// Calling Close does not close the wrapped io.Writer originally
// passed to NewWriterX.
func (z *Writer) Close() error {
if z.err != nil {
return z.err
}
z.write(nil, Z_FINISH)
if z.err != nil {
return z.err
}
C.deflateEnd(&z.strm)
z.err = io.EOF
return nil
}
// this is the main function: it advances the write with either
// new data or something else to do, like a flush
func (z *Writer) write(p []byte, flush int) int {
if len(p) == 0 {
z.strm.next_in = (*C.Bytef)(unsafe.Pointer(nil))
z.strm.avail_in = 0
} else {
z.strm.next_in = (*C.Bytef)(unsafe.Pointer(&p[0]))
z.strm.avail_in = (C.uInt)(len(p))
}
// we loop until we don't get a full output buffer
// each loop completely writes the output buffer to the underlying
// writer
for {
// deflate one buffer
z.strm.next_out = (*C.Bytef)(unsafe.Pointer(&z.out[0]))
z.strm.avail_out = (C.uInt)(len(z.out))
ret := C.deflate(&z.strm, (C.int)(flush))
if ret == Z_STREAM_ERROR {
// all the other error cases are normal,
// and this should never happen
panic(fmt.Errorf("cgzip: Unexpected error (1)"))
}
// write everything
from := 0
have := len(z.out) - int(z.strm.avail_out)
for have > 0 {
var n int
n, z.err = z.w.Write(z.out[from:have])
if z.err != nil {
C.deflateEnd(&z.strm)
return 0
}
from += n
have -= n
}
// we stop trying if we get a partial response
if z.strm.avail_out != 0 {
break
}
}
// the library guarantees this
if z.strm.avail_in != 0 {
panic(fmt.Errorf("cgzip: Unexpected error (2)"))
}
return len(p)
}