Add simple reference counted buffer structure.

2 files changed, 40 insertions, 1 deletions

diff --git a/kernel/include/buffer.h b/kernel/include/buffer.h
new file mode 100644
index 0000000..577ceae
--- /dev/null
+++ b/kernel/include/buffer.h
@@ -0,0 +1,38 @@
+#pragma once
+
+#include <stdint.h>
+#include <stddef.h>
+
+// The buffer_t type is a simple reference-counted buffer type
+// enabling the creation, sharing, slicing and concatenation of buffers
+// without having to copy everything each time
+
+// Once a buffer is allocated, its contents is immutable
+
+// Encoding and decoding functions for buffer contents are provided in
+// a separate file (encode.h)
+
+struct buffer;
+typedef struct buffer buffer_t;
+
+void buffer_ref(buffer_t*);				// increase reference counter
+void buffer_unref(buffer_t*);			// decrease reference counter
+
+size_t buffer_len(buffer_t* buf);
+size_t read_buffer(buffer_t* buf, char* to, size_t begin, size_t n);	// returns num of bytes read
+
+buffer_t* buffer_from_bytes(const char* data, size_t n);	// bytes are COPIED
+buffer_t* buffer_from_bytes_nocopy(const char* data, size_t n);	// bytes are NOT COPIED
+
+// these functions GIVE the buffer in order to create the new buffer, ie they do not increase RC
+// the buffer is NOT GIVED if the new buffer could not be created (ie retval == 0)
+buffer_t* buffer_slice(buffer_t* b, size_t begin, size_t n);
+buffer_t* buffer_concat(buffer_t* a, buffer_t* b);
+
+// these functions KEEP a reference on the buffer (ie RC is incremented)
+// the RC is NOT INCREMENTED if the new buffer cannot be created
+buffer_t* buffer_slice_k(buffer_t* b, size_t begin, size_t n);
+buffer_t* buffer_concat_k(buffer_t* a, buffer_t* b);
+
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/
diff --git a/kernel/include/thread.h b/kernel/include/thread.h
index 4c5f337..757ba00 100644
--- a/kernel/include/thread.h
+++ b/kernel/include/thread.h
@@ -17,6 +17,7 @@ typedef struct saved_context {
 	void (*eip)();
 } saved_context_t;
 
+struct process;
 typedef struct thread {
 	saved_context_t ctx;
 	pagedir_t *current_pd_d;
@@ -25,7 +26,7 @@ typedef struct thread {
 
 	region_info_t *stack_region;
 
-	void* more_data;
+	struct process *proc;		// process : L1 data structure
 
 	struct thread *next_in_queue;
 } thread_t;