二进制编码与解码容器

    bool readBytes(void *dst, int len) {

        if (_pdata + len > _pfree) {

            return false;

        }

        memcpy(dst, _pdata, len);

        _pdata += len;

        assert(_pfree>=_pdata);

        return true;

    }

  void writeString(const char *str) {

        int len = (str ? static_cast(strlen(str)) : 0);

        if (len>0) len ++;

        expand(static_cast(len+sizeof(uint32_t)));

        writeInt32(len);

        if (len>0) {

            memcpy(_pfree, str, len);

            _pfree += (len);

        }

    }

inline void expand(int need) {

        if (_pstart == NULL) {

            int len = 256;

            while (len 1;

            _pfree = _pdata = _pstart = (unsigned char*)malloc(len);

            _pend = _pstart + len;

        } else if (_pend - _pfree // 空间不够

            int flen = static_cast((_pend - _pfree) + (_pdata - _pstart));

            int dlen = static_cast(_pfree - _pdata);

 

            if (flen 4 < dlen) {

                int bufsize = static_cast((_pend - _pstart) * 2);

                while (bufsize - dlen < need)

                    bufsize <<= 1;

 

                unsigned char *newbuf = (unsigned char *)malloc(bufsize);

                if (newbuf == NULL)

                {

                  TBSYS_LOG(ERROR, "expand data buffer failed, length: %d", bufsize);

                }

                assert(newbuf != NULL);

                if (dlen > 0) {

                    memcpy(newbuf, _pdata, dlen);

                }

                free(_pstart);

 

                _pdata = _pstart = newbuf;

                _pfree = _pstart + dlen;

                _pend = _pstart + bufsize;

            } else {

                memmove(_pstart, _pdata, dlen);

                _pfree = _pstart + dlen;

                _pdata = _pstart;

            }

        }

    }