6.44.3.3 Extended binary input functions

Function: get-u8 port

Return the EOF object, the would–block object or a fixnum:

• If a byte is available: return the byte as an octet and update port to point just past that byte.
• If no input byte is seen before an end of file is reached: the EOF object is returned.
• If the underlying device is in non–blocking mode and no bytes are available: return the would–block object.

Function: lookahead-u8 port

Like GET-U8, but it does not update PORT to point past the byte.

Function: get-bytevector-n port count

Return the EOF object, the would–block object or a bytevector:

• If count bytes are available before an end of file: return a bytevector of size count. The input port is updated to point just past the bytes read.
• If fewer than count bytes are available before an end of file: return a bytevector containing those bytes. The input port is updated to point just past the bytes read.
• If an end of file is reached before any bytes are available: return the EOF object.
• If the underlying device is in non–blocking mode and fewer than count bytes are available: return a bytevector containing those bytes. The input port is updated to point just past the bytes read.
• If the underlying device is in non–blocking mode and no bytes are available: return the would–block object.

Function: get-bytevector-n! port dst.bv dst.start count

Return the EOF object, the would–block object or the number of bytes written in the given bytevector:

• If count bytes are available before the end of file: they are written into dst.bv starting at index dst.start, and the result is count. The input port is updated to point just past the bytes read.
• If fewer than count bytes are available before the end of file: the available bytes are written into dst.bv starting at index dst.start, and the result is a number object representing the number of bytes actually read. The input port is updated to point just past the bytes read.
• If the end of file is reached before any bytes are available: return the EOF object.
• If the underlying device is in non–blocking mode and fewer than count bytes are available: the available bytes are written into dst.bv starting at index dst.start, and the result is a number object representing the number of bytes actually read. The input port is updated to point just past the bytes read.
• If the underlying device is in non–blocking mode and no bytes are available: return the would–block object.

Function: get-bytevector-some port

Return the EOF object, the would–block object or a bytevector:

• If bytes are available: return a freshly allocated bytevector containing the initial available bytes (at least one), and update port to point just past these bytes.
• If no input bytes are seen before an end of file is reached: the EOF object is returned.
• If the underlying device is in non–blocking mode and no bytes are available: return the would–block object.