Signed-off-by: Benoit Hudzia <[email protected]>
Signed-off-by: Petter Svard <[email protected]>
Signed-off-by: Aidan Shribman <[email protected]>
Signed-off-by: Orit Wasserman <[email protected]>
---
migration.h | 4 ++
savevm.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 149 insertions(+), 0 deletions(-)
diff --git a/migration.h b/migration.h
index 1ae99f1..7582ecb 100644
--- a/migration.h
+++ b/migration.h
@@ -99,4 +99,8 @@ void migrate_add_blocker(Error *reason);
*/
void migrate_del_blocker(Error *reason);
+int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen,
+ uint8_t *dst, int dlen);
+int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t *dst, int dlen);
+
#endif
diff --git a/savevm.c b/savevm.c
index d1d9020..26e7901 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2374,3 +2374,148 @@ void vmstate_register_ram_global(MemoryRegion *mr)
{
vmstate_register_ram(mr, NULL);
}
+
+/*
+ page = zrun nzrun
+ | zrun nzrun page
+
+ zrun = length
+
+ nzrun = length byte...
+
+ length = uleb128 encoded integer
+ */
+int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen,
+ uint8_t *dst, int dlen)
+{
+ uint32_t zrun_len = 0, nzrun_len = 0;
+ int d = 0 , i = 0;
+ int res, xor;
+ uint8_t *nzrun_start = NULL;
+
+ while (i < slen) {
+ /* overflow */
+ if (d + 2 > dlen) {
+ return -1;
+ }
+
+ /* not aligned to sizeof(long) */
+ res = (slen - i) % sizeof(long);
+ if (res) {
+ while (!(old_buf[i] ^ new_buf[i]) && ++i <= res) {
+ zrun_len++;
+ }
+ }
+
+ xor = (*(long *)(old_buf + i)) ^ (*(long *)(new_buf + i));
+ while (i <= slen - sizeof(long) && !xor) {
+ i += sizeof(long);
+ zrun_len += sizeof(long);
+ xor = (*(long *)(old_buf + i)) ^ (*(long *)(new_buf + i));
+ }
+
+ /* not aligned to sizeof(long) */
+ res = (slen - i) % sizeof(long);
+ if (res) {
+ while (!(old_buf[i] ^ new_buf[i]) && ++i <= res) {
+ zrun_len++;
+ }
+ }
+
+ /* buffer unchanged */
+ if (zrun_len == slen) {
+ return 0;
+ }
+
+ /* skip last zero run */
+ if (i == slen + 1) {
+ return d;
+ }
+
+ d += uleb128_encode_small(dst + d, zrun_len);
+
+ zrun_len = 0;
+ nzrun_start = new_buf + i;
+
+ /* not aligned to sizeof(long) */
+ res = (slen - i) % sizeof(long);
+ if (res) {
+ while ((old_buf[i] ^ new_buf[i]) != 0 && ++i <= res) {
+ nzrun_len++;
+ }
+ }
+
+ xor = (*(long *)(old_buf + i)) ^ (*(long *)(new_buf + i));
+ while (i <= slen - sizeof(long) && xor != 0) {
+ i += sizeof(long);
+ nzrun_len += sizeof(long);
+ xor = (*(long *)(old_buf + i)) ^ (*(long *)(new_buf + i));
+ }
+
+ /* not aligned to sizeof(long) */
+ res = (slen - i) % sizeof(long);
+ if (res) {
+ while ((old_buf[i] ^ new_buf[i]) != 0 && ++i <= res) {
+ nzrun_len++;
+ }
+ }
+
+ /* overflow */
+ if (d + nzrun_len + 2 > dlen) {
+ return -1;
+ }
+
+ d += uleb128_encode_small(dst + d, nzrun_len);
+ memcpy(dst + d, nzrun_start, nzrun_len);
+ d += nzrun_len;
+ nzrun_len = 0;
+ }
+
+ return d;
+}
+
+int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t *dst, int dlen)
+{
+ int i = 0, d = 0;
+ int ret;
+ uint32_t count = 0;
+
+ while (i < slen) {
+
+ /* zrun */
+ ret = uleb128_decode_small(src + i, &count);
+ if (ret < 0) {
+ return -1;
+ }
+ i += ret;
+ d += count;
+
+ /* overflow */
+ if (d > dlen) {
+ return -1;
+ }
+
+ /* completed decoding */
+ if (i == slen - 1) {
+ return d;
+ }
+
+ /* nzrun */
+ ret = uleb128_decode_small(src + i, &count);
+ if (ret < 0) {
+ return -1;
+ }
+ i += ret;
+
+ /* overflow */
+ if (d + count > dlen) {
+ return -1;
+ }
+
+ memcpy(dst + d , src + i, count);
+ d += count;
+ i += count;
+ }
+
+ return d;
+}
--
1.7.7.6
