From ac7d28f7efee5ebd9576ddd577a53240c4ad6765 Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Fri, 29 Sep 2023 15:37:00 -0500
Subject: [PATCH] Fold tests and corresponding fixes.

---
 tests/fold.test     | 24 +++++++++++++++---------
 toys/pending/fold.c | 13 ++++++++-----
 2 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/tests/fold.test b/tests/fold.test
index ab3353dd..e30597e5 100644
--- a/tests/fold.test
+++ b/tests/fold.test
@@ -4,12 +4,18 @@
 
 #testing "name" "command" "result" "infile" "stdin"
 
-#copied from gnu, but according to what i understand the output should be.
-
-testing "fold_test_1" "fold -w2 -s" "a\t\n" "" "a\t"
-testing "fold_test_2" "fold -w4 -s" "abcd\nef \nd\n" "" "abcdef d\n"
-testing "fold_test_3" "fold -w4 -s" "a \ncd \nfgh\n" "" "a cd fgh\n"
-testing "fold_test_4" "fold -w4 -s" "abc \nef\n" "" "abc ef\n"
-
-#the question i posted
-testing "fold_test_5" "fold -w1" "a\nb\nc\nd\n" "" "abcd"
+testcmd 'default wrap' '-w10' 'one two th\nree\nfour five\n' \
+  '' 'one two three\nfour five\n'
+testing "abuse" "fold -w1" "a\nb\nc\nd" "" "abcd"
+testcmd 'first char goes over' '-w2' '\t\n' '' '\t\n'
+testcmd 'tab goes over' '-sw2' 'a\n\t\n' '' 'a\t\n'
+testcmd 'tab goes over unterminated' '-sw2' 'a\n\t' '' 'a\t'
+testcmd '-s' '-sw4' 'abcd\nef g\n' '' 'abcdef g\n'
+testcmd '-s 2' '-sw4' 'abcd\nef \ngh\n' '' 'abcdef gh\n'
+testcmd '-s 3' '-sw4' 'a \ncd \nfgh\n' '' 'a cd fgh\n'
+testcmd '-s 4' '-sw4' 'abcd\n efg\n' '' 'abcd efg\n'
+testcmd '-s 5' '-sw4' 'abc \nef\n' '' 'abc ef\n'
+testcmd '-b tab' '-bw8' 'abc\tdefg\nhi' '' 'abc\tdefghi'
+testcmd '-bs' '-bsw8' 'abc\t\ndefghi' '' 'abc\tdefghi'
+testcmd 'backspace' '-w3' 'abc\bd\nef\n' '' 'abc\bdef\n'
+testcmd '-b backspace' '-bw3' 'abc\n\bde\nf\n' '' 'abc\bdef\n'
diff --git a/toys/pending/fold.c b/toys/pending/fold.c
index 035dca1b..7f118921 100644
--- a/toys/pending/fold.c
+++ b/toys/pending/fold.c
@@ -45,10 +45,12 @@ void do_fold(int fd, char *name)
 
     // Parse next character's byte length and column width
     bb = ww = 1;
-    if (ss[ii]<32) ww = 0;
+    if (ss[ii]<32) ww = FLAG(b);
     if (FLAG(b)) cc = ss[ii];
-    else if ((bb = utf8towc(&cc, ss+ii, 4))>0 && (ww = wcwidth(cc))<0) ww = 0;
-    if (cc=='\t') ww = 8-(width&7);
+    else {
+      if ((bb = utf8towc(&cc, ss+ii, 4))>0 && (ww = wcwidth(cc))<0) ww = 0;
+      if (cc=='\t') ww = 8-(width&7);
+    }
 
     // Did line end?
     if (!cc || cc=='\r' || cc=='\n') {
@@ -64,13 +66,14 @@ void do_fold(int fd, char *name)
       }
 
     // backspace?
-    } else if (cc=='\b') {
+    } else if (!FLAG(b) && cc=='\b') {
       // Find last set bit, and clear it. This handles wide chars and tabs.
       while (width) {
         --width;
         if (TT.bs[width/8]&(1<<(width&7))) break;
       }
       TT.bs[width/8] &= ~(1<<(width&7));
+      ii++;
 
     // Is it time to wrap?
 
@@ -92,7 +95,7 @@ void do_fold(int fd, char *name)
       TT.bs[width/8] |= (1<<(width&7));
       ii += bb;
       width += ww;
-      if (iswspace(cc)) space = ii;
+      if (FLAG(s) && iswspace(cc)) space = ii;
     }
   }
   if (fp != stdin) fclose(fp);
-- 
2.39.2