
self.sample_precision = try reader.takeByte();
self.number_of_lines = try reader.takeInt(u16, .big);
self.samples_per_line = try reader.takeInt(u16, .big);
const number_of_components = try reader.takeByte();
self.components = try gpa.alloc(Component, number_of_components);
errdefer gpa.free(self.components);
for (self.components) |*component| {
component.identifier = try reader.takeByte();
const sampling = try reader.takeByte();
component.horizontal_sampling_factor = @truncate(sampling >> 4);
component.vertical_sampling_factor = @truncate(sampling);
component.quantization_table_destination_selector = try reader.takeByte();
}
return self;
}
pub fn deinit(self: *Self, gpa: std.mem.Allocator) void {
gpa.free(self.components);
self.* = undefined;
}
|
