From 91a08b6abbcfdd02d523b3f0b6fa5e8a1c8b8364 Mon Sep 17 00:00:00 2001
From: Tau <tau@nowhere>
Date: Wed, 7 Nov 2018 16:38:24 -0500
Subject: [PATCH] util/dprintf.c: Add debug printf

---
 util/dprintf.c   | 63 ++++++++++++++++++++++++++++++++++++++++++++++++
 util/dprintf.h   | 22 +++++++++++++++++
 util/meson.build |  2 ++
 3 files changed, 87 insertions(+)
 create mode 100644 util/dprintf.c
 create mode 100644 util/dprintf.h

diff --git a/util/dprintf.c b/util/dprintf.c
new file mode 100644
index 0000000..34941f7
--- /dev/null
+++ b/util/dprintf.c
@@ -0,0 +1,63 @@
+#ifndef NDEBUG
+
+#include <windows.h>
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "util/dprintf.h"
+
+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)
+{
+    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) {
+        return;
+    }
+
+    OutputDebugStringA(dbg_buf);
+    dbg_buf_pos = 0;
+    dbg_buf[0] = '\0';
+}
+
+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
diff --git a/util/dprintf.h b/util/dprintf.h
new file mode 100644
index 0000000..af071b1
--- /dev/null
+++ b/util/dprintf.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <stdarg.h>
+#include <stddef.h>
+
+#ifdef __GNUC__
+#define DPRINTF_CHK __attribute__(( format(printf, 1, 2) ))
+#else
+#define DPRINTF_CHK
+#endif
+
+#ifndef NDEBUG
+void dprintf(const char *fmt, ...) DPRINTF_CHK;
+void dprintfv(const char *fmt, va_list ap);
+void dwprintf(const wchar_t *fmt, ...);
+void dwprintfv(const wchar_t *fmt, va_list ap);
+#else
+#define dprintf(...)
+#define dprintfv(fmt, ap)
+#define dwprintf(...)
+#define dwprintfv(fmt, ap)
+#endif
diff --git a/util/meson.build b/util/meson.build
index ed0929d..0cedae5 100644
--- a/util/meson.build
+++ b/util/meson.build
@@ -7,5 +7,7 @@ util_lib = static_library(
         capnhook.get_variable('hook_dep'),
     ],
     sources : [
+        'dprintf.c',
+        'dprintf.h',
     ],
 )