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
179
180
181
182
183
184
185
186
187
188
189
190
|
// 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 testing = std.testing;
const mem = std.mem;
const assert = std.debug.assert;
/// This turns a byte buffer into an `io.Writer`, `io.Reader`, or `io.SeekableStream`.
/// If the supplied byte buffer is const, then `io.Writer` is not available.
pub fn FixedBufferStream(comptime Buffer: type) type {
return struct {
/// `Buffer` is either a `[]u8` or `[]const u8`.
buffer: Buffer,
pos: usize,
pub const ReadError = error{};
pub const WriteError = error{NoSpaceLeft};
pub const SeekError = error{};
pub const GetSeekPosError = error{};
pub const Reader = io.Reader(*Self, ReadError, read);
/// Deprecated: use `Reader`
pub const InStream = io.InStream(*Self, ReadError, read);
pub const Writer = io.Writer(*Self, WriteError, write);
/// Deprecated: use `Writer`
pub const OutStream = Writer;
pub const SeekableStream = io.SeekableStream(
*Self,
SeekError,
GetSeekPosError,
seekTo,
seekBy,
getPos,
getEndPos,
);
const Self = @This();
pub fn reader(self: *Self) Reader {
return .{ .context = self };
}
/// Deprecated: use `inStream`
pub fn inStream(self: *Self) InStream {
return .{ .context = self };
}
pub fn writer(self: *Self) Writer {
return .{ .context = self };
}
/// Deprecated: use `writer`
pub fn outStream(self: *Self) OutStream {
return .{ .context = self };
}
pub fn seekableStream(self: *Self) SeekableStream {
return .{ .context = self };
}
pub fn read(self: *Self, dest: []u8) ReadError!usize {
const size = std.math.min(dest.len, self.buffer.len - self.pos);
const end = self.pos + size;
mem.copy(u8, dest[0..size], self.buffer[self.pos..end]);
self.pos = end;
return size;
}
/// If the returned number of bytes written is less than requested, the
/// buffer is full. Returns `error.NoSpaceLeft` when no bytes would be written.
/// Note: `error.NoSpaceLeft` matches the corresponding error from
/// `std.fs.File.WriteError`.
pub fn write(self: *Self, bytes: []const u8) WriteError!usize {
if (bytes.len == 0) return 0;
if (self.pos >= self.buffer.len) return error.NoSpaceLeft;
const n = if (self.pos + bytes.len <= self.buffer.len)
bytes.len
else
self.buffer.len - self.pos;
mem.copy(u8, self.buffer[self.pos .. self.pos + n], bytes[0..n]);
self.pos += n;
if (n == 0) return error.NoSpaceLeft;
return n;
}
pub fn seekTo(self: *Self, pos: u64) SeekError!void {
self.pos = if (std.math.cast(usize, pos)) |x| x else |_| self.buffer.len;
}
pub fn seekBy(self: *Self, amt: i64) SeekError!void {
if (amt < 0) {
const abs_amt = std.math.absCast(amt);
const abs_amt_usize = std.math.cast(usize, abs_amt) catch std.math.maxInt(usize);
if (abs_amt_usize > self.pos) {
self.pos = 0;
} else {
self.pos -= abs_amt_usize;
}
} else {
const amt_usize = std.math.cast(usize, amt) catch std.math.maxInt(usize);
const new_pos = std.math.add(usize, self.pos, amt_usize) catch std.math.maxInt(usize);
self.pos = std.math.min(self.buffer.len, new_pos);
}
}
pub fn getEndPos(self: *Self) GetSeekPosError!u64 {
return self.buffer.len;
}
pub fn getPos(self: *Self) GetSeekPosError!u64 {
return self.pos;
}
pub fn getWritten(self: Self) Buffer {
return self.buffer[0..self.pos];
}
pub fn reset(self: *Self) void {
self.pos = 0;
}
};
}
pub fn fixedBufferStream(buffer: anytype) FixedBufferStream(NonSentinelSpan(@TypeOf(buffer))) {
return .{ .buffer = mem.span(buffer), .pos = 0 };
}
fn NonSentinelSpan(comptime T: type) type {
var ptr_info = @typeInfo(mem.Span(T)).Pointer;
ptr_info.sentinel = null;
return @Type(std.builtin.TypeInfo{ .Pointer = ptr_info });
}
test "FixedBufferStream output" {
var buf: [255]u8 = undefined;
var fbs = fixedBufferStream(&buf);
const stream = fbs.writer();
try stream.print("{}{}!", .{ "Hello", "World" });
testing.expectEqualSlices(u8, "HelloWorld!", fbs.getWritten());
}
test "FixedBufferStream output 2" {
var buffer: [10]u8 = undefined;
var fbs = fixedBufferStream(&buffer);
try fbs.writer().writeAll("Hello");
testing.expect(mem.eql(u8, fbs.getWritten(), "Hello"));
try fbs.writer().writeAll("world");
testing.expect(mem.eql(u8, fbs.getWritten(), "Helloworld"));
testing.expectError(error.NoSpaceLeft, fbs.writer().writeAll("!"));
testing.expect(mem.eql(u8, fbs.getWritten(), "Helloworld"));
fbs.reset();
testing.expect(fbs.getWritten().len == 0);
testing.expectError(error.NoSpaceLeft, fbs.writer().writeAll("Hello world!"));
testing.expect(mem.eql(u8, fbs.getWritten(), "Hello worl"));
}
test "FixedBufferStream input" {
const bytes = [_]u8{ 1, 2, 3, 4, 5, 6, 7 };
var fbs = fixedBufferStream(&bytes);
var dest: [4]u8 = undefined;
var read = try fbs.reader().read(dest[0..4]);
testing.expect(read == 4);
testing.expect(mem.eql(u8, dest[0..4], bytes[0..4]));
read = try fbs.reader().read(dest[0..4]);
testing.expect(read == 3);
testing.expect(mem.eql(u8, dest[0..3], bytes[4..7]));
read = try fbs.reader().read(dest[0..4]);
testing.expect(read == 0);
}
|
