Primitive Data Types

The four primitive types of the SANE standard are encoded as follows:

SANE_Byte:

A byte is encoded as an 8 bit value. Since the transport protocol is assumed to be byte-orientd, the bit order is irrelevant.

SANE_Word:

A word is encoded as 4 bytes (32 bits). The bytes are ordered from most-significant to least-significant byte (big-endian byte-order).

SANE_Char:

A character is currently encoded as an 8-bit ISO LATIN-1 value. An extension to support wider character sets (16 or 32 bits) is planned for the future, but not supported at this point.

SANE_String:

A string pointer is encoded as a SANE_Char array. The trailing NUL byte is considered part of the array and a NULL pointer is encoded as a zero-length array.

SANE_Handle:

A handle is encoded like a word. The network backend needs to take care of converting these integer values to the opaque pointer values that are presented to the user of the network backend. Similarly, the SANE daemon needs to take care of converting the opaque pointer values it receives from its backends into 32-bit integers suitable for use for network encoding.

enumeration types:

Enumeration types are encoded like words.