// TypeByBuffer looks up for a blob's mimetype by its contents.
// It uses a magic number database which is described in magic(5).
func (m *Magic) TypeByBuffer(blob []byte) (string, error) {
bytes := unsafe.Pointer(&blob[0])
out := C.magic_buffer(m.db, bytes, C.size_t(len(blob)))
if out == nil {
return "", errors.New(C.GoString(C.magic_error(m.db)))
}
return C.GoString(out), nil
}
func (detector *Detector) detectMime(cinput *C.char, cinputLen C.size_t) (string, error) {
// magic_buffer set EINVAL, even if it succeed(binary?),
// so ignore second value.
mimeStr, _ := C.magic_buffer(detector.magic, unsafe.Pointer(cinput), cinputLen)
if mimeStr == nil {
err := magicError(detector.magic)
if err == nil {
panic("unreachable")
}
return "", err
}
return C.GoString(mimeStr), nil
}
// Buffer returns a textual description of the contents of the buffer argument.
func (m *Magic) Buffer(data []byte) (string, error) {
if m.ptr == nil {
return "", ConnectionError
}
ptr := unsafe.Pointer(&data)
sz := C.size_t(len(data))
cr := C.magic_buffer(m.ptr, ptr, sz)
if cr == nil {
return "", m.check()
}
r := C.GoString(cr)
C.free(unsafe.Pointer(cr))
return r, nil
}