Fix handling of CRLF line endings in read-mps

Author: neil-lindquist

Diff for: .gitattributes

@@ -0,0 +1,4 @@
+
+# ensure line endings are preserved for the mps test files
+t/data/simple-problem.mps text eol=lf
+t/data/simple-problem-crlf.mps text eol=crlf

Diff for: src/external-formats.lisp

@@ -167,9 +167,9 @@ boundaries are supported."
                    (:raw
                      raw)))))
 
-      (iter (for line = (read-line stream))
+      (iter (for line = (string-right-trim '(#\Space #\Return) (read-line stream)))
         (if-let (header-card (unless (char= #\space (aref line 0))
-                               (string-downcase (string-right-trim " " (substring line 0 15)))))
+                               (string-downcase (substring line 0 15))))
           (cond
             ;; do nothing on comments
             ((char= (aref header-card 0) #\*))

Diff for: t/data/simple-problem-crlf.mps

@@ -0,0 +1,14 @@
+*This is a simple MPS problem to test the MPS reader
+NAME          simple
+ROWS
+ N  obj
+ L  row1
+ L  row2
+COLUMNS
+    X         obj       1               row1      3
+    Y         obj       4               row1      1
+    Y         row2      1
+    Z         obj       8               row2      2
+RHS
+    rhs1      row1      8               row2      7
+ENDATA

Diff for: t/external-formats.lisp

@@ -224,8 +224,26 @@
       (is (set-equal '((z . (0 . 4)) (|w| . (0 . 1)) (x . (nil . nil)))
                      (problem-var-bounds problem)))
       (is (simple-linear-constraint-set-equal '((<= ((x . 3) (y . 1)) 8) (<= ((y . 1) (z . 2)) 10) (<= ((|w| . -1) (x . -2) (z . 1)) 1))
-                     (problem-constraints problem))))))
+                     (problem-constraints problem))
 
+       (with-open-file (stream (merge-pathnames "t/data/simple-problem-crlf.mps"
+                                                (asdf:system-source-directory :linear-programming-test))
+                               :direction :input
+                               :external-format :utf-8)
+         (let ((problem (read-mps stream 'max)))
+           (is (typep problem 'problem))
+           (is (eq 'max (problem-type problem)))
+           (is-true (null (symbol-package (problem-objective-var problem))))
+           (is (set-equal '(x y z)
+                          (map 'list #'identity (problem-vars problem))))
+           (is (set-equal '((x . 1) (y . 4) (z . 8))
+                          (problem-objective-func problem)))
+           (is (set-equal '()
+                          (problem-integer-vars problem)))
+           (is (set-equal '()
+                          (problem-var-bounds problem)))
+           (is (simple-linear-constraint-set-equal '((<= ((x . 3) (y . 1)) 8) (<= ((y . 1) (z . 2)) 7))
+                                               (problem-constraints problem)))))))))
 
 (test write-standard-format
   (let* ((problem (make-linear-problem (max (+ x y)) (<= (+ (* 2 x) y) 5)))