libbb: change decode_base32/64 API to return the end of _dst_, not _src_.

function                                             old     new   delta
decode_base64                                        173     178      +5
read_base64                                          222     220      -2
decode_base32                                        186     182      -4
handle_incoming_and_exit                            2263    2239     -24
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/3 up/down: 5/-30)             Total: -25 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 19 insertions, 20 deletions

diff --git a/include/libbb.h b/include/libbb.h
index ef4a34f07..e56fff3e8 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -2035,8 +2035,8 @@ enum {
         /* Sign-extends to a value which never matches fgetc result: */
         BASE64_FLAG_NO_STOP_CHAR = 0x80,
 };
-const char *decode_base64(char **pp_dst, const char *src) FAST_FUNC;
-const char *decode_base32(char **pp_dst, const char *src) FAST_FUNC;
+char *decode_base64(char *dst, const char **pp_src) FAST_FUNC;
+char *decode_base32(char *dst, const char **pp_src) FAST_FUNC;
 void read_base64(FILE *src_stream, FILE *dst_stream, int flags) FAST_FUNC;
 
 typedef struct md5_ctx_t {
diff --git a/libbb/uuencode.c b/libbb/uuencode.c
index 139c60bd5..6e63bfc6a 100644
--- a/libbb/uuencode.c
+++ b/libbb/uuencode.c
@@ -86,9 +86,9 @@ void FAST_FUNC bb_uuencode(char *p, const void *src, int length, const char *tbl
  * If points to '\0', then the source was fully decoded.
  * (*pp_dst): advanced past the last written byte.
  */
-const char* FAST_FUNC decode_base64(char **pp_dst, const char *src)
+char* FAST_FUNC decode_base64(char *dst, const char **pp_src)
 {
-        char *dst = *pp_dst;
+        const char *src = pp_src ? *pp_src : dst; /* for httpd.c, support NULL 2nd param */
         unsigned ch = 0;
         unsigned t;
         int i = 0;
@@ -129,16 +129,17 @@ const char* FAST_FUNC decode_base64(char **pp_dst, const char *src)
                         ch = 0;
                 }
         }
-        *pp_dst = dst;
         /* i is zero here if full 4-char block was decoded */
-        return src - i; /* -i rejects truncations: e.g. "MQ" and "MQ=" (correct encoding is "MQ==" -> "1") */
+        if (pp_src)
+                *pp_src = src - i; /* -i rejects truncations: e.g. "MQ" and "MQ=" (correct encoding is "MQ==" -> "1") */
+        return dst;
 }
 
 #if ENABLE_BASE32
-const char* FAST_FUNC decode_base32(char **pp_dst, const char *src)
+char* FAST_FUNC decode_base32(char *dst, const char **pp_src)
 {
-        char *dst = *pp_dst;
-        int64_t ch = 0;
+        const char *src = *pp_src;
+        uint64_t ch = 0;
         unsigned t;
         int i = 0;
 
@@ -169,9 +170,9 @@ const char* FAST_FUNC decode_base32(char **pp_dst, const char *src)
                         *dst++ = (char) ch;
                 }
         }
-        *pp_dst = dst;
         /* i is zero here if full 8-char block was decoded */
-        return src - i;
+        *pp_src = src - i;
+        return dst;
  tail:
         {
                 const char *s = src;
@@ -192,8 +193,8 @@ const char* FAST_FUNC decode_base32(char **pp_dst, const char *src)
                 *dst++ = (char) ch;
                 dst -= (i+1) * 2 / 3; /* discard last 1, 2, 3 or 4 bytes */
         }
-        *pp_dst = dst;
-        return src;
+        *pp_src = src;
+        return dst;
 }
 #endif
 
@@ -249,13 +250,13 @@ void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
                 if (uu_style_end && strcmp(buf, "====") == 0)
                         return;
 
-                out_tail = buf;
+                in_tail = buf;
 #if ENABLE_BASE32
                 if (base32)
-                        in_tail = decode_base32(&out_tail, buf);
+                        out_tail = decode_base32(buf, &in_tail);
                 else
 #endif
-                        in_tail = decode_base64(&out_tail, buf);
+                        out_tail = decode_base64(buf, &in_tail);
 
                 fwrite(buf, (out_tail - buf), 1, dst_stream);
 
diff --git a/networking/httpd.c b/networking/httpd.c
index 4ffd89c48..4346141ee 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -1015,11 +1015,9 @@ static char *encodeString(const char *string)
  * Parameter: a pointer to a base64 encoded string.
  * Decoded data is stored in-place.
  */
-static void decodeBase64(char *Data)
+static void decodeBase64(char *data)
 {
-        char *eptr = Data;
-        decode_base64(&eptr, Data);
-        *eptr = '\0';
+        decode_base64(data, NULL)[0] = '\0';
 }
 #endif