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/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/StdLibExtras.h>
#include <Kernel/KBufferBuilder.h>
namespace Kernel {
inline bool KBufferBuilder::check_expand(size_t size)
{
if (!m_buffer)
return false;
if ((m_size + size) < m_buffer->capacity())
return true;
if (Checked<size_t>::addition_would_overflow(m_size, size))
return false;
size_t new_buffer_size = m_size + size;
if (Checked<size_t>::addition_would_overflow(new_buffer_size, 1 * MiB))
return false;
new_buffer_size = Memory::page_round_up(new_buffer_size + 1 * MiB);
auto new_buffer_or_error = KBuffer::try_create_with_size(new_buffer_size);
if (new_buffer_or_error.is_error())
return false;
auto new_buffer = new_buffer_or_error.release_value();
memcpy(new_buffer->data(), m_buffer->data(), m_buffer->size());
m_buffer = move(new_buffer);
return true;
}
bool KBufferBuilder::flush()
{
if (!m_buffer)
return false;
m_buffer->set_size(m_size);
return true;
}
OwnPtr<KBuffer> KBufferBuilder::build()
{
if (!flush())
return {};
return move(m_buffer);
}
ErrorOr<KBufferBuilder> KBufferBuilder::try_create()
{
auto buffer = TRY(KBuffer::try_create_with_size(4 * MiB, Memory::Region::Access::ReadWrite));
return KBufferBuilder { move(buffer) };
}
KBufferBuilder::KBufferBuilder(NonnullOwnPtr<KBuffer> buffer)
: m_buffer(move(buffer))
{
}
ErrorOr<void> KBufferBuilder::append_bytes(ReadonlyBytes bytes)
{
if (!check_expand(bytes.size()))
return ENOMEM;
memcpy(insertion_ptr(), bytes.data(), bytes.size());
m_size += bytes.size();
return {};
}
ErrorOr<void> KBufferBuilder::append(StringView str)
{
if (str.is_empty())
return {};
if (!check_expand(str.length()))
return ENOMEM;
memcpy(insertion_ptr(), str.characters_without_null_termination(), str.length());
m_size += str.length();
return {};
}
ErrorOr<void> KBufferBuilder::append(const char* characters, int length)
{
if (!length)
return {};
if (!check_expand(length))
return ENOMEM;
memcpy(insertion_ptr(), characters, length);
m_size += length;
return {};
}
ErrorOr<void> KBufferBuilder::append(char ch)
{
if (!check_expand(1))
return ENOMEM;
insertion_ptr()[0] = ch;
m_size += 1;
return {};
}
ErrorOr<void> KBufferBuilder::append_escaped_for_json(StringView string)
{
for (auto ch : string) {
switch (ch) {
case '\b':
TRY(append("\\b"));
break;
case '\n':
TRY(append("\\n"));
break;
case '\t':
TRY(append("\\t"));
break;
case '\"':
TRY(append("\\\""));
break;
case '\\':
TRY(append("\\\\"));
break;
default:
if (ch >= 0 && ch <= 0x1f)
TRY(append(String::formatted("\\u{:04x}", ch)));
else
TRY(append(ch));
}
}
return {};
}
}
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