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
|
// SPDX-License-Identifier: MIT
// Copyright (c) 2015-2021 Zig Contributors
// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
// The MIT license requires this copyright notice to be included in all copies
// and substantial portions of the software.
const std = @import("../std.zig");
const io = std.io;
const mem = std.mem;
const assert = std.debug.assert;
/// Used to detect if the data written to a stream differs from a source buffer
pub fn ChangeDetectionStream(comptime WriterType: type) type {
return struct {
const Self = @This();
pub const Error = WriterType.Error;
pub const Writer = io.Writer(*Self, Error, write);
anything_changed: bool,
underlying_writer: WriterType,
source_index: usize,
source: []const u8,
pub fn writer(self: *Self) Writer {
return .{ .context = self };
}
fn write(self: *Self, bytes: []const u8) Error!usize {
if (!self.anything_changed) {
const end = self.source_index + bytes.len;
if (end > self.source.len) {
self.anything_changed = true;
} else {
const src_slice = self.source[self.source_index..end];
self.source_index += bytes.len;
if (!mem.eql(u8, bytes, src_slice)) {
self.anything_changed = true;
}
}
}
return self.underlying_writer.write(bytes);
}
pub fn changeDetected(self: *Self) bool {
return self.anything_changed or (self.source_index != self.source.len);
}
};
}
pub fn changeDetectionStream(
source: []const u8,
underlying_writer: anytype,
) ChangeDetectionStream(@TypeOf(underlying_writer)) {
return ChangeDetectionStream(@TypeOf(underlying_writer)){
.anything_changed = false,
.underlying_writer = underlying_writer,
.source_index = 0,
.source = source,
};
}
|
