ladybird/Userland/Utilities/echo.cpp
2022-04-01 21:24:45 +01:00

129 lines
4.1 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/CharacterTypes.h>
#include <AK/GenericLexer.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/System.h>
#include <LibMain/Main.h>
#include <stdio.h>
#include <unistd.h>
static u8 parse_octal_number(GenericLexer& lexer)
{
u32 value = 0;
for (size_t count = 0; count < 3; ++count) {
auto c = lexer.peek();
if (!(c >= '0' && c <= '7'))
break;
value = value * 8 + (c - '0');
lexer.consume();
}
clamp(value, 0, 255);
return value;
}
static Optional<u8> parse_hex_number(GenericLexer& lexer)
{
u8 value = 0;
for (size_t count = 0; count < 2; ++count) {
auto c = lexer.peek();
if (!is_ascii_hex_digit(c))
return {};
value = value * 16 + parse_ascii_hex_digit(c);
lexer.consume();
}
return value;
}
static String interpret_backslash_escapes(StringView string, bool& no_trailing_newline)
{
static constexpr auto escape_map = "a\ab\be\ef\fn\nr\rt\tv\v"sv;
static constexpr auto unescaped_chars = "\a\b\e\f\n\r\t\v\\"sv;
StringBuilder builder;
GenericLexer lexer { string };
while (!lexer.is_eof()) {
auto this_index = lexer.tell();
auto this_char = lexer.consume();
if (this_char == '\\') {
if (lexer.is_eof()) {
builder.append('\\');
break;
}
auto next_char = lexer.peek();
if (next_char == 'c') {
no_trailing_newline = true;
break;
}
if (next_char == '0') {
lexer.consume();
auto octal_number = parse_octal_number(lexer);
builder.append(octal_number);
} else if (next_char == 'x') {
lexer.consume();
auto maybe_hex_number = parse_hex_number(lexer);
if (!maybe_hex_number.has_value()) {
auto bad_substring = string.substring_view(this_index, lexer.tell() - this_index);
builder.append(bad_substring);
} else {
builder.append(maybe_hex_number.release_value());
}
} else if (next_char == 'u') {
lexer.retreat();
auto maybe_code_point = lexer.consume_escaped_code_point();
if (maybe_code_point.is_error()) {
auto bad_substring = string.substring_view(this_index, lexer.tell() - this_index);
builder.append(bad_substring);
} else {
builder.append_code_point(maybe_code_point.release_value());
}
} else {
lexer.retreat();
auto consumed_char = lexer.consume_escaped_character('\\', escape_map);
if (!unescaped_chars.contains(consumed_char))
builder.append('\\');
builder.append(consumed_char);
}
} else {
builder.append(this_char);
}
}
return builder.build();
}
ErrorOr<int> serenity_main(Main::Arguments arguments)
{
TRY(Core::System::pledge("stdio"));
Vector<char const*> text;
bool no_trailing_newline = false;
bool should_interpret_backslash_escapes = false;
Core::ArgsParser args_parser;
args_parser.add_option(no_trailing_newline, "Do not output a trailing newline", nullptr, 'n');
args_parser.add_option(should_interpret_backslash_escapes, "Interpret backslash escapes", nullptr, 'e');
args_parser.add_positional_argument(text, "Text to print out", "text", Core::ArgsParser::Required::No);
args_parser.set_stop_on_first_non_option(true);
args_parser.parse(arguments);
if (text.is_empty()) {
if (!no_trailing_newline)
outln();
return 0;
}
auto output = String::join(' ', text);
if (should_interpret_backslash_escapes)
output = interpret_backslash_escapes(output, no_trailing_newline);
out("{}", output);
if (!no_trailing_newline)
outln();
return 0;
}