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;;; Compatibility shim for Guile, because its implementation of utf16->string
;;; and utf32->string doesn't conform to R6RS.
(define-module (bytestructures guile bytevectors))
(import
(rnrs base)
(rnrs control)
(bytestructures r6 bytevectors))
(re-export
endianness native-endianness bytevector?
make-bytevector bytevector-length bytevector=? bytevector-fill!
bytevector-copy!
bytevector-copy
bytevector-u8-ref bytevector-s8-ref
bytevector-u8-set! bytevector-s8-set! bytevector->u8-list
u8-list->bytevector
bytevector-uint-ref bytevector-uint-set!
bytevector-sint-ref bytevector-sint-set!
bytevector->sint-list bytevector->uint-list
uint-list->bytevector sint-list->bytevector
bytevector-u16-ref bytevector-s16-ref
bytevector-u16-set! bytevector-s16-set!
bytevector-u16-native-ref bytevector-s16-native-ref
bytevector-u16-native-set! bytevector-s16-native-set!
bytevector-u32-ref bytevector-s32-ref
bytevector-u32-set! bytevector-s32-set!
bytevector-u32-native-ref bytevector-s32-native-ref
bytevector-u32-native-set! bytevector-s32-native-set!
bytevector-u64-ref bytevector-s64-ref
bytevector-u64-set! bytevector-s64-set!
bytevector-u64-native-ref bytevector-s64-native-ref
bytevector-u64-native-set! bytevector-s64-native-set!
bytevector-ieee-single-ref
bytevector-ieee-single-set!
bytevector-ieee-single-native-ref
bytevector-ieee-single-native-set!
bytevector-ieee-double-ref
bytevector-ieee-double-set!
bytevector-ieee-double-native-ref
bytevector-ieee-double-native-set!
string->utf8
utf8->string
string->utf16 string->utf32)
(export
(r6rs-utf16->string . utf16->string)
(r6rs-utf32->string . utf32->string))
(define (read-bom16 bv)
(let ((c0 (bytevector-u8-ref bv 0))
(c1 (bytevector-u8-ref bv 1)))
(cond
((and (= c0 #xFE) (= c1 #xFF))
'big)
((and (= c0 #xFF) (= c1 #xFE))
'little)
(else
#f))))
(define r6rs-utf16->string
(case-lambda
((bv default-endianness)
(let ((bom-endianness (read-bom16 bv)))
(if (not bom-endianness)
(utf16->string bv default-endianness)
(substring/shared (utf16->string bv bom-endianness) 1))))
((bv endianness endianness-mandatory?)
(if endianness-mandatory?
(utf16->string bv endianness)
(r6rs-utf16->string bv endianness)))))
(define (read-bom32 bv)
(let ((c0 (bytevector-u8-ref bv 0))
(c1 (bytevector-u8-ref bv 1))
(c2 (bytevector-u8-ref bv 2))
(c3 (bytevector-u8-ref bv 3)))
(cond
((and (= c0 #x00) (= c1 #x00) (= c2 #xFE) (= c3 #xFF))
'big)
((and (= c0 #xFF) (= c1 #xFE) (= c2 #x00) (= c3 #x00))
'little)
(else
#f))))
(define r6rs-utf32->string
(case-lambda
((bv default-endianness)
(let ((bom-endianness (read-bom32 bv)))
(if (not bom-endianness)
(utf32->string bv default-endianness)
(substring/shared (utf32->string bv bom-endianness) 1))))
((bv endianness endianness-mandatory?)
(if endianness-mandatory?
(utf32->string bv endianness)
(r6rs-utf32->string bv endianness)))))
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