RAPIDJSON_FORCEINLINE void ParseStringToStream()

in rapidjson/reader.h [840:905]
60 lines of code
17 McCabe index (conditional complexity)

    RAPIDJSON_FORCEINLINE void ParseStringToStream(InputStream& is, OutputStream& os) {
//!@cond RAPIDJSON_HIDDEN_FROM_DOXYGEN
#define Z16 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
        static const char escape[256] = {
            Z16, Z16, 0, 0,'\"', 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,'/',
            Z16, Z16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,'\\', 0, 0, 0,
            0, 0,'\b', 0, 0, 0,'\f', 0, 0, 0, 0, 0, 0, 0,'\n', 0,
            0, 0,'\r', 0,'\t', 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
            Z16, Z16, Z16, Z16, Z16, Z16, Z16, Z16
        };
#undef Z16
//!@endcond

        for (;;) {
            // Scan and copy string before "\\\"" or < 0x20. This is an optional optimzation.
            if (!(parseFlags & kParseValidateEncodingFlag))
                ScanCopyUnescapedString(is, os);

            Ch c = is.Peek();
            if (RAPIDJSON_UNLIKELY(c == '\\')) {    // Escape
                size_t escapeOffset = is.Tell();    // For invalid escaping, report the inital '\\' as error offset
                is.Take();
                Ch e = is.Peek();
                if ((sizeof(Ch) == 1 || unsigned(e) < 256) && RAPIDJSON_LIKELY(escape[static_cast<unsigned char>(e)])) {
                    is.Take();
                    os.Put(static_cast<typename TEncoding::Ch>(escape[static_cast<unsigned char>(e)]));
                }
                else if (RAPIDJSON_LIKELY(e == 'u')) {    // Unicode
                    is.Take();
                    unsigned codepoint = ParseHex4(is, escapeOffset);
                    RAPIDJSON_PARSE_ERROR_EARLY_RETURN_VOID;
                    if (RAPIDJSON_UNLIKELY(codepoint >= 0xD800 && codepoint <= 0xDBFF)) {
                        // Handle UTF-16 surrogate pair
                        if (RAPIDJSON_UNLIKELY(!Consume(is, '\\') || !Consume(is, 'u')))
                            RAPIDJSON_PARSE_ERROR(kParseErrorStringUnicodeSurrogateInvalid, escapeOffset);
                        unsigned codepoint2 = ParseHex4(is, escapeOffset);
                        RAPIDJSON_PARSE_ERROR_EARLY_RETURN_VOID;
                        if (RAPIDJSON_UNLIKELY(codepoint2 < 0xDC00 || codepoint2 > 0xDFFF))
                            RAPIDJSON_PARSE_ERROR(kParseErrorStringUnicodeSurrogateInvalid, escapeOffset);
                        codepoint = (((codepoint - 0xD800) << 10) | (codepoint2 - 0xDC00)) + 0x10000;
                    }
                    TEncoding::Encode(os, codepoint);
                }
                else
                    RAPIDJSON_PARSE_ERROR(kParseErrorStringEscapeInvalid, escapeOffset);
            }
            else if (RAPIDJSON_UNLIKELY(c == '"')) {    // Closing double quote
                is.Take();
                os.Put('\0');   // null-terminate the string
                return;
            }
            else if (RAPIDJSON_UNLIKELY(static_cast<unsigned>(c) < 0x20)) { // RFC 4627: unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
                if (c == '\0')
                    RAPIDJSON_PARSE_ERROR(kParseErrorStringMissQuotationMark, is.Tell());
                else
                    RAPIDJSON_PARSE_ERROR(kParseErrorStringEscapeInvalid, is.Tell());
            }
            else {
                size_t offset = is.Tell();
                if (RAPIDJSON_UNLIKELY((parseFlags & kParseValidateEncodingFlag ?
                    !Transcoder<SEncoding, TEncoding>::Validate(is, os) :
                    !Transcoder<SEncoding, TEncoding>::Transcode(is, os))))
                    RAPIDJSON_PARSE_ERROR(kParseErrorStringInvalidEncoding, offset);
            }
        }
    }