Manual page for bytevector-copy!(3scm)

bytevector-copy! - copy bytes between bytevectors

LIBRARY

(import (rnrs))                     ;R6RS
(import (rnrs bytevectors))         ;R6RS
(import (scheme base))              ;R7RS

SYNOPSIS

(bytevector-copy! source source-start target target-start k)  ;R6RS
(bytevector-copy! to at from start end)                       ;R7RS

DESCRIPTION

R6RS: Copies the bytes from source at indices source-start, …, source-start + k − 1 to consecutive indices in target starting at target-index.
R7RS: Copies the bytes of bytevector from between start and end to bytevector to, starting at at.

RETURN VALUES

Returns unspecified values.

EXAMPLES

;; R6RS
(let ((b (u8-list->bytevector '(1 2 3 4 5 6 7 8))))
  (bytevector-copy! b 0 b 3 4)
  (bytevector->u8-list b))
   => (1 2 3 1 2 3 4 8)

;; R7RS
(define a (bytevector 1 2 3 4 5))
(define b (bytevector 10 20 30 40 50))
(bytevector-copy! b 1 a 0 2)
   => #u8(10 1 2 40 50)

APPLICATION USAGE

This procedure is common in (de)serialization and processing of binary data. In some situations it becomes cumbersome to maintain the indices and bytevector ports are more suitable.

COMPATIBILITY

R6RS and R7RS specify very different arguments for these procedures. Note in particular that it's not just a different argument order, the last argument is also different.

ERRORS

This procedure can raise exceptions with the following condition types:

&assertion (R6RS): The wrong number of arguments was passed, an argument was outside its domain or the byte ranges were not valid with regard to the bytevector lengths.
R7RS: The assertions described above are errors. Implementations may signal an error, extend the procedure's domain of definition to include such arguments, or fail catastrophically.

STANDARDS

R6RS, R7RS

HISTORY

The arguments used by R7RS are consistent with SRFI-43 whereas R6RS is consistent with SRFI-66.

AUTHORS

This page is part of the scheme-manpages project. It includes materials from the RnRS documents. More information can be found at https://github.com/schemedoc/manpages/.

BUGS

Implementations need to be careful to handle the case where the source and target bytevector ranges overlap in memory.

Markup created by unroff 1.0sc, March 04, 2023.