LBN2PBN: Apply minor fixes and mention reverse conversion in README

Author: al20878

README.md

@@ -27,7 +27,7 @@ gt7cvt | Convert a gt7 magtape dump to a SIMH magtape
 hpconvert | Convert an HP disc image between SIMH and HPDrive formats
 imd2dsk | Convert an ImageDisk (IMD) file to DSK (pure data)
 indent | Convert simulator sources to 4-column tabs
-lbn2pbn | Logical-to-physical converter for single-sided floppy disk images
+lbn2pbn | Logical-to-physical (and reverse) converter for single-sided floppy disk images
 littcvt | Remove density maker from litt format tapes
 m8376 | Assembles 8 PROM files into a 32bit binary file
 mt2tpc | Convert a simh simulated magtape to TPC format

converters/lbn2pbn/lbn2pbn.c

@@ -44,6 +44,9 @@
 #include <stdlib.h>
 #include <string.h>
 
+#define SECTOR_MIN_SIZE 128
+#define SECTOR_MAX_SIZE 512
+
 
 inline
 static size_t filesize(FILE* fp)
@@ -162,8 +165,8 @@ int main(int argc, char* argv[])
             break;
         case 'B':
             sector_size = atoi(optarg);
-            if ((sector_size & (sector_size - 1))
-                ||  sector_size < 128  ||  sector_size > 512) {
+            if (sector_size < SECTOR_MIN_SIZE  ||  sector_size > SECTOR_MAX_SIZE
+                ||  (sector_size & (sector_size - 1))) {
                 sector_size = 0;
             }
             break;
@@ -198,26 +201,26 @@ int main(int argc, char* argv[])
 
     if (!(in = fopen(infile, "rb"))) {
         perror(infile);
-        return 1;
+        return EXIT_FAILURE;
     }
 
     size = filesize(in);
     q = tracks * sectors;
     max_size = q * sector_size;
     if (size > max_size) {
         fprintf(stderr, "%s: file size (%zd) may not exceed %zu\n", infile, size, max_size);
-        return 1;
+        return EXIT_FAILURE;
     }
 
     if (!(out = fopen(outfile, "wb"))) {
         perror(outfile);
-        return 1;
+        return EXIT_FAILURE;
     }
 
     rewind(in);
     round = lcm(sectors, interleave);
     for (p = 0;  p < q;  ++p) {
-        char sector[512];
+        static unsigned char sector[SECTOR_MAX_SIZE];
         int n = lbn2pbn(p);
 #ifdef _DEBUG
         printf("LBN %4d (%2d / %2d)   =   PBN %4d (%2d / %2d)\n",
@@ -236,5 +239,5 @@ int main(int argc, char* argv[])
 
     fclose(out);
     fclose(in);
-    return 0;
+    return EXIT_SUCCESS;
 }