inode: move 'i_extra_size' to 'i_extra' buffer

Usually there will be no extra data and this will save a bit of memory.

diff --git a/include/wimlib/inode.h b/include/wimlib/inode.h
index 514621264f17cb58e5a349bfa6b0cdc072585075..ed6f9de92ee1ea088e1052c3b5f6c78a0b0681dd 100644 (file)
--- a/include/wimlib/inode.h
+++ b/include/wimlib/inode.h
@@ -10,6 +10,7 @@ struct avl_tree_node;
 struct blob_descriptor;
 struct blob_table;
 struct wim_dentry;
+struct wim_inode_extra;
 struct wim_security_data;
 struct wimfs_fd;
 
@@ -140,10 +141,7 @@ struct wim_inode {
         * dentry.  This should be a series of tagged items, each of which
         * represents a bit of extra metadata, such as the file's object ID.
         * See tagged_items.c for more information.  */
-       void *i_extra;
-
-       /* Size of @i_extra buffer in bytes.  If 0, there is no extra data.  */
-       size_t i_extra_size;
+       struct wim_inode_extra *i_extra;
 
        /* Creation time, last access time, and last write time for this inode,
         * in 100-nanosecond intervals since 12:00 a.m UTC January 1, 1601.
@@ -230,6 +228,12 @@ struct wim_inode {
        u32 i_next_stream_id;
 };
 
+/* Optional extra data for a WIM inode  */
+struct wim_inode_extra {
+       size_t size;    /* Size of the extra data in bytes  */
+       u8 data[];      /* The extra data  */
+};
+
 /*
  * The available reparse tags are documented at
  * http://msdn.microsoft.com/en-us/library/dd541667(v=prot.10).aspx.

diff --git a/src/dentry.c b/src/dentry.c
index 13940a32d3b96c2a4c7d6f9a60babea8e3931ceb..ff1a21420f0c2c068d422c1b9645368e96133675 100644 (file)
--- a/src/dentry.c
+++ b/src/dentry.c
@@ -358,7 +358,8 @@ dentry_out_total_length(const struct wim_dentry *dentry)
                                        dentry->d_short_name_nbytes);
        len = ALIGN(len, 8);
 
-       len += ALIGN(inode->i_extra_size, 8);
+       if (inode->i_extra)
+               len += ALIGN(inode->i_extra->size, 8);
 
        if (!(inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED)) {
                /*
@@ -1187,10 +1188,12 @@ read_extra_data(const u8 *p, const u8 *end, struct wim_inode *inode)
                p++;
 
        if (unlikely(p < end)) {
-               inode->i_extra = memdup(p, end - p);
+               inode->i_extra = MALLOC(sizeof(struct wim_inode_extra) +
+                                       end - p);
                if (!inode->i_extra)
                        return WIMLIB_ERR_NOMEM;
-               inode->i_extra_size = end - p;
+               inode->i_extra->size = end - p;
+               memcpy(inode->i_extra->data, p, end - p);
        }
        return 0;
 }
@@ -1774,9 +1777,9 @@ write_dentry(const struct wim_dentry * restrict dentry, u8 * restrict p)
        while ((uintptr_t)p & 7)
                *p++ = 0;
 
-       if (inode->i_extra_size) {
+       if (inode->i_extra) {
                /* Extra tagged items --- not usually present.  */
-               p = mempcpy(p, inode->i_extra, inode->i_extra_size);
+               p = mempcpy(p, inode->i_extra->data, inode->i_extra->size);
 
                /* Align to 8-byte boundary */
                while ((uintptr_t)p & 7)

diff --git a/src/tagged_items.c b/src/tagged_items.c
index 1ed3b4a914454b6938dd193bb31b2d400dd8eba3..723773f94be3e678afe6c0f88bae6a3355a961ce 100644 (file)
--- a/src/tagged_items.c
+++ b/src/tagged_items.c
@@ -74,8 +74,14 @@ inode_get_tagged_item(const struct wim_inode *inode,
                      u32 desired_tag, u32 min_data_len)
 {
        size_t minlen_with_hdr = sizeof(struct tagged_item_header) + min_data_len;
-       size_t len_remaining = inode->i_extra_size;
-       u8 *p = inode->i_extra;
+       size_t len_remaining;
+       u8 *p;
+
+       if (!inode->i_extra)
+               return NULL;
+
+       len_remaining = inode->i_extra->size;
+       p = inode->i_extra->data;
 
        /* Iterate through the tagged items.  */
        while (len_remaining >= minlen_with_hdr) {
@@ -108,26 +114,28 @@ inode_add_tagged_item(struct wim_inode *inode, u32 tag, u32 len)
 {
        size_t itemsize;
        size_t newsize;
-       u8 *buf;
+       struct wim_inode_extra *extra;
        struct tagged_item_header *hdr;
 
        /* We prepend the item instead of appending it because it's easier.  */
 
        itemsize = sizeof(struct tagged_item_header) + ALIGN(len, 8);
-       newsize = itemsize + inode->i_extra_size;
+       newsize = itemsize;
+       if (inode->i_extra)
+               newsize += inode->i_extra->size;
 
-       buf = MALLOC(newsize);
-       if (!buf)
+       extra = MALLOC(sizeof(struct wim_inode_extra) + newsize);
+       if (!extra)
                return NULL;
-
-       if (inode->i_extra_size) {
-               memcpy(buf + itemsize, inode->i_extra, inode->i_extra_size);
+       if (inode->i_extra) {
+               memcpy(&extra->data[itemsize], inode->i_extra->data,
+                      inode->i_extra->size);
                FREE(inode->i_extra);
        }
-       inode->i_extra = buf;
-       inode->i_extra_size = newsize;
+       extra->size = newsize;
+       inode->i_extra = extra;
 
-       hdr = (struct tagged_item_header *)buf;
+       hdr = (struct tagged_item_header *)extra->data;
        hdr->tag = cpu_to_le32(tag);
        hdr->length = cpu_to_le32(len);
        return memset(hdr->data, 0, ALIGN(len, 8));