/**
 * @file llsdserialize.cpp
 * @author Phoenix
 * @date 2006-03-05
 * @brief Implementation of LLSD parsers and formatters
 *
 * $LicenseInfo:firstyear=2006&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "linden_common.h"
#include "llsdserialize.h"
#include "llpointer.h"
#include "llstreamtools.h" // for fullread

#include <iostream>
#include "apr_base64.h"

#include <boost/iostreams/device/array.hpp>
#include <boost/iostreams/stream.hpp>

#ifdef LL_USESYSTEMLIBS
# include <zlib.h>
#else
# include "zlib-ng/zlib.h"  // for davep's dirty little zip functions
#endif

#if !LL_WINDOWS
#include <netinet/in.h> // htonl & ntohl
#endif

#include "lldate.h"
#include "llmemorystream.h"
#include "llsd.h"
#include "llstring.h"
#include "lluri.h"

// File constants
static const size_t MAX_HDR_LEN = 20;
static const S32 UNZIP_LLSD_MAX_DEPTH = 96;
static const char LEGACY_NON_HEADER[] = "<llsd>";
const std::string LLSD_BINARY_HEADER("LLSD/Binary");
const std::string LLSD_XML_HEADER("LLSD/XML");
const std::string LLSD_NOTATION_HEADER("llsd/notation");

//used to deflate a gzipped asset (currently used for navmeshes)
#define windowBits 15
#define ENABLE_ZLIB_GZIP 32

// If we published this in llsdserialize.h, we could use it in the
// implementation of LLSDOStreamer's operator<<().
template <class Formatter>
void format_using(const LLSD& data, std::ostream& ostr,
                  LLSDFormatter::EFormatterOptions options=LLSDFormatter::OPTIONS_PRETTY_BINARY)
{
    LLPointer<Formatter> f{ new Formatter };
    f->format(data, ostr, options);
}

template <class Parser>
S32 parse_using(std::istream& istr, LLSD& data, size_t max_bytes, S32 max_depth=-1)
{
    LLPointer<Parser> p{ new Parser };
    return p->parse(istr, data, max_bytes, max_depth);
}

/**
 * LLSDSerialize
 */

// static
void LLSDSerialize::serialize(const LLSD& sd, std::ostream& str, ELLSD_Serialize type,
                              LLSDFormatter::EFormatterOptions options)
{
    LLPointer<LLSDFormatter> f = NULL;

    switch (type)
    {
    case LLSD_BINARY:
        str << "<? " << LLSD_BINARY_HEADER << " ?>\n";
        f = new LLSDBinaryFormatter;
        break;

    case LLSD_XML:
        str << "<? " << LLSD_XML_HEADER << " ?>\n";
        f = new LLSDXMLFormatter;
        break;

    case LLSD_NOTATION:
        str << "<? " << LLSD_NOTATION_HEADER << " ?>\n";
        f = new LLSDNotationFormatter;
        break;

    default:
        LL_WARNS() << "serialize request for unknown ELLSD_Serialize" << LL_ENDL;
    }

    if (f.notNull())
    {
        f->format(sd, str, options);
    }
}

// static
bool LLSDSerialize::deserialize(LLSD& sd, std::istream& str, llssize max_bytes)
{
    char hdr_buf[MAX_HDR_LEN + 1] = ""; /* Flawfinder: ignore */
    bool fail_if_not_legacy = false;

    /*
     * Get the first line before anything. Don't read more than max_bytes:
     * this get() overload reads no more than (count-1) bytes into the
     * specified buffer. In the usual case when max_bytes exceeds
     * sizeof(hdr_buf), get() will read no more than sizeof(hdr_buf)-2.
     */
    llssize max_hdr_read = MAX_HDR_LEN;
    if (max_bytes != LLSDSerialize::SIZE_UNLIMITED)
    {
        max_hdr_read = llmin(max_bytes + 1, max_hdr_read);
    }
    str.get(hdr_buf, max_hdr_read, '\n');
    auto inbuf = str.gcount();

    // https://en.cppreference.com/w/cpp/io/basic_istream/get
    // When the get() above sees the specified delimiter '\n', it stops there
    // without pulling it from the stream. If it turns out that the stream
    // does NOT contain a header, and the content includes meaningful '\n',
    // it's important to pull that into hdr_buf too.
    if (inbuf < max_bytes && str.get(hdr_buf[inbuf]))
    {
        // got the delimiting '\n'
        ++inbuf;
        // None of the following requires that hdr_buf contain a final '\0'
        // byte. We could store one if needed, since even the incremented
        // inbuf won't exceed sizeof(hdr_buf)-1, but there's no need.
    }
    std::string header{ hdr_buf, static_cast<std::string::size_type>(inbuf) };
    if (str.fail())
    {
        str.clear();
        fail_if_not_legacy = true;
    }

    if (!strncasecmp(LEGACY_NON_HEADER, hdr_buf, strlen(LEGACY_NON_HEADER))) /* Flawfinder: ignore */
    {   // Create a LLSD XML parser, and parse the first chunk read above.
        LLSDXMLParser x;
        x.parsePart(hdr_buf, inbuf);    // Parse the first part that was already read
        auto parsed = x.parse(str, sd, max_bytes - inbuf); // Parse the rest of it
        // Formally we should probably check (parsed != PARSE_FAILURE &&
        // parsed > 0), but since PARSE_FAILURE is -1, this suffices.
        return (parsed > 0);
    }

    if (fail_if_not_legacy)
    {
        LL_WARNS() << "deserialize LLSD parse failure" << LL_ENDL;
        return false;
    }

    /*
    * Remove the newline chars
    */
    std::string::size_type lastchar = header.find_last_not_of("\r\n");
    if (lastchar != std::string::npos)
    {
        // It's important that find_last_not_of() returns size_type, which is
        // why lastchar explicitly declares the type above. erase(size_type)
        // erases from that offset to the end of the string, whereas
        // erase(iterator) erases only a single character.
        header.erase(lastchar+1);
    }

    // trim off the <? ... ?> header syntax
    auto start = header.find_first_not_of("<? ");
    if (start != std::string::npos)
    {
        auto end = header.find_first_of(" ?", start);
        if (end != std::string::npos)
        {
            header = header.substr(start, end - start);
            ws(str);
        }
    }
    /*
     * Create the parser as appropriate
     */
    if (0 == LLStringUtil::compareInsensitive(header, LLSD_BINARY_HEADER))
    {
        return (parse_using<LLSDBinaryParser>(str, sd, max_bytes-inbuf) > 0);
    }
    else if (0 == LLStringUtil::compareInsensitive(header, LLSD_XML_HEADER))
    {
        return (parse_using<LLSDXMLParser>(str, sd, max_bytes-inbuf) > 0);
    }
    else if (0 == LLStringUtil::compareInsensitive(header, LLSD_NOTATION_HEADER))
    {
        return (parse_using<LLSDNotationParser>(str, sd, max_bytes-inbuf) > 0);
    }
    else // no header we recognize
    {
        LLPointer<LLSDParser> p;
        if (inbuf && hdr_buf[0] == '<')
        {
            // looks like XML
            LL_DEBUGS() << "deserialize request with no header, assuming XML" << LL_ENDL;
            p = new LLSDXMLParser;
        }
        else
        {
            // assume notation
            LL_DEBUGS() << "deserialize request with no header, assuming notation" << LL_ENDL;
            p = new LLSDNotationParser;
        }
        // Since we've already read 'inbuf' bytes into 'hdr_buf', prepend that
        // data to whatever remains in 'str'.
        LLMemoryStreamBuf already(reinterpret_cast<const U8*>(hdr_buf), (S32)inbuf);
        cat_streambuf prebuff(&already, str.rdbuf());
        std::istream  prepend(&prebuff);
#if 1
        return (p->parse(prepend, sd, max_bytes) > 0);
#else
        // debugging the reconstituted 'prepend' stream
        // allocate a buffer that we hope is big enough for the whole thing
        std::vector<char> wholemsg((max_bytes == size_t(SIZE_UNLIMITED))? 1024 : max_bytes);
        prepend.read(wholemsg.data(), std::min(max_bytes, wholemsg.size()));
        LLMemoryStream replay(reinterpret_cast<const U8*>(wholemsg.data()), prepend.gcount());
        auto success{ p->parse(replay, sd, prepend.gcount()) > 0 };
        {
            LL_DEBUGS() << (success? "parsed: $$" : "failed: '")
                        << std::string(wholemsg.data(), llmin(prepend.gcount(), 100)) << "$$"
                        << LL_ENDL;
        }
        return success;
#endif
    }
}

/**
 * Endian handlers
 */
#if LL_BIG_ENDIAN
U64 ll_htonll(U64 hostlonglong) { return hostlonglong; }
U64 ll_ntohll(U64 netlonglong) { return netlonglong; }
F64 ll_htond(F64 hostlonglong) { return hostlonglong; }
F64 ll_ntohd(F64 netlonglong) { return netlonglong; }
#else
// I read some comments one a indicating that doing an integer add
// here would be faster than a bitwise or. For now, the or has
// programmer clarity, since the intended outcome matches the
// operation.
U64 ll_htonll(U64 hostlonglong)
{
    return ((U64)(htonl((U32)((hostlonglong >> 32) & 0xFFFFFFFF))) |
            ((U64)(htonl((U32)(hostlonglong & 0xFFFFFFFF))) << 32));
}
U64 ll_ntohll(U64 netlonglong)
{
    return ((U64)(ntohl((U32)((netlonglong >> 32) & 0xFFFFFFFF))) |
            ((U64)(ntohl((U32)(netlonglong & 0xFFFFFFFF))) << 32));
}
union LLEndianSwapper
{
    F64 d;
    U64 i;
};
F64 ll_htond(F64 hostdouble)
{
    LLEndianSwapper tmp;
    tmp.d = hostdouble;
    tmp.i = ll_htonll(tmp.i);
    return tmp.d;
}
F64 ll_ntohd(F64 netdouble)
{
    LLEndianSwapper tmp;
    tmp.d = netdouble;
    tmp.i = ll_ntohll(tmp.i);
    return tmp.d;
}
#endif

/**
 * Local functions.
 */
/**
 * @brief Figure out what kind of string it is (raw or delimited) and handoff.
 *
 * @param istr The stream to read from.
 * @param value [out] The string which was found.
 * @param max_bytes The maximum possible length of the string. Passing in
 * a negative value will skip this check.
 * @return Returns number of bytes read off of the stream. Returns
 * PARSE_FAILURE (-1) on failure.
 */
llssize deserialize_string(std::istream& istr, std::string& value, llssize max_bytes);

/**
 * @brief Parse a delimited string.
 *
 * @param istr The stream to read from, with the delimiter already popped.
 * @param value [out] The string which was found.
 * @param d The delimiter to use.
 * @return Returns number of bytes read off of the stream. Returns
 * PARSE_FAILURE (-1) on failure.
 */
llssize deserialize_string_delim(std::istream& istr, std::string& value, char d);

/**
 * @brief Read a raw string off the stream.
 *
 * @param istr The stream to read from, with the (len) parameter
 * leading the stream.
 * @param value [out] The string which was found.
 * @param d The delimiter to use.
 * @param max_bytes The maximum possible length of the string. Passing in
 * a negative value will skip this check.
 * @return Returns number of bytes read off of the stream. Returns
 * PARSE_FAILURE (-1) on failure.
 */
llssize deserialize_string_raw(
    std::istream& istr,
    std::string& value,
    llssize max_bytes);

/**
 * @brief helper method for dealing with the different notation boolean format.
 *
 * @param istr The stream to read from with the leading character stripped.
 * @param data [out] the result of the parse.
 * @param compare The string to compare the boolean against
 * @param vale The value to assign to data if the parse succeeds.
 * @return Returns number of bytes read off of the stream. Returns
 * PARSE_FAILURE (-1) on failure.
 */
llssize deserialize_boolean(
    std::istream& istr,
    LLSD& data,
    const std::string& compare,
    bool value);

/**
 * @brief Do notation escaping of a string to an ostream.
 *
 * @param value The string to escape and serialize
 * @param str The stream to serialize to.
 */
void serialize_string(const std::string& value, std::ostream& str);


/**
 * Local constants.
 */
static const std::string NOTATION_TRUE_SERIAL("true");
static const std::string NOTATION_FALSE_SERIAL("false");

static const char BINARY_TRUE_SERIAL = '1';
static const char BINARY_FALSE_SERIAL = '0';


/**
 * LLSDParser
 */
LLSDParser::LLSDParser()
    : mCheckLimits(true), mMaxBytesLeft(0), mParseLines(false)
{
}

// virtual
LLSDParser::~LLSDParser()
{ }

S32 LLSDParser::parse(std::istream& istr, LLSD& data, llssize max_bytes, S32 max_depth)
{
    mCheckLimits = LLSDSerialize::SIZE_UNLIMITED != max_bytes;
    mMaxBytesLeft = max_bytes;
    return doParse(istr, data, max_depth);
}


// Parse using routine to get() lines, faster than parse()
S32 LLSDParser::parseLines(std::istream& istr, LLSD& data)
{
    mCheckLimits = false;
    mParseLines = true;
    return doParse(istr, data);
}


int LLSDParser::get(std::istream& istr) const
{
    if(mCheckLimits) --mMaxBytesLeft;
    return istr.get();
}

std::istream& LLSDParser::get(
    std::istream& istr,
    char* s,
    std::streamsize n,
    char delim) const
{
    istr.get(s, n, delim);
    if(mCheckLimits) mMaxBytesLeft -= istr.gcount();
    return istr;
}

std::istream& LLSDParser::get(
        std::istream& istr,
        std::streambuf& sb,
        char delim) const
{
    istr.get(sb, delim);
    if(mCheckLimits) mMaxBytesLeft -= istr.gcount();
    return istr;
}

std::istream& LLSDParser::ignore(std::istream& istr) const
{
    istr.ignore();
    if(mCheckLimits) --mMaxBytesLeft;
    return istr;
}

std::istream& LLSDParser::putback(std::istream& istr, char c) const
{
    istr.putback(c);
    if(mCheckLimits) ++mMaxBytesLeft;
    return istr;
}

std::istream& LLSDParser::read(
    std::istream& istr,
    char* s,
    std::streamsize n) const
{
    istr.read(s, n);
    if(mCheckLimits) mMaxBytesLeft -= istr.gcount();
    return istr;
}

void LLSDParser::account(llssize bytes) const
{
    if(mCheckLimits) mMaxBytesLeft -= bytes;
}


/**
 * LLSDNotationParser
 */
LLSDNotationParser::LLSDNotationParser()
{
}

// virtual
LLSDNotationParser::~LLSDNotationParser()
{ }

// virtual
S32 LLSDNotationParser::doParse(std::istream& istr, LLSD& data, S32 max_depth) const
{
    LL_PROFILE_ZONE_SCOPED_CATEGORY_LLSD;
    // map: { string:object, string:object }
    // array: [ object, object, object ]
    // undef: !
    // boolean: true | false | 1 | 0 | T | F | t | f | TRUE | FALSE
    // integer: i####
    // real: r####
    // uuid: u####
    // string: "g'day" | 'have a "nice" day' | s(size)"raw data"
    // uri: l"escaped"
    // date: d"YYYY-MM-DDTHH:MM:SS.FFZ"
    // binary: b##"ff3120ab1" | b(size)"raw data"
    char c;
    c = istr.peek();
    if (max_depth == 0)
    {
        return PARSE_FAILURE;
    }
    while(isspace(c))
    {
        // pop the whitespace.
        c = get(istr);
        c = istr.peek();
        continue;
    }
    if(!istr.good())
    {
        return 0;
    }
    S32 parse_count = 1;
    switch(c)
    {
    case '{':
    {
        S32 child_count = parseMap(istr, data, max_depth - 1);
        if((child_count == PARSE_FAILURE) || data.isUndefined())
        {
            parse_count = PARSE_FAILURE;
        }
        else
        {
            parse_count += child_count;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading map." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case '[':
    {
        S32 child_count = parseArray(istr, data, max_depth - 1);
        if((child_count == PARSE_FAILURE) || data.isUndefined())
        {
            parse_count = PARSE_FAILURE;
        }
        else
        {
            parse_count += child_count;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading array." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case '!':
        c = get(istr);
        data.clear();
        break;

    case '0':
        c = get(istr);
        data = false;
        break;

    case 'F':
    case 'f':
        ignore(istr);
        c = istr.peek();
        if(isalpha(c))
        {
            auto cnt = deserialize_boolean(
                istr,
                data,
                NOTATION_FALSE_SERIAL,
                false);
            if(PARSE_FAILURE == cnt) parse_count = (S32)cnt;
            else account(cnt);
        }
        else
        {
            data = false;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading boolean." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;

    case '1':
        c = get(istr);
        data = true;
        break;

    case 'T':
    case 't':
        ignore(istr);
        c = istr.peek();
        if(isalpha(c))
        {
            auto cnt = deserialize_boolean(istr,data,NOTATION_TRUE_SERIAL,true);
            if(PARSE_FAILURE == cnt) parse_count = (S32)cnt;
            else account(cnt);
        }
        else
        {
            data = true;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading boolean." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;

    case 'i':
    {
        c = get(istr);
        S32 integer = 0;
        istr >> integer;
        data = integer;
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading integer." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case 'r':
    {
        c = get(istr);
        F64 real = 0.0;
        istr >> real;
        data = real;
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading real." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case 'u':
    {
        c = get(istr);
        LLUUID id;
        istr >> id;
        data = id;
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading uuid." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case '\"':
    case '\'':
    case 's':
        if(!parseString(istr, data))
        {
            parse_count = PARSE_FAILURE;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading string." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;

    case 'l':
    {
        c = get(istr); // pop the 'l'
        c = get(istr); // pop the delimiter
        std::string str;
        auto cnt = deserialize_string_delim(istr, str, c);
        if(PARSE_FAILURE == cnt)
        {
            parse_count = PARSE_FAILURE;
        }
        else
        {
            data = LLURI(str);
            account(cnt);
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading link." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case 'd':
    {
        c = get(istr); // pop the 'd'
        c = get(istr); // pop the delimiter
        std::string str;
        auto cnt = deserialize_string_delim(istr, str, c);
        if(PARSE_FAILURE == cnt)
        {
            parse_count = PARSE_FAILURE;
        }
        else
        {
            data = LLDate(str);
            account(cnt);
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading date." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case 'b':
        if(!parseBinary(istr, data))
        {
            parse_count = PARSE_FAILURE;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading data." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;

    default:
        parse_count = PARSE_FAILURE;
        LL_INFOS() << "Unrecognized character while parsing: int(" << int(c)
            << ")" << LL_ENDL;
        break;
    }
    if(PARSE_FAILURE == parse_count)
    {
        data.clear();
    }
    return parse_count;
}

S32 LLSDNotationParser::parseMap(std::istream& istr, LLSD& map, S32 max_depth) const
{
    LL_PROFILE_ZONE_SCOPED_CATEGORY_LLSD;
    // map: { string:object, string:object }
    map = LLSD::emptyMap();
    S32 parse_count = 0;
    char c = get(istr);
    if(c == '{')
    {
        // eat commas, white
        bool found_name = false;
        std::string name;
        c = get(istr);
        while(c != '}' && istr.good())
        {
            if(!found_name)
            {
                if((c == '\"') || (c == '\'') || (c == 's'))
                {
                    putback(istr, c);
                    found_name = true;
                    auto count = deserialize_string(istr, name, mMaxBytesLeft);
                    if(PARSE_FAILURE == count) return PARSE_FAILURE;
                    account(count);
                }
                c = get(istr);
            }
            else
            {
                if(isspace(c) || (c == ':'))
                {
                    c = get(istr);
                    continue;
                }
                putback(istr, c);
                LLSD child;
                S32 count = doParse(istr, child, max_depth);
                if(count > 0)
                {
                    // There must be a value for every key, thus
                    // child_count must be greater than 0.
                    parse_count += count;
                    map.insert(name, child);
                }
                else
                {
                    return PARSE_FAILURE;
                }
                found_name = false;
                c = get(istr);
            }
        }
        if(c != '}')
        {
            map.clear();
            return PARSE_FAILURE;
        }
    }
    return parse_count;
}

S32 LLSDNotationParser::parseArray(std::istream& istr, LLSD& array, S32 max_depth) const
{
    LL_PROFILE_ZONE_SCOPED_CATEGORY_LLSD;
    // array: [ object, object, object ]
    array = LLSD::emptyArray();
    S32 parse_count = 0;
    char c = get(istr);
    if(c == '[')
    {
        // eat commas, white
        c = get(istr);
        while((c != ']') && istr.good())
        {
            LLSD child;
            if(isspace(c) || (c == ','))
            {
                c = get(istr);
                continue;
            }
            putback(istr, c);
            S32 count = doParse(istr, child, max_depth);
            if(PARSE_FAILURE == count)
            {
                return PARSE_FAILURE;
            }
            else
            {
                parse_count += count;
                array.append(child);
            }
            c = get(istr);
        }
        if(c != ']')
        {
            return PARSE_FAILURE;
        }
    }
    return parse_count;
}

bool LLSDNotationParser::parseString(std::istream& istr, LLSD& data) const
{
    LL_PROFILE_ZONE_SCOPED_CATEGORY_LLSD;
    std::string value;
    auto count = deserialize_string(istr, value, mMaxBytesLeft);
    if(PARSE_FAILURE == count) return false;
    account(count);
    data = value;
    return true;
}

bool LLSDNotationParser::parseBinary(std::istream& istr, LLSD& data) const
{
    LL_PROFILE_ZONE_SCOPED_CATEGORY_LLSD;
    // binary: b##"ff3120ab1"
    // or: b(len)"..."

    // I want to manually control those values here to make sure the
    // parser doesn't break when someone changes a constant somewhere
    // else.
    const U32 BINARY_BUFFER_SIZE = 256;
    const U32 STREAM_GET_COUNT = 255;

    // need to read the base out.
    char buf[BINARY_BUFFER_SIZE];       /* Flawfinder: ignore */
    get(istr, buf, STREAM_GET_COUNT, '"');
    char c = get(istr);
    if(c != '"') return false;
    if(0 == strncmp("b(", buf, 2))
    {
        // We probably have a valid raw binary stream. determine
        // the size, and read it.
        auto len = strtol(buf + 2, NULL, 0);
        if(mCheckLimits && (len > mMaxBytesLeft)) return false;
        std::vector<U8> value;
        if(len)
        {
            value.resize(len);
            account(fullread(istr, (char *)&value[0], len));
        }
        c = get(istr); // strip off the trailing double-quote
        data = value;
    }
    else if(0 == strncmp("b64", buf, 3))
    {
        // *FIX: A bit inefficient, but works for now. To make the
        // format better, I would need to add a hint into the
        // serialization format that indicated how long it was.
        std::stringstream coded_stream;
        get(istr, *(coded_stream.rdbuf()), '\"');
        c = get(istr);
        std::string encoded(coded_stream.str());
        S32 len = apr_base64_decode_len(encoded.c_str());
        std::vector<U8> value;
        if(len)
        {
            value.resize(len);
            len = apr_base64_decode_binary(&value[0], encoded.c_str());
            value.resize(len);
        }
        data = value;
    }
    else if(0 == strncmp("b16", buf, 3))
    {
        // yay, base 16. We pop the next character which is either a
        // double quote or base 16 data. If it's a double quote, we're
        // done parsing. If it's not, put the data back, and read the
        // stream until the next double quote.
        char* read;  /*Flawfinder: ignore*/
        U8 byte;
        U8 byte_buffer[BINARY_BUFFER_SIZE];
        U8* write;
        std::vector<U8> value;
        c = get(istr);
        while(c != '"')
        {
            putback(istr, c);
            read = buf;
            write = byte_buffer;
            get(istr, buf, STREAM_GET_COUNT, '"');
            c = get(istr);
            while(*read != '\0')     /*Flawfinder: ignore*/
            {
                byte = hex_as_nybble(*read++);
                byte = byte << 4;
                byte |= hex_as_nybble(*read++);
                *write++ = byte;
            }
            // copy the data out of the byte buffer
            value.insert(value.end(), byte_buffer, write);
        }
        data = value;
    }
    else
    {
        return false;
    }
    return true;
}


/**
 * LLSDBinaryParser
 */
LLSDBinaryParser::LLSDBinaryParser()
{
}

// virtual
LLSDBinaryParser::~LLSDBinaryParser()
{
}

// virtual
S32 LLSDBinaryParser::doParse(std::istream& istr, LLSD& data, S32 max_depth) const
{
    LL_PROFILE_ZONE_SCOPED_CATEGORY_LLSD;
/**
 * Undefined: '!'<br>
 * Boolean: '1' for true '0' for false<br>
 * Integer: 'i' + 4 bytes network byte order<br>
 * Real: 'r' + 8 bytes IEEE double<br>
 * UUID: 'u' + 16 byte unsigned integer<br>
 * String: 's' + 4 byte integer size + string<br>
 *  strings also secretly support the notation format
 * Date: 'd' + 8 byte IEEE double for seconds since epoch<br>
 * URI: 'l' + 4 byte integer size + string uri<br>
 * Binary: 'b' + 4 byte integer size + binary data<br>
 * Array: '[' + 4 byte integer size  + all values + ']'<br>
 * Map: '{' + 4 byte integer size  every(key + value) + '}'<br>
 *  map keys are serialized as s + 4 byte integer size + string or in the
 *  notation format.
 */
    char c;
    c = get(istr);
    if(!istr.good())
    {
        return 0;
    }
    if (max_depth == 0)
    {
        return PARSE_FAILURE;
    }
    S32 parse_count = 1;
    switch(c)
    {
    case '{':
    {
        S32 child_count = parseMap(istr, data, max_depth - 1);
        if((child_count == PARSE_FAILURE) || data.isUndefined())
        {
            parse_count = PARSE_FAILURE;
        }
        else
        {
            parse_count += child_count;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading binary map." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case '[':
    {
        S32 child_count = parseArray(istr, data, max_depth - 1);
        if((child_count == PARSE_FAILURE) || data.isUndefined())
        {
            parse_count = PARSE_FAILURE;
        }
        else
        {
            parse_count += child_count;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading binary array." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case '!':
        data.clear();
        break;

    case '0':
        data = false;
        break;

    case '1':
        data = true;
        break;

    case 'i':
    {
        U32 value_nbo = 0;
        read(istr, (char*)&value_nbo, sizeof(U32));  /*Flawfinder: ignore*/
        data = (S32)ntohl(value_nbo);
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading binary integer." << LL_ENDL;
        }
        break;
    }

    case 'r':
    {
        F64 real_nbo = 0.0;
        read(istr, (char*)&real_nbo, sizeof(F64));   /*Flawfinder: ignore*/
        data = ll_ntohd(real_nbo);
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading binary real." << LL_ENDL;
        }
        break;
    }

    case 'u':
    {
        LLUUID id;
        read(istr, (char*)(&id.mData), UUID_BYTES);  /*Flawfinder: ignore*/
        data = id;
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading binary uuid." << LL_ENDL;
        }
        break;
    }

    case '\'':
    case '"':
    {
        std::string value;
        auto cnt = deserialize_string_delim(istr, value, c);
        if(PARSE_FAILURE == cnt)
        {
            parse_count = PARSE_FAILURE;
        }
        else
        {
            data = value;
            account(cnt);
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading binary (notation-style) string."
                << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case 's':
    {
        std::string value;
        if(parseString(istr, value))
        {
            data = value;
        }
        else
        {
            parse_count = PARSE_FAILURE;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading binary string." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case 'l':
    {
        std::string value;
        if(parseString(istr, value))
        {
            data = LLURI(value);
        }
        else
        {
            parse_count = PARSE_FAILURE;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading binary link." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case 'd':
    {
        F64 real = 0.0;
        read(istr, (char*)&real, sizeof(F64));   /*Flawfinder: ignore*/
        data = LLDate(real);
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading binary date." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    case 'b':
    {
        // We probably have a valid raw binary stream. determine
        // the size, and read it.
        U32 size_nbo = 0;
        read(istr, (char*)&size_nbo, sizeof(U32));  /*Flawfinder: ignore*/
        S32 size = (S32)ntohl(size_nbo);
        if(mCheckLimits && (size > mMaxBytesLeft))
        {
            parse_count = PARSE_FAILURE;
        }
        else
        {
            std::vector<U8> value;
            if(size > 0)
            {
                value.resize(size);
                account(fullread(istr, (char*)&value[0], size));
            }
            data = value;
        }
        if(istr.fail())
        {
            LL_INFOS() << "STREAM FAILURE reading binary." << LL_ENDL;
            parse_count = PARSE_FAILURE;
        }
        break;
    }

    default:
        parse_count = PARSE_FAILURE;
        LL_INFOS() << "Unrecognized character while parsing: int(" << int(c)
            << ")" << LL_ENDL;
        break;
    }
    if(PARSE_FAILURE == parse_count)
    {
        data.clear();
    }
    return parse_count;
}

S32 LLSDBinaryParser::parseMap(std::istream& istr, LLSD& map, S32 max_depth) const
{
    map = LLSD::emptyMap();
    U32 value_nbo = 0;
    read(istr, (char*)&value_nbo, sizeof(U32));      /*Flawfinder: ignore*/
    S32 size = (S32)ntohl(value_nbo);
    S32 parse_count = 0;
    S32 count = 0;
    char c = get(istr);
    while(c != '}' && (count < size) && istr.good())
    {
        std::string name;
        switch(c)
        {
        case 'k':
            if(!parseString(istr, name))
            {
                return PARSE_FAILURE;
            }
            break;
        case '\'':
        case '"':
        {
            auto cnt = deserialize_string_delim(istr, name, c);
            if(PARSE_FAILURE == cnt) return PARSE_FAILURE;
            account(cnt);
            break;
        }
        }
        LLSD child;
        S32 child_count = doParse(istr, child, max_depth);
        if(child_count > 0)
        {
            // There must be a value for every key, thus child_count
            // must be greater than 0.
            parse_count += child_count;
            map.insert(name, child);
        }
        else
        {
            return PARSE_FAILURE;
        }
        ++count;
        c = get(istr);
    }
    if((c != '}') || (count < size))
    {
        // Make sure it is correctly terminated and we parsed as many
        // as were said to be there.
        return PARSE_FAILURE;
    }
    return parse_count;
}

S32 LLSDBinaryParser::parseArray(std::istream& istr, LLSD& array, S32 max_depth) const
{
    array = LLSD::emptyArray();
    U32 value_nbo = 0;
    read(istr, (char*)&value_nbo, sizeof(U32));      /*Flawfinder: ignore*/
    S32 size = (S32)ntohl(value_nbo);

    // *FIX: This would be a good place to reserve some space in the
    // array...

    S32 parse_count = 0;
    S32 count = 0;
    char c = istr.peek();
    while((c != ']') && (count < size) && istr.good())
    {
        LLSD child;
        S32 child_count = doParse(istr, child, max_depth);
        if(PARSE_FAILURE == child_count)
        {
            return PARSE_FAILURE;
        }
        if(child_count)
        {
            parse_count += child_count;
            array.append(child);
        }
        ++count;
        c = istr.peek();
    }
    c = get(istr);
    if((c != ']') || (count < size))
    {
        // Make sure it is correctly terminated and we parsed as many
        // as were said to be there.
        return PARSE_FAILURE;
    }
    return parse_count;
}

bool LLSDBinaryParser::parseString(
    std::istream& istr,
    std::string& value) const
{
    // *FIX: This is memory inefficient.
    U32 value_nbo = 0;
    read(istr, (char*)&value_nbo, sizeof(U32));      /*Flawfinder: ignore*/
    S32 size = (S32)ntohl(value_nbo);
    if(mCheckLimits && (size > mMaxBytesLeft)) return false;
    if(size < 0) return false;
    std::vector<char> buf;
    if(size)
    {
        buf.resize(size);
        account(fullread(istr, &buf[0], size));
        value.assign(buf.begin(), buf.end());
    }
    return true;
}


/**
 * LLSDFormatter
 */
LLSDFormatter::LLSDFormatter(bool boolAlpha, const std::string& realFmt, EFormatterOptions options):
    mOptions(options)
{
    boolalpha(boolAlpha);
    realFormat(realFmt);
}

// virtual
LLSDFormatter::~LLSDFormatter()
{ }

void LLSDFormatter::boolalpha(bool alpha)
{
    mBoolAlpha = alpha;
}

void LLSDFormatter::realFormat(const std::string& format)
{
    mRealFormat = format;
}

S32 LLSDFormatter::format(const LLSD& data, std::ostream& ostr) const
{
    // pass options captured by constructor
    return format(data, ostr, mOptions);
}

S32 LLSDFormatter::format(const LLSD& data, std::ostream& ostr, EFormatterOptions options) const
{
    return format_impl(data, ostr, options, 0);
}

void LLSDFormatter::formatReal(LLSD::Real real, std::ostream& ostr) const
{
    std::string buffer = llformat(mRealFormat.c_str(), real);
    ostr << buffer;
}

/**
 * LLSDNotationFormatter
 */
LLSDNotationFormatter::LLSDNotationFormatter(bool boolAlpha, const std::string& realFormat,
                                             EFormatterOptions options):
    LLSDFormatter(boolAlpha, realFormat, options)
{
}

// virtual
LLSDNotationFormatter::~LLSDNotationFormatter()
{ }

// static
std::string LLSDNotationFormatter::escapeString(const std::string& in)
{
    std::ostringstream ostr;
    serialize_string(in, ostr);
    return ostr.str();
}

S32 LLSDNotationFormatter::format_impl(const LLSD& data, std::ostream& ostr,
                                       EFormatterOptions options, U32 level) const
{
    S32 format_count = 1;
    std::string pre;
    std::string post;

    if (options & LLSDFormatter::OPTIONS_PRETTY)
    {
        for (U32 i = 0; i < level; i++)
        {
            pre += "    ";
        }
        post = "\n";
    }

    switch(data.type())
    {
    case LLSD::TypeMap:
    {
        if (0 != level) ostr << post << pre;
        ostr << "{";
        std::string inner_pre;
        if (options & LLSDFormatter::OPTIONS_PRETTY)
        {
            inner_pre = pre + "    ";
        }

        bool need_comma = false;
        LLSD::map_const_iterator iter = data.beginMap();
        LLSD::map_const_iterator end = data.endMap();
        for(; iter != end; ++iter)
        {
            if(need_comma) ostr << ",";
            need_comma = true;
            ostr << post << inner_pre << '\'';
            serialize_string((*iter).first, ostr);
            ostr << "':";
            format_count += format_impl((*iter).second, ostr, options, level + 2);
        }
        ostr << post << pre << "}";
        break;
    }

    case LLSD::TypeArray:
    {
        ostr << post << pre << "[";
        bool need_comma = false;
        LLSD::array_const_iterator iter = data.beginArray();
        LLSD::array_const_iterator end = data.endArray();
        for(; iter != end; ++iter)
        {
            if(need_comma) ostr << ",";
            need_comma = true;
            format_count += format_impl(*iter, ostr, options, level + 1);
        }
        ostr << "]";
        break;
    }

    case LLSD::TypeUndefined:
        ostr << "!";
        break;

    case LLSD::TypeBoolean:
        if(mBoolAlpha ||
#if( LL_WINDOWS || __GNUC__ > 2)
           (ostr.flags() & std::ios::boolalpha)
#else
           (ostr.flags() & 0x0100)
#endif
            )
        {
            ostr << (data.asBoolean()
                     ? NOTATION_TRUE_SERIAL : NOTATION_FALSE_SERIAL);
        }
        else
        {
            ostr << (data.asBoolean() ? 1 : 0);
        }
        break;

    case LLSD::TypeInteger:
        ostr << "i" << data.asInteger();
        break;

    case LLSD::TypeReal:
        ostr << "r";
        if(mRealFormat.empty())
        {
            ostr << data.asReal();
        }
        else
        {
            formatReal(data.asReal(), ostr);
        }
        break;

    case LLSD::TypeUUID:
        ostr << "u" << data.asUUID();
        break;

    case LLSD::TypeString:
        ostr << '\'';
        serialize_string(data.asStringRef(), ostr);
        ostr << '\'';
        break;

    case LLSD::TypeDate:
        ostr << "d\"" << data.asDate() << "\"";
        break;

    case LLSD::TypeURI:
        ostr << "l\"";
        serialize_string(data.asString(), ostr);
        ostr << "\"";
        break;

    case LLSD::TypeBinary:
    {
        // *FIX: memory inefficient.
        const std::vector<U8>& buffer = data.asBinary();
        if (options & LLSDFormatter::OPTIONS_PRETTY_BINARY)
        {
            ostr << "b16\"";
            if (! buffer.empty())
            {
                std::ios_base::fmtflags old_flags = ostr.flags();
                ostr.setf( std::ios::hex, std::ios::basefield );
                // It shouldn't strictly matter whether the emitted hex digits
                // are uppercase; LLSDNotationParser handles either; but as of
                // 2020-05-13, Python's llbase.llsd requires uppercase hex.
                ostr << std::uppercase;
                auto oldfill(ostr.fill('0'));
                auto oldwidth(ostr.width());
                for (size_t i = 0; i < buffer.size(); i++)
                {
                    // have to restate setw() before every conversion
                    ostr << std::setw(2) << (int) buffer[i];
                }
                ostr.width(oldwidth);
                ostr.fill(oldfill);
                ostr.flags(old_flags);
            }
        }
        else                        // ! OPTIONS_PRETTY_BINARY
        {
            ostr << "b(" << buffer.size() << ")\"";
            if (! buffer.empty())
            {
                ostr.write((const char*)&buffer[0], buffer.size());
            }
        }
        ostr << "\"";
        break;
    }

    default:
        // *NOTE: This should never happen.
        ostr << "!";
        break;
    }
    return format_count;
}

/**
 * LLSDBinaryFormatter
 */
LLSDBinaryFormatter::LLSDBinaryFormatter(bool boolAlpha, const std::string& realFormat,
                                         EFormatterOptions options):
    LLSDFormatter(boolAlpha, realFormat, options)
{
}

// virtual
LLSDBinaryFormatter::~LLSDBinaryFormatter()
{ }

// virtual
S32 LLSDBinaryFormatter::format_impl(const LLSD& data, std::ostream& ostr,
                                     EFormatterOptions options, U32 level) const
{
    S32 format_count = 1;
    switch(data.type())
    {
    case LLSD::TypeMap:
    {
        ostr.put('{');
        U32 size_nbo = htonl(static_cast<u_long>(data.size()));
        ostr.write((const char*)(&size_nbo), sizeof(U32));
        LLSD::map_const_iterator iter = data.beginMap();
        LLSD::map_const_iterator end = data.endMap();
        for(; iter != end; ++iter)
        {
            ostr.put('k');
            formatString((*iter).first, ostr);
            format_count += format_impl((*iter).second, ostr, options, level+1);
        }
        ostr.put('}');
        break;
    }

    case LLSD::TypeArray:
    {
        ostr.put('[');
        U32 size_nbo = htonl(static_cast<u_long>(data.size()));
        ostr.write((const char*)(&size_nbo), sizeof(U32));
        LLSD::array_const_iterator iter = data.beginArray();
        LLSD::array_const_iterator end = data.endArray();
        for(; iter != end; ++iter)
        {
            format_count += format_impl(*iter, ostr, options, level+1);
        }
        ostr.put(']');
        break;
    }

    case LLSD::TypeUndefined:
        ostr.put('!');
        break;

    case LLSD::TypeBoolean:
        if(data.asBoolean()) ostr.put(BINARY_TRUE_SERIAL);
        else ostr.put(BINARY_FALSE_SERIAL);
        break;

    case LLSD::TypeInteger:
    {
        ostr.put('i');
        U32 value_nbo = htonl(data.asInteger());
        ostr.write((const char*)(&value_nbo), sizeof(U32));
        break;
    }

    case LLSD::TypeReal:
    {
        ostr.put('r');
        F64 value_nbo = ll_htond(data.asReal());
        ostr.write((const char*)(&value_nbo), sizeof(F64));
        break;
    }

    case LLSD::TypeUUID:
    {
        ostr.put('u');
        LLUUID temp = data.asUUID();
        ostr.write((const char*)(&(temp.mData)), UUID_BYTES);
        break;
    }

    case LLSD::TypeString:
        ostr.put('s');
        formatString(data.asStringRef(), ostr);
        break;

    case LLSD::TypeDate:
    {
        ostr.put('d');
        F64 value = data.asReal();
        ostr.write((const char*)(&value), sizeof(F64));
        break;
    }

    case LLSD::TypeURI:
        ostr.put('l');
        formatString(data.asString(), ostr);
        break;

    case LLSD::TypeBinary:
    {
        ostr.put('b');
        const std::vector<U8>& buffer = data.asBinary();
        U32 size_nbo = htonl(static_cast<u_long>(buffer.size()));
        ostr.write((const char*)(&size_nbo), sizeof(U32));
        if(buffer.size()) ostr.write((const char*)&buffer[0], buffer.size());
        break;
    }

    default:
        // *NOTE: This should never happen.
        ostr.put('!');
        break;
    }
    return format_count;
}

void LLSDBinaryFormatter::formatString(
    const std::string& string,
    std::ostream& ostr) const
{
    U32 size_nbo = htonl(static_cast<u_long>(string.size()));
    ostr.write((const char*)(&size_nbo), sizeof(U32));
    ostr.write(string.c_str(), string.size());
}

/**
 * local functions
 */
llssize deserialize_string(std::istream& istr, std::string& value, llssize max_bytes)
{
    int c = istr.get();
    if(istr.fail())
    {
        // No data in stream, bail out but mention the character we
        // grabbed.
        return LLSDParser::PARSE_FAILURE;
    }

    llssize rv = LLSDParser::PARSE_FAILURE;
    switch(c)
    {
    case '\'':
    case '"':
        rv = deserialize_string_delim(istr, value, c);
        break;
    case 's':
        // technically, less than max_bytes, but this is just meant to
        // catch egregious protocol errors. parse errors will be
        // caught in the case of incorrect counts.
        rv = deserialize_string_raw(istr, value, max_bytes);
        break;
    default:
        break;
    }
    if(LLSDParser::PARSE_FAILURE == rv) return rv;
    return rv + 1; // account for the character grabbed at the top.
}

llssize deserialize_string_delim(
    std::istream& istr,
    std::string& value,
    char delim)
{
    std::ostringstream write_buffer;
    bool found_escape = false;
    bool found_hex = false;
    bool found_digit = false;
    U8 byte = 0;
    llssize count = 0;

    while (true)
    {
        int next_byte = istr.get();
        ++count;

        if(istr.fail())
        {
            // If our stream is empty, break out
            value = write_buffer.str();
            return LLSDParser::PARSE_FAILURE;
        }

        char next_char = (char)next_byte; // Now that we know it's not EOF

        if(found_escape)
        {
            // next character(s) is a special sequence.
            if(found_hex)
            {
                if(found_digit)
                {
                    found_digit = false;
                    found_hex = false;
                    found_escape = false;
                    byte = byte << 4;
                    byte |= hex_as_nybble(next_char);
                    write_buffer << byte;
                    byte = 0;
                }
                else
                {
                    // next character is the first nybble of
                    //
                    found_digit = true;
                    byte = hex_as_nybble(next_char);
                }
            }
            else if(next_char == 'x')
            {
                found_hex = true;
            }
            else
            {
                switch(next_char)
                {
                case 'a':
                    write_buffer << '\a';
                    break;
                case 'b':
                    write_buffer << '\b';
                    break;
                case 'f':
                    write_buffer << '\f';
                    break;
                case 'n':
                    write_buffer << '\n';
                    break;
                case 'r':
                    write_buffer << '\r';
                    break;
                case 't':
                    write_buffer << '\t';
                    break;
                case 'v':
                    write_buffer << '\v';
                    break;
                default:
                    write_buffer << next_char;
                    break;
                }
                found_escape = false;
            }
        }
        else if(next_char == '\\')
        {
            found_escape = true;
        }
        else if(next_char == delim)
        {
            break;
        }
        else
        {
            write_buffer << next_char;
        }
    }

    value = write_buffer.str();
    return count;
}

llssize deserialize_string_raw(
    std::istream& istr,
    std::string& value,
    llssize max_bytes)
{
    llssize count = 0;
    const S32 BUF_LEN = 20;
    char buf[BUF_LEN];      /* Flawfinder: ignore */
    istr.get(buf, BUF_LEN - 1, ')');
    count += istr.gcount();
    int c = istr.get();
    c = istr.get();
    count += 2;
    if(((c == '"') || (c == '\'')) && (buf[0] == '('))
    {
        // We probably have a valid raw string. determine
        // the size, and read it.
        // *FIX: This is memory inefficient.
        auto len = strtol(buf + 1, NULL, 0);
        if((max_bytes>0)&&(len>max_bytes)) return LLSDParser::PARSE_FAILURE;
        std::vector<char> buf;
        if(len)
        {
            buf.resize(len);
            count += fullread(istr, (char *)&buf[0], len);
            value.assign(buf.begin(), buf.end());
        }
        c = istr.get();
        ++count;
        if(!((c == '"') || (c == '\'')))
        {
            return LLSDParser::PARSE_FAILURE;
        }
    }
    else
    {
        return LLSDParser::PARSE_FAILURE;
    }
    return count;
}

static const char* NOTATION_STRING_CHARACTERS[256] =
{
    "\\x00",    // 0
    "\\x01",    // 1
    "\\x02",    // 2
    "\\x03",    // 3
    "\\x04",    // 4
    "\\x05",    // 5
    "\\x06",    // 6
    "\\a",      // 7
    "\\b",      // 8
    "\\t",      // 9
    "\\n",      // 10
    "\\v",      // 11
    "\\f",      // 12
    "\\r",      // 13
    "\\x0e",    // 14
    "\\x0f",    // 15
    "\\x10",    // 16
    "\\x11",    // 17
    "\\x12",    // 18
    "\\x13",    // 19
    "\\x14",    // 20
    "\\x15",    // 21
    "\\x16",    // 22
    "\\x17",    // 23
    "\\x18",    // 24
    "\\x19",    // 25
    "\\x1a",    // 26
    "\\x1b",    // 27
    "\\x1c",    // 28
    "\\x1d",    // 29
    "\\x1e",    // 30
    "\\x1f",    // 31
    " ",        // 32
    "!",        // 33
    "\"",       // 34
    "#",        // 35
    "$",        // 36
    "%",        // 37
    "&",        // 38
    "\\'",      // 39
    "(",        // 40
    ")",        // 41
    "*",        // 42
    "+",        // 43
    ",",        // 44
    "-",        // 45
    ".",        // 46
    "/",        // 47
    "0",        // 48
    "1",        // 49
    "2",        // 50
    "3",        // 51
    "4",        // 52
    "5",        // 53
    "6",        // 54
    "7",        // 55
    "8",        // 56
    "9",        // 57
    ":",        // 58
    ";",        // 59
    "<",        // 60
    "=",        // 61
    ">",        // 62
    "?",        // 63
    "@",        // 64
    "A",        // 65
    "B",        // 66
    "C",        // 67
    "D",        // 68
    "E",        // 69
    "F",        // 70
    "G",        // 71
    "H",        // 72
    "I",        // 73
    "J",        // 74
    "K",        // 75
    "L",        // 76
    "M",        // 77
    "N",        // 78
    "O",        // 79
    "P",        // 80
    "Q",        // 81
    "R",        // 82
    "S",        // 83
    "T",        // 84
    "U",        // 85
    "V",        // 86
    "W",        // 87
    "X",        // 88
    "Y",        // 89
    "Z",        // 90
    "[",        // 91
    "\\\\",     // 92
    "]",        // 93
    "^",        // 94
    "_",        // 95
    "`",        // 96
    "a",        // 97
    "b",        // 98
    "c",        // 99
    "d",        // 100
    "e",        // 101
    "f",        // 102
    "g",        // 103
    "h",        // 104
    "i",        // 105
    "j",        // 106
    "k",        // 107
    "l",        // 108
    "m",        // 109
    "n",        // 110
    "o",        // 111
    "p",        // 112
    "q",        // 113
    "r",        // 114
    "s",        // 115
    "t",        // 116
    "u",        // 117
    "v",        // 118
    "w",        // 119
    "x",        // 120
    "y",        // 121
    "z",        // 122
    "{",        // 123
    "|",        // 124
    "}",        // 125
    "~",        // 126
    "\\x7f",    // 127
    "\\x80",    // 128
    "\\x81",    // 129
    "\\x82",    // 130
    "\\x83",    // 131
    "\\x84",    // 132
    "\\x85",    // 133
    "\\x86",    // 134
    "\\x87",    // 135
    "\\x88",    // 136
    "\\x89",    // 137
    "\\x8a",    // 138
    "\\x8b",    // 139
    "\\x8c",    // 140
    "\\x8d",    // 141
    "\\x8e",    // 142
    "\\x8f",    // 143
    "\\x90",    // 144
    "\\x91",    // 145
    "\\x92",    // 146
    "\\x93",    // 147
    "\\x94",    // 148
    "\\x95",    // 149
    "\\x96",    // 150
    "\\x97",    // 151
    "\\x98",    // 152
    "\\x99",    // 153
    "\\x9a",    // 154
    "\\x9b",    // 155
    "\\x9c",    // 156
    "\\x9d",    // 157
    "\\x9e",    // 158
    "\\x9f",    // 159
    "\\xa0",    // 160
    "\\xa1",    // 161
    "\\xa2",    // 162
    "\\xa3",    // 163
    "\\xa4",    // 164
    "\\xa5",    // 165
    "\\xa6",    // 166
    "\\xa7",    // 167
    "\\xa8",    // 168
    "\\xa9",    // 169
    "\\xaa",    // 170
    "\\xab",    // 171
    "\\xac",    // 172
    "\\xad",    // 173
    "\\xae",    // 174
    "\\xaf",    // 175
    "\\xb0",    // 176
    "\\xb1",    // 177
    "\\xb2",    // 178
    "\\xb3",    // 179
    "\\xb4",    // 180
    "\\xb5",    // 181
    "\\xb6",    // 182
    "\\xb7",    // 183
    "\\xb8",    // 184
    "\\xb9",    // 185
    "\\xba",    // 186
    "\\xbb",    // 187
    "\\xbc",    // 188
    "\\xbd",    // 189
    "\\xbe",    // 190
    "\\xbf",    // 191
    "\\xc0",    // 192
    "\\xc1",    // 193
    "\\xc2",    // 194
    "\\xc3",    // 195
    "\\xc4",    // 196
    "\\xc5",    // 197
    "\\xc6",    // 198
    "\\xc7",    // 199
    "\\xc8",    // 200
    "\\xc9",    // 201
    "\\xca",    // 202
    "\\xcb",    // 203
    "\\xcc",    // 204
    "\\xcd",    // 205
    "\\xce",    // 206
    "\\xcf",    // 207
    "\\xd0",    // 208
    "\\xd1",    // 209
    "\\xd2",    // 210
    "\\xd3",    // 211
    "\\xd4",    // 212
    "\\xd5",    // 213
    "\\xd6",    // 214
    "\\xd7",    // 215
    "\\xd8",    // 216
    "\\xd9",    // 217
    "\\xda",    // 218
    "\\xdb",    // 219
    "\\xdc",    // 220
    "\\xdd",    // 221
    "\\xde",    // 222
    "\\xdf",    // 223
    "\\xe0",    // 224
    "\\xe1",    // 225
    "\\xe2",    // 226
    "\\xe3",    // 227
    "\\xe4",    // 228
    "\\xe5",    // 229
    "\\xe6",    // 230
    "\\xe7",    // 231
    "\\xe8",    // 232
    "\\xe9",    // 233
    "\\xea",    // 234
    "\\xeb",    // 235
    "\\xec",    // 236
    "\\xed",    // 237
    "\\xee",    // 238
    "\\xef",    // 239
    "\\xf0",    // 240
    "\\xf1",    // 241
    "\\xf2",    // 242
    "\\xf3",    // 243
    "\\xf4",    // 244
    "\\xf5",    // 245
    "\\xf6",    // 246
    "\\xf7",    // 247
    "\\xf8",    // 248
    "\\xf9",    // 249
    "\\xfa",    // 250
    "\\xfb",    // 251
    "\\xfc",    // 252
    "\\xfd",    // 253
    "\\xfe",    // 254
    "\\xff"     // 255
};

void serialize_string(const std::string& value, std::ostream& str)
{
    std::string::const_iterator it = value.begin();
    std::string::const_iterator end = value.end();
    U8 c;
    for(; it != end; ++it)
    {
        c = (U8)(*it);
        str << NOTATION_STRING_CHARACTERS[c];
    }
}

llssize deserialize_boolean(
    std::istream& istr,
    LLSD& data,
    const std::string& compare,
    bool value)
{
    //
    // this method is a little goofy, because it gets the stream at
    // the point where the t or f has already been
    // consumed. Basically, parse for a patch to the string passed in
    // starting at index 1. If it's a match:
    //  * assign data to value
    //  * return the number of bytes read
    // otherwise:
    //  * set data to LLSD::null
    //  * return LLSDParser::PARSE_FAILURE (-1)
    //
    llssize bytes_read = 0;
    std::string::size_type ii = 0;
    char c = istr.peek();
    while((++ii < compare.size())
          && (tolower(c) == (int)compare[ii])
          && istr.good())
    {
        istr.ignore();
        ++bytes_read;
        c = istr.peek();
    }
    if(compare.size() != ii)
    {
        data.clear();
        return LLSDParser::PARSE_FAILURE;
    }
    data = value;
    return bytes_read;
}

std::ostream& operator<<(std::ostream& s, const LLSD& llsd)
{
    s << LLSDNotationStreamer(llsd);
    return s;
}


//dirty little zippers -- yell at davep if these are horrid

//return a string containing gzipped bytes of binary serialized LLSD
// VERY inefficient -- creates several copies of LLSD block in memory
std::string zip_llsd(LLSD& data)
{
    std::stringstream llsd_strm;

    LLSDSerialize::toBinary(data, llsd_strm);

    const U32 CHUNK = 65536;

    z_stream strm;
    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
    strm.opaque = Z_NULL;

    S32 ret = deflateInit(&strm, Z_BEST_COMPRESSION);
    if (ret != Z_OK)
    {
        LL_WARNS() << "Failed to compress LLSD block." << LL_ENDL;
        return std::string();
    }

    std::string source = llsd_strm.str();

    U8 out[CHUNK];

    strm.avail_in = narrow<size_t>(source.size());
    strm.next_in = (U8*) source.data();
    U8* output = NULL;

    U32 cur_size = 0;

    U32 have = 0;

    do
    {
        strm.avail_out = CHUNK;
        strm.next_out = out;

        ret = deflate(&strm, Z_FINISH);
        if (ret == Z_OK || ret == Z_STREAM_END)
        { //copy result into output
            if (strm.avail_out >= CHUNK)
            {
                deflateEnd(&strm);
                if(output)
                    free(output);
                LL_WARNS() << "Failed to compress LLSD block." << LL_ENDL;
                return std::string();
            }

            have = CHUNK-strm.avail_out;
            U8* new_output = (U8*) realloc(output, cur_size+have);
            if (new_output == NULL)
            {
                LL_WARNS() << "Failed to compress LLSD block: can't reallocate memory, current size: " << cur_size << " bytes; requested " << cur_size + have << " bytes." << LL_ENDL;
                deflateEnd(&strm);
                if (output)
                {
                    free(output);
                }
                return std::string();
            }
            output = new_output;
            memcpy(output+cur_size, out, have);
            cur_size += have;
        }
        else
        {
            deflateEnd(&strm);
            if(output)
                free(output);
            LL_WARNS() << "Failed to compress LLSD block." << LL_ENDL;
            return std::string();
        }
    }
    while (ret == Z_OK);

    std::string::size_type size = cur_size;

    std::string result((char*) output, size);
    deflateEnd(&strm);
    if(output)
        free(output);

    return result;
}

//decompress a block of LLSD from provided istream
// not very efficient -- creats a copy of decompressed LLSD block in memory
// and deserializes from that copy using LLSDSerialize
LLUZipHelper::EZipRresult LLUZipHelper::unzip_llsd(LLSD& data, std::istream& is, S32 size)
{
    std::unique_ptr<U8[]> in = std::unique_ptr<U8[]>(new(std::nothrow) U8[size]);
    if (!in)
    {
        return ZR_MEM_ERROR;
    }
    is.read((char*) in.get(), size);

    return unzip_llsd(data, in.get(), size);
}

LLUZipHelper::EZipRresult LLUZipHelper::unzip_llsd(LLSD& data, const U8* in, S32 size)
{
    U8* result = NULL;
    llssize cur_size = 0;
    z_stream strm;

    constexpr U32 CHUNK = 1024 * 512;

    static thread_local std::unique_ptr<U8[]> out;
    if (!out)
    {
        out = std::unique_ptr<U8[]>(new(std::nothrow) U8[CHUNK]);
    }

    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
    strm.opaque = Z_NULL;
    strm.avail_in = size;
    strm.next_in = const_cast<U8*>(in);

    S32 ret = inflateInit(&strm);

    do
    {
        strm.avail_out = CHUNK;
        strm.next_out = out.get();
        ret = inflate(&strm, Z_NO_FLUSH);
        switch (ret)
        {
        case Z_NEED_DICT:
        case Z_DATA_ERROR:
        {
            inflateEnd(&strm);
            free(result);
            return ZR_DATA_ERROR;
        }
        case Z_STREAM_ERROR:
        case Z_BUF_ERROR:
        {
            inflateEnd(&strm);
            free(result);
            return ZR_BUFFER_ERROR;
        }

        case Z_MEM_ERROR:
        {
            inflateEnd(&strm);
            free(result);
            return ZR_MEM_ERROR;
        }
        }

        U32 have = CHUNK-strm.avail_out;

        U8* new_result = (U8*)realloc(result, cur_size + have);
        if (new_result == NULL)
        {
            inflateEnd(&strm);
            if (result)
            {
                free(result);
            }
            return ZR_MEM_ERROR;
        }
        result = new_result;
        memcpy(result+cur_size, out.get(), have);
        cur_size += have;

    } while (ret == Z_OK && ret != Z_STREAM_END);

    inflateEnd(&strm);

    if (ret != Z_STREAM_END)
    {
        free(result);
        return ZR_DATA_ERROR;
    }

    //result now points to the decompressed LLSD block
    {
        char* result_ptr = strip_deprecated_header((char*)result, cur_size);

        boost::iostreams::stream<boost::iostreams::array_source> istrm(result_ptr, cur_size);

        if (!LLSDSerialize::fromBinary(data, istrm, cur_size, UNZIP_LLSD_MAX_DEPTH))
        {
            free(result);
            return ZR_PARSE_ERROR;
        }
    }

    free(result);
    return ZR_OK;
}
//This unzip function will only work with a gzip header and trailer - while the contents
//of the actual compressed data is the same for either format (gzip vs zlib ), the headers
//and trailers are different for the formats.
U8* unzip_llsdNavMesh( bool& valid, size_t& outsize, std::istream& is, S32 size )
{
    if (size == 0)
    {
        LL_WARNS() << "No data to unzip." << LL_ENDL;
        return NULL;
    }

    U8* result = NULL;
    U32 cur_size = 0;
    z_stream strm;

    const U32 CHUNK = 0x4000;

    U8 *in = new(std::nothrow) U8[size];
    if (in == NULL)
    {
        LL_WARNS() << "Memory allocation failure." << LL_ENDL;
        return NULL;
    }
    is.read((char*) in, size);

    U8 out[CHUNK];

    strm.zalloc = Z_NULL;
    strm.zfree = Z_NULL;
    strm.opaque = Z_NULL;
    strm.avail_in = size;
    strm.next_in = in;


    S32 ret = inflateInit2(&strm,  windowBits | ENABLE_ZLIB_GZIP );
    do
    {
        strm.avail_out = CHUNK;
        strm.next_out = out;
        ret = inflate(&strm, Z_NO_FLUSH);
        if (ret == Z_STREAM_ERROR)
        {
            inflateEnd(&strm);
            free(result);
            delete [] in;
            valid = false;
        }

        switch (ret)
        {
        case Z_NEED_DICT:
            ret = Z_DATA_ERROR;
        case Z_DATA_ERROR:
        case Z_MEM_ERROR:
            inflateEnd(&strm);
            free(result);
            delete [] in;
            valid = false;
            break;
        }

        U32 have = CHUNK-strm.avail_out;

        U8* new_result = (U8*) realloc(result, cur_size + have);
        if (new_result == NULL)
        {
            LL_WARNS() << "Failed to unzip LLSD NavMesh block: can't reallocate memory, current size: " << cur_size
                << " bytes; requested " << cur_size + have
                << " bytes; total syze: ." << size << " bytes."
                << LL_ENDL;
            inflateEnd(&strm);
            if (result)
            {
                free(result);
            }
            delete[] in;
            valid = false;
            return NULL;
        }
        result = new_result;
        memcpy(result+cur_size, out, have);
        cur_size += have;

    } while (ret == Z_OK);

    inflateEnd(&strm);
    delete [] in;

    if (ret != Z_STREAM_END)
    {
        free(result);
        valid = false;
        return NULL;
    }

    //result now points to the decompressed LLSD block
    {
        outsize= cur_size;
        valid = true;
    }

    return result;
}

char* strip_deprecated_header(char* in, llssize& cur_size, llssize* header_size)
{
    const char* deprecated_header = "<? LLSD/Binary ?>";
    constexpr size_t deprecated_header_size = 17;

    if (cur_size > deprecated_header_size
        && memcmp(in, deprecated_header, deprecated_header_size) == 0)
    {
        in = in + deprecated_header_size;
        cur_size = cur_size - deprecated_header_size;
        if (header_size)
        {
            *header_size = deprecated_header_size + 1;
        }
    }

    return in;
}