From 116795dc0d21bbec9856b235b2dfc4f531a15150 Mon Sep 17 00:00:00 2001 From: Chris Hanson Date: Fri, 10 Jul 1992 21:56:55 +0000 Subject: [PATCH] Eliminate unused variable. Reorganize somewhat. --- v7/src/6001/pic-read.scm | 166 ++++++++++++++++++++++----------------- 1 file changed, 95 insertions(+), 71 deletions(-) diff --git a/v7/src/6001/pic-read.scm b/v7/src/6001/pic-read.scm index ec5f5288a..64c25e334 100644 --- a/v7/src/6001/pic-read.scm +++ b/v7/src/6001/pic-read.scm @@ -1,53 +1,88 @@ -;; Procedures to read a file in raw pgm format into a picture +#| -*-Scheme-*- -(declare (usual-integrations)) +$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/6001/pic-read.scm,v 1.3 1992/07/10 21:56:55 cph Exp $ + +Copyright (c) 1991-92 Massachusetts Institute of Technology + +This material was developed by the Scheme project at the Massachusetts +Institute of Technology, Department of Electrical Engineering and +Computer Science. Permission to copy this software, to redistribute +it, and to use it for any purpose is granted, subject to the following +restrictions and understandings. + +1. Any copy made of this software must include this copyright notice +in full. + +2. Users of this software agree to make their best efforts (a) to +return to the MIT Scheme project any improvements or extensions that +they make, so that these may be included in future releases; and (b) +to inform MIT of noteworthy uses of this software. + +3. All materials developed as a consequence of the use of this +software shall duly acknowledge such use, in accordance with the usual +standards of acknowledging credit in academic research. + +4. MIT has made no warrantee or representation that the operation of +this software will be error-free, and MIT is under no obligation to +provide any services, by way of maintenance, update, or otherwise. + +5. In conjunction with products arising from the use of this material, +there shall be no use of the name of the Massachusetts Institute of +Technology nor of any adaptation thereof in any advertising, +promotional, or sales literature without prior written consent from +MIT in each case. |# + +;;;; Procedures to read a file in raw pgm format into a picture +(declare (usual-integrations)) + (define (pgm-file->picture filename) - (let* ((path-name (->pathname filename)) - (file-name (if (pathname-type path-name) - path-name - (if (file-exists? path-name) - path-name - (pathname-new-type path-name "pgm"))))) - - (call-with-input-file file-name (lambda (port) - (get-body port (get-header port)))))) + (call-with-input-file (standard-pathname filename "pgm") + (lambda (port) + (get-body port (get-header port))))) -(define (get-line port result) ; read a line of data - (let ((c (read-char port))) - (cond ((eof-object? c) (reverse result)) - ((eq? c #\Linefeed) - (let ((res (reverse result))) - (if (eq? (car res) #\#) ; ignore comments - (get-line port '()) - res))) - (else (get-line port (cons c result)))))) +(define (standard-pathname filename type) + (let ((pathname (->pathname filename))) + (if (or (pathname-type pathname) + (file-exists? pathname)) + pathname + (pathname-new-type pathname type)))) (define (get-header port) - (let* ((type (list->string (get-line port '()))) - (dims (list->string (get-line port '()))) - (no-of-greys (string->number - (list->string (get-line port '())))) - (spc-index (string-find-next-char dims #\space)) - (length (string->number - (string-head dims spc-index))) - (width (string->number - (string-tail dims (1+ spc-index))))) + (let* ((type (get-line port)) + (dims (get-line port)) + (no-of-greys (string->number (get-line port))) + (spc-index (string-find-next-char dims #\space))) (if (not (equal? type "P5")) ; P5 is the magic number for raw PGM format - (error "Unrecognized format. (Convert to raw PGM) -- PICTURE-READ") - (vector type length width no-of-greys)))) + (error "Unrecognized format (Convert to raw PGM).")) + (vector type + (string->number (string-head dims spc-index)) + (string->number (string-tail dims (+ spc-index 1))) + no-of-greys))) + +(define get-line + (let ((delimiters (char-set #\newline))) + (lambda (port) + (let loop () + (let ((line (read-string delimiters port))) + (if (eof-object? line) + (error "EOF encountered when parsing line.")) + ;; ignore comments + (if (and (not (string-null? line)) + (char=? #\# (string-ref line 0))) + (loop) + line)))))) (define (get-body port attributes) (let* ((length (vector-ref attributes 1)) (width (vector-ref attributes 2)) - (max-grey (vector-ref attributes 3)) (pic (make-picture length width)) - (data (make-initialized-vector - width - (lambda (index) - index ; ignored - (make-floating-vector length 0.))))) ;initialize to blank - + (data + (make-initialized-vector + width + (lambda (index) + index ; ignored + (make-floating-vector length 0.))))) ;initialize to blank (side-effecting-iter width (lambda (n) @@ -55,42 +90,31 @@ (side-effecting-iter length (lambda (m) - (floating-vector-set! nth-row m - (exact->inexact (char->ascii (read-char port))))))))) + (floating-vector-set! + nth-row + m + (exact->inexact (char->ascii (read-char port))))))))) (picture-set-data! pic data) -;; (%picture-set-min! pic 0.) ; set min, max of picture according to -;; (%picture-set-max! pic (exact->inexact max-grey)) ; information in file pic)) - -;;; Procedure to read in a picture that was previously saved using + +;;; Procedure to read in a picture that was previously saved using ;;; picture-write. (define (picture-read filename) - (let* ((path-name (->pathname filename)) - (pic-mimic (fasload (if (pathname-type path-name) - path-name - (if (file-exists? path-name) - path-name - (pathname-new-type path-name "pic")))))) + (let ((pic-mimic (fasload (standard-pathname filename "pic")))) (if (not (record? pic-mimic)) - (error "Object loaded is not a picture -- PICTURE-READ")) - - (define mimic-type (record-type-descriptor pic-mimic)) - - (if (not (equal? (record-type-field-names mimic-type) - (record-type-field-names picture-type))) - (error "Object loaded is not a picture -- PICTURE-READ")) - - (define mimic-width (record-accessor mimic-type 'width)) - (define mimic-height (record-accessor mimic-type 'height)) - (define mimic-data (record-accessor mimic-type 'data)) - (define mimic-min (record-accessor mimic-type 'min)) - (define mimic-max (record-accessor mimic-type 'max)) - - (define new-pic (make-picture (mimic-width pic-mimic) - (mimic-height pic-mimic))) - (picture-set-data! new-pic (mimic-data pic-mimic)) - (%picture-set-min! new-pic (mimic-min pic-mimic)) - (%picture-set-max! new-pic (mimic-max pic-mimic)) - new-pic)) - + (error "Object loaded is not a record:" pic-mimic)) + (let ((mimic-type (record-type-descriptor pic-mimic))) + (if (not (equal? (record-type-field-names mimic-type) + (record-type-field-names picture-type))) + (error "Object loaded is not a picture:" pic-mimic)) + (let ((new-pic + (make-picture ((record-accessor mimic-type 'width) pic-mimic) + ((record-accessor mimic-type 'height) pic-mimic)))) + (picture-set-data! new-pic + ((record-accessor mimic-type 'data) pic-mimic)) + (%picture-set-min! new-pic + ((record-accessor mimic-type 'min) pic-mimic)) + (%picture-set-max! new-pic + ((record-accessor mimic-type 'max) pic-mimic)) + new-pic)))) \ No newline at end of file -- 2.25.1