1 files changed, 79 insertions, 0 deletions
diff --git a/coroutine/copy/Context.h b/coroutine/copy/Context.h
new file mode 100644
index 0000000000..a62efa4e8a
--- /dev/null
+++ b/coroutine/copy/Context.h
@@ -0,0 +1,79 @@
+/*
+ *  This file is part of the "Coroutine" project and released under the MIT License.
+ *
+ *  Created by Samuel Williams on 27/6/2019.
+ *  Copyright, 2019, by Samuel Williams. All rights reserved.
+*/
+
+#pragma once
+
+#include <assert.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <string.h>
+#include <stdlib.h>
+#include <alloca.h>
+
+#define COROUTINE __attribute__((noreturn)) void
+
+// This stack copying implementation which uses a private stack for each coroutine, including the main one.
+#define COROUTINE_PRIVATE_STACK
+
+struct coroutine_context
+{
+    // Private stack:
+    void *stack;
+    size_t size, used;
+
+    // The top (or bottom) of the currently executing stack:
+    void *base;
+
+    jmp_buf state;
+
+    struct coroutine_context *from;
+};
+
+typedef COROUTINE(*coroutine_start)(struct coroutine_context *from, struct coroutine_context *self);
+
+int coroutine_save_stack(struct coroutine_context * context);
+COROUTINE coroutine_restore_stack(struct coroutine_context *context);
+
+// @param stack The private stack area memory allocation (pointer to lowest address).
+// @param size The size of the private stack area.
+// @param base A stack pointer to the base of the main stack. On x86 hardware, this is the upper extent of the region that will be copied to the private stack.
+static inline void coroutine_initialize_main(struct coroutine_context *context, void *stack, size_t size, void *base) {
+    context->stack = stack;
+    context->size = size;
+    context->used = 0;
+
+    assert(base);
+    context->base = base;
+
+    context->from = NULL;
+}
+
+// @param start The start function to invoke.
+static inline void coroutine_initialize(
+    struct coroutine_context *context,
+    coroutine_start start,
+    void *stack,
+    size_t size,
+    void *base
+) {
+    assert(start && stack && size >= 1024);
+
+    coroutine_initialize_main(context, stack, size, base);
+
+    if (coroutine_save_stack(context)) {
+        start(context->from, context);
+    }
+}
+
+struct coroutine_context *coroutine_transfer(struct coroutine_context *current, register struct coroutine_context *target);
+
+static inline void coroutine_destroy(struct coroutine_context *context)
+{
+    context->stack = NULL;
+    context->size = 0;
+    context->from = NULL;
+}