libds

commit 79305390876395bbd5e1d7de4c598425d4347689
parent 321aa046d5eb8d5e44eacfd268f8eef4269a7851
Author: sin <sin@2f30.org>
Date:   Tue,  8 Apr 2014 10:14:56 +0100

Add simple fifo implementation

Diffstat:
M
Makefile
 | 
2
+-
M
ds.h
 | 
6
++++++
A
fifo.c
 | 
73
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

3 files changed, 80 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
@@ -3,7 +3,7 @@
 
 include config.mk
 
-SRC = vector.c
+SRC = vector.c fifo.c
 OBJ = ${SRC:.c=.o}
 SOUT = ${NAME}.a
 
diff --git a/ds.h b/ds.h
@@ -11,4 +11,10 @@ void *vector_get(struct vector *, size_t);
 size_t vector_len(struct vector *);
 void vector_walk(struct vector *, void (*)(struct vector *, void *));
 
+/* fifo.c */
+struct fifo *fifo_init(size_t);
+void fifo_free(struct fifo *);
+int fifo_enqueue(struct fifo *, const void *, size_t)
+int fifo_dequeue(struct fifo *, void *, size_t);
+
 #endif
diff --git a/fifo.c b/fifo.c
@@ -0,0 +1,73 @@
+#include <stdlib.h>
+#include <string.h>
+
+struct fifo {
+	unsigned char *buf;
+	size_t sz;
+	size_t cap;
+};
+
+struct fifo *
+fifo_init(size_t cap)
+{
+	struct fifo *fifo;
+
+	fifo = malloc(sizeof(*fifo));
+	if (!fifo)
+		return NULL;
+	if (cap > 0) {
+		fifo->buf = malloc(cap);
+		if (!fifo->buf) {
+			free(fifo);
+			return NULL;
+		}
+	}
+	fifo->sz = 0;
+	fifo->cap = cap;
+	return fifo;
+}
+
+void
+fifo_free(struct fifo *fifo)
+{
+	free(fifo->buf);
+	free(fifo);
+}
+
+int
+fifo_enqueue(struct fifo *fifo, const void *buf, size_t sz)
+{
+	void *tmp;
+
+	if (!sz)
+		return 0;
+
+	if (fifo->cap - fifo->sz >= sz) {
+		memcpy(fifo->buf + fifo->sz, buf, sz);
+		fifo->sz += sz;
+		return 0;
+	}
+
+	tmp = realloc(fifo->buf, fifo->cap + sz);
+	if (!tmp)
+		return -1;
+	fifo->buf = tmp;
+	memcpy(fifo->buf + fifo->sz, buf, sz);
+	fifo->sz += sz;
+	fifo->cap += sz;
+	return 0;
+}
+
+int
+fifo_dequeue(struct fifo *fifo, void *buf, size_t sz)
+{
+	if (!sz)
+		return 0;
+
+	if (fifo->sz < sz)
+		return -1;
+	memcpy(buf, fifo->buf, sz);
+	memmove(fifo->buf, fifo->buf + sz, fifo->sz - sz);
+	fifo->sz -= sz;
+	return 0;
+}