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#include <AK/JsonArray.h>
#include <AK/JsonObject.h>
#include <AK/JsonParser.h>
#include <AK/StringBuilder.h>
namespace AK {
static inline bool is_whitespace(char ch)
{
return ch == ' ' || ch == '\n' || ch == '\t' || ch == '\v' || ch == '\r';
}
char JsonParser::peek() const
{
if (m_index < m_input.length())
return m_input[m_index];
return '\0';
}
char JsonParser::consume()
{
if (m_index < m_input.length())
return m_input[m_index++];
return '\0';
}
template<typename C>
void JsonParser::consume_while(C condition)
{
while (condition(peek()))
consume();
}
template<typename C>
String JsonParser::extract_while(C condition)
{
StringBuilder builder;
while (condition(peek()))
builder.append(consume());
return builder.to_string();
};
void JsonParser::consume_whitespace()
{
consume_while([](char ch) { return is_whitespace(ch); });
}
void JsonParser::consume_specific(char expected_ch)
{
char consumed_ch = consume();
ASSERT(consumed_ch == expected_ch);
}
String JsonParser::consume_quoted_string()
{
consume_specific('"');
StringBuilder builder;
for (;;) {
char ch = peek();
if (ch == '"')
break;
if (ch != '\\') {
builder.append(consume());
continue;
}
consume();
char escaped_ch = consume();
switch (escaped_ch) {
case 'n':
builder.append('\n');
break;
case 'r':
builder.append('\n');
break;
case 't':
builder.append('\t');
break;
case 'b':
builder.append('\b');
break;
case 'f':
builder.append('\f');
break;
case 'u':
// FIXME: Implement \uXXXX
ASSERT_NOT_REACHED();
break;
default:
builder.append(escaped_ch);
break;
}
}
consume_specific('"');
return builder.to_string();
}
JsonValue JsonParser::parse_object()
{
JsonObject object;
consume_specific('{');
for (;;) {
consume_whitespace();
if (peek() == '}')
break;
consume_whitespace();
auto name = consume_quoted_string();
consume_whitespace();
consume_specific(':');
consume_whitespace();
auto value = parse();
object.set(name, move(value));
consume_whitespace();
if (peek() == '}')
break;
consume_specific(',');
}
consume_specific('}');
return object;
}
JsonValue JsonParser::parse_array()
{
JsonArray array;
consume_specific('[');
for (;;) {
consume_whitespace();
if (peek() == ']')
break;
array.append(parse());
consume_whitespace();
if (peek() == ']')
break;
consume_specific(',');
}
consume_whitespace();
consume_specific(']');
return array;
}
JsonValue JsonParser::parse_string()
{
return consume_quoted_string();
}
JsonValue JsonParser::parse_number()
{
auto number_string = extract_while([](char ch) { return ch == '-' || (ch >= '0' && ch <= '9'); });
bool ok;
auto value = JsonValue(number_string.to_uint(ok));
if (!ok)
value = JsonValue(number_string.to_int(ok));
ASSERT(ok);
return value;
}
void JsonParser::consume_string(const char* str)
{
for (size_t i = 0, length = strlen(str); i < length; ++i)
consume_specific(str[i]);
}
JsonValue JsonParser::parse_true()
{
consume_string("true");
return JsonValue(true);
}
JsonValue JsonParser::parse_false()
{
consume_string("false");
return JsonValue(false);
}
JsonValue JsonParser::parse_null()
{
consume_string("null");
return JsonValue(JsonValue::Type::Null);
}
JsonValue JsonParser::parse_undefined()
{
consume_string("undefined");
return JsonValue(JsonValue::Type::Undefined);
}
JsonValue JsonParser::parse()
{
consume_whitespace();
auto type_hint = peek();
switch (type_hint) {
case '{':
return parse_object();
case '[':
return parse_array();
case '"':
return parse_string();
case '-':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
return parse_number();
case 'f':
return parse_false();
case 't':
return parse_true();
case 'n':
return parse_null();
case 'u':
return parse_undefined();
}
return JsonValue();
}
}
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