modified copyright tags

[palacios.git] / palacios / src / geekos / ring_buffer.c

diff --git a/palacios/src/geekos/ring_buffer.c b/palacios/src/geekos/ring_buffer.c
index 0e2f9b1..71d4dc7 100644 (file)
--- a/palacios/src/geekos/ring_buffer.c
+++ b/palacios/src/geekos/ring_buffer.c
@@ -1,7 +1,10 @@
+/* (c) 2008, Jack Lange <jarusl@cs.northwestern.edu> */
+/* (c) 2008, The V3VEE Project <http://www.v3vee.org> */
+
 #include <geekos/ring_buffer.h>
 #include <geekos/malloc.h>
 #include <geekos/ktypes.h>
-
+#include <geekos/debug.h>
 
 
 void init_ring_buffer(struct ring_buffer * ring, uint_t size) {
@@ -31,46 +34,151 @@ void free_ring_buffer(struct ring_buffer * ring) {
 
 
 
-static inline uchar_t * get_buf_ptr(struct ring_buffer * ring) {
-  return (uchar_t *)&(ring->buf + ring->start);
+static inline uchar_t * get_read_ptr(struct ring_buffer * ring) {
+  return (uchar_t *)(ring->buf + ring->start);
+}
+
+static inline uchar_t * get_write_ptr(struct ring_buffer * ring) {
+  return (uchar_t *)(ring->buf + ring->end);
 }
 
 
-static inline int get_section_size(struct ring_buffer * ring) {
+static inline int get_read_section_size(struct ring_buffer * ring) {
   return ring->size - ring->start;
 }
 
-static inline int is_loop(struct ring_buffer * ring, uint_t len) {
+static inline int get_write_section_size(struct ring_buffer * ring) {
+  return ring->size - ring->end;
+}
+
+static inline int is_read_loop(struct ring_buffer * ring, uint_t len) {
   if ((ring->start >= ring->end) && (ring->current_len > 0)) {
     // end is past the end of the buffer
-    if (get_section_size(ring) < len) {
+    if (get_read_section_size(ring) < len) {
       return 1;
     }
   }
+  return 0;
+}
 
+
+static inline int is_write_loop(struct ring_buffer * ring, uint_t len) {
+  if ((ring->end >= ring->start) && (ring->current_len < ring->size)) {
+    // end is past the end of the buffer
+    if (get_write_section_size(ring) < len) {
+      return 1;
+    }
+  }
   return 0;
 }
 
 
+int rb_data_len(struct ring_buffer * ring) {
+  return ring->current_len;
+}
+
+int rb_capacity(struct ring_buffer * ring) {
+  return ring->size;
+}
+
 int rb_read(struct ring_buffer * ring, char * dst, uint_t len) {
   int read_len = 0;
   int ring_data_len = ring->current_len;
 
   read_len = (len > ring_data_len) ? ring_data_len : len;
 
-  if (is_loop(ring, read_len)) {
-    int first_len = get_section_size(ring);
+  if (is_read_loop(ring, read_len)) {
+    int section_len = get_read_section_size(ring);
+
+    memcpy(dst, get_read_ptr(ring), section_len);
+    memcpy(dst + section_len, ring->buf, read_len - section_len);
+    
+    ring->start = read_len - section_len;
+  } else {
+    memcpy(dst, get_read_ptr(ring), read_len);
+    
+    ring->start += read_len;
+  }
+
+  ring->current_len -= read_len;
+
+  return read_len;
+}
+
+
+
+
+int rb_peek(struct ring_buffer * ring, char * dst, uint_t len) {
+  int read_len = 0;
+  int ring_data_len = ring->current_len;
 
-    memcpy(dst, get_buf_ptr(ring), first_len);
-    read_len -= first_len;
-    ring->start = 0;
+  read_len = (len > ring_data_len) ? ring_data_len : len;
 
-    memcpy(dst + first_len, get_buf_ptr, read_len);
+  if (is_read_loop(ring, read_len)) {
+    int section_len = get_read_section_size(ring);
 
+    memcpy(dst, get_read_ptr(ring), section_len);
+    memcpy(dst + section_len, ring->buf, read_len - section_len);
   } else {
-    memcpy(dst, get_buf_ptr(ring), read_len);
+    memcpy(dst, get_read_ptr(ring), read_len);
   }
 
   return read_len;
+}
+
+
+int rb_delete(struct ring_buffer * ring, uint_t len) {
+  int del_len = 0;
+  int ring_data_len = ring->current_len;
+
+  del_len = (len > ring_data_len) ? ring_data_len : len;
+
+  if (is_read_loop(ring, del_len)) {
+    int section_len = get_read_section_size(ring);
+    ring->start = del_len - section_len;
+  } else {
+    ring->start += del_len;
+  }
+
+  ring->current_len -= del_len;
+  return del_len;
+}
+
+
+int rb_write(struct ring_buffer * ring, char * src, uint_t len) {
+  int write_len = 0;
+  int ring_avail_space = ring->size - ring->current_len;
   
+  write_len = (len > ring_avail_space) ? ring_avail_space : len;
+
+
+  if (is_write_loop(ring, write_len)) {
+    int section_len = get_write_section_size(ring);
+    
+    memcpy(get_write_ptr(ring), src, section_len);
+    ring->end = 0;
+
+    memcpy(get_write_ptr(ring), src + section_len, write_len - section_len);
+
+    ring->end += write_len - section_len;
+  } else {
+    memcpy(get_write_ptr(ring), src, write_len);
+
+    ring->end += write_len;
+  }
+
+  ring->current_len += write_len;
+
+  return write_len;
+}
+
+
+void print_ring_buffer(struct ring_buffer * ring) {
+  int ctr = 0;
+  
+  for (ctr = 0; ctr < ring->current_len; ctr++) {
+    int index = (ctr + ring->start) % ring->size;
+
+    PrintBoth("Entry %d (index=%d): %c\n", ctr, index, ring->buf[index]);
+  }
 }