From: Andreas Rottmann Date: Sun, 21 Nov 2010 22:17:54 +0000 (+0100) Subject: Add implementation of "transcoded ports" X-Git-Url: http://git.hcoop.net/bpt/guile.git/commitdiff_plain/1044537dff91146ed17f13cfa8d1eca5f92f4307 Add implementation of "transcoded ports" * libguile/r6rs-ports.c (make_tp, tp_write, tp_fill_input, tp_flush) (tp_close, initialize_transcoded_ports, scm_i_make_transcoded_port): New functions. (scm_init_r6rs_ports): Call `initialize_transcoded_ports'. * module/rnrs/ports.scm (transcoded-port): Actually implement, using `%make-transcoded-port'. * test-suite/tests/r6rs-ports.test ("8.2.6 Input and output ports"): Added a few tests for `transcoded-port'. Signed-off-by: Ludovic Courtès --- diff --git a/libguile/r6rs-ports.c b/libguile/r6rs-ports.c index ea6200f02..232509ce2 100644 --- a/libguile/r6rs-ports.c +++ b/libguile/r6rs-ports.c @@ -1076,6 +1076,148 @@ initialize_custom_binary_output_ports (void) } +/* Transcoded ports ("tp" for short). */ +static scm_t_bits transcoded_port_type = 0; + +#define TP_INPUT_BUFFER_SIZE 4096 + +#define SCM_TP_BINARY_PORT(_port) SCM_PACK (SCM_STREAM (_port)) + +static inline SCM +make_tp (SCM binary_port, unsigned long mode) +{ + SCM port; + scm_t_port *c_port; + const unsigned long mode_bits = SCM_OPN | mode; + + scm_i_pthread_mutex_lock (&scm_i_port_table_mutex); + + port = scm_new_port_table_entry (transcoded_port_type); + + SCM_SETSTREAM (port, SCM_UNPACK (binary_port)); + + SCM_SET_CELL_TYPE (port, transcoded_port_type | mode_bits); + + if (SCM_INPUT_PORT_P (port)) + { + c_port = SCM_PTAB_ENTRY (port); + c_port->read_buf = scm_gc_malloc_pointerless (TP_INPUT_BUFFER_SIZE, + "port buffer"); + c_port->read_pos = c_port->read_end = c_port->read_buf; + c_port->read_buf_size = TP_INPUT_BUFFER_SIZE; + + SCM_SET_CELL_WORD_0 (port, SCM_CELL_WORD_0 (port) & ~SCM_BUF0); + } + + scm_i_pthread_mutex_unlock (&scm_i_port_table_mutex); + + return port; +} + +static void +tp_write (SCM port, const void *data, size_t size) +{ + scm_c_write (SCM_TP_BINARY_PORT (port), data, size); +} + +static int +tp_fill_input (SCM port) +{ + size_t count; + scm_t_port *c_port = SCM_PTAB_ENTRY (port); + SCM bport = SCM_TP_BINARY_PORT (port); + scm_t_port *c_bport = SCM_PTAB_ENTRY (bport); + + /* We can't use `scm_c_read' here, since it blocks until the whole + block has been read or EOF. */ + + if (c_bport->rw_active == SCM_PORT_WRITE) + scm_force_output (bport); + + if (c_bport->read_pos >= c_bport->read_end) + scm_fill_input (bport); + + count = c_bport->read_end - c_bport->read_pos; + if (count > c_port->read_buf_size) + count = c_port->read_buf_size; + + memcpy (c_port->read_buf, c_bport->read_pos, count); + c_bport->read_pos += count; + + if (c_bport->rw_random) + c_bport->rw_active = SCM_PORT_READ; + + if (count == 0) + return EOF; + else + { + c_port->read_pos = c_port->read_buf; + c_port->read_end = c_port->read_buf + count; + return *c_port->read_buf; + } +} + +static void +tp_flush (SCM port) +{ + SCM binary_port = SCM_TP_BINARY_PORT (port); + scm_t_port *c_port = SCM_PTAB_ENTRY (port); + size_t count = c_port->write_pos - c_port->write_buf; + + scm_c_write (binary_port, c_port->write_buf, count); + + c_port->write_pos = c_port->write_buf; + c_port->rw_active = SCM_PORT_NEITHER; + + scm_force_output (binary_port); +} + +static int +tp_close (SCM port) +{ + if (SCM_OUTPUT_PORT_P (port)) + tp_flush (port); + return scm_is_true (scm_close_port (SCM_TP_BINARY_PORT (port))) ? 0 : -1; +} + +static inline void +initialize_transcoded_ports (void) +{ + transcoded_port_type = + scm_make_port_type ("r6rs-transcoded-port", tp_fill_input, tp_write); + + scm_set_port_flush (transcoded_port_type, tp_flush); + scm_set_port_close (transcoded_port_type, tp_close); +} + +SCM_DEFINE (scm_i_make_transcoded_port, + "%make-transcoded-port", 1, 0, 0, + (SCM port), + "Return a new port which reads and writes to @var{port}") +#define FUNC_NAME s_scm_i_make_transcoded_port +{ + SCM result; + unsigned long mode = 0; + + SCM_VALIDATE_PORT (SCM_ARG1, port); + + if (scm_is_true (scm_output_port_p (port))) + mode |= SCM_WRTNG; + else if (scm_is_true (scm_input_port_p (port))) + mode |= SCM_RDNG; + + result = make_tp (port, mode); + + /* FIXME: We should actually close `port' "in a special way" here, + according to R6RS. As there is no way to do that in Guile without + rendering the underlying port unusable for our purposes as well, we + just leave it open. */ + + return result; +} +#undef FUNC_NAME + + /* Initialization. */ void @@ -1096,4 +1238,5 @@ scm_init_r6rs_ports (void) initialize_custom_binary_input_ports (); initialize_bytevector_output_ports (); initialize_custom_binary_output_ports (); + initialize_transcoded_ports (); } diff --git a/module/rnrs/io/ports.scm b/module/rnrs/io/ports.scm index 31c1e2935..73271add8 100644 --- a/module/rnrs/io/ports.scm +++ b/module/rnrs/io/ports.scm @@ -191,8 +191,13 @@ ;; So far, we don't support transcoders other than the binary transcoder. #t) -(define (transcoded-port port) - (error "port transcoders are not supported" port)) +(define (transcoded-port port transcoder) + "Return a new textual port based on @var{port}, using +@var{transcoder} to encode and decode data written to or +read from its underlying binary port @var{port}." + (let ((result (%make-transcoded-port port))) + (set-port-encoding! result (transcoder-codec transcoder)) + result)) (define (port-position port) "Return the offset (an integer) indicating where the next octet will be diff --git a/test-suite/tests/r6rs-ports.test b/test-suite/tests/r6rs-ports.test index 56ecbb63a..7d746cab9 100644 --- a/test-suite/tests/r6rs-ports.test +++ b/test-suite/tests/r6rs-ports.test @@ -497,6 +497,29 @@ (not eof?) (bytevector=? sink source))))) +(with-test-prefix "8.2.6 Input and output ports" + (pass-if "transcoded-port [output]" + (let ((s "Hello\nÄÖÜ")) + (bytevector=? + (string->utf8 s) + (call-with-bytevector-output-port + (lambda (bv-port) + (call-with-port (transcoded-port bv-port (make-transcoder (utf-8-codec))) + (lambda (utf8-port) + (put-string utf8-port s)))))))) + (pass-if "transcoded-port [input]" + (let ((s "Hello\nÄÖÜ")) + (string=? + s + (get-string-all + (transcoded-port (open-bytevector-input-port (string->utf8 s)) + (make-transcoder (utf-8-codec))))))) + (pass-if "transcoded-port [input line]" + (string=? "ÄÖÜ" + (get-line (transcoded-port + (open-bytevector-input-port (string->utf8 "ÄÖÜ\nFooBar")) + (make-transcoder (utf-8-codec))))))) + ;;; Local Variables: ;;; mode: scheme ;;; End: