unalf: Add -n and -s options.

8 files changed, 121 insertions, 25 deletions

diff --git a/CHANGES.txt b/CHANGES.txt
index d88259b..c376a11 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,5 +1,6 @@
 0.4.0:
 - alf and unalf now detect duplicate Atari filenames.
+- unalf can extract by file number (-n) rather than wildcards.
 
 0.3.2:
 - unalf: truncation is a fatal error again (avoids segfaults).
diff --git a/TODO.txt b/TODO.txt
index cd010ec..5b0b9d9 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,4 +1,4 @@
-- unalf: -s option (split alf file), -n (extract by number)
+- error checking for unalf -n (dup option, bad #, wildcards)
 
 - maybe: alf foo.alf unix.filename=ATARI.NAM  ...unalf could use this too.
 
diff --git a/src/extract.c b/src/extract.c
index 98523db..6f24c0d 100644
--- a/src/extract.c
+++ b/src/extract.c
@@ -76,27 +76,81 @@ void set_datetime() {
 	}
 }
 
-void make_backup(void) {
+void make_backup(const char *fname) {
 	/* up to 12-char FILENAME.EXT, plus a ~, plus null terminator = 14 */
-	char backup[14];
+	/* has to handle up to 16 chars for -s option: LONGFILE.NAME.ALF */
+	char backup[20];
 
-	strncpy(backup, out_filename, 13);
-	strncat(backup, "~", 13);
+	strncpy(backup, fname, 19);
+	strncat(backup, "~", 19);
 
 	/* silently ignore errors! */
-	rename(out_filename, backup);
+	rename(fname, backup);
+}
+
+void open_out_file(const char *fname) {
+	if(opts.testonly) {
+		fname = "/dev/null";
+	} else if(!opts.overwrite) {
+		make_backup(fname);
+	}
+
+	if(!(out_file = fopen(fname, "wb"))) {
+		fprintf(stderr, "%s: fatal:  ", self);
+		perror(fname);
+		exit(1);
+	}
+}
+
+void truncated_err(void);
+
+void write_split_file(void) {
+	int i, c;
+	unsigned int len;
+	char splitname[20];
+
+	strncpy(splitname, out_filename, 13);
+	strncat(splitname, ".ALF", 6);
+
+	if(!opts.quiet)
+		printf("Writing %s\n", splitname);
+
+	len = getquad(alf_hdr_compsize0);
+
+	open_out_file(splitname);
+	fwrite(&mem[alf_header], 1, 29, out_file);
+	for(i = 0; i < len; i++) {
+		c = fgetc(in_file);
+		if(c == EOF) {
+			truncated_err();
+		}
+		fputc(c, out_file);
+	}
+	fclose(out_file);
 }
 
 void extract_alf(void) {
+	int files_extracted = 0, skip, file_number = 0;
+
 	/* get ready to call fake 6502 stuff. set up memory like the Atari. */
 	dpoke(MEMTOP, 0xbc1f);
 
 	while(read_alf_header()) {
+		file_number++;
+		skip = 0;
+
 		out_filename = (char *)(mem + alf_hdr_filename);
 
 		fix_filename();
 
-		if(!file_wanted(out_filename)) {
+		if(opts.extract_num)
+			skip = (opts.extract_num != file_number);
+		else
+			skip = !file_wanted(out_filename);
+
+		if(skip) {
+			if(!opts.quiet)
+				printf("Skipping %s\n", out_filename);
 			if(fseek(in_file, getquad(alf_hdr_compsize0), SEEK_CUR) != 0) {
 				fprintf(stderr, "%s: fatal: seek failed on input!\n", self);
 				exit(1);
@@ -105,6 +159,13 @@ void extract_alf(void) {
 			continue;
 		}
 
+		files_extracted++;
+
+		if(opts.split) {
+			write_split_file();
+			continue;
+		}
+
 		if(!opts.quiet) {
 			printf("%s %s\n", opts.testonly ? "Testing" : "Uncrunching", out_filename);
 		}
@@ -112,21 +173,7 @@ void extract_alf(void) {
 		if(opts.extract_to_stdout) {
 			out_file = stdout;
 		} else {
-			char *realname = out_filename;
-
-			if(opts.testonly) {
-				out_filename = "/dev/null";
-			} else if(!opts.overwrite) {
-				make_backup();
-			}
-
-			if(!(out_file = fopen(out_filename, "wb"))) {
-				fprintf(stderr, "%s: fatal:  ", self);
-				perror(out_filename);
-				exit(1);
-			}
-
-			out_filename = realname;
+			open_out_file(out_filename);
 		}
 
 		bad_checksum = bytes_written = 0;
@@ -153,6 +200,10 @@ void extract_alf(void) {
 		else
 			printf("All files OK.\n");
 	}
+
+	if(!opts.quiet && !files_extracted) {
+		printf("No files %s!\n", opts.testonly ? "tested" : "extracted");
+	}
 }
 
 void chksum_err(void) {
diff --git a/src/opts.c b/src/opts.c
index 977a10d..06ad9dc 100644
--- a/src/opts.c
+++ b/src/opts.c
@@ -1,6 +1,6 @@
 #include "unalf.h"
 
-#define OPTIONS "aefFklLopqtTvVd:x:"
+#define OPTIONS "aefFklLon:pqstTvVd:x:"
 
 /* uncomment to test exclude/include glob lists */
 // #define DEBUG_GLOBS
@@ -25,6 +25,10 @@ static void show_globs(void) {
 }
 #endif
 
+int parsenum(const char opt, const char *arg) {
+	return atoi(arg); /* TODO: use strtol(), die on error */
+}
+
 void parse_opts(int argc, char * const *argv) {
 	int opt;
 	char **ig;
@@ -41,9 +45,11 @@ void parse_opts(int argc, char * const *argv) {
 			case 'F': opts.force++; break;
 			case 'l': opts.listonly++; opts.testonly = 0; break;
 			case 'L': opts.lowercase++; break;
+			case 'n': opts.extract_num = parsenum('n', optarg); break;
 			case 'o': opts.overwrite++; break;
 			case 'p': opts.extract_to_stdout++; opts.quiet++; break;
 			case 'q': opts.quiet++; break;
+			case 's': opts.split++; opts.testonly = 0; opts.listonly = 0; break;
 			case 't': opts.testonly++; opts.listonly = 0; break;
 			case 'T': opts.ignore_datetime = 1; break;
 			case 'v': opts.listonly = 1; opts.testonly = 0; opts.verbose_list++; break;
diff --git a/src/unalf.1 b/src/unalf.1
index 743cc27..9af4d47 100644
--- a/src/unalf.1
+++ b/src/unalf.1
@@ -36,7 +36,7 @@ unalf \- extract Atari 8-bit ALF archives
 .
 .SH SYNOPSIS
 .sp
-unalf [\fB\-\-help\fP] [\fB\-aehtklLopqtv\fP] [\fB\-d\fP \fIdir\fP] [\fB\-x\fP \fIwildcard\fP] \fIalf\-file\fP [\fIwildcard\fP ...]
+unalf [\fB\-\-help\fP] [\fB\-aehtklLopqstv\fP] [\fB\-d\fP \fIdir\fP] [\fB\-n\fP \fInumber\fP] [\fB\-x\fP \fIwildcard\fP] \fIalf\-file\fP [\fIwildcard\fP ...]
 .SH DESCRIPTION
 .sp
 \fBunalf\fP lists, extracts, or tests the contents of an \fIALF\fP archive.
@@ -154,6 +154,15 @@ Lowercase filenames. Example: \fBFOO.TXT\fP will extract to \fBfoo.txt\fP\&.
 .
 .INDENT 0.0
 .TP
+.BI \-n \ number
+Only extract the \fInumber\fPth file. \fIwildcards\fP are ignored when using
+this option. Numbering begins at 1 for the first file in the archive;
+\fB\-n0\fP is an error.
+.UNINDENT
+.\" extract only file #<number> (counting from 1).
+.
+.INDENT 0.0
+.TP
 .B  \-o
 Overwrite files, if they already exist. The default is to rename
 existing files, adding a \fB~\fP suffix. Note that renaming \fBfile\fP
@@ -188,6 +197,16 @@ doesn\(aqt do anything when used with \fB\-l\fP or \fB\-v\fP\&.
 .
 .INDENT 0.0
 .TP
+.B  \-s
+Split \fIALF\fP file into multiple \fIALF\fP files, one per archive member.
+The new \fIALF\fP files are named after the filenames in the input
+\fIALF\fP file, with ".ALF" appended. There is no corresponding option
+to join them back together, but you can use \fBcat\fP(1) for that.
+.UNINDENT
+.\" split ALF file into multiple ALFs.
+.
+.INDENT 0.0
+.TP
 .B  \-t
 Test archive. Same as extraction, except the files are not written
 anywhere.
diff --git a/src/unalf.h b/src/unalf.h
index 4adaeb3..f03ae04 100644
--- a/src/unalf.h
+++ b/src/unalf.h
@@ -81,6 +81,8 @@ typedef struct {
 	int fixjunk;
 	int ignore_datetime;
 	int force;
+	int extract_num;
+	int split;
 } opts_t;
 
 #define MAX_EXCLUDES 256
diff --git a/src/unalf.rst b/src/unalf.rst
index ed89d2d..9d8e14a 100644
--- a/src/unalf.rst
+++ b/src/unalf.rst
@@ -21,7 +21,7 @@ extract Atari 8-bit ALF archives
 SYNOPSIS
 ========
 
-unalf [**--help**] [**-aehtklLopqtv**] [**-d** *dir*] [**-x** *wildcard*] *alf-file* [*wildcard* ...]
+unalf [**--help**] [**-aehtklLopqstv**] [**-d** *dir*] [**-n** *number*] [**-x** *wildcard*] *alf-file* [*wildcard* ...]
 
 DESCRIPTION
 ===========
@@ -122,6 +122,13 @@ OPTIONS
 
 .. use lowercase filenames.
 
+-n number
+  Only extract the *number*\th file. *wildcards* are ignored when using
+  this option. Numbering begins at 1 for the first file in the archive;
+  **-n0** is an error.
+
+.. extract only file #<number> (counting from 1).
+
 -o
   Overwrite files, if they already exist. The default is to rename
   existing files, adding a **~** suffix. Note that renaming **file**
@@ -150,6 +157,14 @@ OPTIONS
 
 .. quiet: don't print filenames during extraction/testing.
 
+-s
+  Split *ALF* file into multiple *ALF* files, one per archive member.
+  The new *ALF* files are named after the filenames in the input
+  *ALF* file, with ".ALF" appended. There is no corresponding option
+  to join them back together, but you can use **cat**\(1) for that.
+
+.. split ALF file into multiple ALFs.
+
 -t
   Test archive. Same as extraction, except the files are not written
   anywhere.
diff --git a/src/usage.c b/src/usage.c
index 0f43fca..f03a373 100644
--- a/src/usage.c
+++ b/src/usage.c
@@ -9,9 +9,11 @@ const char *usage_msg[] = {
 	"  -k: keep trailing periods (dots) in filenames.",
 	"  -l: list files in archive (filenames only).",
 	"  -L: use lowercase filenames.",
+	"  -n: extract only file #<number> (counting from 1).",
 	"  -o: overwrite files (do not create file~ backups).",
 	"  -p: extract to stdout (enables -q).",
 	"  -q: quiet: don't print filenames during extraction/testing.",
+	"  -s: split ALF file into multiple ALFs.",
 	"  -t: test archive.",
 	"  -v: verbose listing of archive contents.",
 	"  -V: show version number.",