jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
3 * Copyright (c) 2022, Eli Youngs <eli.m.youngs@gmail.com>
4 *
5 * SPDX-License-Identifier: BSD-2-Clause
6 */
7
8#include <AK/Array.h>
9#include <LibCore/ArgsParser.h>
10#include <LibCore/File.h>
11#include <LibCore/System.h>
12#include <LibMain/Main.h>
13#include <ctype.h>
14#include <string.h>
15
16static constexpr size_t LINE_LENGTH_BYTES = 16;
17
18enum class State {
19 Print,
20 PrintFiller,
21 SkipPrint
22};
23
24ErrorOr<int> serenity_main(Main::Arguments args)
25{
26 TRY(Core::System::pledge("stdio rpath"));
27
28 Core::ArgsParser args_parser;
29 StringView path;
30 bool verbose = false;
31 Optional<size_t> max_bytes;
32 Optional<size_t> seek_to;
33
34 args_parser.add_positional_argument(path, "Input", "input", Core::ArgsParser::Required::No);
35 args_parser.add_option(verbose, "Display all input data", "verbose", 'v');
36 args_parser.add_option(max_bytes, "Truncate to a fixed number of bytes", nullptr, 'n', "bytes");
37 args_parser.add_option(seek_to, "Seek to a byte offset", "seek", 's', "offset");
38 args_parser.parse(args);
39
40 auto file = TRY(Core::File::open_file_or_standard_stream(path, Core::File::OpenMode::Read));
41 if (seek_to.has_value())
42 TRY(file->seek(seek_to.value(), SeekMode::SetPosition));
43
44 auto print_line = [](Bytes line) {
45 VERIFY(line.size() <= LINE_LENGTH_BYTES);
46 for (size_t i = 0; i < LINE_LENGTH_BYTES; ++i) {
47 if (i < line.size())
48 out("{:02x} ", line[i]);
49 else
50 out(" ");
51
52 if (i == 7)
53 out(" ");
54 }
55
56 out(" |");
57
58 for (auto const& byte : line) {
59 if (isprint(byte))
60 putchar(byte);
61 else
62 putchar('.');
63 }
64
65 putchar('|');
66 putchar('\n');
67 };
68
69 Array<u8, BUFSIZ> contents;
70 Bytes bytes;
71 Bytes previous_line;
72 static_assert(LINE_LENGTH_BYTES * 2 <= contents.size(), "Buffer is too small?!");
73 size_t total_bytes_read = 0;
74
75 auto state = State::Print;
76 bool is_input_remaining = true;
77 while (is_input_remaining) {
78 auto bytes_to_read = contents.size() - bytes.size();
79
80 if (max_bytes.has_value()) {
81 auto bytes_remaining = max_bytes.value() - total_bytes_read;
82 if (bytes_remaining < bytes_to_read) {
83 bytes_to_read = bytes_remaining;
84 is_input_remaining = false;
85 }
86 }
87
88 bytes = contents.span().slice(0, bytes_to_read);
89 bytes = TRY(file->read_some(bytes));
90
91 total_bytes_read += bytes.size();
92
93 if (bytes.size() < bytes_to_read) {
94 is_input_remaining = false;
95 }
96
97 while (bytes.size() > LINE_LENGTH_BYTES) {
98 auto current_line = bytes.slice(0, LINE_LENGTH_BYTES);
99 bytes = bytes.slice(LINE_LENGTH_BYTES);
100
101 if (verbose) {
102 print_line(current_line);
103 continue;
104 }
105
106 bool is_same_contents = (current_line == previous_line);
107 if (!is_same_contents)
108 state = State::Print;
109 else if (is_same_contents && (state != State::SkipPrint))
110 state = State::PrintFiller;
111
112 // Coalesce repeating lines
113 switch (state) {
114 case State::Print:
115 print_line(current_line);
116 break;
117 case State::PrintFiller:
118 outln("*");
119 state = State::SkipPrint;
120 break;
121 case State::SkipPrint:
122 break;
123 }
124 previous_line = current_line;
125 }
126 }
127
128 if (bytes.size() > 0)
129 print_line(bytes);
130
131 return 0;
132}