Initial Commit

util/dprintf.c

@@ -0,0 +1,85 @@
+#ifndef NDEBUG
+
+#include <windows.h>
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "util/dprintf.h"
+
+static long dbg_buf_lock_init;
+static CRITICAL_SECTION dbg_buf_lock;
+static char dbg_buf[16384];
+static size_t dbg_buf_pos;
+
+void dprintf(const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    dprintfv(fmt, ap);
+    va_end(ap);
+}
+
+void dprintfv(const char *fmt, va_list ap)
+{
+    long init;
+
+    /* Static constructors in C are difficult to do in a way that works under
+       both GCC and MSVC, so we have to use atomic ops to ensure that the
+       buffer mutex is correctly initialized instead. */
+
+    do {
+        init = InterlockedCompareExchange(&dbg_buf_lock_init, 0, 1);
+
+        if (init == 0) {
+            /* We won the init race, global variable is now set to 1, other
+               threads will spin until it becomes -1. */
+            InitializeCriticalSection(&dbg_buf_lock);
+            dbg_buf_lock_init = -1;
+            init = -1;
+        }
+    } while (init >= 0);
+
+    EnterCriticalSection(&dbg_buf_lock);
+
+    dbg_buf_pos += vsnprintf_s(
+            dbg_buf + dbg_buf_pos,
+            sizeof(dbg_buf) - dbg_buf_pos,
+            sizeof(dbg_buf) - dbg_buf_pos - 1,
+            fmt,
+            ap);
+
+    if (dbg_buf_pos + 1 > sizeof(dbg_buf)) {
+        abort();
+    }
+
+    if (strchr(dbg_buf, '\n') != NULL) {
+        OutputDebugStringA(dbg_buf);
+        dbg_buf_pos = 0;
+        dbg_buf[0] = '\0';
+    }
+
+    LeaveCriticalSection(&dbg_buf_lock);
+}
+
+void dwprintf(const wchar_t *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    dwprintfv(fmt, ap);
+    va_end(ap);
+}
+
+void dwprintfv(const wchar_t *fmt, va_list ap)
+{
+    wchar_t msg[512];
+
+    _vsnwprintf_s(msg, _countof(msg), _countof(msg) - 1, fmt, ap);
+    OutputDebugStringW(msg);
+}
+
+#endif