vbyte.hpp

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#pragma once

#include <tudocomp/util.hpp>

namespace tdc {

template<class int_t>
inline int_t read_vbyte(std::istream& is) {
    constexpr size_t data_width = sizeof(std::istream::char_type)*8 - 1; // each byte of a vbyte-array stores 7bits of data, 1bit for marking that this byte is not the end byte
    int_t ret = 0;
    uint8_t which_byte = 0;
    while(is.good()) {
        uint8_t byte = is.get();
        ret |= (byte & ((1UL<<data_width)-1))<<(data_width * which_byte++);
        if( !(byte & (1UL<<data_width))) return ret;
    }
    DCHECK(false) << "VByte ended without reading a byte with the most significant bit equals zero.";
    return 0;
}

template<class int_t>
inline void write_vbyte(std::ostream& os, int_t v) {
    constexpr size_t data_width = sizeof(std::ostream::char_type)*8 - 1; // each byte of a vbyte-array stores 7bits of data, 1bit for marking that this byte is not the end byte
    do {
        uint8_t byte = v & ((1UL<<data_width)-1);
        v >>= data_width;
        if(v > 0) byte |= (1UL<<data_width);
        os << byte;
    } while(v > 0);
}


}//ns