C++构造解析json

// Copyright 2007-2011 Baptiste Lepilleur // Copyright (C) 2016 InfoTeCS JSC. All rights reserved. // Distributed under MIT license, or public domain if desired and // recognized in your jurisdiction. // See file LICENSE for detail or copy at http://jsoncpp.sourceforge.net/LICENSE #if !defined(JSON_IS_AMALGAMATION) #include "assertions.h" #include "reader.h" #include "value.h" #include "json_tool.h" #endif // if !defined(JSON_IS_AMALGAMATION) #include <utility> #include <cstdio> #include <cassert> #include <cstring> #include <istream> #include <sstream> #include <memory> #include <set> #include <limits> #if defined(_MSC_VER) #if !defined(WINCE) && defined(__STDC_SECURE_LIB__) && _MSC_VER >= 1500 // VC++ 9.0 and above #define snprintf sprintf_s #elif _MSC_VER >= 1900 // VC++ 14.0 and above #define snprintf std::snprintf #else #define snprintf _snprintf #endif #elif defined(__ANDROID__) || defined(__QNXNTO__) #define snprintf snprintf #elif __cplusplus >= 201103L #if !defined(__MINGW32__) && !defined(__CYGWIN__) #define snprintf std::snprintf #endif #endif #if defined(__QNXNTO__) #define sscanf std::sscanf #endif #if defined(_MSC_VER) && _MSC_VER >= 1400 // VC++ 8.0 // Disable warning about strdup being deprecated. #pragma warning(disable : 4996) #endif // Define JSONCPP_DEPRECATED_STACK_LIMIT as an appropriate integer at compile time to change the stack limit #if !defined(JSONCPP_DEPRECATED_STACK_LIMIT) #define JSONCPP_DEPRECATED_STACK_LIMIT 1000 #endif static size_t const stackLimit_g = JSONCPP_DEPRECATED_STACK_LIMIT; // see readValue() namespace Json { #if __cplusplus >= 201103L || (defined(_CPPLIB_VER) && _CPPLIB_VER >= 520) typedef std::unique_ptr<CharReader> CharReaderPtr; #else typedef std::auto_ptr<CharReader> CharReaderPtr; #endif // Implementation of class Features // //////////////////////////////// Features::Features() : allowComments_(true), strictRoot_(false), allowDroppedNullPlaceholders_(false), allowNumericKeys_(false) {} Features Features::all() { return Features(); } Features Features::strictMode() { Features features; features.allowComments_ = false; features.strictRoot_ = true; features.allowDroppedNullPlaceholders_ = false; features.allowNumericKeys_ = false; return features; } // Implementation of class Reader // //////////////////////////////// static bool containsNewLine(Reader::Location begin, Reader::Location end) { for (; begin < end; ++begin) if (*begin == '\n' || *begin == '\r') return true; return false; } // Class Reader // ////////////////////////////////////////////////////////////////// Reader::Reader() : errors_(), document_(), begin_(), end_(), current_(), lastValueEnd_(), lastValue_(), commentsBefore_(), features_(Features::all()), collectComments_() {} Reader::Reader(const Features& features) : errors_(), document_(), begin_(), end_(), current_(), lastValueEnd_(), lastValue_(), commentsBefore_(), features_(features), collectComments_() { } bool Reader::parse(const std::string& document, Value& root, bool collectComments) { JSONCPP_STRING documentCopy(document.data(), document.data() + document.capacity()); std::swap(documentCopy, document_); const char* begin = document_.c_str(); const char* end = begin + document_.length(); return parse(begin, end, root, collectComments); } bool Reader::parse(std::istream& sin, Value& root, bool collectComments) { // std::istream_iterator<char> begin(sin); // std::istream_iterator<char> end; // Those would allow streamed input from a file, if parse() were a // template function. // Since JSONCPP_STRING is reference-counted, this at least does not // create an extra copy. JSONCPP_STRING doc; std::getline(sin, doc, (char)EOF); return parse(doc.data(), doc.data() + doc.size(), root, collectComments); } bool Reader::parse(const char* beginDoc, const char* endDoc, Value& root, bool collectComments) { if (!features_.allowComments_) { collectComments = false; } begin_ = beginDoc; end_ = endDoc; collectComments_ = collectComments; current_ = begin_; lastValueEnd_ = 0; lastValue_ = 0; commentsBefore_ = ""; errors_.clear(); while (!nodes_.empty()) nodes_.pop(); nodes_.push(&root); bool successful = readValue(); Token token; skipCommentTokens(token); if (collectComments_ && !commentsBefore_.empty()) root.setComment(commentsBefore_, commentAfter); if (features_.strictRoot_) { if (!root.isArray() && !root.isObject()) { // Set error location to start of doc, ideally should be first token found // in doc token.type_ = tokenError; token.start_ = beginDoc; token.end_ = endDoc; addError( "A valid JSON document must be either an array or an object value.", token); return false; } } return successful; } bool Reader::readValue() { // readValue() may call itself only if it calls readObject() or ReadArray(). // These methods execute nodes_.push() just before and nodes_.pop)() just after calling readValue(). // parse() executes one nodes_.push(), so > instead of >=. if (nodes_.size() > stackLimit_g) throwRuntimeError("Exceeded stackLimit in readValue()."); Token token; skipCommentTokens(token); bool successful = true; if (collectComments_ && !commentsBefore_.empty()) { currentValue().setComment(commentsBefore_, commentBefore); commentsBefore_ = ""; } switch (token.type_) { case tokenObjectBegin: successful = readObject(token); currentValue().setOffsetLimit(current_ - begin_); break; case tokenArrayBegin: successful = readArray(token); currentValue().setOffsetLimit(current_ - begin_); break; case tokenNumber: successful = decodeNumber(token); break; case tokenString: successful = decodeString(token); break; case tokenTrue: { Value v(true); currentValue().swapPayload(v); currentValue().setOffsetStart(token.start_ - begin_); currentValue().setOffsetLimit(token.end_ - begin_); } break; case tokenFalse: { Value v(false); currentValue().swapPayload(v); currentValue().setOffsetStart(token.start_ - begin_); currentValue().setOffsetLimit(token.end_ - begin_); } break; case tokenNull: { Value v; currentValue().swapPayload(v); currentValue().setOffsetStart(token.start_ - begin_); currentValue().setOffsetLimit(token.end_ - begin_); } break; case tokenArraySeparator: case tokenObjectEnd: case tokenArrayEnd: if (features_.allowDroppedNullPlaceholders_) { // "Un-read" the current token and mark the current value as a null // token. current_--; Value v; currentValue().swapPayload(v); currentValue().setOffsetStart(current_ - begin_ - 1); currentValue().setOffsetLimit(current_ - begin_); break; } // Else, fall through... default: currentValue().setOffsetStart(token.start_ - begin_); currentValue().setOffsetLimit(token.end_ - begin_); return addError("Syntax error: value, object or array expected.", token); } if (collectComments_) { lastValueEnd_ = current_; lastValue_ = &currentValue(); } return successful; } void Reader::skipCommentTokens(Token& token) { if (features_.allowComments_) { do { readToken(token); } while (token.type_ == tokenComment); } else { readToken(token); } } bool Reader::readToken(Token& token) { skipSpaces(); token.start_ = current_; Char c = getNextChar(); bool ok = true; switch (c) { case '{': token.type_ = tokenObjectBegin; break; case '}': token.type_ = tokenObjectEnd; break; case '[': token.type_ = tokenArrayBegin; break; case ']': token.type_ = tokenArrayEnd; break; case '"': token.type_ = tokenString; ok = readString(); break; case '/': token.type_ =