initial

1 files changed, 78 insertions, 0 deletions

diff --git a/buffer.c b/buffer.c
new file mode 100644
index 0000000..167db65
--- /dev/null
+++ b/buffer.c
@@ -0,0 +1,78 @@
+#include "buffer.h"
+#include "xwrap.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+
+void binit(struct buffer *b, size_t size)
+{
+	char *p;
+
+	p = (char *) xmalloc(size);
+	b->addr = b->begin = b->end = p;
+	b->size = size;
+}
+
+void bfree(struct buffer *b)
+{
+	if (b->addr != NULL) {
+		free(b->addr);
+		b->addr = b->begin = b->end = NULL;
+		b->size = 0;
+	}
+}
+
+static inline int bavail_write(struct buffer *b)
+{
+	return b->end - b->begin;
+}
+
+static inline int bavail_read(struct buffer *b)
+{
+	return b->addr + b->size - b->end;
+}
+
+int bread(struct buffer *b, int fd)
+{
+	int size;
+	int n;
+
+	size = bavail_read(b);
+	if (size == 0)
+		return 0;
+
+	n = read(fd, b->end, size);
+	if (n < 1)
+		return -1;
+	b->end += n;
+	return n;
+}
+
+int bwrite(struct buffer *b, int fd)
+{
+	int size;
+	int n;
+
+	size = bavail_write(b);
+	if (size == 0)
+		return 0;
+	
+	n = write(fd, b->begin, size);
+	if (n < 1)
+		return -1;
+	b->begin += n;
+	if (b->begin == b->end)
+		b->begin = b->end = b->addr;
+	return n;
+}
+
+int bcanfill(struct buffer *b)
+{
+	return bavail_read(b) > 0;
+}
+
+int bhasdata(struct buffer *b)
+{
+	return bavail_write(b) > 0;
+}
+