libunarchive, and recovery from my previous commit

include/unarchive.h

@@ -0,0 +1,42 @@
+#include <stdio.h>	// for off_t
+
+enum extract_functions_e {
+	extract_verbose_list = 1,
+	extract_list = 2,
+	extract_one_to_buffer = 4,
+	extract_to_stdout = 8,
+	extract_all_to_fs = 16,
+	extract_preserve_date = 32,
+	extract_data_tar_gz = 64,
+	extract_control_tar_gz = 128,
+	extract_unzip_only = 256,
+	extract_unconditional = 512,
+	extract_create_leading_dirs = 1024,
+	extract_quiet = 2048,
+	extract_exclude_list = 4096
+};
+
+typedef struct file_headers_s {
+	char *name;
+	char *link_name;
+	off_t size;
+	uid_t uid;
+	gid_t gid;
+	mode_t mode;
+	time_t mtime;
+	dev_t device;
+} file_header_t;
+
+file_header_t *get_header_ar(FILE *in_file);
+file_header_t *get_header_cpio(FILE *src_stream);
+file_header_t *get_header_tar(FILE *tar_stream);
+
+void seek_sub_file(FILE *src_stream, const int count);
+
+extern off_t archive_offset;
+
+char *unarchive(FILE *src_stream, FILE *out_stream, file_header_t *(*get_headers)(FILE *),
+	const int extract_function, const char *prefix, char **include_name, char **exclude_name);
+
+char *deb_extract(const char *package_filename, FILE *out_stream, const int extract_function,
+	const char *prefix, const char *filename);