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/*
* Copyright (c) 2021, Marcin Undak <mcinek@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "BootPPMParser.h"
namespace Kernel {
BootPPMParser::BootPPMParser(u8 const* buffer, u32 buffer_size)
{
m_cursor = reinterpret_cast<char const*>(buffer);
m_buffer_end = m_cursor + buffer_size;
}
bool BootPPMParser::parse()
{
if (!check_position()) {
return false;
}
if (!parse_magic()) {
return false;
}
if (!parse_new_line()) {
return false;
}
if (!parse_comment()) {
return false;
}
if (!parse_integer(image.width)) {
return false;
}
if (!parse_integer(image.height)) {
return false;
}
u32 max_color_value;
if (!parse_integer(max_color_value) || max_color_value != 255) {
return false;
}
image.pixel_data = reinterpret_cast<u8 const*>(m_cursor);
return true;
}
bool BootPPMParser::check_position() const
{
if (m_cursor >= m_buffer_end) {
return false;
}
return true;
}
bool BootPPMParser::parse_magic()
{
if (m_cursor[0] != 'P' || m_cursor[1] != '6') {
return false;
}
m_cursor += 2;
return check_position();
}
bool BootPPMParser::parse_new_line()
{
if (*m_cursor != '\n') {
return false;
}
++m_cursor;
return check_position();
}
bool BootPPMParser::parse_comment()
{
if (*m_cursor == '#') {
// Skip to the next new line character
while (check_position() && *m_cursor != '\n') {
++m_cursor;
}
++m_cursor;
}
return check_position();
}
bool BootPPMParser::parse_integer(u32& value)
{
auto begin = m_cursor;
while (check_position() && *m_cursor != ' ' && *m_cursor != '\n') {
++m_cursor;
}
auto end = m_cursor;
++m_cursor;
if (!check_position()) {
return false;
}
value = 0;
u32 multiplier = 1;
while (--end >= begin) {
value += multiplier * (*end - '0');
multiplier *= 10;
}
return true;
}
}
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