1 /* (c) 2008, Jack Lange <jarusl@cs.northwestern.edu> */
2 /* (c) 2008, The V3VEE Project <http://www.v3vee.org> */
4 #include <geekos/ring_buffer.h>
5 #include <geekos/malloc.h>
6 #include <geekos/ktypes.h>
7 #include <geekos/debug.h>
10 void init_ring_buffer(struct ring_buffer * ring, uint_t size) {
11 ring->buf = Malloc(size);
16 ring->current_len = 0;
20 struct ring_buffer * create_ring_buffer(uint_t size) {
21 struct ring_buffer * ring = (struct ring_buffer *)Malloc(sizeof(struct ring_buffer));
23 init_ring_buffer(ring, size);
28 void free_ring_buffer(struct ring_buffer * ring) {
37 static inline uchar_t * get_read_ptr(struct ring_buffer * ring) {
38 return (uchar_t *)(ring->buf + ring->start);
41 static inline uchar_t * get_write_ptr(struct ring_buffer * ring) {
42 return (uchar_t *)(ring->buf + ring->end);
46 static inline int get_read_section_size(struct ring_buffer * ring) {
47 return ring->size - ring->start;
50 static inline int get_write_section_size(struct ring_buffer * ring) {
51 return ring->size - ring->end;
54 static inline int is_read_loop(struct ring_buffer * ring, uint_t len) {
55 if ((ring->start >= ring->end) && (ring->current_len > 0)) {
56 // end is past the end of the buffer
57 if (get_read_section_size(ring) < len) {
65 static inline int is_write_loop(struct ring_buffer * ring, uint_t len) {
66 if ((ring->end >= ring->start) && (ring->current_len < ring->size)) {
67 // end is past the end of the buffer
68 if (get_write_section_size(ring) < len) {
76 int rb_data_len(struct ring_buffer * ring) {
77 return ring->current_len;
80 int rb_capacity(struct ring_buffer * ring) {
84 int rb_read(struct ring_buffer * ring, char * dst, uint_t len) {
86 int ring_data_len = ring->current_len;
88 read_len = (len > ring_data_len) ? ring_data_len : len;
90 if (is_read_loop(ring, read_len)) {
91 int section_len = get_read_section_size(ring);
93 memcpy(dst, get_read_ptr(ring), section_len);
94 memcpy(dst + section_len, ring->buf, read_len - section_len);
96 ring->start = read_len - section_len;
98 memcpy(dst, get_read_ptr(ring), read_len);
100 ring->start += read_len;
103 ring->current_len -= read_len;
111 int rb_peek(struct ring_buffer * ring, char * dst, uint_t len) {
113 int ring_data_len = ring->current_len;
115 read_len = (len > ring_data_len) ? ring_data_len : len;
117 if (is_read_loop(ring, read_len)) {
118 int section_len = get_read_section_size(ring);
120 memcpy(dst, get_read_ptr(ring), section_len);
121 memcpy(dst + section_len, ring->buf, read_len - section_len);
123 memcpy(dst, get_read_ptr(ring), read_len);
130 int rb_delete(struct ring_buffer * ring, uint_t len) {
132 int ring_data_len = ring->current_len;
134 del_len = (len > ring_data_len) ? ring_data_len : len;
136 if (is_read_loop(ring, del_len)) {
137 int section_len = get_read_section_size(ring);
138 ring->start = del_len - section_len;
140 ring->start += del_len;
143 ring->current_len -= del_len;
148 int rb_write(struct ring_buffer * ring, char * src, uint_t len) {
150 int ring_avail_space = ring->size - ring->current_len;
152 write_len = (len > ring_avail_space) ? ring_avail_space : len;
155 if (is_write_loop(ring, write_len)) {
156 int section_len = get_write_section_size(ring);
158 memcpy(get_write_ptr(ring), src, section_len);
161 memcpy(get_write_ptr(ring), src + section_len, write_len - section_len);
163 ring->end += write_len - section_len;
165 memcpy(get_write_ptr(ring), src, write_len);
167 ring->end += write_len;
170 ring->current_len += write_len;
176 void print_ring_buffer(struct ring_buffer * ring) {
179 for (ctr = 0; ctr < ring->current_len; ctr++) {
180 int index = (ctr + ring->start) % ring->size;
182 PrintBoth("Entry %d (index=%d): %c\n", ctr, index, ring->buf[index]);