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#include "varint.h"

#include "zigzag.h"

#include <util/generic/yexception.h>

namespace NYson {
    //////////////////////////////////////////////////////////////////////////////// 

    int WriteVarUInt64(IOutputStream* output, ui64 value) { 
        bool stop = false; 
        int bytesWritten = 0; 
        while (!stop) { 
            ++bytesWritten; 
            ui8 byte = static_cast<ui8>(value | 0x80); 
            value >>= 7; 
            if (value == 0) { 
                stop = true; 
                byte &= 0x7F; 
            } 
            output->Write(byte); 
        }
        return bytesWritten; 
    }

    int WriteVarInt32(IOutputStream* output, i32 value) { 
        return WriteVarUInt64(output, static_cast<ui64>(ZigZagEncode32(value))); 
    } 

    int WriteVarInt64(IOutputStream* output, i64 value) { 
        return WriteVarUInt64(output, static_cast<ui64>(ZigZagEncode64(value))); 
    } 

    int ReadVarUInt64(IInputStream* input, ui64* value) { 
        size_t count = 0; 
        ui64 result = 0; 

        ui8 byte = 0; 
        do { 
            if (7 * count > 8 * sizeof(ui64)) { 
                ythrow yexception() << "The data is too long to read ui64"; 
            } 
            if (input->Read(&byte, 1) != 1) { 
                ythrow yexception() << "The data is too long to read ui64"; 
            } 
            result |= (static_cast<ui64>(byte & 0x7F)) << (7 * count); 
            ++count; 
        } while (byte & 0x80); 
 
        *value = result; 
        return count; 
    } 
 
    int ReadVarInt32(IInputStream* input, i32* value) { 
        ui64 varInt; 
        int bytesRead = ReadVarUInt64(input, &varInt); 
        if (varInt > Max<ui32>()) { 
            ythrow yexception() << "The data is too long to read ui64";
        }
        *value = ZigZagDecode32(static_cast<ui32>(varInt)); 
        return bytesRead; 
    } 

    int ReadVarInt64(IInputStream* input, i64* value) { 
        ui64 varInt; 
        int bytesRead = ReadVarUInt64(input, &varInt); 
        *value = ZigZagDecode64(varInt); 
        return bytesRead; 
    }

} // namespace NYson