ringbuffers: initial implementation

src/include/Makefile

@@ -1,6 +1,6 @@
 objects := $(patsubst %.c,%.o,$(wildcard *.c))
-subdirs := stdio string hashtable
+subdirs := stdio string hashtable ringbuffer
-OBJPATH=$(OBJDIR)/include
+OBJPATH=$(OBJDIR)/include/ringbuffer/
 export
 
 all: $(subdirs) $(objects)

src/include/ringbuffer.h

@@ -0,0 +1,20 @@
+#ifndef _RINGBUFFER_H_INCLUDE
+#define _RINGBUFFER_H_INCLUDE
+
+#include <stdint.h>
+#include <stddef.h>
+
+typedef struct{
+	int lock;
+	size_t size;
+	uintmax_t write, read;
+	void* data;
+} ringbuffer_t;
+
+
+int ringbuffer_init(ringbuffer_t* ringbuffer, size_t size);
+size_t ringbuffer_read(ringbuffer_t* ringbuffer, void* buffer, size_t count);
+size_t ringbuffer_write(ringbuffer_t* ringbuffer, void* buffer, size_t count);
+
+
+#endif

src/include/ringbuffer/Makefile

@@ -0,0 +1,12 @@
+objects := $(patsubst %.c,%.o,$(wildcard *.c))
+subdirs := 
+OBJPATH=$(OBJDIR)/include
+export
+
+all: $(subdirs) $(objects)
+	for subdir in $(subdirs) ; do $(MAKE) -C $${subdir} ; done
+
+%.o: %.c
+	$(CC) $(CFLAGS) -o $@ $<
+	mkdir -p $(OBJPATH) 
+	cp $@ $(OBJPATH)/$@

src/include/ringbuffer/ringbuffer.c

@@ -0,0 +1,69 @@
+#include <ringbuffer.h>
+#include <errno.h>
+#include <arch/spinlock.h>
+#include <kernel/alloc.h>
+
+int ringbuffer_init(ringbuffer_t* ringbuffer, size_t size){
+	
+	ringbuffer->data = alloc(size);
+	
+	if(!ringbuffer->data)
+		return ENOMEM;
+
+	ringbuffer->size = size;
+
+	return 0;
+}
+
+size_t ringbuffer_read(ringbuffer_t* ringbuffer, void* buffer, size_t count){
+	
+	spinlock_acquire(&ringbuffer->lock);
+	
+	size_t readc = 0;
+
+	for(;readc < count; ++readc){
+		if(ringbuffer->read == ringbuffer->write)
+			break;
+
+		uintmax_t readoffset = ringbuffer->read % ringbuffer->size;
+		uint8_t* buf = buffer + readc;
+		uint8_t* rbuf = ringbuffer->data + readoffset;
+
+		*buf = *rbuf;
+
+		++ringbuffer->read;
+		
+	}
+
+
+	spinlock_release(&ringbuffer->lock);
+	
+	return readc;
+
+}
+
+size_t ringbuffer_write(ringbuffer_t* ringbuffer, void* buffer, size_t count){
+	
+	spinlock_acquire(&ringbuffer->lock);
+	
+	size_t writec = 0;
+	
+	for(;writec < count; ++writec){
+		if(ringbuffer->write == ringbuffer->read + ringbuffer->size)
+			break;
+		
+		uintmax_t writeoffset = ringbuffer->write % ringbuffer->size;
+		uint8_t* buf = buffer + writec;
+		uint8_t* wbuf = ringbuffer->data + writeoffset;
+
+		*wbuf = *buf;
+		
+		++ringbuffer->write;
+
+	}
+	
+	spinlock_release(&ringbuffer->lock);
+
+	return writec;
+
+}