diff --git a/include/pcp/buffer.h b/include/pcp/buffer.h
index 52d6a8e..cdf2228 100644
--- a/include/pcp/buffer.h
+++ b/include/pcp/buffer.h
@@ -34,6 +34,8 @@
 #ifndef HAVE_PCP_BUFFER_H
 #define HAVE_PCP_BUFFER_H
 
+#include <stdio.h>
+#include <stdarg.h>
 #include "mem.h"
 #include "util.h"
 #include "defines.h"
@@ -46,6 +48,7 @@ struct _pcp_buffer {
   size_t size;
   size_t offset;  /* read position */
   size_t end;     /* write position, data end */
+  uint8_t isstring; /* treat as char array */
   void *buf;
 };
 
@@ -54,6 +57,9 @@ typedef struct _pcp_buffer Buffer;
 /* create a new buffer, initially alloc'd to blocksize and zero-filled */
 Buffer *buffer_new(size_t blocksize, char *name);
 
+/* same, but enable isstring */
+Buffer *buffer_new_str(char *name);
+
 /* initialize buffer vars */
 void buffer_init(Buffer *b, size_t blocksize, char *name);
 
@@ -72,6 +78,12 @@ void buffer_add(Buffer *b, const void *data, size_t len);
 /* the same but use another buffer as source */
 void buffer_add_buf(Buffer *dst, Buffer *src);
 
+/* add a string, support printf style */
+void buffer_add_str(Buffer *b, const char * fmt, ...);
+
+/* add some binary data to the buffer, but as hex string */
+void buffer_add_hex(Buffer *b, void *data, size_t len);
+
 /* resize the buffer if necessary */
 void buffer_resize(Buffer *b, size_t len);
 
diff --git a/libpcp/buffer.c b/libpcp/buffer.c
index 1dc8b8a..59955c5 100644
--- a/libpcp/buffer.c
+++ b/libpcp/buffer.c
@@ -34,12 +34,19 @@ void buffer_init(Buffer *b, size_t blocksize, char *name) {
   b->name = ucmalloc(strlen(name)+1);
   b->size = blocksize;
   b->allocated = 1;
+  b->isstring = 0;
   b->offset = 0;
   b->end = 0;
   b->blocksize = blocksize;
   memcpy(b->name, name, strlen(name)+1);
 }
 
+Buffer *buffer_new_str(char *name) {
+  Buffer *b = buffer_new(256, name);
+  b->isstring = 1;
+  return b;
+}
+
 void buffer_free(Buffer *b) {
   if(b != NULL) {
     if(b->allocated == 1) {
@@ -68,6 +75,26 @@ void buffer_add(Buffer *b, const void *data, size_t len) {
   b->end += len;
 }
 
+void buffer_add_str(Buffer *b, const char * fmt, ...) {
+  va_list ap;
+  char *dst;
+  va_start(ap, fmt);
+  vasprintf(&dst, fmt, ap);
+  va_end(ap);
+  if(b->end > 0)
+    b->end--;
+  buffer_add(b, dst, strlen(dst)+1);
+  free(dst);
+}
+
+void buffer_add_hex(Buffer *b, void *data, size_t len) {
+  size_t i;
+  unsigned char *d = data;
+  for(i=0; i<len; ++i) {
+    buffer_add_str(b, "%02x", d[i]);
+  }
+}
+
 void buffer_add_buf(Buffer *dst, Buffer *src) {
   buffer_add(dst, buffer_get(src), buffer_size(src));
 }