archive-zip: use enum for compression method

Add an enumeration to assign names to the magic values that determine
the ZIP compression method to use.  Use those names to improve code
readability.

Signed-off-by: René Scharfe <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: rscharfe

archive-zip.c

@@ -24,6 +24,11 @@ static unsigned int max_creator_version;
 #define ZIP_STREAM	(1 <<  3)
 #define ZIP_UTF8	(1 << 11)
 
+enum zip_method {
+	ZIP_METHOD_STORE = 0,
+	ZIP_METHOD_DEFLATE = 8
+};
+
 struct zip_local_header {
 	unsigned char magic[4];
 	unsigned char version[2];
@@ -291,7 +296,7 @@ static int write_zip_entry(struct archiver_args *args,
 	unsigned long attr2;
 	unsigned long compressed_size;
 	unsigned long crc;
-	int method;
+	enum zip_method method;
 	unsigned char *out;
 	void *deflated = NULL;
 	void *buffer;
@@ -320,7 +325,7 @@ static int write_zip_entry(struct archiver_args *args,
 	}
 
 	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
-		method = 0;
+		method = ZIP_METHOD_STORE;
 		attr2 = 16;
 		out = NULL;
 		size = 0;
@@ -330,13 +335,13 @@ static int write_zip_entry(struct archiver_args *args,
 		enum object_type type = oid_object_info(args->repo, oid,
 							&size);
 
-		method = 0;
+		method = ZIP_METHOD_STORE;
 		attr2 = S_ISLNK(mode) ? ((mode | 0777) << 16) :
 			(mode & 0111) ? ((mode) << 16) : 0;
 		if (S_ISLNK(mode) || (mode & 0111))
 			creator_version = 0x0317;
 		if (S_ISREG(mode) && args->compression_level != 0 && size > 0)
-			method = 8;
+			method = ZIP_METHOD_DEFLATE;
 
 		if (S_ISREG(mode) && type == OBJ_BLOB && !args->convert &&
 		    size > big_file_threshold) {
@@ -358,7 +363,7 @@ static int write_zip_entry(struct archiver_args *args,
 						    buffer, size);
 			out = buffer;
 		}
-		compressed_size = (method == 0) ? size : 0;
+		compressed_size = (method == ZIP_METHOD_STORE) ? size : 0;
 	} else {
 		return error(_("unsupported file mode: 0%o (SHA1: %s)"), mode,
 				oid_to_hex(oid));
@@ -367,13 +372,13 @@ static int write_zip_entry(struct archiver_args *args,
 	if (creator_version > max_creator_version)
 		max_creator_version = creator_version;
 
-	if (buffer && method == 8) {
+	if (buffer && method == ZIP_METHOD_DEFLATE) {
 		out = deflated = zlib_deflate_raw(buffer, size,
 						  args->compression_level,
 						  &compressed_size);
 		if (!out || compressed_size >= size) {
 			out = buffer;
-			method = 0;
+			method = ZIP_METHOD_STORE;
 			compressed_size = size;
 		}
 	}
@@ -420,7 +425,7 @@ static int write_zip_entry(struct archiver_args *args,
 		zip_offset += ZIP64_EXTRA_SIZE;
 	}
 
-	if (stream && method == 0) {
+	if (stream && method == ZIP_METHOD_STORE) {
 		unsigned char buf[STREAM_BUFFER_SIZE];
 		ssize_t readlen;
 
@@ -443,7 +448,7 @@ static int write_zip_entry(struct archiver_args *args,
 		zip_offset += compressed_size;
 
 		write_zip_data_desc(size, compressed_size, crc);
-	} else if (stream && method == 8) {
+	} else if (stream && method == ZIP_METHOD_DEFLATE) {
 		unsigned char buf[STREAM_BUFFER_SIZE];
 		ssize_t readlen;
 		git_zstream zstream;