first commit

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Eric 2025-05-26 00:06:22 +02:00
commit 9b1fe95a8e
7 changed files with 234 additions and 0 deletions

2
.gitignore vendored Normal file
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b64
*.o

13
Makefile Normal file
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CFLAGS = -g -Wall -Wextra -Werror
objects = main.o input.o trans.o
b64 : $(objects)
cc -o b64 $(objects)
main.o trans.o input.o : input.h
main.o trans.o : trans.h
.PHONY : clean
clean :
rm -f b64 $(objects)

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input.c Normal file
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#include "input.h"
#define OBUFSIZE 4
#define SBUFSIZE 5
#define PADDING '='
unsigned char o[OBUFSIZE];
unsigned char s[SBUFSIZE];
unsigned char *
getocts(FILE *fp, int *np)
{
int n, c;
n = 0;
while (n < OBUFSIZE-1 && (c = fgetc(fp)) != EOF)
o[n++] = c;
*np = n;
return (*np) ? o : NULL;
}
unsigned char *
getsxts(FILE *fp, int *np)
{
int n, p, c;
n = p = 0;
while (n < SBUFSIZE-1 && (c = fgetc(fp)) != EOF && c != PADDING)
s[n++] = c;
while (n+p < SBUFSIZE-1)
s[n+p++] = PADDING;
*np = n;
return (n) ? s : NULL;
}

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input.h Normal file
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#ifndef HEADER_INPUT
#define HEADER_INPUT
#include <stdio.h>
extern unsigned char o[];
extern unsigned char s[];
unsigned char *
getocts(FILE *fp, int *np);
unsigned char *
getsxts(FILE *fp, int *np);
#endif

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main.c Normal file
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#include <stdio.h>
#include <stdlib.h>
#include "input.h"
#include "trans.h"
int
main(int argc, char *argv[])
{
int c, n, dec, hlp;
char *prog = *argv;
unsigned char *b;
FILE *fp;
dec = hlp = 0;
while (--argc > 0 && (*++argv)[0] == '-')
while ((c = *++argv[0]))
switch (c) {
case 'd':
dec = 1;
break;
case 'h':
hlp = 1;
break;
default:
fprintf(stderr, "%s: illegal option %c\n", prog, c);
exit(EXIT_FAILURE);
break;
}
if (hlp) {
fprintf(stdout, "Usage: %s -d -h file\n", prog);
} else if (argc != 1) {
if (dec) {
while ((b = getsxts(stdin, &n))) {
b = decode(b, &n);
fwrite(b, sizeof(*b), n, stdout);
}
} else {
while ((b = getocts(stdin, &n)))
printf("%s", encode(b, n));
}
} else {
if ((fp = fopen(*argv, "r")) == NULL) {
fprintf(stderr, "%s: can't open %s\n", prog, *argv);
exit(EXIT_FAILURE);
}
else if (dec) {
while ((b = getsxts(fp, &n))) {
b = decode(b, &n);
fwrite(b, sizeof(*b), n, stdout);
}
} else {
while ((b = getocts(fp, &n)))
printf("%s", encode(b, n));
}
fclose(fp);
}
exit(EXIT_SUCCESS);
}

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trans.c Normal file
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#include "trans.h"
#define PADDING '='
unsigned char b64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
"abcdefghijklmnopqrstuvwxyz" \
"0123456789" \
"+/";
unsigned char *
encode(unsigned char *op, int np)
{
extern unsigned char s[];
unsigned char *sp;
int n;
sp = s;
switch (np) {
case 3:
*sp++ = b64[(*op & ~3) >> 2];
n = (*op++ & 3) << 4;
*sp++ = b64[n + ((*op & ~15) >> 4)];
n = (*op++ & 15) << 2;
*sp++ = b64[n + ((*op & 192) >> 6)];
*sp = b64[*op & ~192];
break;
case 2:
*sp++ = b64[(*op & ~3) >> 2];
n = (*op++ & 3) << 4;
*sp++ = b64[n + ((*op & ~15) >> 4)];
*sp++ = b64[(*op & 15) << 2];
*sp = PADDING;
break;
case 1:
*sp++ = b64[(*op & ~3) >> 2];
*sp++ = b64[(*op & 3) << 4];
*sp++ = PADDING;
*sp = PADDING;
break;
}
return s;
}
unsigned char *
decode(unsigned char *sp, int *np)
{
extern unsigned char o[];
unsigned char *op;
int n, b, atob(int c);
op = o;
switch (*np) {
case 4:
n = atob(*sp++) << 2;
b = atob(*sp++);
*op++ = n + ((b & ~15) >> 4);
n = (b & 15) << 4;
b = atob(*sp++);
*op++ = n + ((b & ~3) >> 2);
*op = ((b & 3) << 6) + atob(*sp);
break;
case 3:
n = atob(*sp++) << 2;
b = atob(*sp++);
*op++ = n + ((b & ~15) >> 4);
n = (b & 15) << 4;
*op = n + ((atob(*sp) & ~3) >> 2);
break;
case 2:
n = atob(*sp++) << 2;
*op = n + ((atob(*sp) & ~15) >> 4);
break;
}
*np = op-o+1;
return o;
}
int atob(int c)
{
if (c >= 'A' && c <= 'Z')
c -= 'A';
else if (c >= 'a' && c <= 'z')
c = c - 'a' + 26;
else if (c >= '0' && c <= '9')
c = c - '0' + 26 * 2;
else if (c == '+')
c = 62;
else
c = 63;
return c;
}

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trans.h Normal file
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#ifndef HEADER_TRANS
#define HEADER_TRANS
#include "input.h"
unsigned char *
encode(unsigned char *op, int np);
unsigned char *
decode(unsigned char *sp, int *np);
#endif