ladybird/AK/String.cpp

/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <AK/ByteBuffer.h>
#include <AK/FlyString.h>
#include <AK/Format.h>
#include <AK/Memory.h>
#include <AK/StdLibExtras.h>
#include <AK/String.h>
#include <AK/StringView.h>
#include <AK/Vector.h>

namespace AK {

String::String(const StringView& view)
{
    m_impl = StringImpl::create(view.characters_without_null_termination(), view.length());
}

bool String::operator==(const FlyString& fly_string) const
{
    return *this == String(fly_string.impl());
}

bool String::operator==(const String& other) const
{
    if (!m_impl)
        return !other.m_impl;

    if (!other.m_impl)
        return false;

    return *m_impl == *other.m_impl;
}

bool String::operator==(const StringView& other) const
{
    if (!m_impl)
        return !other.m_characters;

    if (!other.m_characters)
        return false;

    if (length() != other.length())
        return false;

    return !memcmp(characters(), other.characters_without_null_termination(), length());
}

bool String::operator<(const String& other) const
{
    if (!m_impl)
        return other.m_impl;

    if (!other.m_impl)
        return false;

    return strcmp(characters(), other.characters()) < 0;
}

bool String::operator>(const String& other) const
{
    if (!m_impl)
        return other.m_impl;

    if (!other.m_impl)
        return false;

    return strcmp(characters(), other.characters()) > 0;
}

String String::empty()
{
    return StringImpl::the_empty_stringimpl();
}

bool String::copy_characters_to_buffer(char* buffer, size_t buffer_size) const
{
    // We must fit at least the NUL-terminator.
    VERIFY(buffer_size > 0);

    size_t characters_to_copy = min(length(), buffer_size - 1);
    __builtin_memcpy(buffer, characters(), characters_to_copy);
    buffer[characters_to_copy] = 0;

    return characters_to_copy == length();
}

String String::isolated_copy() const
{
    if (!m_impl)
        return {};
    if (!m_impl->length())
        return empty();
    char* buffer;
    auto impl = StringImpl::create_uninitialized(length(), buffer);
    memcpy(buffer, m_impl->characters(), m_impl->length());
    return String(move(*impl));
}

String String::substring(size_t start) const
{
    VERIFY(m_impl);
    VERIFY(start <= length());
    return { characters() + start, length() - start };
}

String String::substring(size_t start, size_t length) const
{
    if (!length)
        return "";
    VERIFY(m_impl);
    VERIFY(start + length <= m_impl->length());
    // FIXME: This needs some input bounds checking.
    return { characters() + start, length };
}

StringView String::substring_view(size_t start, size_t length) const
{
    VERIFY(m_impl);
    VERIFY(start + length <= m_impl->length());
    // FIXME: This needs some input bounds checking.
    return { characters() + start, length };
}

StringView String::substring_view(size_t start) const
{
    VERIFY(m_impl);
    VERIFY(start <= length());
    return { characters() + start, length() - start };
}

Vector<String> String::split(char separator, bool keep_empty) const
{
    return split_limit(separator, 0, keep_empty);
}

Vector<String> String::split_limit(char separator, size_t limit, bool keep_empty) const
{
    if (is_empty())
        return {};

    Vector<String> v;
    size_t substart = 0;
    for (size_t i = 0; i < length() && (v.size() + 1) != limit; ++i) {
        char ch = characters()[i];
        if (ch == separator) {
            size_t sublen = i - substart;
            if (sublen != 0 || keep_empty)
                v.append(substring(substart, sublen));
            substart = i + 1;
        }
    }
    size_t taillen = length() - substart;
    if (taillen != 0 || keep_empty)
        v.append(substring(substart, taillen));
    return v;
}

Vector<StringView> String::split_view(const char separator, bool keep_empty) const
{
    if (is_empty())
        return {};

    Vector<StringView> v;
    size_t substart = 0;
    for (size_t i = 0; i < length(); ++i) {
        char ch = characters()[i];
        if (ch == separator) {
            size_t sublen = i - substart;
            if (sublen != 0 || keep_empty)
                v.append(substring_view(substart, sublen));
            substart = i + 1;
        }
    }
    size_t taillen = length() - substart;
    if (taillen != 0 || keep_empty)
        v.append(substring_view(substart, taillen));
    return v;
}

ByteBuffer String::to_byte_buffer() const
{
    if (!m_impl)
        return {};
    return ByteBuffer::copy(reinterpret_cast<const u8*>(characters()), length());
}

template<typename T>
Optional<T> String::to_int() const
{
    return StringUtils::convert_to_int<T>(view());
}

template Optional<i8> String::to_int() const;
template Optional<i16> String::to_int() const;
template Optional<i32> String::to_int() const;
template Optional<i64> String::to_int() const;

template<typename T>
Optional<T> String::to_uint() const
{
    return StringUtils::convert_to_uint<T>(view());
}

template Optional<u8> String::to_uint() const;
template Optional<u16> String::to_uint() const;
template Optional<u32> String::to_uint() const;
template Optional<u64> String::to_uint() const;

bool String::starts_with(const StringView& str, CaseSensitivity case_sensitivity) const
{
    return StringUtils::starts_with(*this, str, case_sensitivity);
}

bool String::starts_with(char ch) const
{
    if (is_empty())
        return false;
    return characters()[0] == ch;
}

bool String::ends_with(const StringView& str, CaseSensitivity case_sensitivity) const
{
    return StringUtils::ends_with(*this, str, case_sensitivity);
}

bool String::ends_with(char ch) const
{
    if (is_empty())
        return false;
    return characters()[length() - 1] == ch;
}

String String::repeated(char ch, size_t count)
{
    if (!count)
        return empty();
    char* buffer;
    auto impl = StringImpl::create_uninitialized(count, buffer);
    memset(buffer, ch, count);
    return *impl;
}

String String::repeated(const StringView& string, size_t count)
{
    if (!count || string.is_empty())
        return empty();
    char* buffer;
    auto impl = StringImpl::create_uninitialized(count * string.length(), buffer);
    for (size_t i = 0; i < count; i++)
        __builtin_memcpy(buffer + i * string.length(), string.characters_without_null_termination(), string.length());
    return *impl;
}

String String::bijective_base_from(size_t value, unsigned base, StringView map)
{
    if (map.is_null())
        map = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"sv;

    VERIFY(base >= 2 && base <= map.length());

    // The '8 bits per byte' assumption may need to go?
    Array<char, round_up_to_power_of_two(sizeof(size_t) * 8 + 1, 2)> buffer;
    size_t i = 0;
    do {
        buffer[i++] = map[value % base];
        value /= base;
    } while (value > 0);

    // NOTE: Weird as this may seem, the thing that comes after 'Z' is 'AA', which as a number would be '00'
    //       to make this work, only the most significant digit has to be in a range of (1..25) as opposed to (0..25),
    //       but only if it's not the only digit in the string.
    if (i > 1)
        --buffer[i - 1];

    for (size_t j = 0; j < i / 2; ++j)
        swap(buffer[j], buffer[i - j - 1]);

    return String { ReadonlyBytes(buffer.data(), i) };
}

bool String::matches(const StringView& mask, Vector<MaskSpan>& mask_spans, CaseSensitivity case_sensitivity) const
{
    return StringUtils::matches(*this, mask, case_sensitivity, &mask_spans);
}

bool String::matches(const StringView& mask, CaseSensitivity case_sensitivity) const
{
    return StringUtils::matches(*this, mask, case_sensitivity);
}

bool String::contains(const StringView& needle, CaseSensitivity case_sensitivity) const
{
    return StringUtils::contains(*this, needle, case_sensitivity);
}

bool String::equals_ignoring_case(const StringView& other) const
{
    return StringUtils::equals_ignoring_case(view(), other);
}

Vector<size_t> String::find_all(const String& needle) const
{
    Vector<size_t> positions;
    size_t start = 0, pos;
    for (;;) {
        const char* ptr = strstr(characters() + start, needle.characters());
        if (!ptr)
            break;

        pos = ptr - characters();
        positions.append(pos);

        start = pos + 1;
    }
    return positions;
}

int String::replace(const String& needle, const String& replacement, bool all_occurrences)
{
    if (is_empty())
        return 0;

    Vector<size_t> positions;
    if (all_occurrences) {
        positions = find_all(needle);
    } else {
        auto pos = find(needle);
        if (!pos.has_value())
            return 0;
        positions.append(pos.value());
    }

    if (!positions.size())
        return 0;

    StringBuilder b;
    size_t lastpos = 0;
    for (auto& pos : positions) {
        b.append(substring_view(lastpos, pos - lastpos));
        b.append(replacement);
        lastpos = pos + needle.length();
    }
    b.append(substring_view(lastpos, length() - lastpos));
    m_impl = StringImpl::create(b.build().characters());
    return positions.size();
}

size_t String::count(const String& needle) const
{
    size_t count = 0;
    size_t start = 0, pos;
    for (;;) {
        const char* ptr = strstr(characters() + start, needle.characters());
        if (!ptr)
            break;

        pos = ptr - characters();
        count++;
        start = pos + 1;
    }
    return count;
}

String String::reverse() const
{
    StringBuilder reversed_string;
    for (size_t i = length(); i-- > 0;) {
        reversed_string.append(characters()[i]);
    }
    return reversed_string.to_string();
}

String escape_html_entities(const StringView& html)
{
    StringBuilder builder;
    for (size_t i = 0; i < html.length(); ++i) {
        if (html[i] == '<')
            builder.append("&lt;");
        else if (html[i] == '>')
            builder.append("&gt;");
        else if (html[i] == '&')
            builder.append("&amp;");
        else
            builder.append(html[i]);
    }
    return builder.to_string();
}

String::String(const FlyString& string)
    : m_impl(string.impl())
{
}

String String::to_lowercase() const
{
    if (!m_impl)
        return {};
    return m_impl->to_lowercase();
}

String String::to_uppercase() const
{
    if (!m_impl)
        return {};
    return m_impl->to_uppercase();
}

String String::to_snakecase() const
{
    return StringUtils::to_snakecase(*this);
}

bool operator<(const char* characters, const String& string)
{
    if (!characters)
        return !string.is_null();

    if (string.is_null())
        return false;

    return __builtin_strcmp(characters, string.characters()) < 0;
}

bool operator>=(const char* characters, const String& string)
{
    return !(characters < string);
}

bool operator>(const char* characters, const String& string)
{
    if (!characters)
        return !string.is_null();

    if (string.is_null())
        return false;

    return __builtin_strcmp(characters, string.characters()) > 0;
}

bool operator<=(const char* characters, const String& string)
{
    return !(characters > string);
}

bool String::operator==(const char* cstring) const
{
    if (is_null())
        return !cstring;
    if (!cstring)
        return false;
    return !__builtin_strcmp(characters(), cstring);
}

StringView String::view() const
{
    return { characters(), length() };
}

InputStream& operator>>(InputStream& stream, String& string)
{
    StringBuilder builder;

    for (;;) {
        char next_char;
        stream >> next_char;

        if (stream.has_any_error()) {
            stream.set_fatal_error();
            string = nullptr;
            return stream;
        }

        if (next_char) {
            builder.append(next_char);
        } else {
            string = builder.to_string();
            return stream;
        }
    }
}

String String::vformatted(StringView fmtstr, TypeErasedFormatParams params)
{
    StringBuilder builder;
    vformat(builder, fmtstr, params);
    return builder.to_string();
}

Optional<size_t> String::find(char c, size_t start) const
{
    return find(StringView { &c, 1 }, start);
}

Optional<size_t> String::find(StringView const& view, size_t start) const
{
    auto index = StringUtils::find(substring_view(start), view);
    if (!index.has_value())
        return {};
    return index.value() + start;
}

}