New function StrBufDecodeQP() to decode a quoted-printable StrBuf in-place without...

[citadel.git] / libcitadel / lib / stringbuf.c

diff --git a/libcitadel/lib/stringbuf.c b/libcitadel/lib/stringbuf.c
index 12fd259e4582ef93d9da48158582d4a0ca0bca40..8398757ded3a2c2a71c4960195029372b2609c3c 100644 (file)
--- a/libcitadel/lib/stringbuf.c
+++ b/libcitadel/lib/stringbuf.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1987-2013 by the citadel.org team
+ * Copyright (c) 1987-2017 by the citadel.org team
  *
  * This program is open source software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -5622,3 +5622,44 @@ void StrBufStripSlashes(StrBuf *Dir, int RemoveTrailingSlash)
 }
 
 
+/*
+ * Decode a quoted-printable encoded StrBuf buffer "in place"
+ * This is possible because the decoded will always be shorter than the encoded
+ * so we don't have to worry about the buffer being to small.
+ */
+void StrBufDecodeQP(StrBuf *Buf)
+{
+       if (!Buf) {                             // sanity check #1
+               return;
+       }
+
+       int source_len = StrLength(Buf);
+       if (source_len < 1) {                   // sanity check #2
+               return;
+       }
+
+       int spos = 0;                           // source position
+       int tpos = 0;                           // target position
+
+       while (spos < source_len) {
+               if (!strncmp(&Buf->buf[spos], "=\r\n", 3)) {
+                       spos += 3;
+               }
+               else if (!strncmp(&Buf->buf[spos], "=\n", 2)) {
+                       spos += 2;
+               }
+               else if (Buf->buf[spos] == '=') {
+                       ++spos;
+                       int ch;
+                       sscanf(&Buf->buf[spos], "%02x", &ch);
+                       Buf->buf[tpos++] = ch;
+                       spos +=2;
+               }
+               else {
+                       Buf->buf[tpos++] = Buf->buf[spos++];
+               }
+       }
+
+       Buf->buf[tpos] = 0;
+       Buf->BufUsed = tpos;
+}