From 7a45bca630b205c7dd14a3467d5b162ff353684c Mon Sep 17 00:00:00 2001
From: ken rector <kdrhoo@yahoo.com>
Date: Tue, 20 Dec 2022 19:11:05 -0800
Subject: [PATCH] added mt2tap.c

---
 mt2tap.c | 158 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 158 insertions(+)
 create mode 100644 mt2tap.c

diff --git a/mt2tap.c b/mt2tap.c
new file mode 100644
index 0000000..d6a4e78
--- /dev/null
+++ b/mt2tap.c
@@ -0,0 +1,158 @@
+/*  mt2tap - convert siggy format .mt file to simh .tap  */
+ 
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#define FLPSIZ 65536*2
+int main (int argc, char *argv[])
+{
+    int k, fc, wc, rc;
+    
+    int pwc;
+    
+    char pad = 0;
+    
+    int bin,bout,errorflag = 0;
+    unsigned char bc[4] = { 0 };
+    unsigned char tapemark[4] = {0};
+    unsigned char buf[FLPSIZ];
+    char *progname = argv[0];
+    char *ppos, oname[256];
+    FILE *ifile, *ofile;
+    
+    if (argc < 2) {
+        fprintf (stderr, "Usage:  %s file \n", progname);
+        fprintf (stderr, "This will create a simh tap file named file.tap from a Keith Calkins CPV PO image file\n");
+        exit (0);
+    }
+    
+    
+    strcpy (oname, argv[1]);
+    if ((ppos = strrchr (oname, '.')))
+        strcpy (ppos, ".tap");
+    else
+        strcat (oname, ".tap");
+    ifile = fopen (argv[1], "rb");
+    if (ifile == NULL) {
+        printf ("Error opening file: %s\n", argv[1]);
+        exit (0);
+        
+    }
+    ofile = fopen (oname, "wb");
+    if (ofile == NULL) {
+        printf ("Error opening file: %s\n", oname);
+        exit (0);
+        
+    }
+    
+    printf ("Processing file %s\n", argv[1]);
+    fc = 1; rc = 0;
+    
+    bin = bout = 0;
+    
+    // skip tape mark on input po tape
+    k = fread (bc, sizeof (bc), 1, ifile);
+    if (k != 1) {
+        printf("error reading bot mark\n");
+        exit (1);
+    }
+    bin += sizeof(bc);
+    
+    for (;;) {
+        // leading record size, or tape mark
+        k = fread (bc, sizeof (bc), 1, ifile);
+        bin += sizeof(bc);
+        
+        if (k != 1) {
+            printf("error reading next size\n");
+            exit (1);
+        }
+        wc = (bc[3]<<24) + (bc[2]<<16) + (bc[1]<<8) + bc[0];
+        
+        if (wc <= 0) {
+            // just read trailing file size
+            // read next file size
+            k = fread (bc, sizeof (bc), 1, ifile);
+            bin += sizeof(bc);
+            if (k != 1) {
+                printf("error or EOT reading file size at tape mark \n");
+                // write tape mark on output
+                fwrite(tapemark,sizeof (char),4,ofile);
+                exit (1);
+            }
+            wc = (bc[3]<<24) + (bc[2]<<16) + (bc[1]<<8) + bc[0];
+            printf("file size %x %x\n",bin,wc);
+            
+            // write tape mark on output
+            fwrite(tapemark,sizeof (char),4,ofile);
+            // read current record size
+            k = fread (bc, sizeof (bc), 1, ifile);
+            bin += sizeof(bc);
+            
+            if (k != 1) {
+                printf("error reading current size at tape mark \n");
+                exit (1);
+            }
+            wc = (bc[3]<<24) + (bc[2]<<16) + (bc[1]<<8) + bc[0];
+            if (wc == 0) {
+                // zero length record, read trailing length (zero)
+                k = fread (bc, sizeof (bc), 1, ifile);
+                bin += sizeof(bc);
+                // read next file mark
+                //k = fread (bc, sizeof (bc), 1, ifile);
+                // read current record size
+                k = fread (bc, sizeof (bc), 1, ifile);
+                bin += sizeof(bc);
+                wc = (bc[3]<<24) + (bc[2]<<16) + (bc[1]<<8) + bc[0];
+            }
+        }
+        
+        if (wc > 0x800)
+            printf("BIG %x\n",wc);
+        bout += wc;
+        fwrite(&wc,1,4,ofile);      // write leading size
+        printf("WC  %x %x\n",bin,wc);
+        pwc = wc;
+        
+        if (wc) {
+            // copy the record
+            k = fread (buf, 1, wc, ifile);
+                bin += wc;
+            buf[wc] = 0;            // pad just in case
+            fwrite (buf, sizeof (char), wc, ofile);
+            
+            if (wc & 1)
+                fwrite (&pad,1,1,ofile);  // force even size
+            // read trailing size
+            k = fread (bc, sizeof (bc), 1, ifile);
+            bin += sizeof(bc);
+            if (k != 1) {
+                printf("error reading trailing size\n");
+                exit (1);
+            }
+            wc = (bc[3]<<24) + (bc[2]<<16) + (bc[1]<<8) + bc[0];
+            if (wc != pwc)
+                printf("record size error %x %x\n",pwc,wc);
+                       
+            fwrite(&wc,1,4,ofile);  // write trailing size
+            rc++;
+            
+        }
+        else {
+            if (rc)
+                printf ("End of file %d, record count = %d\n", fc, rc);
+            else
+                printf ("End of tape\n");
+            fc++;
+            rc = 0;
+            exit (0);
+        }
+    }
+    fclose (ifile);
+    fclose (ofile);
+    
+    
+    return 0;
+}