From c38d58b7fe66b54fe5ea23f2e1f3eb188009310d Mon Sep 17 00:00:00 2001
From: Avril <flanchan@cumallover.me>
Date: Wed, 3 Nov 2021 05:44:44 +0000
Subject: [PATCH] Rework C API shim. Now bridges: librngxx (main library C++
 interface) @ rngxx.hpp -> >|capi-bridge.cpp <-> capi-bridge.h <-> capi.c|> ->
 rngxx.h
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Fortune for rngxx's current commit: Small blessing − 小吉
---
 include/rngxx.h     |  7 ++++++-
 src/capi-bridge.cpp | 19 +++++++++++++++++++
 src/capi-bridge.h   | 25 +++++++++++++++++++++++++
 src/capi.c          | 11 +++++++++++
 src/capi.cpp        | 17 -----------------
 5 files changed, 61 insertions(+), 18 deletions(-)
 create mode 100644 src/capi-bridge.cpp
 create mode 100644 src/capi-bridge.h
 create mode 100644 src/capi.c
 delete mode 100644 src/capi.cpp

diff --git a/include/rngxx.h b/include/rngxx.h
index 09abe8e..9037f0a 100644
--- a/include/rngxx.h
+++ b/include/rngxx.h
@@ -10,6 +10,9 @@
 #endif
 
 #ifdef __cplusplus
+#ifndef _RNGXX_IMPL_ONLY_TYPES
+#warning "C++ compilers might not like this header file. Please use the C++ interface for C++ TUs"
+#endif
 extern "C" {
 #endif
 
@@ -19,8 +22,10 @@ enum rng_kind {
 	RNG_KIND_CRAND,
 };
 
-extern rng_t* rng_new(enum rng_kind kind, u64 seed[static restrict 1]);
+#ifndef _RNGXX_IMPL_ONLY_TYPES
+rng_t* rng_new(enum rng_kind kind, u64 seed[static restrict 1]);
 
+#endif
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/capi-bridge.cpp b/src/capi-bridge.cpp
new file mode 100644
index 0000000..e94cfdc
--- /dev/null
+++ b/src/capi-bridge.cpp
@@ -0,0 +1,19 @@
+// Contains the work-doing code for the C API interface, which should be exported to the C API shim in the header "capi-bridge.h"
+
+#include <rngxx.hpp>
+#include <rngxx/crand.h>
+
+#include "capi-bridge.h"
+
+extern "C" {
+	_export(internal)	
+	rng_t* RNG_IMPL(mkdriver)(rng_kind kind, u64* restrict seed)
+	{
+		switch(kind)
+		{
+			case RNG_KIND_CRAND:
+				return new rng::crand(seed[0]); 
+			default: return NULL;
+		}
+	}
+}
diff --git a/src/capi-bridge.h b/src/capi-bridge.h
new file mode 100644
index 0000000..b2977b2
--- /dev/null
+++ b/src/capi-bridge.h
@@ -0,0 +1,25 @@
+// Bridges the working TU `capi-bridge.cpp`, which handles interfacing with rngxx's C++ API, and the C API shim TU defined in `capi.c`
+// This file must be useable by both C and C++ compilers, and everything here must have C linkage
+// 
+// Other headers shouldn't be included here. The only ones included are included for the types they define
+#ifndef _RNG_CAPI_BRIDGE_H
+#define _RNG_CAPI_BRIDGE_H
+
+#define _RNGXX_IMPL_ONLY_TYPES
+#include <rngxx.h>
+#undef _RNGXX_IMPL_ONLY_TYPES
+#include <common.h>
+
+#define RNG_IMPL(name) _rng__internal_ ## name
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+rng_t* RNG_IMPL(mkdriver)(enum rng_kind kind, u64* restrict seed) _export(internal);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RNG_CAPI_BRIDGE_H */
diff --git a/src/capi.c b/src/capi.c
new file mode 100644
index 0000000..e52848b
--- /dev/null
+++ b/src/capi.c
@@ -0,0 +1,11 @@
+// Contains the library exported C API functions. 
+// Actual work may be done in `capi-bridge.cpp`, `capi-bridge.h` bridges this shim TU with that working one
+
+#include <rngxx.h>
+
+#include "capi-bridge.h"
+
+rng_t* rng_new(enum rng_kind kind, u64 seed[static restrict 1])
+{
+	return RNG_IMPL(mkdriver) (kind, &seed[0]);
+}
diff --git a/src/capi.cpp b/src/capi.cpp
deleted file mode 100644
index c1da629..0000000
--- a/src/capi.cpp
+++ /dev/null
@@ -1,17 +0,0 @@
-#include <rngxx.hpp>
-#include <rngxx/crand.h>
-
-#include <rngxx.h>
-
-extern "C" {
-	//TODO: Make these C++ compiled ones intermediate, so the C interface used here can be used. use internal linkage for the C++ intermediates
-	rng_t* rng_new(rng_kind kind, u64 seed[static restrict 1])
-	{
-		switch(kind)
-		{
-			case RNG_KIND_CRAND:
-				return new rng::crand(seed[0]); 
-			default: return NULL;
-		}
-	}
-}