alf: swap -A and -a, add -aa (to match unalf).

4 files changed, 44 insertions, 18 deletions

diff --git a/src/alf.1 b/src/alf.1
index 9445969..608aeaf 100644
--- a/src/alf.1
+++ b/src/alf.1
@@ -27,7 +27,7 @@ level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
 .in \\n[rst2man-indent\\n[rst2man-indent-level]]u
 ..
-.TH "ALF" 1 "2025-12-16" "0.4.1" "Urchlay's Atari 8-bit Tools"
+.TH "ALF" 1 "2025-12-25" "0.4.1" "Urchlay's Atari 8-bit Tools"
 .SH NAME
 alf \- create Atari 8-bit ALF archives
 .\" RST source for alf(1) man page. Convert with:
@@ -67,7 +67,7 @@ Options can be combined (e.g. \fB\-ov\fP means \fB\-o\fP \fB\-v\fP), though the
 an error; \fB\-vtd\fP is OK).
 .INDENT 0.0
 .TP
-.B  \-a
+.B  \-A
 Append to \fIalf\-file\fP\&. The files are added to the end of the archive. Be
 careful not to add a file with the same name as as existing member of
 the archive. If \fIalf\-file\fP doesn\(aqt exist, it will be created. No backup
@@ -77,11 +77,18 @@ is made with \fB\-a\fP\&.
 .
 .INDENT 0.0
 .TP
-.B  \-A
-Convert line endings and tabs from ASCII to ATASCII in all input
-files. This will corrupt any executables or non\-text data files,
-so use with caution. There is no way to autodetect text files,
-unlike \fBunalf\fP\&.
+.B  \-a
+Convert text file line endings and tabs from ASCII to ATASCII. Text
+files are detected by looking at the first 2 bytes of the file. If both
+are printable ASCII, the file is considered text.
+.UNINDENT
+.\" convert EOLs and tabs in text files.
+.
+.INDENT 0.0
+.TP
+.BI \-a\fB a
+Convert line endings and tabs in \fIall\fP input files. This will
+corrupt any executables or non\-text data files, so use with caution.
 .UNINDENT
 .\" convert EOLs and tabs in all input files.
 .
diff --git a/src/alf.c b/src/alf.c
index e8090f9..1558107 100644
--- a/src/alf.c
+++ b/src/alf.c
@@ -177,9 +177,22 @@ void make_backup(void) {
 	}
 }
 
+int is_printable(u8 c) {
+	return (c == '\n' || c == '\t' || (c >= 0x20 && c <= 0x7c));
+}
+
+int is_text_file(void) {
+	if(input_len < 2) return 0;
+	return (is_printable(input_buf[0]) && is_printable(input_buf[1]));
+}
+
 void convert_eols(void) {
 	int i;
 
+	if(opt_verbose) {
+		fprintf(stderr, "%s: converting EOLs/tabs in %s\n", self, in_filename);
+	}
+
 	for(i = 0; i < input_len; i++) {
 		if(input_buf[i] == '\n')
 			input_buf[i] = 0x9b;
@@ -214,7 +227,7 @@ void crunch_file(const char *filename_arg) {
 			fprintf(stderr, "%s: %s: this file is too large; only compressing the first 16MB.\n", self, in_filename);
 	}
 
-	if(opt_txtconv)
+	if(opt_txtconv > 1 || (opt_txtconv && is_text_file()))
 		convert_eols();
 
 	output_len = 0;
@@ -324,8 +337,8 @@ int main(int argc, char **argv) {
 
 	while((opt = getopt(argc, argv, "aAt:oqvV")) != -1) {
 		switch(opt) {
-			case 'A': opt_txtconv = 1; break;
-			case 'a': opt_append = 1; opt_overwrite = 1; break;
+			case 'a': opt_txtconv++; break;
+			case 'A': opt_append = 1; opt_overwrite = 1; break;
 			case 'o': opt_overwrite = 1; opt_append = 0; break;
 			case 'q': opt_quiet = 1; break;
 			case 't': opt_zerotime = opt_alftime = opt_gmtime = 0;
diff --git a/src/alf.rst b/src/alf.rst
index 0c72aa2..aa5978c 100644
--- a/src/alf.rst
+++ b/src/alf.rst
@@ -55,7 +55,7 @@ Options can be combined (e.g. **-ov** means **-o** **-v**), though the
 **-td**, **-tu**, **-tz** options must appear last (**-tdv** would be
 an error; **-vtd** is OK).
 
--a
+-A
   Append to *alf-file*. The files are added to the end of the archive. Be
   careful not to add a file with the same name as as existing member of
   the archive. If *alf-file* doesn't exist, it will be created. No backup
@@ -63,11 +63,16 @@ an error; **-vtd** is OK).
 
 .. append to ALF file.
 
--A
-  Convert line endings and tabs from ASCII to ATASCII in all input
-  files. This will corrupt any executables or non-text data files,
-  so use with caution. There is no way to autodetect text files,
-  unlike **unalf**.
+-a
+  Convert text file line endings and tabs from ASCII to ATASCII. Text
+  files are detected by looking at the first 2 bytes of the file. If both
+  are printable ASCII, the file is considered text.
+
+.. convert EOLs and tabs in text files.
+
+-aa
+  Convert line endings and tabs in *all* input files. This will
+  corrupt any executables or non-text data files, so use with caution.
 
 .. convert EOLs and tabs in all input files.
 
diff --git a/src/alfusage.c b/src/alfusage.c
index a3eb8f5..4040b32 100644
--- a/src/alfusage.c
+++ b/src/alfusage.c
@@ -1,6 +1,7 @@
 const char *usage_msg[] = {
-	"  -a: append to ALF file.",
-	"  -A: convert EOLs and tabs in all input files.",
+	"  -A: append to ALF file.",
+	"  -a: convert EOLs and tabs in text files.",
+	"  -aa: convert EOLs and tabs in all input files.",
 	"  -h: show this help message.",
 	"  -o: overwrite ALF file if it exists (don't create file~ backup).",
 	"  -q: quiet.",