From: Eric Biggers <ebiggers3@gmail.com>
Date: Sat, 30 May 2015 20:48:16 +0000 (-0500)
Subject: New helper macro: ALIGN()
X-Git-Tag: v1.8.2~105
X-Git-Url: https://wimlib.net/git/?p=wimlib;a=commitdiff_plain;h=f50557a7095444c554a066b3837c2999ecd1be31

New helper macro: ALIGN()
---

diff --git a/include/wimlib/util.h b/include/wimlib/util.h
index 7f34cbf3..c3bac7ab 100644
--- a/include/wimlib/util.h
+++ b/include/wimlib/util.h
@@ -24,6 +24,10 @@
 /* Get the number of elements of an array type.  */
 #define ARRAY_LEN(array)	(sizeof(array) / sizeof((array)[0]))
 
+/* Round 'v' up to the next 'alignment'-byte aligned boundary.  'alignment' must
+ * be a power of 2.  */
+#define ALIGN(v, alignment)	(((v) + ((alignment) - 1)) & ~((alignment) - 1))
+
 /* Maximum number of bytes that can be allocated on the stack.
  *
  * Note: this isn't a hard bound on the stack space used, since this is just for
diff --git a/src/compress_common.c b/src/compress_common.c
index e2ad298e..8b85d9d5 100644
--- a/src/compress_common.c
+++ b/src/compress_common.c
@@ -125,7 +125,7 @@ sort_symbols(unsigned num_syms, const u32 freqs[restrict],
 	 * Tests were done with building the codes for LZX.  Results may
 	 * vary for different compression algorithms...!  */
 
-	num_counters = (DIV_ROUND_UP(num_syms, 4) + 3) & ~3;
+	num_counters = ALIGN(DIV_ROUND_UP(num_syms, 4), 4);
 
 	unsigned counters[num_counters];
 
diff --git a/src/dentry.c b/src/dentry.c
index 6a759388..a19e02c8 100644
--- a/src/dentry.c
+++ b/src/dentry.c
@@ -347,7 +347,7 @@ stream_out_total_length(const struct wim_inode_stream *strm)
 		len += utf16le_len_bytes(strm->stream_name) + 2;
 
 	/* Account for any necessary padding to the next 8-byte boundary.  */
-	return (len + 7) & ~7;
+	return ALIGN(len, 8);
 }
 
 /*
@@ -364,12 +364,9 @@ dentry_out_total_length(const struct wim_dentry *dentry)
 
 	len = dentry_min_len_with_names(dentry->file_name_nbytes,
 					dentry->short_name_nbytes);
-	len = (len + 7) & ~7;
+	len = ALIGN(len, 8);
 
-	if (inode->i_extra_size) {
-		len += inode->i_extra_size;
-		len = (len + 7) & ~7;
-	}
+	len += ALIGN(inode->i_extra_size, 8);
 
 	if (!(inode->i_attributes & FILE_ATTRIBUTE_ENCRYPTED)) {
 		/*
@@ -396,8 +393,8 @@ dentry_out_total_length(const struct wim_dentry *dentry)
 
 		if (have_named_data_stream || have_reparse_point_stream) {
 			if (have_reparse_point_stream)
-				len += (sizeof(struct wim_extra_stream_entry_on_disk) + 7) & ~7;
-			len += (sizeof(struct wim_extra_stream_entry_on_disk) + 7) & ~7;
+				len += ALIGN(sizeof(struct wim_extra_stream_entry_on_disk), 8);
+			len += ALIGN(sizeof(struct wim_extra_stream_entry_on_disk), 8);
 		}
 	}
 
@@ -1331,10 +1328,7 @@ setup_inode_streams(const u8 *p, const u8 *end, struct wim_inode *inode,
 		disk_strm = (const struct wim_extra_stream_entry_on_disk *)p;
 
 		/* Read the length field  */
-		length = le64_to_cpu(disk_strm->length);
-
-		/* 8-byte align the length  */
-		length = (length + 7) & ~7;
+		length = ALIGN(le64_to_cpu(disk_strm->length), 8);
 
 		/* Make sure the length field is neither so small it doesn't
 		 * include all the fixed-length data nor so large it overflows
@@ -1424,7 +1418,7 @@ read_dentry(const u8 * restrict buf, size_t buf_len,
 	disk_dentry = (const struct wim_dentry_on_disk*)p;
 
 	/* Get dentry length.  */
-	length = (le64_to_cpu(disk_dentry->length) + 7) & ~7;
+	length = ALIGN(le64_to_cpu(disk_dentry->length), 8);
 
 	/* Check for end-of-directory.  */
 	if (length <= 8) {
diff --git a/src/metadata_resource.c b/src/metadata_resource.c
index a3faa9c9..014d16b9 100644
--- a/src/metadata_resource.c
+++ b/src/metadata_resource.c
@@ -150,7 +150,7 @@ recalculate_security_data_length(struct wim_security_data *sd)
 	u32 total_length = sizeof(u64) * sd->num_entries + 2 * sizeof(u32);
 	for (u32 i = 0; i < sd->num_entries; i++)
 		total_length += sd->sizes[i];
-	sd->total_length = (total_length + 7) & ~7;
+	sd->total_length = ALIGN(total_length, 8);
 }
 
 static int
@@ -185,16 +185,12 @@ prepare_metadata_resource(WIMStruct *wim, int image,
 		imd->root_dentry = root;
 	}
 
-	/* Offset of first child of the root dentry.  It's equal to:
-	 * - The total length of the security data, rounded to the next 8-byte
-	 *   boundary,
-	 * - plus the total length of the root dentry,
-	 * - plus 8 bytes for an end-of-directory entry following the root
-	 *   dentry (shouldn't really be needed, but just in case...)
-	 */
+	/* The offset of the first child of the root dentry is equal to the
+	 * total length of the security data, plus the total length of the root
+	 * dentry, plus 8 bytes for an end-of-directory entry following the root
+	 * dentry (shouldn't really be needed, but just in case...)  */
 	recalculate_security_data_length(sd);
-	subdir_offset = (((u64)sd->total_length + 7) & ~7) +
-			dentry_out_total_length(root) + 8;
+	subdir_offset = sd->total_length + dentry_out_total_length(root) + 8;
 
 	/* Calculate the subdirectory offsets for the entire dentry tree.  */
 	calculate_subdir_offsets(root, &subdir_offset);
diff --git a/src/security.c b/src/security.c
index b49ba69c..f160d683 100644
--- a/src/security.c
+++ b/src/security.c
@@ -157,8 +157,8 @@ read_wim_security_data(const u8 *buf, size_t buf_len,
 		p += sd->sizes[i];
 	}
 out_align_total_length:
-	total_len = (total_len + 7) & ~7;
-	sd->total_length = (sd->total_length + 7) & ~7;
+	total_len = ALIGN(total_len, 8);
+	sd->total_length = ALIGN(sd->total_length, 8);
 	if (total_len != sd->total_length) {
 		WARNING("Expected WIM security data total length of "
 			"%u bytes, but calculated %u bytes",
diff --git a/src/tagged_items.c b/src/tagged_items.c
index 1ae227c8..1ed3b4a9 100644
--- a/src/tagged_items.c
+++ b/src/tagged_items.c
@@ -85,7 +85,7 @@ inode_get_tagged_item(const struct wim_inode *inode,
 
 		hdr = (struct tagged_item_header *)p;
 		tag = le32_to_cpu(hdr->tag);
-		len = (le32_to_cpu(hdr->length) + 7) & ~7;
+		len = ALIGN(le32_to_cpu(hdr->length), 8);
 
 		/* Length overflow?  */
 		if (unlikely(len > len_remaining - sizeof(struct tagged_item_header)))
@@ -113,7 +113,7 @@ inode_add_tagged_item(struct wim_inode *inode, u32 tag, u32 len)
 
 	/* We prepend the item instead of appending it because it's easier.  */
 
-	itemsize = sizeof(struct tagged_item_header) + ((len + 7) & ~7);
+	itemsize = sizeof(struct tagged_item_header) + ALIGN(len, 8);
 	newsize = itemsize + inode->i_extra_size;
 
 	buf = MALLOC(newsize);
@@ -130,7 +130,7 @@ inode_add_tagged_item(struct wim_inode *inode, u32 tag, u32 len)
 	hdr = (struct tagged_item_header *)buf;
 	hdr->tag = cpu_to_le32(tag);
 	hdr->length = cpu_to_le32(len);
-	return memset(hdr->data, 0, (len + 7) & ~7);
+	return memset(hdr->data, 0, ALIGN(len, 8));
 }
 
 static inline struct wimlib_unix_data_disk *