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#include "varint.h" 
 
#include <util/generic/yexception.h> 
#include <util/stream/input.h> 
#include <util/stream/output.h> 
 
namespace NMonitoring { 
    ui32 WriteVarUInt32(IOutputStream* output, ui32 value) { 
        bool stop = false; 
        ui32 written = 0; 
        while (!stop) { 
            ui8 byte = static_cast<ui8>(value | 0x80); 
            value >>= 7; 
            if (value == 0) { 
                stop = true; 
                byte &= 0x7F; 
            } 
            output->Write(byte); 
            written++; 
        } 
        return written; 
    } 
 
    ui32 ReadVarUInt32(IInputStream* input) { 
        ui32 value = 0;
        switch (TryReadVarUInt32(input, &value)) {
            case EReadResult::OK:
                return value;
            case EReadResult::ERR_OVERFLOW:
                ythrow yexception() << "the data is too long to read ui32"; 
            case EReadResult::ERR_UNEXPECTED_EOF:
                ythrow yexception() << "the data unexpectedly ended"; 
            default:
                ythrow yexception() << "unknown error while reading varint";
        }
    } 
 
    size_t ReadVarUInt32(const ui8* buf, size_t len, ui32* result) { 
        size_t count = 0; 
        ui32 value = 0; 
 
        ui8 byte = 0; 
        do { 
            if (7 * count > 8 * sizeof(ui32)) { 
                ythrow yexception() << "the data is too long to read ui32"; 
            } 
            if (count == len) { 
                ythrow yexception() << "the data unexpectedly ended"; 
            } 
            byte = buf[count]; 
            value |= (static_cast<ui32>(byte & 0x7F)) << (7 * count); 
            ++count; 
        } while (byte & 0x80); 
 
        *result = value; 
        return count; 
    } 
 
EReadResult TryReadVarUInt32(IInputStream* input, ui32* value) {
        size_t count = 0; 
        ui32 result = 0; 
 
        ui8 byte = 0; 
        do { 
            if (7 * count > 8 * sizeof(ui32)) { 
                return EReadResult::ERR_OVERFLOW;
            } 
            if (input->Read(&byte, 1) != 1) { 
                return EReadResult::ERR_UNEXPECTED_EOF;
            } 
            result |= (static_cast<ui32>(byte & 0x7F)) << (7 * count); 
            ++count; 
        } while (byte & 0x80); 
 
        *value = result; 
        return EReadResult::OK;
    } 
 
}