11.18 srfi.74 - Octet-addressed binary blocks

Module: srfi.74 ¶

This module provides procedures to deal with blob, or a sequence of octets. In Gauche, a blob is simply an u8vector.

Most functionalities of this module is available in binary.io module (see binary.io - Binary I/O), and in fact this module is a thin wrapper to it. We provide this module for the compatibility. If you’re writing Gauche-specific code, we recommend to use binary.io directly.

Macro: endianness e ¶

[SRFI-74]{srfi.74} The argument e must be one of the symbols big, little, or native. It expands to the implementation-specific endianness designator. In Gauche, the result is one of the symbols; see Endianness, for the details.

Function: make-blob size ¶

[SRFI-74]{srfi.74} Returns a freshly created blob that can hold size octets. In Gauche, this is the same as (make-u8vector size).

Function: blob? obj ¶

[SRFI-74]{srfi.74} Returns #t if obj is a blob, #f otherwise. In Gauche, this is the same as (u8vector? obj).

Function: blob-length blob ¶

[SRFI-74]{srfi.74} Returns the size of the blob, in octets. In Gauche, this is the same as (u8vector-length blob).

Function: blob-uint-ref size endian blob pos ¶

Function: blob-sint-ref size endian blob pos ¶

[SRFI-74]{srfi.74} Read an unsigned or signed integer of size octets beginning at the position of pos from blob, respectively.

These are wrappers of (get-uint size blob pos endian) and (get-sint size blob pos endian) in binary.io module (see binary.io - Binary I/O), except that blob-uint-ref/blob-sint-ref only accept u8vector as blob.

Function: blob-uint-set! size endian blob pos val ¶

Function: blob-sint-set! size endian blob pos val ¶

[SRFI-74]{srfi.74} Store an unsigned or signed integer val of size octets into blob starting at the position of pos, respectively.

These are wrappers of (put-uint! size blob pos val endian) and (put-sint! size blob pos val endian) in binary.io module (see binary.io - Binary I/O), except that blob-uint-set!/blob-sint-set! only accept u8vector as blob.

Function: blob-u8-ref blob pos ¶

Function: blob-u8-set! blob pos val ¶

Function: blob-s8-ref blob pos ¶

Function: blob-s8-set! blob pos val ¶

[SRFI-74]{srfi.74} Get/set an unsigned or signed integer as a octet at pos from/to blob.

These are wrappers of get-u8, put-u8!, get-s8 and put-s8! in binary.io, respectively.

Function: blob-u16-ref endian blob pos ¶

Function: blob-u16-set! endian blob pos val ¶

Function: blob-s16-ref endian blob pos ¶

Function: blob-s16-set! endian blob pos val ¶

Function: blob-u32-ref endian blob pos ¶

Function: blob-u32-set! endian blob pos val ¶

Function: blob-s32-ref endian blob pos ¶

Function: blob-s32-set! endian blob pos val ¶

Function: blob-u64-ref endian blob pos ¶

Function: blob-u64-set! endian blob pos val ¶

Function: blob-s64-ref endian blob pos ¶

Function: blob-s64-set! endian blob pos val ¶

[SRFI-74]{srfi.74} Get/set an unsigned or signed integer of the indicated length at pos from/to blob, using the specified endian.

These are wrappers of corresponding get-XX and put-XX! in binary.io; note that the argument orders differ, though.

Function: blob-u16-native-ref blob pos ¶

Function: blob-u16-native-set! blob pos val ¶

Function: blob-s16-native-ref blob pos ¶

Function: blob-s16-native-set! blob pos val ¶

Function: blob-u32-native-ref blob pos ¶

Function: blob-u32-native-set! blob pos val ¶

Function: blob-s32-native-ref blob pos ¶

Function: blob-s32-native-set! blob pos val ¶

Function: blob-u64-native-ref blob pos ¶

Function: blob-u64-native-set! blob pos val ¶

Function: blob-s64-native-ref blob pos ¶

Function: blob-s64-native-set! blob pos val ¶

[SRFI-74]{srfi.74} Get/set an unsigned or signed integer of the indicated length at pos from/to blob, using the native endianness.

These are wrappers of corresponding get-XX and put-XX! in binary.io; note that the argument orders differ, though.

Note: SRFI-74 only requires these procedures to work with alined pos, which is the multiple of the size of the integer in octets. Gauche doesn’t have such restriction, but keep this in mind when you’re writing a portable code.

Function: blob=? blob1 blob2 ¶

[SRFI-74]{srfi.74} This is the same as u8vector=? in gauche.uvector.

Function: blob-copy! src sstart target tstart n ¶

[SRFI-74]{srfi.74} Copy n octets from the source blob src starting from sstart into the target blob target starting from tstart.

Note that the order of arguments differs from other *-copy! procedures (e.g. R7RS’s string-copy! and vector-copy!, and gauche.uvector’s u8vector-copy!)), which have the following signature: (*-copy! target tstart src sstart send)

Function: blob-copy blob ¶

[SRFI-74]{srfi.74} Returns a fresh copy of blob. The same as u8vector-copy in gauche.uvector.

Function: blob->u8-list blob ¶

Function: u8-list->blob list ¶

[SRFI-74]{srfi.74} Wrappers of u8vector->list and list->u8vector, except those don’t take optional start/end arguments.

Function: blob->uint-list size endian blob ¶

Function: blob->sint-list size endian blob ¶

[SRFI-74]{srfi.74} Read a sequence of unsigned or signed integers of size octets from blob with endian, and returns them as a list.

(blob->uint-list 3 (endianness big) '#u8(0 0 1 0 0 2 0 0 3))
  ⇒ (1 2 3)

Function: uint-list->blob size endian list ¶

Function: sint-list->blob size endian list ¶

[SRFI-74]{srfi.74} Convert a list of unsigned or signed integers to a blob. The resulting blob has (* size (length list)) octets. Each integer occupies size octets.

(uint-list->blob 3 (endianness little) '(1 2 3))
  ⇒ #u8(1 0 0 2 0 0 3 0 0)