From 15d3ee525aea4e7cea3133039bd23f4c14a978ba Mon Sep 17 00:00:00 2001
From: bumbread <thebumboni@gmail.com>
Date: Tue, 21 Feb 2023 10:15:02 +1100
Subject: [PATCH] condition variables pt. 1

---
 inc/os_win/threads_types.h |  7 +++++--
 inc/threads.h              |  6 +-----
 src/os_win/thread.c        | 28 ++++++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/inc/os_win/threads_types.h b/inc/os_win/threads_types.h
index 1da440f..4ef470f 100644
--- a/inc/os_win/threads_types.h
+++ b/inc/os_win/threads_types.h
@@ -1,6 +1,8 @@
 
 // Note(bumbread): this file is included into threads.h when compiled under
-// windows.
+// windows. Here we avoid including windows.h directly because it may be
+// undesireable to include a bunch of non-standard names and types into user's
+// files just to get a few of them.
 
 #pragma once
 
@@ -21,8 +23,9 @@ typedef union once_flag {
     void *ptr;
 } once_flag;
 
+// This mirrors CONDITION_VARIABLE type (aka _RTL_CONDITION_VARIABLE)
 typedef struct cnd_t {
-    int idk_yet;
+    void *ptr;
 } cnd_t;
 
 typedef struct mtx_t {
diff --git a/inc/threads.h b/inc/threads.h
index c9b594d..800d810 100644
--- a/inc/threads.h
+++ b/inc/threads.h
@@ -83,11 +83,7 @@ int  cnd_broadcast(cnd_t *cond);
 void cnd_destroy  (cnd_t *cond);
 int  cnd_signal   (cnd_t *cond);
 int  cnd_wait     (cnd_t *cond, mtx_t *mtx);
-int  cnd_timedwait(
-    cnd_t *restrict cond,
-    mtx_t *restrict mtx,
-    const struct timespec *restrict ts
-);
+int  cnd_timedwait(cnd_t *restrict cond, mtx_t *restrict mtx, const struct timespec *restrict ts);
 
 // Call once
 void call_once(once_flag *flag, void (*func)(void));
diff --git a/src/os_win/thread.c b/src/os_win/thread.c
index d3505d6..3130cd7 100644
--- a/src/os_win/thread.c
+++ b/src/os_win/thread.c
@@ -200,6 +200,34 @@ void call_once(once_flag *flag, void (*func)(void)) {
     InitOnceExecuteOnce((void *)flag, _call_once_trampoline, funcp, NULL);
 }
 
+// Condition variables
+
+int cnd_init(cnd_t *cond) {
+    InitializeConditionVariable((void *)cond);
+}
+
+int cnd_broadcast(cnd_t *cond) {
+    WakeAllConditionVariable((void *)cond);
+    return thrd_success;
+}
+
+void cnd_destroy(cnd_t *cond) {
+    return; // Does nothing
+}
+
+int cnd_signal(cnd_t *cond) {
+    WakeConditionVariable((void *)cond);
+    return thrd_success;
+}
+
+int cnd_wait(cnd_t *cond, mtx_t *mtx) {
+    return thrd_error; // TODO after mutexes
+}
+
+int cnd_timedwait(cnd_t *restrict cond, mtx_t *restrict mtx, const struct timespec *restrict ts) {
+    return thrd_error; // TODO after mutexes
+}
+
 // Mutex functions
 
 void mtx_destroy(mtx_t *mtx) {