[WIP] [PATCH 10/12] erofs-utils: fuse: cleanup erofs_read_data_compression()

[Gao Xiang via Linux-erofs]

[ let's fold in to the original patch. ]
Signed-off-by: Gao Xiang <hsiang...@aol.com>
---
 fuse/read.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/fuse/read.c b/fuse/read.c
index 46be5cc64a90..f3aa628945e3 100644
--- a/fuse/read.c
+++ b/fuse/read.c
@@ -80,10 +80,10 @@ finished:
 }
 
 size_t erofs_read_data_compression(struct erofs_vnode *vnode, char *buffer,
-                      size_t size, off_t offset)
+                                  erofs_off_t size, erofs_off_t offset)
 {
        int ret;
-       size_t end, count, ofs, sum = size;
+       erofs_off_t end, length, skip;
        struct erofs_map_blocks map = {
                .index = UINT_MAX,
        };
@@ -91,8 +91,8 @@ size_t erofs_read_data_compression(struct erofs_vnode *vnode, 
char *buffer,
        unsigned int algorithmformat;
        char raw[EROFS_BLKSIZ];
 
-       while (sum) {
-               end = offset + sum;
+       end = offset + size;
+       while (end > offset) {
                map.m_la = end - 1;
 
                ret = z_erofs_map_blocks_iter(vnode, &map);
@@ -100,7 +100,7 @@ size_t erofs_read_data_compression(struct erofs_vnode 
*vnode, char *buffer,
                        return ret;
 
                if (!(map.m_flags & EROFS_MAP_MAPPED)) {
-                       sum -= map.m_llen;
+                       end = map.m_la;
                        continue;
                }
 
@@ -117,28 +117,28 @@ size_t erofs_read_data_compression(struct erofs_vnode 
*vnode, char *buffer,
                 * larger than requested, and set up partial flag as well.
                 */
                if (end < map.m_la + map.m_llen) {
-                       count = end - map.m_la;
+                       length = end - map.m_la;
                        partial = true;
                } else {
                        ASSERT(end == map.m_la + map_m_llen);
-                       count = map.m_llen;
+                       length = map.m_llen;
                        partial = !(map.m_flags & EROFS_MAP_FULL_MAPPED);
                }
 
-               if ((off_t)map.m_la < offset) {
-                       ofs = offset - map.m_la;
-                       sum = 0;
+               if (map.m_la < offset) {
+                       skip = offset - map.m_la;
+                       end = offset;
                } else {
-                       ofs = 0;
-                       sum -= count;
+                       skip = 0;
+                       end = map.m_la;
                }
 
                ret = z_erofs_decompress(&(struct z_erofs_decompress_req) {
                                        .in = raw,
-                                       .out = buffer + sum,
-                                       .decodedskip = ofs,
-                                       .inputsize = EROFS_BLKSIZ,
-                                       .decodedlength = count,
+                                       .out = buffer + end - offset,
+                                       .decodedskip = skip,
+                                       .inputsize = map.m_plen,
+                                       .decodedlength = length,
                                        .alg = algorithmformat,
                                        .partial_decoding = partial
                                         });
-- 
2.24.0