X-Git-Url: https://git.distorted.org.uk/~mdw/mLib/blobdiff_plain/0bfb14313759dbbb677c373eac9b980972cf498d..4aee39a18184ae8595936a03ad254c27d149a0eb:/base64.c

diff --git a/base64.c b/base64.c
index 10ce91e..8fda2b5 100644
--- a/base64.c
+++ b/base64.c
@@ -1,13 +1,13 @@
 /* -*-c-*-
  *
- * $Id: base64.c,v 1.3 1999/05/21 22:14:30 mdw Exp $
+ * $Id: base64.c,v 1.7 2004/04/08 01:36:11 mdw Exp $
  *
  * Base64 encoding and decoding.
  *
  * (c) 1997 Straylight/Edgeware
  */
 
-/*----- Licensing notice --------------------------------------------------* 
+/*----- Licensing notice --------------------------------------------------*
  *
  * This file is part of the mLib utilities library.
  *
@@ -15,32 +15,18 @@
  * it under the terms of the GNU Library General Public License as
  * published by the Free Software Foundation; either version 2 of the
  * License, or (at your option) any later version.
- * 
+ *
  * mLib is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU Library General Public License for more details.
- * 
+ *
  * You should have received a copy of the GNU Library General Public
  * License along with mLib; if not, write to the Free
  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  * MA 02111-1307, USA.
  */
 
-/*----- Revision history --------------------------------------------------*
- *
- * $Log: base64.c,v $
- * Revision 1.3  1999/05/21 22:14:30  mdw
- * Take advantage of the new dynamic string macros.
- *
- * Revision 1.2  1999/05/18 21:45:27  mdw
- * Allow Base64 encode and decode of arbitrary rubbish.
- *
- * Revision 1.1  1999/05/17 20:35:00  mdw
- * Base64 encoding and decoding support.
- *
- */
-
 /*----- Header files ------------------------------------------------------*/
 
 #include <stdio.h>
@@ -52,11 +38,11 @@
 
 /*----- Important tables --------------------------------------------------*/
 
-static const char base64_encodeMap[] = { "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-					 "abcdefghijklmnopqrstuvwxyz" 
-					 "0123456789+/" };
+static const char encodemap[] = { "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+				  "abcdefghijklmnopqrstuvwxyz"
+				  "0123456789+/" };
 
-static const signed char base64_decodeMap[] = {
+static const signed char decodemap[] = {
   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 0x */
   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  /* 1x */
   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,  /* 2x */
@@ -65,7 +51,7 @@ static const signed char base64_decodeMap[] = {
   15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,  /* 5x */
   -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36 ,37, 38, 39, 40,  /* 6x */
   41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1   /* 7x */
-};  
+};
 
 /*----- Main code ---------------------------------------------------------*/
 
@@ -96,10 +82,10 @@ void base64_encode(base64_ctx *ctx,
       qsz++;
       sz--;
       if (qsz == 3) {
-	DPUTC(d, base64_encodeMap[(acc >> 18) & 0x3f]);
-	DPUTC(d, base64_encodeMap[(acc >> 12) & 0x3f]);
-	DPUTC(d, base64_encodeMap[(acc >>  6) & 0x3f]);
-	DPUTC(d, base64_encodeMap[(acc >>  0) & 0x3f]);
+	DPUTC(d, encodemap[(acc >> 18) & 0x3f]);
+	DPUTC(d, encodemap[(acc >> 12) & 0x3f]);
+	DPUTC(d, encodemap[(acc >>  6) & 0x3f]);
+	DPUTC(d, encodemap[(acc >>  0) & 0x3f]);
 	ctx->lnlen += 4;
 	if (ctx->maxline && ctx->lnlen >= ctx->maxline) {
 	  dstr_puts(d, ctx->indent);
@@ -121,17 +107,17 @@ void base64_encode(base64_ctx *ctx,
 	break;
       case 1:
 	acc <<= 16;
-	DPUTC(d, base64_encodeMap[(acc >> 18) & 0x3f]);
-	DPUTC(d, base64_encodeMap[(acc >> 12) & 0x3f]);
+	DPUTC(d, encodemap[(acc >> 18) & 0x3f]);
+	DPUTC(d, encodemap[(acc >> 12) & 0x3f]);
 	DPUTC(d, '=');
 	DPUTC(d, '=');
 	ctx->lnlen += 4;
 	break;
       case 2:
 	acc <<= 8;
-	DPUTC(d, base64_encodeMap[(acc >> 18) & 0x3f]);
-	DPUTC(d, base64_encodeMap[(acc >> 12) & 0x3f]);
-	DPUTC(d, base64_encodeMap[(acc >>  6) & 0x3f]);
+	DPUTC(d, encodemap[(acc >> 18) & 0x3f]);
+	DPUTC(d, encodemap[(acc >> 12) & 0x3f]);
+	DPUTC(d, encodemap[(acc >>  6) & 0x3f]);
 	DPUTC(d, '=');
 	ctx->lnlen += 4;
 	break;
@@ -172,7 +158,7 @@ void base64_decode(base64_ctx *ctx,
       if (ch >= 128 || ch < 0)
 	ch = -1;
       else
-	ch = base64_decodeMap[ch];
+	ch = decodemap[ch];
       sz--;
       if (ch == -1)
 	continue;
@@ -212,14 +198,24 @@ void base64_decode(base64_ctx *ctx,
     unsigned long acc = ctx->acc;
     unsigned qsz = ctx->qsz;
 
-    /* --- Now fiddle with everything else --- */
+    /* --- Now fiddle with everything else --- *
+     *
+     * There's a bodge here for invalid encodings which have only one hextet
+     * in the final group.  I'm not sure this is really worth having, but it
+     * might save some unexpected behaviour.  (Not that you won't still get
+     * unexpected behaviour if the stream is completely empty, of course.)
+     */
 
-    acc <<= 6 * (4 - qsz);
-    qsz *= 6;
-    while (qsz > 8) {
-      DPUTC(d, (acc >> 16) & 0xff);
-      acc <<= 8;
-      qsz -= 8;
+    if (qsz) {
+      acc <<= 6 * (4 - qsz);
+      qsz *= 6;
+      if (qsz < 8)
+	qsz = 8;
+      while (qsz >= 8) {
+	DPUTC(d, (acc >> 16) & 0xff);
+	acc <<= 8;
+	qsz -= 8;
+      }
     }
 
     /* --- That seems to be good enough --- */
@@ -256,7 +252,7 @@ int main(int argc, char *argv[])
   unsigned char buf[BUFSIZ];
   dstr d = DSTR_INIT;
   base64_ctx ctx;
-  void (*proc)(base64_ctx *, const unsigned char *, size_t, dstr *);
+  void (*proc)(base64_ctx *, const void *, size_t, dstr *);
   size_t sz;
 
   base64_init(&ctx);