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#include "encode.h"

#include <util/generic/singleton.h> 

namespace NUri {
    namespace NEncode { 
// http://tools.ietf.org/html/rfc3986#section-2.2
#define GENDELIMS0 ":/?#[]@"
#define SUBDELIMS0 "!$&'()*+,;="
// http://tools.ietf.org/html/rfc3986#section-2.3
#define UNRESERVED "-._~"

// now find subsets which can sometimes be decoded

// remove '#' which can't ever be decoded
// don't mark anything allowed for pass (pass is completely encoded)
// safe in path, qry, frag
#define GENDELIMS1 ":@"
// allowed in qry, frag
#define GENDELIMS2 "/?"

// qry-unsafe chars
#define SUBDELIMS1 "&+=;"
// rest allowed in qry, frag
#define SUBDELIMS2 "!$'()*,"

        const TEncoder::TGrammar& TEncoder::Grammar() { 
            return *Singleton<TEncoder::TGrammar>(); 
        } 

        // initialize the grammar map 
        TEncoder::TGrammar::TGrammar() { 
            // first set up unreserved characters safe in any field 
            const ui64 featUnres = TFeature::FeatureDecodeUnreserved; 
            AddRng('0', '9', ECFDigit, featUnres); 
            AddRng('A', 'Z', ECFUpper, featUnres | TFeature::FeatureToLower); 
            AddRng('a', 'z', ECFLower, featUnres); 
            Add(UNRESERVED, ECFUnres, featUnres); 

            // XXX: standard "safe" set used previously "-_.!~*();/:@$,", with comment: 
            //  alnum + reserved + mark + ( '[', ']') - ('=' '+' '&' '\'' '"' '\\' '?') 
            Add("!*();/:@$,", ECFStdrd, TFeature::FeatureDecodeStandardExtra); 

            // now field-specific subsets of reserved characters (gen-delims + sub-delims) 
            const ui64 featSafe = TFeature::FeatureDecodeFieldAllowed; 

            Add(GENDELIMS1, 0, featSafe, TField::FlagPath | TField::FlagQuery | TField::FlagFrag); 
            Add(GENDELIMS2, 0, featSafe, TField::FlagQuery | TField::FlagFrag); 

            Add(SUBDELIMS1, 0, featSafe, TField::FlagUser); 
            Add(SUBDELIMS2, 0, featSafe, TField::FlagUser | TField::FlagQuery | TField::FlagFrag); 

            // control chars 
            AddRng(0x00, 0x20, TFeature::FeatureEncodeCntrl); 
            Add(0x7f, TFeature::FeatureEncodeCntrl); 

            // '%' starts a percent-encoded sequence 
            Add('%', TFeature::FeatureDecodeANY | TFeature::FeatureEncodePercent); 

            // extended ASCII 
            AddRng(128, 255, TFeature::FeatureEncodeExtendedASCII | TFeature::FeatureDecodeExtendedASCII); 

            // extended delims 
            Add("\"<>[\\]^`{|}", TFeature::FeatureEncodeExtendedDelim | TFeature::FeatureDecodeExtendedDelim); 

            // add characters with other features 
            Add(' ', TFeature::FeatureEncodeSpace | TFeature::FeatureEncodeSpaceAsPlus); 
            Add("'\"\\", TFeature::FeatureEncodeForSQL); 

            GetMutable(':').EncodeFld |= TField::FlagUser; 
            GetMutable('?').EncodeFld |= TField::FlagPath; 
            GetMutable('#').EncodeFld |= TField::FlagPath | TField::FlagQuery; 
            GetMutable('&').EncodeFld |= TField::FlagQuery; 
            GetMutable('+').EncodeFld |= TField::FlagQuery; 
        } 

        // should we decode an encoded character 
        bool TCharFlags::IsDecode(ui32 fldmask, ui64 flags) const { 
            const ui64 myflags = flags & FeatFlags; 
            if (myflags & TFeature::FeaturesEncode) 
                return false; 
            if (myflags & TFeature::FeaturesDecode) 
                return true; 
            return (fldmask & DecodeFld) && (flags & TFeature::FeatureDecodeFieldAllowed); 
        } 

        const int dD = 'a' - 'A'; 

        int TEncodeMapper::EncodeSym(unsigned char& ch) const { 
            const TCharFlags& chflags = TEncoder::GetFlags(ch); 
            const ui64 flags = Flags & chflags.FeatFlags; 

            if (flags & TFeature::FeatureToLower) 
                ch += dD; 

            if (Q_DecodeAny) 
                return -1; 

            if (flags & TFeature::FeaturesEncode) 
                return 1; 

            if (' ' == ch) { 
                if (Q_EncodeSpcAsPlus) 
                    ch = '+'; 
                return 0; 
            } 

            return 0; 
        } 

        int TEncodeMapper::EncodeHex(unsigned char& ch) const { 
            const TCharFlags& chflags = TEncoder::GetFlags(ch); 
            const ui64 flags = Flags & chflags.FeatFlags; 

            if (flags & TFeature::FeatureToLower) 
                ch += dD; 

            if (Q_DecodeAny) 
                return -1; 

            if (chflags.IsDecode(FldMask, Flags)) 
                return 0; 

            if (' ' == ch) { 
                if (!Q_EncodeSpcAsPlus) 
                    return 1; 
                ch = '+'; 
                return 0; 
            } 
 
            return 1;
        } 

        bool TEncodeToMapper::Encode(unsigned char ch) const { 
            if (Q_DecodeAny) 
                return false; 

            const TCharFlags& chflags = TEncoder::GetFlags(ch); 
            if (FldMask & chflags.EncodeFld) 
                return true; 

            const ui64 flags = Flags & chflags.FeatFlags; 
            return (flags & TFeature::FeaturesEncode); 
        } 

        TEncoder::TEncoder(IOutputStream& out, const TEncodeMapper& fldsrc, const TEncodeToMapper& flddst) 
            : Out(out) 
            , FldSrc(fldsrc) 
            , FldDst(flddst) 
            , OutFlags(0) 
            , HexValue(0) 
        { 
        } 

        IOutputStream& TEncoder::Hex(IOutputStream& out, unsigned char val) { 
            static const char sHexCodes[] = "0123456789ABCDEF"; 
            return out << sHexCodes[(val >> 4) & 0xF] << sHexCodes[val & 0xF]; 
        } 

        IOutputStream& TEncoder::EncodeAll(IOutputStream& out, const TStringBuf& val) { 
            for (size_t i = 0; i != val.length(); ++i) 
                Encode(out, val[i]); 
            return out; 
        } 

        IOutputStream& TEncoder::EncodeNotAlnum(IOutputStream& out, const TStringBuf& val) { 
            for (size_t i = 0; i != val.length(); ++i) { 
                const char c = val[i]; 
                if (IsAlnum(c)) 
                    out << c; 
                else 
                    Encode(out, c); 
            } 
            return out; 
        } 

        IOutputStream& TEncoder::EncodeField( 
            IOutputStream& out, const TStringBuf& val, TField::EField fld) { 
            const ui32 fldmask = ui32(1) << fld; 
            for (size_t i = 0; i != val.length(); ++i) { 
                const char ch = val[i]; 
                if (GetFlags(ch).IsAllowed(fldmask)) 
                    out << ch; 
                else 
                    Encode(out, ch); 
            } 
            return out; 
        } 

        IOutputStream& TEncoder::EncodeField( 
            IOutputStream& out, const TStringBuf& val, TField::EField fld, ui64 flags) { 
            const ui32 fldmask = ui32(1) << fld; 
            for (size_t i = 0; i != val.length(); ++i) { 
                const char ch = val[i]; 
                if (GetFlags(ch).IsDecode(fldmask, flags)) 
                    out << ch; 
                else 
                    Encode(out, ch); 
            } 
            return out; 
        } 

        void TEncoder::Do(unsigned char ch, int res) { 
            OutFlags |= GetFlags(ch).FeatFlags; 

            bool escapepct = false; 
            if (0 < res) // definitely encode 
                escapepct = FldDst.Enabled(); 
            else if (0 != res || !FldDst.Enabled() || !FldDst.Encode(ch)) { 
                Out << ch; 
                return; 
            } 

            Out << '%'; 
            if (escapepct) 
                Out.Write("25", 2); // '%' 
            Hex(Out, ch); 
        } 
    }
}