forked from mirrors/gecko-dev
403 lines
14 KiB
C++
403 lines
14 KiB
C++
// Copyright 2007-2010 Baptiste Lepilleur and The JsonCpp Authors
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// Distributed under MIT license, or public domain if desired and
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// recognized in your jurisdiction.
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// See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE
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#ifndef JSON_READER_H_INCLUDED
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#define JSON_READER_H_INCLUDED
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#if !defined(JSON_IS_AMALGAMATION)
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#include "json_features.h"
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#include "value.h"
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#endif // if !defined(JSON_IS_AMALGAMATION)
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#include <deque>
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#include <iosfwd>
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#include <istream>
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#include <stack>
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#include <string>
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// Disable warning C4251: <data member>: <type> needs to have dll-interface to
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// be used by...
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#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
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#pragma warning(push)
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#pragma warning(disable : 4251)
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#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
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#pragma pack(push, 8)
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namespace Json {
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/** \brief Unserialize a <a HREF="http://www.json.org">JSON</a> document into a
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* Value.
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*
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* \deprecated Use CharReader and CharReaderBuilder.
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*/
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class JSONCPP_DEPRECATED(
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"Use CharReader and CharReaderBuilder instead.") JSON_API Reader {
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public:
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using Char = char;
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using Location = const Char*;
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/** \brief An error tagged with where in the JSON text it was encountered.
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*
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* The offsets give the [start, limit) range of bytes within the text. Note
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* that this is bytes, not codepoints.
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*/
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struct StructuredError {
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ptrdiff_t offset_start;
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ptrdiff_t offset_limit;
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String message;
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};
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/** \brief Constructs a Reader allowing all features for parsing.
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*/
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JSONCPP_DEPRECATED("Use CharReader and CharReaderBuilder instead")
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Reader();
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/** \brief Constructs a Reader allowing the specified feature set for parsing.
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*/
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JSONCPP_DEPRECATED("Use CharReader and CharReaderBuilder instead")
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Reader(const Features& features);
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/** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
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* document.
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*
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* \param document UTF-8 encoded string containing the document
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* to read.
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* \param[out] root Contains the root value of the document if it
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* was successfully parsed.
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* \param collectComments \c true to collect comment and allow writing
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* them back during serialization, \c false to
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* discard comments. This parameter is ignored
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* if Features::allowComments_ is \c false.
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* \return \c true if the document was successfully parsed, \c false if an
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* error occurred.
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*/
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bool parse(const std::string& document, Value& root,
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bool collectComments = true);
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/** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
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* document.
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*
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* \param beginDoc Pointer on the beginning of the UTF-8 encoded
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* string of the document to read.
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* \param endDoc Pointer on the end of the UTF-8 encoded string
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* of the document to read. Must be >= beginDoc.
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* \param[out] root Contains the root value of the document if it
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* was successfully parsed.
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* \param collectComments \c true to collect comment and allow writing
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* them back during serialization, \c false to
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* discard comments. This parameter is ignored
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* if Features::allowComments_ is \c false.
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* \return \c true if the document was successfully parsed, \c false if an
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* error occurred.
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*/
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bool parse(const char* beginDoc, const char* endDoc, Value& root,
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bool collectComments = true);
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/// \brief Parse from input stream.
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/// \see Json::operator>>(std::istream&, Json::Value&).
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bool parse(IStream& is, Value& root, bool collectComments = true);
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/** \brief Returns a user friendly string that list errors in the parsed
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* document.
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*
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* \return Formatted error message with the list of errors with their
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* location in the parsed document. An empty string is returned if no error
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* occurred during parsing.
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* \deprecated Use getFormattedErrorMessages() instead (typo fix).
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*/
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JSONCPP_DEPRECATED("Use getFormattedErrorMessages() instead.")
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String getFormatedErrorMessages() const;
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/** \brief Returns a user friendly string that list errors in the parsed
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* document.
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*
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* \return Formatted error message with the list of errors with their
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* location in the parsed document. An empty string is returned if no error
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* occurred during parsing.
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*/
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String getFormattedErrorMessages() const;
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/** \brief Returns a vector of structured errors encountered while parsing.
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*
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* \return A (possibly empty) vector of StructuredError objects. Currently
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* only one error can be returned, but the caller should tolerate multiple
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* errors. This can occur if the parser recovers from a non-fatal parse
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* error and then encounters additional errors.
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*/
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std::vector<StructuredError> getStructuredErrors() const;
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/** \brief Add a semantic error message.
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*
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* \param value JSON Value location associated with the error
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* \param message The error message.
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* \return \c true if the error was successfully added, \c false if the Value
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* offset exceeds the document size.
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*/
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bool pushError(const Value& value, const String& message);
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/** \brief Add a semantic error message with extra context.
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*
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* \param value JSON Value location associated with the error
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* \param message The error message.
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* \param extra Additional JSON Value location to contextualize the error
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* \return \c true if the error was successfully added, \c false if either
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* Value offset exceeds the document size.
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*/
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bool pushError(const Value& value, const String& message, const Value& extra);
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/** \brief Return whether there are any errors.
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*
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* \return \c true if there are no errors to report \c false if errors have
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* occurred.
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*/
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bool good() const;
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private:
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enum TokenType {
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tokenEndOfStream = 0,
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tokenObjectBegin,
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tokenObjectEnd,
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tokenArrayBegin,
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tokenArrayEnd,
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tokenString,
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tokenNumber,
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tokenTrue,
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tokenFalse,
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tokenNull,
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tokenArraySeparator,
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tokenMemberSeparator,
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tokenComment,
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tokenError
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};
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class Token {
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public:
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TokenType type_;
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Location start_;
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Location end_;
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};
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class ErrorInfo {
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public:
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Token token_;
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String message_;
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Location extra_;
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};
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using Errors = std::deque<ErrorInfo>;
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bool readToken(Token& token);
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void skipSpaces();
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bool match(const Char* pattern, int patternLength);
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bool readComment();
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bool readCStyleComment();
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bool readCppStyleComment();
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bool readString();
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void readNumber();
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bool readValue();
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bool readObject(Token& token);
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bool readArray(Token& token);
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bool decodeNumber(Token& token);
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bool decodeNumber(Token& token, Value& decoded);
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bool decodeString(Token& token);
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bool decodeString(Token& token, String& decoded);
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bool decodeDouble(Token& token);
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bool decodeDouble(Token& token, Value& decoded);
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bool decodeUnicodeCodePoint(Token& token, Location& current, Location end,
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unsigned int& unicode);
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bool decodeUnicodeEscapeSequence(Token& token, Location& current,
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Location end, unsigned int& unicode);
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bool addError(const String& message, Token& token, Location extra = nullptr);
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bool recoverFromError(TokenType skipUntilToken);
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bool addErrorAndRecover(const String& message, Token& token,
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TokenType skipUntilToken);
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void skipUntilSpace();
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Value& currentValue();
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Char getNextChar();
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void getLocationLineAndColumn(Location location, int& line,
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int& column) const;
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String getLocationLineAndColumn(Location location) const;
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void addComment(Location begin, Location end, CommentPlacement placement);
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void skipCommentTokens(Token& token);
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static bool containsNewLine(Location begin, Location end);
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static String normalizeEOL(Location begin, Location end);
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using Nodes = std::stack<Value*>;
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Nodes nodes_;
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Errors errors_;
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String document_;
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Location begin_{};
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Location end_{};
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Location current_{};
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Location lastValueEnd_{};
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Value* lastValue_{};
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String commentsBefore_;
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Features features_;
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bool collectComments_{};
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}; // Reader
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/** Interface for reading JSON from a char array.
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*/
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class JSON_API CharReader {
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public:
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virtual ~CharReader() = default;
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/** \brief Read a Value from a <a HREF="http://www.json.org">JSON</a>
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* document. The document must be a UTF-8 encoded string containing the
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* document to read.
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*
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* \param beginDoc Pointer on the beginning of the UTF-8 encoded string
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* of the document to read.
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* \param endDoc Pointer on the end of the UTF-8 encoded string of the
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* document to read. Must be >= beginDoc.
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* \param[out] root Contains the root value of the document if it was
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* successfully parsed.
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* \param[out] errs Formatted error messages (if not NULL) a user
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* friendly string that lists errors in the parsed
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* document.
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* \return \c true if the document was successfully parsed, \c false if an
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* error occurred.
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*/
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virtual bool parse(char const* beginDoc, char const* endDoc, Value* root,
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String* errs) = 0;
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class JSON_API Factory {
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public:
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virtual ~Factory() = default;
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/** \brief Allocate a CharReader via operator new().
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* \throw std::exception if something goes wrong (e.g. invalid settings)
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*/
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virtual CharReader* newCharReader() const = 0;
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}; // Factory
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}; // CharReader
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/** \brief Build a CharReader implementation.
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*
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* Usage:
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* \code
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* using namespace Json;
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* CharReaderBuilder builder;
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* builder["collectComments"] = false;
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* Value value;
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* String errs;
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* bool ok = parseFromStream(builder, std::cin, &value, &errs);
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* \endcode
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*/
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class JSON_API CharReaderBuilder : public CharReader::Factory {
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public:
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// Note: We use a Json::Value so that we can add data-members to this class
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// without a major version bump.
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/** Configuration of this builder.
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* These are case-sensitive.
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* Available settings (case-sensitive):
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* - `"collectComments": false or true`
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* - true to collect comment and allow writing them back during
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* serialization, false to discard comments. This parameter is ignored
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* if allowComments is false.
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* - `"allowComments": false or true`
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* - true if comments are allowed.
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* - `"allowTrailingCommas": false or true`
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* - true if trailing commas in objects and arrays are allowed.
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* - `"strictRoot": false or true`
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* - true if root must be either an array or an object value
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* - `"allowDroppedNullPlaceholders": false or true`
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* - true if dropped null placeholders are allowed. (See
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* StreamWriterBuilder.)
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* - `"allowNumericKeys": false or true`
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* - true if numeric object keys are allowed.
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* - `"allowSingleQuotes": false or true`
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* - true if '' are allowed for strings (both keys and values)
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* - `"stackLimit": integer`
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* - Exceeding stackLimit (recursive depth of `readValue()`) will cause an
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* exception.
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* - This is a security issue (seg-faults caused by deeply nested JSON), so
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* the default is low.
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* - `"failIfExtra": false or true`
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* - If true, `parse()` returns false when extra non-whitespace trails the
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* JSON value in the input string.
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* - `"rejectDupKeys": false or true`
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* - If true, `parse()` returns false when a key is duplicated within an
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* object.
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* - `"allowSpecialFloats": false or true`
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* - If true, special float values (NaNs and infinities) are allowed and
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* their values are lossfree restorable.
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*
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* You can examine 'settings_` yourself to see the defaults. You can also
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* write and read them just like any JSON Value.
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* \sa setDefaults()
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*/
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Json::Value settings_;
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CharReaderBuilder();
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~CharReaderBuilder() override;
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CharReader* newCharReader() const override;
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/** \return true if 'settings' are legal and consistent;
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* otherwise, indicate bad settings via 'invalid'.
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*/
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bool validate(Json::Value* invalid) const;
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/** A simple way to update a specific setting.
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*/
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Value& operator[](const String& key);
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/** Called by ctor, but you can use this to reset settings_.
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* \pre 'settings' != NULL (but Json::null is fine)
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* \remark Defaults:
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* \snippet src/lib_json/json_reader.cpp CharReaderBuilderDefaults
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*/
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static void setDefaults(Json::Value* settings);
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/** Same as old Features::strictMode().
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* \pre 'settings' != NULL (but Json::null is fine)
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* \remark Defaults:
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* \snippet src/lib_json/json_reader.cpp CharReaderBuilderStrictMode
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*/
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static void strictMode(Json::Value* settings);
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};
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/** Consume entire stream and use its begin/end.
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* Someday we might have a real StreamReader, but for now this
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* is convenient.
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*/
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bool JSON_API parseFromStream(CharReader::Factory const&, IStream&, Value* root,
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String* errs);
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/** \brief Read from 'sin' into 'root'.
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*
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* Always keep comments from the input JSON.
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*
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* This can be used to read a file into a particular sub-object.
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* For example:
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* \code
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* Json::Value root;
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* cin >> root["dir"]["file"];
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* cout << root;
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* \endcode
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* Result:
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* \verbatim
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* {
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* "dir": {
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* "file": {
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* // The input stream JSON would be nested here.
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* }
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* }
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* }
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* \endverbatim
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* \throw std::exception on parse error.
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* \see Json::operator<<()
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*/
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JSON_API IStream& operator>>(IStream&, Value&);
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} // namespace Json
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#pragma pack(pop)
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#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
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#pragma warning(pop)
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#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
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#endif // JSON_READER_H_INCLUDED
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