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ATOB-22.C
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C/C++ Source or Header
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1987-04-17
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5KB
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190 lines
D PRG/ATOB-22.C
/*
* atob version 2.2 for cpm/msdos on packet radio
* a program to transform binary to printable ASCII at a minimal*
* 'cost' in conversion space - ratio is about 5/4
*
* atob: version 4.0
* stream filter to change printable ascii from "btoa" back into 8 bit*
* bytes if bad chars, or Csums do not match: exit(1) [and NO output] *
*
* Paul Rutter Joe Orost
* philabs!per petsd!joe
*
*
* *
* 86May30 - corrected 'y' as file name in duplicate target file and *
* added ability to have garbage in front of, on the same *
* line with the 'xbtoa Begin' line |br| ka2bqe *
* 86May19 - modified to command line parsing, and recovery of input *
* file name from header line. Should be able to handle ver*
* sion 1.0 files w/o file name in header |br| - ka2bqe *
* 86May05 - modified to compile/run for packet radio under cpm-80 & *
* msdos by Brian B. Riley (ka2bqe) - RATS *
* Hacked to work with non-UNIX machines by Brian Lloyd, 86/04/17 *
* *
*/
#include <stdio.h>
#define reg register
#define streq(s0, s1) strcmp(s0, s1) == 0
#define times85(x) ((((((x<<2)+x)<<2)+x)<<2)+x)
long int Ceor = 0;
long int Csum = 0;
long int Crot = 0;
long int word = 0;
long int bcount = 0;
FILE * inf;
FILE * outf;
#define DE(c) ((c) - '!')
/*
* main - this is the ASCII-to-BINARY recovery routine. It queries for
* and opens files and stream decodes and verifies checksum
*/
main(argc, argv)
char **argv;
{
reg c;
reg long int i;
char infile[64];
char outfile[64];
char buf[100];
long int n1, n2, oeor, osum, orot;
printf("\n atob: Ascii-to-Binary recovery\n RATS v2.2\n");
if(argc<2) {printf("Usage: atob infile \n");exit(2);}
strcpy(infile,argv[1]); /* get inputfile name */
while ((inf = fopen(infile, "r")) == NULL) {
printf("\n Error opening file - %s\n Input file: ",infile);
if (gets(infile)==NULL) exit();
}
/*search for header line*/
while ((c=getc(inf))!=EOF) {/* look for 'x'*/
if (c=='x') {
if (fgets(buf, sizeof buf, inf) != NULL) {
if (strncmp(buf, "btoa Begin",10) == 0) break;
} else {printf("\n\7 *** EOF in header scan.\n" ); exit(0);}
}
}
if (c==EOF) {printf("\n\7 *** EOF in header scan.\n");exit(0);}
outfile[0] = '\0'; /* null outfile name string */
sscanf(buf,"btoa Begin %s\n",outfile);
if (strlen(outfile) ) {
printf("\n Header found ===> File: [%s] ",outfile);
} else {
printf( "\n Possible OLD header - Enter output file: ");
if (gets(outfile)==NULL) exit();
}
while ((outf = fopen(outfile,"r")) != NULL) {
fclose(outf);
printf("\n Target file name exists! Overwrite (Y/N) ? ");
gets(buf);
if (toupper(buf[0]) == 'Y') {break;}
else {
printf (" Enter new output filename : ");
gets(outfile);
}
}
fclose(outf);
printf(" ===> Decoding ");
if ((outf = fopen(outfile, "w")) == NULL) {
printf( " File OPEN ERROR - [%s] - Disk full ???\n",outfile);
fclose(outf);
exit();
}
while ((c = getc(inf)) != EOF) {
if (c == '\n') {continue;}
else if (c=='\r') {continue;}
else if (c == 'x') {break;}
else {decode(c);}
}
printf(" ===> *** EOF ***\n Checking trailer now");
if(fscanf(inf,"btoa End N %ld %lx E %lx S %lx R %lx\n",
&n1, &n2, &oeor, &osum, &orot) != 5) {
printf(" ===> \7Failure reading the trailer line.\n" );
exit(0);
}
if ((n1 != n2) || (oeor != Ceor) || (osum != Csum) || (orot != Crot)) {
printf(" ===> \7File checksum is bad.\n");
exit(0);
} else {
printf(" ===> File checksum is good.\n");
}
fclose( inf );
fclose( outf );
exit(0);
}
/*
* byteout - outputs a single binary byte to file *
*/
byteout(c)
reg c;
{
Ceor ^= c;
Csum += c;
Csum += 1;
if ((Crot & 0x80000000L)) {
Crot <<= 1;
Crot += 1;
} else {
Crot <<= 1;
}
Crot += c;
putc(c, outf);
}
/*
* decode - stream decodes 5 'digit' ASCII back to 4 byte binary *
*/
decode(c)
reg c;
{
if (c == 'z') {
if (bcount != 0) {
printf("z not on word boundary in decode.\n");
exit(0);
} else {
byteout(0);
byteout(0);
byteout(0);
byteout(0);
}
} else if ((c >= '!') && (c < ('!' + 85))) {
if (bcount == 0) {
word = DE(c);
++bcount;
} else if (bcount < 4) {
word = times85(word);
word += DE(c);
++bcount;
} else {
word = times85(word) + DE(c);
byteout((int)((word >> 24) & 255));
byteout((int)((word >> 16) & 255));
byteout((int)((word >> 8) & 255));
byteout((int)(word & 255));
word = 0;
bcount = 0;
}
} else {
printf("Input character out of range in decode.(%02x)\n",c);
exit(0);
}
}