byte-length generic word for determining alien buffer sizes of byte-arrays and float-arrays

core/alien/alien-docs.factor

@@ -34,6 +34,10 @@ HELP: <alien>
 { $description "Creates an alien object, wrapping a raw memory address." }
 { $notes "Alien objects are invalidated between image saves and loads." } ;
 
+HELP: byte-length
+{ $values { "seq" "A byte array or float array" } { "n" "a non-negative integer" } }
+{ $contract "Outputs the size of the byte array or float array data in bytes as presented to the C library interface." } ;
+
 HELP: c-ptr
 { $class-description "Class of objects consisting of aliens, byte arrays and " { $link f } ". These objects can convert to pointer C types, which are all aliases of " { $snippet "void*" } "." } ;
 

core/alien/alien.factor

@@ -28,6 +28,8 @@ PREDICATE: alien pinned-alien
 UNION: pinned-c-ptr
     pinned-alien POSTPONE: f ;
 
+GENERIC: byte-length ( seq -- n ) flushable
+
 M: f expired? drop t ;
 
 : <alien> ( address -- alien )

core/byte-arrays/byte-arrays.factor

@@ -15,6 +15,9 @@ M: byte-array new drop <byte-array> ;
 M: byte-array equal?
     over byte-array? [ sequence= ] [ 2drop f ] if ;
 
+M: byte-array byte-length
+    length ;
+
 INSTANCE: byte-array sequence
 INSTANCE: byte-array simple-c-ptr
 INSTANCE: byte-array c-ptr

core/float-arrays/float-arrays-docs.factor

@@ -32,7 +32,7 @@ HELP: <float-array> ( n initial -- float-array )
 
 HELP: >float-array
 { $values { "seq" "a sequence" } { "float-array" float-array } }
-{ $description "Outputs a freshly-allocated float array whose elements have the same boolean values as a given sequence." }
+{ $description "Outputs a freshly-allocated float array whose elements have the same floating-point values as a given sequence." }
 { $errors "Throws an error if the sequence contains elements other than real numbers." } ;
 
 HELP: 1float-array

core/float-arrays/float-arrays.factor

@@ -1,6 +1,6 @@
 ! Copyright (C) 2007, 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: kernel kernel.private alien sequences
+USING: kernel kernel.private alien alien.c-types sequences
 sequences.private math math.private ;
 IN: float-arrays
 
@@ -12,6 +12,7 @@ PRIVATE>
 
 M: float-array clone (clone) ;
 M: float-array length array-capacity ;
+M: float-array byte-length array-capacity "float" heap-size * ;
 
 M: float-array nth-unsafe
     float-array@ alien-double ;