Tool to copy, remove, insert tape records, files, marks.

Usage: cut36 [-W<input word format>] [-O<output word format>] [-7] [-9]
             [input] [commands...]

Read from an input file (or stdin), and write to stdout.  Commands can
be put on the command line, or typed to stdin.

Commands take a numeric argument which defaults to 1.

sw - skip word in input.
sr - skip record in input.
sf - skip file in input.
sa - skip all input.

cw - copy word from input to output.
cr - copy record from input to output.
cf - copy file from input to output.
ca - copy all input to output.

r - insert record boundary.
m - insert tape mark.

.gitignore

@@ -1,6 +1,7 @@
 *~
 *.o
 cat36
+cut36
 ipak
 itsarc
 dis10

Makefile

@@ -12,7 +12,7 @@ WORDS =  aa-word.o bin-word.o cadr-word.o core-word.o data8-word.o \
 OBJS =	pdp10-opc.o info.o dis.o symbols.o \
 	timing.o timing_ka10.o timing_ki10.o memory.o weenix.o
 
-UTILS =	cat36 itsarc magdmp magfrm dskdmp dump \
+UTILS =	cat36 cut36 itsarc magdmp magfrm dskdmp dump \
 	macdmp macro-tapes tape-dir harscntopbm palx cross \
 	ipak kldcp klfedr scrmbl unscr tvpic tito dart od10 \
 	constantinople
@@ -40,6 +40,9 @@ libwords.a: word.o $(WORDS)
 cat36: cat36.o libwords.a
 	$(CC) $(CFLAGS) $^ -o $@
 
+cut36: cut36.o libwords.a
+	$(CC) $(CFLAGS) $^ -o $@
+
 dump: dump.c $(OBJS) libfiles.a libwords.a
 	$(CC) $(CFLAGS) $^ -o $@
 

README.md

@@ -14,6 +14,7 @@
 - Scramble or unscramble an encrypted file.
 - Make a picture file suitable for displaying on a Knight TV.
 - Write out a core image in some of the supported executable formats.
+- Copy, remove, insert tape records, files, marks.
 - Analyze a CONSTANTS area.
 
 A Linux FUSE implementation of the networking filesystem protocol MLDEV

cut36.c

@@ -0,0 +1,324 @@
+/* Copyright (C) 2022 Lars Brinkhoff <lars@nocrew.org>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "dis.h"
+
+static word_t data;
+static int words = 0;
+static int records = 0;
+static int files = 0;
+static int marks = 0;
+
+static void
+count (word_t word)
+{
+  if (word & (START_TAPE | START_FILE | START_RECORD))
+    fprintf (stderr, "Files: %d, Records: %d, Words: %d\n",
+             files, records, words);
+  words++;
+  if (word & (START_FILE | START_RECORD))
+    records++;
+  if (word & START_FILE)
+    files++;
+}
+
+static void
+output (word_t word)
+{
+#if 0
+  if (word & START_TAPE)
+    fprintf (stderr, "Start of tape\n");
+  else if (word & START_FILE)
+    fprintf (stderr, "Start of file\n");
+  else if (word & START_RECORD)
+    fprintf (stderr, "Start of record\n");
+  fprintf (stderr, "Output: %012llo\n", word);
+#endif
+  write_word (stdout, word);
+  marks = 0;
+}
+
+static void end (void)
+{
+  if (data != -1)
+    {
+      count (data);
+      output (data);
+    }
+  count (START_TAPE);
+  flush_word (stdout);
+  exit (0);
+}
+
+static void skip_word (FILE *f, unsigned n)
+{
+  unsigned i;
+
+  for (i = 0; i < n; i++)
+    {
+      count (data);
+      data = get_word (f);
+      if (data == -1)
+        end ();
+    }
+}
+
+static void skip_record (FILE *f, unsigned n)
+{
+  unsigned i;
+
+  for (i = 0; i < n; )
+    {
+      count (data);
+      data = get_word (f);
+      if (data == -1)
+        end ();
+      if (data & (START_RECORD | START_FILE))
+        i++;
+    }
+}
+
+static void skip_file (FILE *f, unsigned n)
+{
+  unsigned i;
+
+  for (i = 0; i < n; )
+    {
+      count (data);
+      data = get_word (f);
+      if (data == -1)
+        end ();
+      if (data & START_FILE)
+        i++;
+    }
+}
+
+static void
+skip_all (FILE *f, unsigned n)
+{
+  (void)n;
+  for (;;)
+    {
+      count (data);
+      data = get_word (f);
+      if (data == -1)
+        end ();
+    }
+}
+
+static void copy_word (FILE *f, unsigned n)
+{
+  unsigned i;
+
+  for (i = 0; i < n; i++)
+    {
+      count (data);
+      output (data);
+      data = get_word (f);
+      if (data == -1)
+        end ();
+    }
+}
+
+static void copy_record (FILE *f, unsigned n)
+{
+  unsigned i;
+
+  for (i = 0; i < n; )
+    {
+      count (data);
+      output (data);
+      data = get_word (f);
+      if (data == -1)
+        end ();
+      if (data & (START_RECORD | START_FILE))
+        i++;
+    }
+}
+
+static void copy_file (FILE *f, unsigned n)
+{
+  unsigned i;
+
+  for (i = 0; i < n; )
+    {
+      count (data);
+      output (data);
+      data = get_word (f);
+      if (data == -1)
+        end ();
+      if (data & START_FILE)
+        i++;
+    }
+}
+
+static void
+copy_all (FILE *f, unsigned n)
+{
+  (void)n;
+  for (;;)
+    {
+      count (data);
+      output (data);
+      data = get_word (f);
+      if (data == -1)
+        end ();
+    }
+}
+
+static void
+record (FILE *f, unsigned n)
+{
+  (void)f;
+  (void)n;
+  data |= START_RECORD;
+}
+
+static void
+mark (FILE *f, unsigned n)
+{
+  (void)f;
+  (void)n;
+  marks++;
+  if (marks == 1)
+    data |= START_FILE;
+  else if (marks >= 0)
+    data |= START_TAPE;
+}
+
+struct dispatch
+{
+  const char *command;
+  void (*action) (FILE *f, unsigned n);
+};
+
+static struct dispatch table[] =
+  {
+    { "sw", skip_word },
+    { "sr", skip_record },
+    { "sf", skip_file },
+    { "sa", skip_all },
+    { "cw", copy_word },
+    { "cr", copy_record },
+    { "cf", copy_file },
+    { "ca", copy_all },
+    { "r", record },
+    { "m", mark }
+  };
+
+static void
+execute (FILE *f, char *command)
+{
+  char *end;
+  size_t i;
+
+  for (i = 0; i < sizeof table / sizeof table[0]; i++)
+    {
+      int n = strlen (table[i].command);
+      if (strncmp (command, table[i].command, n) == 0) {
+        unsigned arg = strtol (command + n, &end, 10);
+        if (end == command + n)
+          arg = 1;
+        table[i].action (f, arg);
+      }
+    }
+}
+
+static void
+convert_line (FILE *f, char **command)
+{
+  while (*command)
+    execute (f, *command++);
+  end ();
+}
+
+static void
+convert_stdin (FILE *f)
+{
+  while (!feof (stdin))
+    {
+      char command[100];
+      fgets (command, sizeof command, stdin);
+      execute (f, command);
+    }
+  end ();
+}
+
+static void
+usage (char **argv)
+{
+  fprintf (stderr, "Usage: %s [-79] [-W<input word format>] [-O<output word format>] [<input files...>]\n\n", argv[0]);
+  usage_word_format ();
+  exit (1);
+}
+
+int
+main (int argc, char **argv)
+{
+  FILE *f;
+  int opt;
+
+  output_word_format = &tape_word_format;
+
+  while ((opt = getopt (argc, argv, "79W:O:")) != -1)
+    {
+      switch (opt)
+        {
+        case '7':
+          input_word_format = output_word_format = &tape7_word_format;
+          break;
+        case '9':
+          input_word_format = output_word_format = &tape_word_format;
+          break;
+        case 'W':
+          if (parse_input_word_format (optarg))
+            usage (argv);
+          break;
+        case 'O':
+          if (parse_output_word_format (optarg))
+            usage (argv);
+          break;
+        default:
+          usage (argv);
+        }
+    }
+
+  if (optind == argc)
+    f = stdin;
+  else
+    {
+      f = fopen (argv[optind++], "rb");
+      if (f == NULL)
+        {
+          fprintf (stderr, "%s: Error opening %s: %s\n",
+                   argv[0], argv[optind - 1], strerror (errno));
+          exit (1);
+        }
+    }
+
+  data = get_word (f);
+  data |= START_TAPE | START_FILE | START_RECORD;
+  if (optind == argc)
+    convert_stdin (f);
+  else
+    convert_line (f, &argv[optind]);
+  return 0;
+}