add unit tests and man page for scan_ldapescape

textcode/scan_ldapescape.3

@@ -0,0 +1,33 @@
+.TH scan_ldapescape 3
+.SH NAME
+scan_ldapescape \- parse LDIF escaped string
+.SH SYNTAX
+.B #include <libowfat/textcode.h>
+
+size_t \fBscan_ldapescape\fP(const char *\fIsrc\fR,char *\fIdest\fR,size_t* \fIdestlen\fR);
+
+.SH DESCRIPTION
+scan_ldapescape parses LDIF escaped text from src into dest.
+Parsing stops at the 0 terminator or invalid input characters.
+
+This function will turn backslash escaped characters into their binary
+equivalent, i.e. \0a to new-line and \5c to backslash.
+
+scan_cescape will then write the number of bytes in dest into *destlen,
+and return the number of bytes decoded from src.
+
+dest can be NULL. destlen can be NULL.
+
+To make sure dest is large enough, either allocate strlen(src)+1 bytes
+or call scan_ldapescape twice, the first time with dest == NULL (*destlen
+will still be written).
+
+.SH "RETURN VALUE"
+scan_ldapescape returns the number of bytes successfully parsed
+from src.
+
+.SH EXAMPLES
+scan_ldapescape("test\5C\\");",buf,&i) -> return 7, i=5, buf="test\\" (C notation).
+
+.SH "SEE ALSO"
+fmt_ldapescape(3), scan_cescape(3), scan_ldapescape(3)

textcode/scan_ldapescape.c

@@ -9,16 +9,32 @@ size_t scan_ldapescape(const char *src,char *dest,size_t *destlen) {
     if (s[i]=='\\') {
       int j=scan_fromhex(s[i+1]);
       if (j<0) break;
-      dest[written]=j<<4;
+      if (dest) dest[written]=j<<4;
       j=scan_fromhex(s[i+2]);
       if (j<0) break;
-      dest[written]|=j;
+      if (dest) dest[written]|=j;
       i+=2;
     } else {
-      dest[written]=s[i];
+      if (dest) dest[written]=s[i];
     }
     ++written;
   }
-  *destlen=written;
+  if (destlen) *destlen=written;
   return i;
 }
+
+#ifdef UNITTEST
+#include <assert.h>
+#undef UNITTEST
+#include <scan/scan_fromhex.c>
+
+int main() {
+  size_t dl;
+  char buf[100];
+  assert(scan_ldapescape("test\\n\");",buf,&dl)==4 && dl==4 && !memcmp(buf,"test",4));
+  /* check hex escaping */
+  assert(scan_ldapescape("test\\0afoo",buf,&dl)==10 && dl==8 && !memcmp(buf,"test\nfoo",8));
+  /* check that short sequences are rejected */
+  assert(scan_ldapescape("test\\ax",buf,&dl)==4 && dl==4 && !memcmp(buf,"test",4));
+}
+#endif