busybox/coreutils/uudecode.c
Denys Vlasenko 6f80fe71f0 uudecode,base64: code shrink
function                                             old     new   delta
read_base64                                          373     358     -15

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
2010-09-01 13:24:05 +02:00

293 lines
7.0 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Copyright 2003, Glenn McGrath
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*
* Based on specification from
* http://www.opengroup.org/onlinepubs/007904975/utilities/uuencode.html
*
* Bugs: the spec doesn't mention anything about "`\n`\n" prior to the
* "end" line
*/
#include "libbb.h"
#if ENABLE_UUDECODE
static void read_stduu(FILE *src_stream, FILE *dst_stream)
{
char *line;
while ((line = xmalloc_fgetline(src_stream)) != NULL) {
int encoded_len, str_len;
char *line_ptr, *dst;
if (strcmp(line, "end") == 0) {
return; /* the only non-error exit */
}
line_ptr = line;
while (*line_ptr) {
*line_ptr = (*line_ptr - 0x20) & 0x3f;
line_ptr++;
}
str_len = line_ptr - line;
encoded_len = line[0] * 4 / 3;
/* Check that line is not too short. (we tolerate
* overly _long_ line to accomodate possible extra '`').
* Empty line case is also caught here. */
if (str_len <= encoded_len) {
break; /* go to bb_error_msg_and_die("short file"); */
}
if (encoded_len <= 0) {
/* Ignore the "`\n" line, why is it even in the encode file ? */
free(line);
continue;
}
if (encoded_len > 60) {
bb_error_msg_and_die("line too long");
}
dst = line;
line_ptr = line + 1;
do {
/* Merge four 6 bit chars to three 8 bit chars */
*dst++ = line_ptr[0] << 2 | line_ptr[1] >> 4;
encoded_len--;
if (encoded_len == 0) {
break;
}
*dst++ = line_ptr[1] << 4 | line_ptr[2] >> 2;
encoded_len--;
if (encoded_len == 0) {
break;
}
*dst++ = line_ptr[2] << 6 | line_ptr[3];
line_ptr += 4;
encoded_len -= 2;
} while (encoded_len > 0);
fwrite(line, 1, dst - line, dst_stream);
free(line);
}
bb_error_msg_and_die("short file");
}
#endif
static void read_base64(FILE *src_stream, FILE *dst_stream)
{
int term_count = 0;
while (1) {
unsigned char translated[4];
int count = 0;
/* Process one group of 4 chars */
while (count < 4) {
char *table_ptr;
int ch;
/* Get next _valid_ character.
* bb_uuenc_tbl_base64[] contains this string:
* 0 1 2 3 4 5 6
* 012345678901234567890123456789012345678901234567890123456789012345
* "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
*/
do {
ch = fgetc(src_stream);
if (ch == EOF) {
if (ENABLE_BASE64
&& (!ENABLE_UUDECODE || applet_name[0] == 'b')
&& count == 0
) {
return;
}
bb_error_msg_and_die("short file");
}
table_ptr = strchr(bb_uuenc_tbl_base64, ch);
} while (!table_ptr);
/* Convert encoded character to decimal */
ch = table_ptr - bb_uuenc_tbl_base64;
if (ch == 65 /* '\n' */) {
/* Terminating "====" line? */
if (term_count == 4)
return; /* yes */
term_count = 0;
continue;
}
/* ch is 64 is char was '=', otherwise 0..63 */
translated[count] = ch & 63; /* 64 -> 0 */
if (ch == 64) {
term_count++;
break;
}
count++;
}
/* Merge 6 bit chars to 8 bit.
* count can be < 4 when we decode the tail:
* "eQ==" -> "y", not "y NUL NUL"
*/
if (count > 1)
fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
if (count > 2)
fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
if (count > 3)
fputc(translated[2] << 6 | translated[3], dst_stream);
} /* while (1) */
}
#if ENABLE_UUDECODE
int uudecode_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int uudecode_main(int argc UNUSED_PARAM, char **argv)
{
FILE *src_stream;
char *outname = NULL;
char *line;
opt_complementary = "?1"; /* 1 argument max */
getopt32(argv, "o:", &outname);
argv += optind;
if (!argv[0])
*--argv = (char*)"-";
src_stream = xfopen_stdin(argv[0]);
/* Search for the start of the encoding */
while ((line = xmalloc_fgetline(src_stream)) != NULL) {
void (*decode_fn_ptr)(FILE *src, FILE *dst);
char *line_ptr;
FILE *dst_stream;
int mode;
if (strncmp(line, "begin-base64 ", 13) == 0) {
line_ptr = line + 13;
decode_fn_ptr = read_base64;
} else if (strncmp(line, "begin ", 6) == 0) {
line_ptr = line + 6;
decode_fn_ptr = read_stduu;
} else {
free(line);
continue;
}
/* begin line found. decode and exit */
mode = bb_strtou(line_ptr, NULL, 8);
if (outname == NULL) {
outname = strchr(line_ptr, ' ');
if ((outname == NULL) || (*outname == '\0')) {
break;
}
outname++;
}
dst_stream = stdout;
if (NOT_LONE_DASH(outname)) {
dst_stream = xfopen_for_write(outname);
fchmod(fileno(dst_stream), mode & (S_IRWXU | S_IRWXG | S_IRWXO));
}
free(line);
decode_fn_ptr(src_stream, dst_stream);
/* fclose_if_not_stdin(src_stream); - redundant */
return EXIT_SUCCESS;
}
bb_error_msg_and_die("no 'begin' line");
}
#endif
//applet:IF_BASE64(APPLET(base64, _BB_DIR_BIN, _BB_SUID_DROP))
//kbuild:lib-$(CONFIG_BASE64) += uudecode.o
//config:config BASE64
//config: bool "base64"
//config: default y
//config: help
//config: Base64 encode and decode
//usage:#define base64_trivial_usage
//usage: "[-d] [FILE]"
//usage:#define base64_full_usage "\n\n"
//usage: "Base64 encode or decode FILE to standard output"
//usage: "\nOptions:"
//usage: "\n -d Decode data"
////usage: "\n -w COL Wrap lines at COL (default 76, 0 disables)"
////usage: "\n -i When decoding, ignore non-alphabet characters"
#if ENABLE_BASE64
int base64_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int base64_main(int argc UNUSED_PARAM, char **argv)
{
FILE *src_stream;
unsigned opts;
opt_complementary = "?1"; /* 1 argument max */
opts = getopt32(argv, "d");
argv += optind;
if (!argv[0])
*--argv = (char*)"-";
src_stream = xfopen_stdin(argv[0]);
if (opts) {
read_base64(src_stream, stdout);
} else {
enum {
SRC_BUF_SIZE = 76/4*3, /* This *MUST* be a multiple of 3 */
DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
};
char src_buf[SRC_BUF_SIZE];
char dst_buf[DST_BUF_SIZE + 1];
int src_fd = fileno(src_stream);
while (1) {
size_t size = full_read(src_fd, src_buf, SRC_BUF_SIZE);
if (!size)
break;
if ((ssize_t)size < 0)
bb_perror_msg_and_die(bb_msg_read_error);
/* Encode the buffer we just read in */
bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
xwrite(STDOUT_FILENO, dst_buf, 4 * ((size + 2) / 3));
bb_putchar('\n');
fflush(stdout);
}
}
fflush_stdout_and_exit(EXIT_SUCCESS);
}
#endif
/* Test script.
Put this into an empty dir with busybox binary, an run.
#!/bin/sh
test -x busybox || { echo "No ./busybox?"; exit; }
ln -sf busybox uudecode
ln -sf busybox uuencode
>A_null
echo -n A >A
echo -n AB >AB
echo -n ABC >ABC
echo -n ABCD >ABCD
echo -n ABCDE >ABCDE
echo -n ABCDEF >ABCDEF
cat busybox >A_bbox
for f in A*; do
echo uuencode $f
./uuencode $f <$f >u_$f
./uuencode -m $f <$f >m_$f
done
mkdir unpk_u unpk_m 2>/dev/null
for f in u_*; do
./uudecode <$f -o unpk_u/${f:2}
diff -a ${f:2} unpk_u/${f:2} >/dev/null 2>&1
echo uudecode $f: $?
done
for f in m_*; do
./uudecode <$f -o unpk_m/${f:2}
diff -a ${f:2} unpk_m/${f:2} >/dev/null 2>&1
echo uudecode $f: $?
done
*/