Move *_pemify() function to PEM module
diff --git a/library/pem.c b/library/pem.c
index 8a6de3a..ff7f32c 100644
--- a/library/pem.c
+++ b/library/pem.c
@@ -363,6 +363,56 @@
     return( 0 );
 }
 
+int pem_write_buffer( const char *header, const char *footer,
+                      const unsigned char *der_data, size_t der_len,
+                      unsigned char *buf, size_t buf_len, size_t *olen )
+{
+    int ret;
+    unsigned char *encode_buf, *c, *p = buf;
+    size_t len = 0, use_len = 0;
+    size_t add_len = strlen( header ) + strlen( footer ) + ( use_len / 64 ) + 1;
+
+    base64_encode( NULL, &use_len, der_data, der_len );
+    if( use_len + add_len > buf_len )
+    {
+        *olen = use_len + add_len;
+        return( POLARSSL_ERR_BASE64_BUFFER_TOO_SMALL );
+    }
+
+    if( ( encode_buf = polarssl_malloc( use_len ) ) == NULL )
+        return( POLARSSL_ERR_PEM_MALLOC_FAILED );
+
+    if( ( ret = base64_encode( encode_buf, &use_len, der_data,
+                               der_len ) ) != 0 )
+    {
+        polarssl_free( encode_buf );
+        return( ret );
+    }
+
+    memcpy( p, header, strlen( header ) );
+    p += strlen( header );
+    c = encode_buf;
+
+    while( use_len )
+    {
+        len = ( use_len > 64 ) ? 64 : use_len;
+        memcpy( p, c, len );
+        use_len -= len;
+        p += len;
+        c += len;
+        *p++ = '\n';
+    }
+
+    memcpy( p, footer, strlen( footer ) );
+    p += strlen( footer );
+
+    *p++ = '\0';
+    *olen = p - buf;
+
+    polarssl_free( encode_buf );
+    return( 0 );
+}
+
 void pem_free( pem_context *ctx )
 {
     if( ctx->buf )