From a1e56851b1d1db0f8c687c769c1f0a37373c34f9 Mon Sep 17 00:00:00 2001
From: doodspav <doodspav@gmail.com>
Date: Wed, 6 Mar 2024 16:40:28 +0200
Subject: [PATCH] GHI #32 Add memory_order.h header

---
 CMakeLists.txt                       |   1 +
 include/patomic/types/align.h        |   2 +-
 include/patomic/types/ids.h          |   4 +-
 include/patomic/types/memory_order.h | 114 +++++++++++++++++++++++++++
 4 files changed, 119 insertions(+), 2 deletions(-)
 create mode 100644 include/patomic/types/memory_order.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d306c81f4..7833a1bf2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -41,6 +41,7 @@ target_sources(
     # include/types
     include/patomic/types/align.h
     include/patomic/types/ids.h
+    include/patomic/types/memory_order.h
 )
 
 # add /src files to target
diff --git a/include/patomic/types/align.h b/include/patomic/types/align.h
index 28cc0b431..af5370fe0 100644
--- a/include/patomic/types/align.h
+++ b/include/patomic/types/align.h
@@ -161,7 +161,7 @@ patomic_align_meets_minimum(
 
 
 #ifdef __cplusplus
-};
+}  /* extern "C" */
 #endif
 
 #endif  /* PATOMIC_ALIGN_H */
diff --git a/include/patomic/types/ids.h b/include/patomic/types/ids.h
index 574aeac90..8c2f34974 100644
--- a/include/patomic/types/ids.h
+++ b/include/patomic/types/ids.h
@@ -70,6 +70,7 @@ typedef unsigned long patomic_id_t;
  */
 
 typedef enum {
+
     /** @brief The implementation kind is unknown. */
     patomic_kind_UNKN  = 0x0
 
@@ -94,6 +95,7 @@ typedef enum {
                          patomic_kind_LIB  |
                          patomic_kind_BLTN |
                          patomic_kind_ASM
+
 } patomic_kind_t;
 
 
@@ -137,7 +139,7 @@ patomic_get_kind(
 
 
 #ifdef __cplusplus
-};
+}  /* extern "C" */
 #endif
 
 #endif  /* PATOMIC_IDS_H */
diff --git a/include/patomic/types/memory_order.h b/include/patomic/types/memory_order.h
new file mode 100644
index 000000000..db87673eb
--- /dev/null
+++ b/include/patomic/types/memory_order.h
@@ -0,0 +1,114 @@
+#ifndef PATOMIC_MEMORY_ORDER_H
+#define PATOMIC_MEMORY_ORDER_H
+
+#include <patomic/patomic_export.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/**
+ * @addtogroup mem_order
+ *
+ * @brief
+ *   Enum constants specifying how memory accesses are to be ordered around an
+ *   atomic operation.
+ *
+ * @details
+ *   Each enum label's value and semantics are identical to C++11's
+ *   std::memory_order's values and semantics.
+ *
+ * @note
+ *   Consume is only present for compatibility. It is not and will not be
+ *   implemented, and will always be treated as patomic_ACQUIRE.
+ */
+
+typedef enum {
+    patomic_RELAXED,
+    patomic_CONSUME,
+    patomic_ACQUIRE,
+    patomic_RELEASE,
+    patomic_ACQ_REL,
+    patomic_SEQ_CST
+} patomic_memory_order_t;
+
+
+/**
+ * @addtogroup mem_order
+ *
+ * @brief
+ *   Checks that order has a value corresponding to a label in
+ *   patomic_memory_order_t.
+ *
+ * @returns If the check succeeds returns 1, else 0.
+ */
+
+PATOMIC_EXPORT int
+patomic_is_valid_order(int order);
+
+
+/**
+ * @addtogroup mem_order
+ *
+ * @brief
+ *   Checks that order has a value corresponding to a label in
+ *   patomic_memory_order_t, and is valid to use for an atomic store operation.
+ *
+ * @returns If the check succeeds returns 1, else 0.
+ */
+
+PATOMIC_EXPORT int
+patomic_is_valid_store_order(int order);
+
+
+/**
+ * @addtogroup mem_order
+ *
+ * @brief
+ *   Checks that order has a value corresponding to a label in
+ *   patomic_memory_order_t, and is valid to use for an atomic load operation.
+ *
+ * @returns If the check succeeds returns 1, else 0.
+ */
+
+PATOMIC_EXPORT int
+patomic_is_valid_load_order(int order);
+
+
+/**
+ * @addtogroup mem_order
+ *
+ * @brief
+ *   Checks that both succ and fail have a value corresponding to a label in
+ *   patomic_memory_order_t, and fail is not stronger than succ or equal to
+ *   patomic_RELEASE or patomic_ACQ_REL.
+ *
+ * @returns If the check succeeds returns 1, else 0.
+ */
+
+PATOMIC_EXPORT int
+patomic_is_valid_fail_order(int succ, int fail);
+
+
+/**
+ * @addtogroup mem_order
+ *
+ * @brief
+ *   Returns the strictest memory order that would satisfy the checks done by
+ *   patomic_is_valid_fail_order(succ, <return>).
+ *
+ * @warning
+ *   If an invalid memory order is passed to this function, it will be returned
+ *   unmodified.
+ */
+
+PATOMIC_EXPORT int
+patomic_cmpxchg_fail_order(int succ);
+
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif  /* PATOMIC_MEMORY_ORDER_H */