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#define XERR "memorybuf"
#include "memorybuf.ih"
// overrides
ios::pos_type MemoryBuf::seekoff(
ios::off_type step, ios::seekdir way, ios::openmode mode)
{
off_type offset;
switch (way)
{
default: // ios::beg: buffOffset is step
offset = step;
break;
case ios::cur:
switch (d_last)
{
// default: case SEEK
default: // no read/write used so far
offset = d_bridge.offset();
break; // add step to bufOffset (below)
case READ: // setg was used, set bufOffset to
// the abs offset of gptr()
offset = d_bridge.blockBegin() + gptr() - eback();
break;
case WRITE: // setp was used, set bufOffset to
// the abs offset of pptr()
offset = d_bridge.blockBegin() + pptr() - pbase();
d_bridge.writtenUntil(offset);
break;
}
offset += step; // add the step
break;
case ios::end: // shift from the last write position
offset = d_bridge.writtenUntil() + step;
break;
}
if (offset < 0)
offset = 0; // offset always >= 0
d_last = SEEK;
noBuffers();
d_bridge.offset(offset);
return offset; // the updated offset
}
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