commit a5744d7100b84f5998fe87f7a2ff3637fd28be64
from: Stefan Sperling <stsp@stsp.name>
date: Sat Jan 12 22:00:44 2019 UTC

don't bother with memcpy of header when writing the file index

commit - 784955db0f639c53fd5aeb70d0f006cad99a815f
commit + a5744d7100b84f5998fe87f7a2ff3637fd28be64
blob - afdeab746035bdafbbd04d8bf67736896f49b640
blob + 4562e971c3719cdb1db04abc44e8a19bd0de5a5b
--- lib/fileindex.c
+++ lib/fileindex.c
@@ -300,9 +300,6 @@ got_fileindex_write(struct got_fileindex *fileindex, F
 	SHA1_CTX ctx;
 	uint8_t sha1[SHA1_DIGEST_LENGTH];
 	size_t n;
-	const size_t len = sizeof(hdr.signature) + sizeof(hdr.version) +
-	    sizeof(hdr.nentries);
-	uint8_t buf[len];
 	struct got_fileindex_entry *entry;
 
 	SHA1Init(&ctx);
@@ -311,11 +308,18 @@ got_fileindex_write(struct got_fileindex *fileindex, F
 	hdr.version = htobe32(GOT_FILE_INDEX_VERSION);
 	hdr.nentries = htobe32(fileindex->nentries);
 
-	memcpy(buf, &hdr, len);
-	SHA1Update(&ctx, buf, len);
-	n = fwrite(buf, 1, len, outfile);
-	if (n != len)
+	SHA1Update(&ctx, (uint8_t *)&hdr.signature, sizeof(hdr.signature));
+	SHA1Update(&ctx, (uint8_t *)&hdr.version, sizeof(hdr.version));
+	SHA1Update(&ctx, (uint8_t *)&hdr.nentries, sizeof(hdr.nentries));
+	n = fwrite(&hdr.signature, 1, sizeof(hdr.signature), outfile);
+	if (n != sizeof(hdr.signature))
+		return got_ferror(outfile, GOT_ERR_IO);
+	n = fwrite(&hdr.version, 1, sizeof(hdr.version), outfile);
+	if (n != sizeof(hdr.version))
 		return got_ferror(outfile, GOT_ERR_IO);
+	n = fwrite(&hdr.nentries, 1, sizeof(hdr.nentries), outfile);
+	if (n != sizeof(hdr.nentries))
+		return got_ferror(outfile, GOT_ERR_IO);
 
 	RB_FOREACH(entry, got_fileindex_tree, &fileindex->entries) {
 		entry->flags &= ~GOT_INDEX_ENTRY_F_INTENT_TO_ADD;