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LibPDF: Move consume and match helper functions to the Reader class

This commit is contained in:
Julian Offenhäuser 2022-08-15 11:02:38 +02:00 committed by Sam Atkins
parent 8de7a91571
commit 9f4659cc63
5 changed files with 173 additions and 160 deletions

View file

@ -108,7 +108,7 @@ PDFErrorOr<void> Parser::parse_header()
if (minor_ver < '0' || minor_ver > '7')
return error(String::formatted("Unknown minor version \"{}\"", minor_ver));
consume_eol();
m_reader.consume_eol();
// Parse optional high-byte comment, which signifies a binary file
// FIXME: Do something with this?
@ -300,7 +300,7 @@ PDFErrorOr<NonnullRefPtr<XRefTable>> Parser::parse_xref_table()
if (!m_reader.matches("xref"))
return error("Expected \"xref\"");
m_reader.move_by(4);
if (!consume_eol())
if (!m_reader.consume_eol())
return error("Expected newline after \"xref\"");
auto table = adopt_ref(*new XRefTable());
@ -319,12 +319,12 @@ PDFErrorOr<NonnullRefPtr<XRefTable>> Parser::parse_xref_table()
for (int i = 0; i < object_count; i++) {
auto offset_string = String(m_reader.bytes().slice(m_reader.offset(), 10));
m_reader.move_by(10);
if (!consume(' '))
if (!m_reader.consume(' '))
return error("Malformed xref entry");
auto generation_string = String(m_reader.bytes().slice(m_reader.offset(), 5));
m_reader.move_by(5);
if (!consume(' '))
if (!m_reader.consume(' '))
return error("Malformed xref entry");
auto letter = m_reader.read();
@ -334,8 +334,8 @@ PDFErrorOr<NonnullRefPtr<XRefTable>> Parser::parse_xref_table()
// The line ending sequence can be one of the following:
// SP CR, SP LF, or CR LF
if (m_reader.matches(' ')) {
consume();
auto ch = consume();
m_reader.consume();
auto ch = m_reader.consume();
if (ch != '\r' && ch != '\n')
return error("Malformed xref entry");
} else {
@ -351,34 +351,34 @@ PDFErrorOr<NonnullRefPtr<XRefTable>> Parser::parse_xref_table()
}
table->add_section({ starting_index, object_count, entries });
} while (matches_number());
} while (m_reader.matches_number());
return table;
}
PDFErrorOr<NonnullRefPtr<DictObject>> Parser::parse_file_trailer()
{
while (matches_eol())
consume_eol();
while (m_reader.matches_eol())
m_reader.consume_eol();
if (!m_reader.matches("trailer"))
return error("Expected \"trailer\" keyword");
m_reader.move_by(7);
consume_whitespace();
m_reader.consume_whitespace();
auto dict = TRY(parse_dict());
if (!m_reader.matches("startxref"))
return error("Expected \"startxref\"");
m_reader.move_by(9);
consume_whitespace();
m_reader.consume_whitespace();
m_reader.move_until([&](auto) { return matches_eol(); });
VERIFY(consume_eol());
m_reader.move_until([&](auto) { return m_reader.matches_eol(); });
VERIFY(m_reader.consume_eol());
if (!m_reader.matches("%%EOF"))
return error("Expected \"%%EOF\"");
m_reader.move_by(5);
consume_whitespace();
m_reader.consume_whitespace();
return dict;
}
@ -492,18 +492,18 @@ bool Parser::navigate_to_before_eof_marker()
m_reader.set_reading_backwards();
while (!m_reader.done()) {
m_reader.move_until([&](auto) { return matches_eol(); });
m_reader.move_until([&](auto) { return m_reader.matches_eol(); });
if (m_reader.done())
return false;
consume_eol();
m_reader.consume_eol();
if (!m_reader.matches("%%EOF"))
continue;
m_reader.move_by(5);
if (!matches_eol())
if (!m_reader.matches_eol())
continue;
consume_eol();
m_reader.consume_eol();
return true;
}
@ -515,15 +515,15 @@ bool Parser::navigate_to_after_startxref()
m_reader.set_reading_backwards();
while (!m_reader.done()) {
m_reader.move_until([&](auto) { return matches_eol(); });
m_reader.move_until([&](auto) { return m_reader.matches_eol(); });
auto offset = m_reader.offset() + 1;
consume_eol();
m_reader.consume_eol();
if (!m_reader.matches("startxref"))
continue;
m_reader.move_by(9);
if (!matches_eol())
if (!m_reader.matches_eol())
continue;
m_reader.move_to(offset);
@ -538,14 +538,14 @@ String Parser::parse_comment()
if (!m_reader.matches('%'))
return {};
consume();
m_reader.consume();
auto comment_start_offset = m_reader.offset();
m_reader.move_until([&](auto) {
return matches_eol();
return m_reader.matches_eol();
});
String str = StringView(m_reader.bytes().slice(comment_start_offset, m_reader.offset() - comment_start_offset));
consume_eol();
consume_whitespace();
m_reader.consume_eol();
m_reader.consume_whitespace();
return str;
}
@ -555,23 +555,23 @@ PDFErrorOr<Value> Parser::parse_value()
if (m_reader.matches("null")) {
m_reader.move_by(4);
consume_whitespace();
m_reader.consume_whitespace();
return Value(nullptr);
}
if (m_reader.matches("true")) {
m_reader.move_by(4);
consume_whitespace();
m_reader.consume_whitespace();
return Value(true);
}
if (m_reader.matches("false")) {
m_reader.move_by(5);
consume_whitespace();
m_reader.consume_whitespace();
return Value(false);
}
if (matches_number())
if (m_reader.matches_number())
return parse_possible_indirect_value_or_ref();
if (m_reader.matches('/'))
@ -596,7 +596,7 @@ PDFErrorOr<Value> Parser::parse_value()
PDFErrorOr<Value> Parser::parse_possible_indirect_value_or_ref()
{
auto first_number = TRY(parse_number());
if (!matches_number())
if (!m_reader.matches_number())
return first_number;
m_reader.save();
@ -608,8 +608,8 @@ PDFErrorOr<Value> Parser::parse_possible_indirect_value_or_ref()
if (m_reader.matches('R')) {
m_reader.discard();
consume();
consume_whitespace();
m_reader.consume();
m_reader.consume_whitespace();
return Value(Reference(first_number.get<int>(), second_number.value().get<int>()));
}
@ -631,16 +631,16 @@ PDFErrorOr<NonnullRefPtr<IndirectValue>> Parser::parse_indirect_value(u32 index,
if (!m_reader.matches("obj"))
return error("Expected \"obj\" at beginning of indirect value");
m_reader.move_by(3);
if (matches_eol())
consume_eol();
if (m_reader.matches_eol())
m_reader.consume_eol();
push_reference({ index, generation });
auto value = TRY(parse_value());
if (!m_reader.matches("endobj"))
return error("Expected \"endobj\" at end of indirect value");
consume(6);
consume_whitespace();
m_reader.consume(6);
m_reader.consume_whitespace();
pop_reference();
@ -665,16 +665,16 @@ PDFErrorOr<Value> Parser::parse_number()
bool consumed_digit = false;
if (m_reader.matches('+') || m_reader.matches('-'))
consume();
m_reader.consume();
while (!m_reader.done()) {
if (m_reader.matches('.')) {
if (is_float)
break;
is_float = true;
consume();
m_reader.consume();
} else if (isdigit(m_reader.peek())) {
consume();
m_reader.consume();
consumed_digit = true;
} else {
break;
@ -684,7 +684,7 @@ PDFErrorOr<Value> Parser::parse_number()
if (!consumed_digit)
return error("Invalid number");
consume_whitespace();
m_reader.consume_whitespace();
auto string = String(m_reader.bytes().slice(start_offset, m_reader.offset() - start_offset));
float f = strtof(string.characters(), nullptr);
@ -697,19 +697,19 @@ PDFErrorOr<Value> Parser::parse_number()
PDFErrorOr<NonnullRefPtr<NameObject>> Parser::parse_name()
{
if (!consume('/'))
if (!m_reader.consume('/'))
return error("Expected Name object to start with \"/\"");
StringBuilder builder;
while (true) {
if (!matches_regular_character())
if (!m_reader.matches_regular_character())
break;
if (m_reader.matches('#')) {
int hex_value = 0;
for (int i = 0; i < 2; i++) {
auto ch = consume();
auto ch = m_reader.consume();
VERIFY(isxdigit(ch));
hex_value *= 16;
if (ch <= '9') {
@ -722,17 +722,17 @@ PDFErrorOr<NonnullRefPtr<NameObject>> Parser::parse_name()
continue;
}
builder.append(consume());
builder.append(m_reader.consume());
}
consume_whitespace();
m_reader.consume_whitespace();
return make_object<NameObject>(builder.to_string());
}
NonnullRefPtr<StringObject> Parser::parse_string()
{
ScopeGuard guard([&] { consume_whitespace(); });
ScopeGuard guard([&] { m_reader.consume_whitespace(); });
String string;
bool is_binary_string;
@ -768,31 +768,31 @@ NonnullRefPtr<StringObject> Parser::parse_string()
String Parser::parse_literal_string()
{
VERIFY(consume('('));
VERIFY(m_reader.consume('('));
StringBuilder builder;
auto opened_parens = 0;
while (true) {
if (m_reader.matches('(')) {
opened_parens++;
builder.append(consume());
builder.append(m_reader.consume());
} else if (m_reader.matches(')')) {
consume();
m_reader.consume();
if (opened_parens == 0)
break;
opened_parens--;
builder.append(')');
} else if (m_reader.matches('\\')) {
consume();
if (matches_eol()) {
consume_eol();
m_reader.consume();
if (m_reader.matches_eol()) {
m_reader.consume_eol();
continue;
}
if (m_reader.done())
return {};
auto ch = consume();
auto ch = m_reader.consume();
switch (ch) {
case 'n':
builder.append('\n');
@ -822,7 +822,7 @@ String Parser::parse_literal_string()
if (ch >= '0' && ch <= '7') {
int octal_value = ch - '0';
for (int i = 0; i < 2; i++) {
auto octal_ch = consume();
auto octal_ch = m_reader.consume();
if (octal_ch < '0' || octal_ch > '7')
break;
octal_value = octal_value * 8 + (octal_ch - '0');
@ -833,11 +833,11 @@ String Parser::parse_literal_string()
}
}
}
} else if (matches_eol()) {
consume_eol();
} else if (m_reader.matches_eol()) {
m_reader.consume_eol();
builder.append('\n');
} else {
builder.append(consume());
builder.append(m_reader.consume());
}
}
@ -846,23 +846,23 @@ String Parser::parse_literal_string()
String Parser::parse_hex_string()
{
VERIFY(consume('<'));
VERIFY(m_reader.consume('<'));
StringBuilder builder;
while (true) {
if (m_reader.matches('>')) {
consume();
m_reader.consume();
return builder.to_string();
} else {
int hex_value = 0;
for (int i = 0; i < 2; i++) {
auto ch = consume();
auto ch = m_reader.consume();
if (ch == '>') {
// The hex string contains an odd number of characters, and the last character
// is assumed to be '0'
consume();
m_reader.consume();
hex_value *= 16;
builder.append(static_cast<char>(hex_value));
return builder.to_string();
@ -887,26 +887,26 @@ String Parser::parse_hex_string()
PDFErrorOr<NonnullRefPtr<ArrayObject>> Parser::parse_array()
{
if (!consume('['))
if (!m_reader.consume('['))
return error("Expected array to start with \"[\"");
consume_whitespace();
m_reader.consume_whitespace();
Vector<Value> values;
while (!m_reader.matches(']'))
values.append(TRY(parse_value()));
VERIFY(consume(']'));
consume_whitespace();
VERIFY(m_reader.consume(']'));
m_reader.consume_whitespace();
return make_object<ArrayObject>(values);
}
PDFErrorOr<NonnullRefPtr<DictObject>> Parser::parse_dict()
{
if (!consume('<') || !consume('<'))
if (!m_reader.consume('<') || !m_reader.consume('<'))
return error("Expected dict to start with \"<<\"");
consume_whitespace();
m_reader.consume_whitespace();
HashMap<FlyString, Value> map;
while (!m_reader.done()) {
@ -917,9 +917,9 @@ PDFErrorOr<NonnullRefPtr<DictObject>> Parser::parse_dict()
map.set(name, value);
}
if (!consume('>') || !consume('>'))
if (!m_reader.consume('>') || !m_reader.consume('>'))
return error("Expected dict to end with \">>\"");
consume_whitespace();
m_reader.consume_whitespace();
return make_object<DictObject>(map);
}
@ -936,11 +936,11 @@ PDFErrorOr<RefPtr<DictObject>> Parser::conditionally_parse_page_tree_node(u32 ob
return error(String::formatted("Invalid page tree offset {}", object_index));
m_reader.move_by(3);
consume_whitespace();
m_reader.consume_whitespace();
VERIFY(consume('<') && consume('<'));
VERIFY(m_reader.consume('<') && m_reader.consume('<'));
consume_whitespace();
m_reader.consume_whitespace();
HashMap<FlyString, Value> map;
while (true) {
@ -967,8 +967,8 @@ PDFErrorOr<RefPtr<DictObject>> Parser::conditionally_parse_page_tree_node(u32 ob
map.set(name->name(), value);
}
VERIFY(consume('>') && consume('>'));
consume_whitespace();
VERIFY(m_reader.consume('>') && m_reader.consume('>'));
m_reader.consume_whitespace();
return make_object<DictObject>(map);
}
@ -978,7 +978,7 @@ PDFErrorOr<NonnullRefPtr<StreamObject>> Parser::parse_stream(NonnullRefPtr<DictO
if (!m_reader.matches("stream"))
return error("Expected stream to start with \"stream\"");
m_reader.move_by(6);
if (!consume_eol())
if (!m_reader.consume_eol())
return error("Expected \"stream\" to be followed by a newline");
ReadonlyBytes bytes;
@ -991,15 +991,15 @@ PDFErrorOr<NonnullRefPtr<StreamObject>> Parser::parse_stream(NonnullRefPtr<DictO
m_reader.load();
bytes = m_reader.bytes().slice(m_reader.offset(), length);
m_reader.move_by(length);
consume_whitespace();
m_reader.consume_whitespace();
} else {
// We have to look for the endstream keyword
auto stream_start = m_reader.offset();
while (true) {
m_reader.move_until([&](auto) { return matches_eol(); });
m_reader.move_until([&](auto) { return m_reader.matches_eol(); });
auto potential_stream_end = m_reader.offset();
consume_eol();
m_reader.consume_eol();
if (!m_reader.matches("endstream"))
continue;
@ -1009,7 +1009,7 @@ PDFErrorOr<NonnullRefPtr<StreamObject>> Parser::parse_stream(NonnullRefPtr<DictO
}
m_reader.move_by(9);
consume_whitespace();
m_reader.consume_whitespace();
auto stream_object = make_object<StreamObject>(dict, MUST(ByteBuffer::copy(bytes)));
@ -1043,7 +1043,7 @@ PDFErrorOr<Vector<Operator>> Parser::parse_operators()
if (is_operator_char(ch)) {
auto operator_start = m_reader.offset();
while (is_operator_char(ch)) {
consume();
m_reader.consume();
if (m_reader.done())
break;
ch = m_reader.peek();
@ -1053,7 +1053,7 @@ PDFErrorOr<Vector<Operator>> Parser::parse_operators()
auto operator_type = Operator::operator_type_from_symbol(operator_string);
operators.append(Operator(operator_type, move(operator_args)));
operator_args = Vector<Value>();
consume_whitespace();
m_reader.consume_whitespace();
continue;
}
@ -1064,73 +1064,6 @@ PDFErrorOr<Vector<Operator>> Parser::parse_operators()
return operators;
}
bool Parser::matches_eol() const
{
return m_reader.matches_any(0xa, 0xd);
}
bool Parser::matches_whitespace() const
{
return matches_eol() || m_reader.matches_any(0, 0x9, 0xc, ' ');
}
bool Parser::matches_number() const
{
if (m_reader.done())
return false;
auto ch = m_reader.peek();
return isdigit(ch) || ch == '-' || ch == '+';
}
bool Parser::matches_delimiter() const
{
return m_reader.matches_any('(', ')', '<', '>', '[', ']', '{', '}', '/', '%');
}
bool Parser::matches_regular_character() const
{
return !matches_delimiter() && !matches_whitespace();
}
bool Parser::consume_eol()
{
if (m_reader.done()) {
return false;
}
if (m_reader.matches("\r\n")) {
consume(2);
return true;
}
auto consumed = consume();
return consumed == 0xd || consumed == 0xa;
}
bool Parser::consume_whitespace()
{
bool consumed = false;
while (matches_whitespace()) {
consumed = true;
consume();
}
return consumed;
}
char Parser::consume()
{
return m_reader.read();
}
void Parser::consume(int amount)
{
for (size_t i = 0; i < static_cast<size_t>(amount); i++)
consume();
}
bool Parser::consume(char ch)
{
return consume() == ch;
}
Error Parser::error(
String const& message
#ifdef PDF_DEBUG