1 files changed, 105 insertions, 0 deletions
diff --git a/core/logger.c b/core/logger.c
new file mode 100644
index 0000000..af41dcc
--- /dev/null
+++ b/core/logger.c
@@ -0,0 +1,105 @@
+#include <assert.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <time.h>
+#include <unistd.h>
+
+#define LOG_LINE_SIZE 1024
+
+enum LogLevel {
+    INFO,
+    WARN,
+};
+
+void log_msg_to_buff(char *out, int size, enum LogLevel level, bool colored, const char *format, va_list args) {
+    assert(out);
+    assert(size);
+    assert(level == INFO || level == WARN);
+    assert(format);
+
+    struct timespec ts;
+    clock_gettime(CLOCK_REALTIME, &ts);
+    long msec = ts.tv_nsec / 1000000;
+    struct tm tm = *localtime(&ts.tv_sec);
+    pid_t pid = getpid();
+    const char *level_str = NULL;
+
+    switch (level) {
+    case INFO:
+        level_str = "INFO";
+        break;
+    case WARN:
+        level_str = "WARN";
+        break;
+    default:
+        assert(false);
+    }
+
+    const char *color_code = NULL;
+    if (colored) {
+        switch (level) {
+        case INFO:
+            color_code = "\033[1;32m";
+            break;
+        case WARN:
+            color_code = "\033[1;33m";
+            break;
+        default:
+            assert(false);
+        }
+    }
+
+    // Imitate formatting style configured in 'salis.py'
+    int col = snprintf(
+        out,
+        size,
+        "%s%d-%02d-%02d %02d:%02d:%02d,%03ld %07d [%s]%s ",
+        colored ? color_code : "",
+        tm.tm_year + 1900,
+        tm.tm_mon + 1,
+        tm.tm_mday,
+        tm.tm_hour,
+        tm.tm_min,
+        tm.tm_sec,
+        msec,
+        pid,
+        level_str,
+        colored ? "\033[0m" : ""
+    );
+
+    vsnprintf(out + col, size - col, format, args);
+}
+
+void log_msg(enum LogLevel level, bool colored, const char *format, va_list args) {
+    assert(level == INFO || level == WARN);
+    assert(format);
+
+    char buff[LOG_LINE_SIZE];
+    log_msg_to_buff(buff, LOG_LINE_SIZE, level, colored, format, args);
+    printf("\r%s\n", buff);
+    fflush(stdout);
+}
+
+void log_info_default(const char *format, ...) {
+    assert(format);
+
+    va_list args;
+    va_start(args, format);
+    log_msg(INFO, true, format, args);
+    va_end(args);
+}
+
+void log_warn_default(const char *format, ...) {
+    assert(format);
+
+    va_list args;
+    va_start(args, format);
+    log_msg(WARN, true, format, args);
+    va_end(args);
+}
+
+// Client may install their own loggers
+void (*log_info)(const char *fmt, ...) = log_info_default;
+void (*log_warn)(const char *fmt, ...) = log_warn_default;