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https://github.com/ashinn/chibi-scheme.git
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8b5eb68238
They can be close()d explicitly with close-file-descriptor, and will close() on gc, but only explicitly closing the last port on them will close the fileno. Notably needed for network sockets where we open separate input and output ports on the same socket.
70 lines
2 KiB
Scheme
70 lines
2 KiB
Scheme
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;;> \section{Additional accessors}
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(define (bytevector-u16-ref-le str i)
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(+ (bytevector-u8-ref str i)
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(arithmetic-shift (bytevector-u8-ref str (+ i 1)) 8)))
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(define (bytevector-u16-ref-be str i)
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(+ (arithmetic-shift (bytevector-u8-ref str i) 8)
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(bytevector-u8-ref str (+ i 1))))
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(define (bytevector-u32-ref-le str i)
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(+ (bytevector-u8-ref str i)
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(arithmetic-shift (bytevector-u8-ref str (+ i 1)) 8)
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(arithmetic-shift (bytevector-u8-ref str (+ i 2)) 16)
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(arithmetic-shift (bytevector-u8-ref str (+ i 3)) 24)))
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(define (bytevector-u32-ref-be str i)
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(+ (arithmetic-shift (bytevector-u8-ref str i) 24)
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(arithmetic-shift (bytevector-u8-ref str (+ i 1)) 16)
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(arithmetic-shift (bytevector-u8-ref str (+ i 2)) 8)
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(bytevector-u8-ref str (+ i 3))))
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;;> \section{Integer conversion}
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(define (integer->bytevector n)
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(cond
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((zero? n)
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(make-bytevector 1 0))
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((negative? n)
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(error "can't convert a negative integer to bytevector" n))
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(else
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(let lp ((n n) (res '()))
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(if (zero? n)
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(let* ((len (length res))
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(bv (make-bytevector len 0)))
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(do ((i 0 (+ i 1))
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(ls res (cdr ls)))
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((= i len) bv)
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(bytevector-u8-set! bv i (car ls))))
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(lp (quotient n 256) (cons (remainder n 256) res)))))))
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(define (bytevector->integer bv)
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(let ((len (bytevector-length bv)))
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(let lp ((i 0) (n 0))
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(if (>= i len)
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n
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(lp (+ i 1)
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(+ (arithmetic-shift n 8)
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(bytevector-u8-ref bv i)))))))
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;;> \section{Hex string conversion}
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;;> Big-endian conversion, guaranteed padded to even length.
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(define (integer->hex-string n)
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(let* ((res (number->string n 16))
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(len (string-length res)))
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(if (even? len)
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res
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(string-append "0" res))))
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(define (hex-string->integer str)
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(string->number str 16))
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(define (bytevector->hex-string bv)
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(integer->hex-string (bytevector->integer bv)))
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(define (hex-string->bytevector str)
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(integer->bytevector (hex-string->integer str)))
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