Cache compression format in 'struct wim_resource_spec'

[wimlib] / src / resource.c

diff --git a/src/resource.c b/src/resource.c
index b7713977abbf7c5c03f46733b3b285e5f6ce4c06..116873ffc16b68d9be4c590631a4f2167964722a 100644 (file)
--- a/src/resource.c
+++ b/src/resource.c
@@ -175,37 +175,21 @@ read_compressed_wim_resource(const struct wim_resource_spec * const rspec,
 
        /* Get the maximum size of uncompressed chunks in this resource, which
         * we require be a power of 2.  */
-       u32 chunk_size = 0;
        u64 cur_read_offset = rspec->offset_in_wim;
-       int ctype = WIMLIB_COMPRESSION_TYPE_NONE;
+       int ctype = rspec->compression_type;
+       u32 chunk_size = rspec->chunk_size;
        if (alt_chunk_table) {
                /* Alternate chunk table format.  Its header specifies the chunk
-                * size and compression format.  */
-               struct alt_chunk_table_header_disk hdr;
-
-               ret = full_pread(in_fd, &hdr, sizeof(hdr), cur_read_offset);
-               if (ret)
-                       goto read_error;
-               cur_read_offset += sizeof(hdr);
-
-               chunk_size = le32_to_cpu(hdr.chunk_size);
-               ctype = le32_to_cpu(hdr.compression_format);
-
-               /* Format numbers must be the same as in WIMGAPI to be
-                * compatible.  */
-               BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_NONE != 0);
-               BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_LZX != 1);
-               BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_XPRESS != 2);
-               BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_LZMS != 3);
-       } else {
-               /* "Normal" format: the maximum uncompressed chunk size and the
-                * compression format default to those of the WIM itself.  */
-               chunk_size = rspec->wim->chunk_size;
-               ctype = rspec->wim->compression_type;
+                * size and compression format.  Note: it could be read here;
+                * however, the relevant data was already loaded into @rspec by
+                * read_wim_lookup_table().  */
+               cur_read_offset += sizeof(struct alt_chunk_table_header_disk);
        }
+
        if (!is_power_of_2(chunk_size)) {
                ERROR("Invalid compressed resource: "
-                     "expected power-of-2 chunk size (got %u)", chunk_size);
+                     "expected power-of-2 chunk size (got %"PRIu32")",
+                     chunk_size);
                ret = WIMLIB_ERR_INVALID_CHUNK_SIZE;
                goto out_free_memory;
        }
@@ -253,11 +237,9 @@ read_compressed_wim_resource(const struct wim_resource_spec * const rspec,
        const u64 num_chunk_entries = (alt_chunk_table ? num_chunks : num_chunks - 1);
 
        /* Set the size of each chunk table entry based on the resource's
-        * uncompressed size.  XXX:  Does the alternate chunk table really
-        * always have 4-byte entries?  */
-       const u64 chunk_entry_size =
-               (rspec->uncompressed_size > (1ULL << 32) && !alt_chunk_table)
-                       ? 8 : 4;
+        * uncompressed size.  */
+       const u64 chunk_entry_size = get_chunk_entry_size(rspec->uncompressed_size,
+                                                         alt_chunk_table);
 
        /* Calculate the size of the chunk table in bytes.  */
        const u64 chunk_table_size = num_chunk_entries * chunk_entry_size;
@@ -1379,7 +1361,10 @@ sha1_stream(struct wim_lookup_table_entry *lte)
 }
 
 /* Convert a short WIM resource header to a stand-alone WIM resource
- * specification.  */
+ * specification.
+ *
+ * Note: for packed resources some fields still need to be overridden.
+ */
 void
 wim_res_hdr_to_spec(const struct wim_reshdr *reshdr, WIMStruct *wim,
                    struct wim_resource_spec *rspec)
@@ -1391,6 +1376,13 @@ wim_res_hdr_to_spec(const struct wim_reshdr *reshdr, WIMStruct *wim,
        INIT_LIST_HEAD(&rspec->stream_list);
        rspec->flags = reshdr->flags;
        rspec->is_pipable = wim_is_pipable(wim);
+       if (rspec->flags & WIM_RESHDR_FLAG_COMPRESSED) {
+               rspec->compression_type = wim->compression_type;
+               rspec->chunk_size = wim->chunk_size;
+       } else {
+               rspec->compression_type = WIMLIB_COMPRESSION_TYPE_NONE;
+               rspec->chunk_size = 0;
+       }
 }
 
 /* Convert a stand-alone resource specification to a WIM resource header.  */