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			326 lines
		
	
	
	
		
			8.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			326 lines
		
	
	
	
		
			8.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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|  * All rights reserved.
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|  *
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|  * Redistribution and use in source and binary forms, with or without
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|  * modification, are permitted provided that the following conditions are met:
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|  *
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|  * 1. Redistributions of source code must retain the above copyright notice, this
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|  *    list of conditions and the following disclaimer.
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|  *
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|  * 2. Redistributions in binary form must reproduce the above copyright notice,
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|  *    this list of conditions and the following disclaimer in the documentation
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|  *    and/or other materials provided with the distribution.
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|  *
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|  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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|  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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|  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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|  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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|  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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|  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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|  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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|  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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|  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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|  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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|  */
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| 
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| #include <AK/JsonArray.h>
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| #include <AK/JsonObject.h>
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| #include <AK/JsonParser.h>
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| #include <AK/Memory.h>
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| 
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| namespace AK {
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| 
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| static inline bool is_whitespace(char ch)
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| {
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|     return ch == ' ' || ch == '\n' || ch == '\t' || ch == '\v' || ch == '\r';
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| }
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| 
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| char JsonParser::peek() const
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| {
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|     if (m_index < m_input.length())
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|         return m_input[m_index];
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|     return '\0';
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| }
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| 
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| char JsonParser::consume()
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| {
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|     if (m_index < m_input.length())
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|         return m_input[m_index++];
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|     return '\0';
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| }
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| 
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| template<typename C>
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| void JsonParser::consume_while(C condition)
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| {
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|     while (condition(peek()))
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|         consume();
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| }
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| 
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| void JsonParser::consume_whitespace()
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| {
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|     consume_while([](char ch) { return is_whitespace(ch); });
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| }
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| 
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| void JsonParser::consume_specific(char expected_ch)
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| {
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|     char consumed_ch = consume();
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|     ASSERT(consumed_ch == expected_ch);
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| }
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| 
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| String JsonParser::consume_quoted_string()
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| {
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|     consume_specific('"');
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|     Vector<char, 1024> buffer;
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| 
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|     for (;;) {
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|         size_t peek_index = m_index;
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|         char ch = 0;
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|         for (;;) {
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|             if (peek_index == m_input.length())
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|                 break;
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|             ch = m_input[peek_index];
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|             if (ch == '"' || ch == '\\')
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|                 break;
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|             ++peek_index;
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|         }
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| 
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|         if (peek_index != m_index) {
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|             buffer.append(m_input.characters_without_null_termination() + m_index, peek_index - m_index);
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|             m_index = peek_index;
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|         }
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| 
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|         if (m_index == m_input.length())
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|             break;
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|         if (ch == '"')
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|             break;
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|         if (ch != '\\') {
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|             buffer.append(consume());
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|             continue;
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|         }
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|         consume();
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|         char escaped_ch = consume();
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|         switch (escaped_ch) {
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|         case 'n':
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|             buffer.append('\n');
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|             break;
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|         case 'r':
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|             buffer.append('\r');
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|             break;
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|         case 't':
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|             buffer.append('\t');
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|             break;
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|         case 'b':
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|             buffer.append('\b');
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|             break;
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|         case 'f':
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|             buffer.append('\f');
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|             break;
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|         case 'u': {
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|             StringBuilder sb;
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|             sb.append(consume());
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|             sb.append(consume());
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|             sb.append(consume());
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|             sb.append(consume());
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| 
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|             bool ok;
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|             u32 codepoint = AK::StringUtils::convert_to_uint_from_hex(sb.to_string(), ok);
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|             if (ok && codepoint < 128) {
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|                 buffer.append((char)codepoint);
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|             } else {
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|                 // FIXME: This is obviously not correct, but we don't have non-ASCII support so meh.
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|                 buffer.append('?');
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|             }
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|         } break;
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|         default:
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|             buffer.append(escaped_ch);
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|             break;
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|         }
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|     }
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|     consume_specific('"');
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| 
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|     if (buffer.is_empty())
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|         return String::empty();
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| 
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|     auto& last_string_starting_with_character = m_last_string_starting_with_character[(u8)buffer.first()];
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|     if (last_string_starting_with_character.length() == buffer.size()) {
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|         if (!memcmp(last_string_starting_with_character.characters(), buffer.data(), buffer.size()))
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|             return last_string_starting_with_character;
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|     }
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| 
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|     last_string_starting_with_character = String::copy(buffer);
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|     return last_string_starting_with_character;
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| }
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| 
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| JsonObject JsonParser::parse_object()
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| {
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|     JsonObject object;
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|     consume_specific('{');
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|     for (;;) {
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|         consume_whitespace();
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|         if (peek() == '}')
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|             break;
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|         consume_whitespace();
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|         auto name = consume_quoted_string();
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|         consume_whitespace();
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|         consume_specific(':');
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|         consume_whitespace();
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|         auto value = parse();
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|         object.set(name, move(value));
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|         consume_whitespace();
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|         if (peek() == '}')
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|             break;
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|         consume_specific(',');
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|     }
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|     consume_specific('}');
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|     return object;
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| }
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| 
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| JsonArray JsonParser::parse_array()
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| {
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|     JsonArray array;
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|     consume_specific('[');
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|     for (;;) {
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|         consume_whitespace();
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|         if (peek() == ']')
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|             break;
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|         array.append(parse());
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|         consume_whitespace();
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|         if (peek() == ']')
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|             break;
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|         consume_specific(',');
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|     }
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|     consume_whitespace();
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|     consume_specific(']');
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|     return array;
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| }
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| 
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| JsonValue JsonParser::parse_string()
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| {
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|     return consume_quoted_string();
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| }
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| 
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| JsonValue JsonParser::parse_number()
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| {
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|     bool ok;
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|     JsonValue value;
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|     Vector<char, 128> number_buffer;
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|     Vector<char, 128> fraction_buffer;
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| 
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|     bool is_double = false;
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|     for (;;) {
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|         char ch = peek();
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|         if (ch == '.') {
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|             is_double = true;
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|             ++m_index;
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|             continue;
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|         }
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|         if (ch == '-' || (ch >= '0' && ch <= '9')) {
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|             if (is_double)
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|                 fraction_buffer.append(ch);
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|             else
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|                 number_buffer.append(ch);
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|             ++m_index;
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|             continue;
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|         }
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|         break;
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|     }
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| 
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|     StringView number_string(number_buffer.data(), number_buffer.size());
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|     StringView fraction_string(fraction_buffer.data(), fraction_buffer.size());
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| 
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| #ifndef KERNEL
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|     if (is_double) {
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|         int whole = number_string.to_uint(ok);
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|         if (!ok)
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|             whole = number_string.to_int(ok);
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|         ASSERT(ok);
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| 
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|         int fraction = fraction_string.to_uint(ok);
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|         fraction *= (whole < 0) ? -1 : 1;
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|         ASSERT(ok);
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| 
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|         auto divider = 1;
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|         for (size_t i = 0; i < fraction_buffer.size(); ++i) {
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|             divider *= 10;
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|         }
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|         value = JsonValue((double)whole + ((double)fraction / divider));
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|     } else {
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| #endif
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|         value = JsonValue(number_string.to_uint(ok));
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|         if (!ok)
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|             value = JsonValue(number_string.to_int(ok));
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|         ASSERT(ok);
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| #ifndef KERNEL
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|     }
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| #endif
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| 
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|     return value;
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| }
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| 
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| void JsonParser::consume_string(const char* str)
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| {
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|     for (size_t i = 0, length = strlen(str); i < length; ++i)
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|         consume_specific(str[i]);
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| }
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| 
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| JsonValue JsonParser::parse_true()
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| {
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|     consume_string("true");
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|     return JsonValue(true);
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| }
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| 
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| JsonValue JsonParser::parse_false()
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| {
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|     consume_string("false");
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|     return JsonValue(false);
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| }
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| 
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| JsonValue JsonParser::parse_null()
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| {
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|     consume_string("null");
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|     return JsonValue(JsonValue::Type::Null);
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| }
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| 
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| JsonValue JsonParser::parse_undefined()
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| {
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|     consume_string("undefined");
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|     return JsonValue(JsonValue::Type::Undefined);
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| }
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| 
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| JsonValue JsonParser::parse()
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| {
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|     consume_whitespace();
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|     auto type_hint = peek();
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|     switch (type_hint) {
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|     case '{':
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|         return parse_object();
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|     case '[':
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|         return parse_array();
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|     case '"':
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|         return parse_string();
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|     case '-':
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|     case '0':
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|     case '1':
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|     case '2':
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|     case '3':
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|     case '4':
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|     case '5':
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|     case '6':
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|     case '7':
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|     case '8':
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|     case '9':
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|         return parse_number();
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|     case 'f':
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|         return parse_false();
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|     case 't':
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|         return parse_true();
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|     case 'n':
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|         return parse_null();
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|     case 'u':
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|         return parse_undefined();
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|     }
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| 
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|     return JsonValue();
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| }
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| }
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