From 6f80fe71f0c3d586dddc0749f744f1112ef8c473 Mon Sep 17 00:00:00 2001
From: Denys Vlasenko <dvlasenk@redhat.com>
Date: Wed, 1 Sep 2010 13:24:05 +0200
Subject: uudecode,base64: code shrink
function old new delta
read_base64 373 358 -15
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
---
coreutils/uudecode.c | 53 ++++++++++++++++++++++++++--------------------------
1 file changed, 26 insertions(+), 27 deletions(-)
diff --git a/coreutils/uudecode.c b/coreutils/uudecode.c
index 207fb0b8d..0da9b0988 100644
--- a/coreutils/uudecode.c
+++ b/coreutils/uudecode.c
@@ -77,18 +77,21 @@ static void read_stduu(FILE *src_stream, FILE *dst_stream)
static void read_base64(FILE *src_stream, FILE *dst_stream)
{
- int term_count = 1;
+ 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.
- * global vector bb_uuenc_tbl_base64[] contains this string:
+ * bb_uuenc_tbl_base64[] contains this string:
+ * 0 1 2 3 4 5 6
+ * 012345678901234567890123456789012345678901234567890123456789012345
* "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
*/
do {
@@ -103,42 +106,38 @@ static void read_base64(FILE *src_stream, FILE *dst_stream)
bb_error_msg_and_die("short file");
}
table_ptr = strchr(bb_uuenc_tbl_base64, ch);
- } while (table_ptr == NULL);
+ } while (!table_ptr);
/* Convert encoded character to decimal */
ch = table_ptr - bb_uuenc_tbl_base64;
- if (*table_ptr == '=') {
- if (term_count == 0) {
- translated[count] = '\0';
- break;
- }
- term_count++;
- } else if (*table_ptr == '\n') {
- /* Check for terminating line */
- if (term_count == 5) {
- return;
- }
- term_count = 1;
- continue;
- } else {
- translated[count] = ch;
- count++;
+ 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 */
- if (count > 1) {
+ /* 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) {
+ if (count > 2)
fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
- }
- if (count > 3) {
+ if (count > 3)
fputc(translated[2] << 6 | translated[3], dst_stream);
- }
- }
+ } /* while (1) */
}
#if ENABLE_UUDECODE
--
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