- make it look more like a pair of qcow2_compress - rename the function
and its parameters
- drop extra out_len variable, check filling of output buffer by strm
structure itself
- fix code style
- add some documentation
Signed-off-by: Vladimir Sementsov-Ogievskiy
---
block/qcow2.c | 56 ---
1 file changed, 35 insertions(+), 21 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index b45a6c4135..e9d24b801e 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3758,32 +3758,46 @@ static ssize_t qcow2_compress(void *dest, size_t
dest_size,
return ret;
}
-static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
- const uint8_t *buf, int buf_size)
+/* qcow2_decompress()
+ *
+ * Decompress some data (not more than @src_size bytes) to produce exactly
+ * @dest_size bytes.
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ * -1 on fail
+ */
+static ssize_t qcow2_decompress(void *dest, size_t dest_size,
+const void *src, size_t src_size)
{
-z_stream strm1, *strm =
-int ret, out_len;
-
-memset(strm, 0, sizeof(*strm));
+int ret = 0;
+z_stream strm;
-strm->next_in = (uint8_t *)buf;
-strm->avail_in = buf_size;
-strm->next_out = out_buf;
-strm->avail_out = out_buf_size;
+memset(, 0, sizeof(strm));
+strm.avail_in = src_size;
+strm.next_in = (void *) src;
+strm.avail_out = dest_size;
+strm.next_out = dest;
-ret = inflateInit2(strm, -12);
+ret = inflateInit2(, -12);
if (ret != Z_OK) {
return -1;
}
-ret = inflate(strm, Z_FINISH);
-out_len = strm->next_out - out_buf;
-if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
-out_len != out_buf_size) {
-inflateEnd(strm);
-return -1;
+
+ret = inflate(, Z_FINISH);
+if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || strm.avail_out != 0) {
+/* We approve Z_BUF_ERROR because we need @dest buffer to be filled,
but
+ * @src buffer may be processed partly (because in qcow2 we know size
of
+ * compressed data with precision of one sector)
+ */
+ret = -1;
}
-inflateEnd(strm);
-return 0;
+
+inflateEnd();
+
+return ret;
}
#define MAX_COMPRESS_THREADS 4
@@ -3973,8 +3987,8 @@ int qcow2_decompress_cluster(BlockDriverState *bs,
uint64_t cluster_offset)
if (ret < 0) {
return ret;
}
-if (decompress_buffer(s->cluster_cache, s->cluster_size,
- s->cluster_data + sector_offset, csize) < 0) {
+if (qcow2_decompress(s->cluster_cache, s->cluster_size,
+ s->cluster_data + sector_offset, csize) < 0) {
return -EIO;
}
s->cluster_cache_offset = coffset;
--
2.18.0
