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Diffstat (limited to 'src/s3select/rapidjson/example/filterkeydom/filterkeydom.cpp')
-rw-r--r-- | src/s3select/rapidjson/example/filterkeydom/filterkeydom.cpp | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/src/s3select/rapidjson/example/filterkeydom/filterkeydom.cpp b/src/s3select/rapidjson/example/filterkeydom/filterkeydom.cpp new file mode 100644 index 000000000..732cc81f1 --- /dev/null +++ b/src/s3select/rapidjson/example/filterkeydom/filterkeydom.cpp @@ -0,0 +1,170 @@ +// JSON filterkey example which populates filtered SAX events into a Document. + +// This example parses JSON text from stdin with validation. +// During parsing, specified key will be filtered using a SAX handler. +// And finally the filtered events are used to populate a Document. +// As an example, the document is written to standard output. + +#include "rapidjson/document.h" +#include "rapidjson/writer.h" +#include "rapidjson/filereadstream.h" +#include "rapidjson/filewritestream.h" +#include "rapidjson/error/en.h" +#include <stack> + +using namespace rapidjson; + +// This handler forwards event into an output handler, with filtering the descendent events of specified key. +template <typename OutputHandler> +class FilterKeyHandler { +public: + typedef char Ch; + + FilterKeyHandler(OutputHandler& outputHandler, const Ch* keyString, SizeType keyLength) : + outputHandler_(outputHandler), keyString_(keyString), keyLength_(keyLength), filterValueDepth_(), filteredKeyCount_() + {} + + bool Null() { return filterValueDepth_ > 0 ? EndValue() : outputHandler_.Null() && EndValue(); } + bool Bool(bool b) { return filterValueDepth_ > 0 ? EndValue() : outputHandler_.Bool(b) && EndValue(); } + bool Int(int i) { return filterValueDepth_ > 0 ? EndValue() : outputHandler_.Int(i) && EndValue(); } + bool Uint(unsigned u) { return filterValueDepth_ > 0 ? EndValue() : outputHandler_.Uint(u) && EndValue(); } + bool Int64(int64_t i) { return filterValueDepth_ > 0 ? EndValue() : outputHandler_.Int64(i) && EndValue(); } + bool Uint64(uint64_t u) { return filterValueDepth_ > 0 ? EndValue() : outputHandler_.Uint64(u) && EndValue(); } + bool Double(double d) { return filterValueDepth_ > 0 ? EndValue() : outputHandler_.Double(d) && EndValue(); } + bool RawNumber(const Ch* str, SizeType len, bool copy) { return filterValueDepth_ > 0 ? EndValue() : outputHandler_.RawNumber(str, len, copy) && EndValue(); } + bool String (const Ch* str, SizeType len, bool copy) { return filterValueDepth_ > 0 ? EndValue() : outputHandler_.String (str, len, copy) && EndValue(); } + + bool StartObject() { + if (filterValueDepth_ > 0) { + filterValueDepth_++; + return true; + } + else { + filteredKeyCount_.push(0); + return outputHandler_.StartObject(); + } + } + + bool Key(const Ch* str, SizeType len, bool copy) { + if (filterValueDepth_ > 0) + return true; + else if (len == keyLength_ && std::memcmp(str, keyString_, len) == 0) { + filterValueDepth_ = 1; + return true; + } + else { + ++filteredKeyCount_.top(); + return outputHandler_.Key(str, len, copy); + } + } + + bool EndObject(SizeType) { + if (filterValueDepth_ > 0) { + filterValueDepth_--; + return EndValue(); + } + else { + // Use our own filtered memberCount + SizeType memberCount = filteredKeyCount_.top(); + filteredKeyCount_.pop(); + return outputHandler_.EndObject(memberCount) && EndValue(); + } + } + + bool StartArray() { + if (filterValueDepth_ > 0) { + filterValueDepth_++; + return true; + } + else + return outputHandler_.StartArray(); + } + + bool EndArray(SizeType elementCount) { + if (filterValueDepth_ > 0) { + filterValueDepth_--; + return EndValue(); + } + else + return outputHandler_.EndArray(elementCount) && EndValue(); + } + +private: + FilterKeyHandler(const FilterKeyHandler&); + FilterKeyHandler& operator=(const FilterKeyHandler&); + + bool EndValue() { + if (filterValueDepth_ == 1) // Just at the end of value after filtered key + filterValueDepth_ = 0; + return true; + } + + OutputHandler& outputHandler_; + const char* keyString_; + const SizeType keyLength_; + unsigned filterValueDepth_; + std::stack<SizeType> filteredKeyCount_; +}; + +// Implements a generator for Document::Populate() +template <typename InputStream> +class FilterKeyReader { +public: + typedef char Ch; + + FilterKeyReader(InputStream& is, const Ch* keyString, SizeType keyLength) : + is_(is), keyString_(keyString), keyLength_(keyLength), parseResult_() + {} + + // SAX event flow: reader -> filter -> handler + template <typename Handler> + bool operator()(Handler& handler) { + FilterKeyHandler<Handler> filter(handler, keyString_, keyLength_); + Reader reader; + parseResult_ = reader.Parse(is_, filter); + return parseResult_; + } + + const ParseResult& GetParseResult() const { return parseResult_; } + +private: + FilterKeyReader(const FilterKeyReader&); + FilterKeyReader& operator=(const FilterKeyReader&); + + InputStream& is_; + const char* keyString_; + const SizeType keyLength_; + ParseResult parseResult_; +}; + +int main(int argc, char* argv[]) { + if (argc != 2) { + fprintf(stderr, "filterkeydom key < input.json > output.json\n"); + return 1; + } + + // Prepare input stream. + char readBuffer[65536]; + FileReadStream is(stdin, readBuffer, sizeof(readBuffer)); + + // Prepare Filter + FilterKeyReader<FileReadStream> reader(is, argv[1], static_cast<SizeType>(strlen(argv[1]))); + + // Populates the filtered events from reader + Document document; + document.Populate(reader); + ParseResult pr = reader.GetParseResult(); + if (!pr) { + fprintf(stderr, "\nError(%u): %s\n", static_cast<unsigned>(pr.Offset()), GetParseError_En(pr.Code())); + return 1; + } + + // Prepare JSON writer and output stream. + char writeBuffer[65536]; + FileWriteStream os(stdout, writeBuffer, sizeof(writeBuffer)); + Writer<FileWriteStream> writer(os); + + // Write the document to standard output + document.Accept(writer); + return 0; +} |