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synced 2025-04-30 03:40:34 +02:00
commit
e4eb0e39b4
3 changed files with 203 additions and 16 deletions
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@ -1792,6 +1792,10 @@ indicating the position of the next byte is to read.
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Finally, if @var{close} is not @code{#f}, it must be a thunk. It is
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invoked when the custom binary input port is closed.
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The returned port is fully buffered by default, but its buffering mode
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can be changed using @code{setvbuf} (@pxref{Ports and File Descriptors,
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@code{setvbuf}}).
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Using a custom binary input port, the @code{open-bytevector-input-port}
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procedure could be implemented as follows:
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@ -37,6 +37,7 @@
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#include "libguile/validate.h"
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#include "libguile/values.h"
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#include "libguile/vectors.h"
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#include "libguile/ports-internal.h"
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@ -272,18 +273,59 @@ cbp_close (SCM port)
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static scm_t_bits custom_binary_input_port_type = 0;
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/* Size of the buffer embedded in custom binary input ports. */
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#define CBIP_BUFFER_SIZE 4096
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/* Initial size of the buffer embedded in custom binary input ports. */
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#define CBIP_BUFFER_SIZE 8192
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/* Return the bytevector associated with PORT. */
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#define SCM_CBIP_BYTEVECTOR(_port) \
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SCM_SIMPLE_VECTOR_REF (SCM_PACK (SCM_STREAM (_port)), 4)
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/* Set BV as the bytevector associated with PORT. */
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#define SCM_SET_CBIP_BYTEVECTOR(_port, _bv) \
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SCM_SIMPLE_VECTOR_SET (SCM_PACK (SCM_STREAM (_port)), 4, (_bv))
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/* Return the various procedures of PORT. */
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#define SCM_CBIP_READ_PROC(_port) \
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SCM_SIMPLE_VECTOR_REF (SCM_PACK (SCM_STREAM (_port)), 0)
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/* Set PORT's internal buffer according to READ_SIZE. */
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static void
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cbip_setvbuf (SCM port, long read_size, long write_size)
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{
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SCM bv;
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scm_t_port *pt;
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pt = SCM_PTAB_ENTRY (port);
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bv = SCM_CBIP_BYTEVECTOR (port);
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switch (read_size)
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{
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case 0:
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/* Unbuffered: keep PORT's bytevector as is (it will be used in
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future 'scm_c_read' calls), but point to the one-byte buffer. */
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pt->read_buf = &pt->shortbuf;
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pt->read_buf_size = 1;
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break;
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case -1:
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/* Preferred size: keep the current bytevector and use it as the
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backing store. */
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pt->read_buf = (unsigned char *) SCM_BYTEVECTOR_CONTENTS (bv);
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pt->read_buf_size = SCM_BYTEVECTOR_LENGTH (bv);
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break;
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default:
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/* Fully buffered: allocate a buffer of READ_SIZE bytes. */
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bv = scm_c_make_bytevector (read_size);
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SCM_SET_CBIP_BYTEVECTOR (port, bv);
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pt->read_buf = (unsigned char *) SCM_BYTEVECTOR_CONTENTS (bv);
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pt->read_buf_size = read_size;
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}
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pt->read_pos = pt->read_end = pt->read_buf;
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}
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static inline SCM
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make_cbip (SCM read_proc, SCM get_position_proc,
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SCM set_position_proc, SCM close_proc)
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@ -330,26 +372,39 @@ cbip_fill_input (SCM port)
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int result;
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scm_t_port *c_port = SCM_PTAB_ENTRY (port);
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again:
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if (c_port->read_pos >= c_port->read_end)
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{
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/* Invoke the user's `read!' procedure. */
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int buffered;
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size_t c_octets, c_requested;
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SCM bv, read_proc, octets;
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c_requested = c_port->read_buf_size;
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/* Use the bytevector associated with PORT as the buffer passed to the
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`read!' procedure, thereby avoiding additional allocations. */
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bv = SCM_CBIP_BYTEVECTOR (port);
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read_proc = SCM_CBIP_READ_PROC (port);
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/* The assumption here is that C_PORT's internal buffer wasn't changed
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behind our back. */
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assert (c_port->read_buf ==
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(unsigned char *) SCM_BYTEVECTOR_CONTENTS (bv));
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assert ((unsigned) c_port->read_buf_size
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== SCM_BYTEVECTOR_LENGTH (bv));
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bv = SCM_CBIP_BYTEVECTOR (port);
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buffered =
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(c_port->read_buf == (unsigned char *) SCM_BYTEVECTOR_CONTENTS (bv));
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if (buffered)
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/* Make sure the buffer isn't corrupt. BV can be passed directly
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to READ_PROC. */
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assert (c_port->read_buf_size == SCM_BYTEVECTOR_LENGTH (bv));
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else
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{
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/* This is an unbuffered port. When called via the
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'get-bytevector-*' procedures, and thus via 'scm_c_read', we
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are passed the caller-provided buffer, so we need to check its
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size. */
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if (SCM_BYTEVECTOR_LENGTH (bv) < c_requested)
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{
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/* Bad luck: we have to make another allocation. Save that
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bytevector for later reuse, in the hope that the application
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has regular access patterns. */
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bv = scm_c_make_bytevector (c_requested);
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SCM_SET_CBIP_BYTEVECTOR (port, bv);
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}
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}
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octets = scm_call_3 (read_proc, bv, SCM_INUM0,
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scm_from_size_t (c_requested));
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@ -357,11 +412,15 @@ cbip_fill_input (SCM port)
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if (SCM_UNLIKELY (c_octets > c_requested))
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scm_out_of_range (FUNC_NAME, octets);
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c_port->read_pos = (unsigned char *) SCM_BYTEVECTOR_CONTENTS (bv);
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if (!buffered)
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/* Copy the data back to the internal buffer. */
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memcpy ((char *) c_port->read_pos, SCM_BYTEVECTOR_CONTENTS (bv),
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c_octets);
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c_port->read_end = (unsigned char *) c_port->read_pos + c_octets;
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if (c_octets > 0)
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goto again;
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if (c_octets != 0 || c_requested == 0)
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result = (int) *c_port->read_pos;
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else
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result = EOF;
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}
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@ -410,6 +469,7 @@ initialize_custom_binary_input_ports (void)
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scm_set_port_seek (custom_binary_input_port_type, cbp_seek);
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scm_set_port_close (custom_binary_input_port_type, cbp_close);
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scm_set_port_setvbuf (custom_binary_input_port_type, cbip_setvbuf);
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}
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@ -456,6 +456,129 @@ not `set-port-position!'"
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(u8-list->bytevector
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(map char->integer (string->list "Port!")))))))
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(pass-if-equal "custom binary input port unbuffered & 'port-position'"
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'(0 2 5 11)
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;; Check that the value returned by 'port-position' is correct, and
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;; that each 'port-position' call leads one call to the
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;; 'get-position' method.
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(let* ((str "Hello Port!")
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(output (make-bytevector (string-length str)))
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(source (with-fluids ((%default-port-encoding "UTF-8"))
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(open-string-input-port str)))
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(read! (lambda (bv start count)
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(let ((r (get-bytevector-n! source bv start count)))
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(if (eof-object? r)
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0
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r))))
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(pos '())
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(get-pos (lambda ()
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(let ((p (port-position source)))
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(set! pos (cons p pos))
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p)))
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(port (make-custom-binary-input-port "the port" read!
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get-pos #f #f)))
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(setvbuf port _IONBF)
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(and (= 0 (port-position port))
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(begin
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(get-bytevector-n! port output 0 2)
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(= 2 (port-position port)))
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(begin
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(get-bytevector-n! port output 2 3)
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(= 5 (port-position port)))
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(let ((bv (string->utf8 (get-string-all port))))
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(bytevector-copy! bv 0 output 5 (bytevector-length bv))
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(= (string-length str) (port-position port)))
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(bytevector=? output (string->utf8 str))
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(reverse pos))))
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(pass-if-equal "custom binary input port unbuffered & 'read!' calls"
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`((2 "He") (3 "llo") (42 " Port!"))
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(let* ((str "Hello Port!")
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(source (with-fluids ((%default-port-encoding "UTF-8"))
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(open-string-input-port str)))
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(reads '())
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(read! (lambda (bv start count)
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(set! reads (cons count reads))
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(let ((r (get-bytevector-n! source bv start count)))
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(if (eof-object? r)
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0
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r))))
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(port (make-custom-binary-input-port "the port" read!
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#f #f #f)))
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(setvbuf port _IONBF)
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(let ((ret (list (get-bytevector-n port 2)
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(get-bytevector-n port 3)
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(get-bytevector-n port 42))))
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(zip (reverse reads)
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(map (lambda (obj)
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(if (bytevector? obj)
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(utf8->string obj)
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obj))
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ret)))))
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(pass-if-equal "custom binary input port, unbuffered then buffered"
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`((6 "Lorem ") (12 "ipsum dolor ") (777 "sit amet, consectetur…")
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(777 ,(eof-object)))
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(let* ((str "Lorem ipsum dolor sit amet, consectetur…")
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(source (with-fluids ((%default-port-encoding "UTF-8"))
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(open-string-input-port str)))
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(reads '())
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(read! (lambda (bv start count)
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(set! reads (cons count reads))
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(let ((r (get-bytevector-n! source bv start count)))
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(if (eof-object? r)
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0
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r))))
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(port (make-custom-binary-input-port "the port" read!
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#f #f #f)))
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(setvbuf port _IONBF)
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(let ((ret (list (get-bytevector-n port 6)
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(get-bytevector-n port 12)
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(begin
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(setvbuf port _IOFBF 777)
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(get-bytevector-n port 42))
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(get-bytevector-n port 42))))
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(zip (reverse reads)
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(map (lambda (obj)
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(if (bytevector? obj)
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(utf8->string obj)
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obj))
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ret)))))
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(pass-if-equal "custom binary input port, buffered then unbuffered"
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`((18
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42 14 ; scm_c_read tries to fill the 42-byte buffer
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42)
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("Lorem " "ipsum dolor " "sit amet, consectetur bla…" ,(eof-object)))
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(let* ((str "Lorem ipsum dolor sit amet, consectetur bla…")
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(source (with-fluids ((%default-port-encoding "UTF-8"))
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(open-string-input-port str)))
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(reads '())
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(read! (lambda (bv start count)
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(set! reads (cons count reads))
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(let ((r (get-bytevector-n! source bv start count)))
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(if (eof-object? r)
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0
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r))))
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(port (make-custom-binary-input-port "the port" read!
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#f #f #f)))
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(setvbuf port _IOFBF 18)
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(let ((ret (list (get-bytevector-n port 6)
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(get-bytevector-n port 12)
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(begin
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(setvbuf port _IONBF)
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(get-bytevector-n port 42))
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(get-bytevector-n port 42))))
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(list (reverse reads)
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(map (lambda (obj)
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(if (bytevector? obj)
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(utf8->string obj)
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obj))
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ret)))))
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(pass-if "custom binary input port `close-proc' is called"
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(let* ((closed? #f)
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(read! (lambda (bv start count) 0))
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