diff -r b7d1317b138e -r fae240d633fc src/logging.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/logging.c	Tue Oct 17 16:15:41 2017 +0200
@@ -0,0 +1,106 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2017 Olaf Wintermann. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "ucx/logging.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+#include <time.h>
+
+UcxLogger *ucx_logger_new(void *stream, unsigned int level, unsigned int mask) {
+    UcxLogger *logger = (UcxLogger*) malloc(sizeof(UcxLogger));
+    if (logger != NULL) {
+        logger->stream = stream;
+        logger->writer = (write_func)fwrite;
+        logger->dateformat = (char*) "%F %T %z ";
+        logger->level = level;
+        logger->mask = mask;
+        logger->levels = ucx_map_new(8);
+        
+        unsigned int l;
+        l = UCX_LOGGER_ERROR;
+        ucx_map_int_put(logger->levels, l, (void*) "[ERROR]");
+        l = UCX_LOGGER_WARN;
+        ucx_map_int_put(logger->levels, l, (void*) "[WARNING]");
+        l = UCX_LOGGER_INFO;
+        ucx_map_int_put(logger->levels, l, (void*) "[INFO]");
+        l = UCX_LOGGER_TRACE;
+        ucx_map_int_put(logger->levels, l, (void*) "[TRACE]");
+    }
+
+    return logger;
+}
+
+void ucx_logger_free(UcxLogger *logger) {
+    ucx_map_free(logger->levels);
+    free(logger);
+}
+
+// estimated max. message length (documented)
+#define UCX_LOGGER_MSGMAX 4096
+
+void ucx_logger_logf(UcxLogger *logger, unsigned int level, const char* file,
+        const unsigned int line, const char *format, ...) {
+    if (level <= logger->level) {
+        char msg[UCX_LOGGER_MSGMAX];
+        char *text;
+        size_t k = 0;
+        size_t n;
+        
+        if ((logger->mask & UCX_LOGGER_LEVEL) > 0) {
+            text = (char*) ucx_map_int_get(logger->levels, level);
+            n = strlen(text);
+            n = n > 256 ? 256 : n;
+            memcpy(msg+k, text, n);
+            k += n;
+            msg[k++] = ' ';
+        }
+        if ((logger->mask & UCX_LOGGER_TIMESTAMP) > 0) {
+            time_t now = time(NULL);
+            k += strftime(msg+k, 128, logger->dateformat, localtime(&now));
+        }
+        if ((logger->mask & UCX_LOGGER_SOURCE) > 0) {
+            n = strlen(file);
+            memcpy(msg+k, file, n);
+            k += n;
+            k += sprintf(msg+k, ":%u ", line);
+        }
+        
+        msg[k++] = '-'; msg[k++] = ' ';
+        
+        va_list args;
+        va_start (args, format);
+        k += vsnprintf(msg+k, UCX_LOGGER_MSGMAX-k-1, format, args);
+        va_end (args);        
+        
+        msg[k++] = '\n';
+        
+        logger->writer(msg, 1, k, logger->stream);
+    }
+}