cleanup: split tar code up, remove some duplications

This commit attempts to split some of the monolitic tar parsing code up
into multiple functions in seperate files. Also, some code duplication
(like reading a record into memory which was implemented twice) is
removed.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 47 insertions, 0 deletions

diff --git a/lib/tar/read_sparse_map.c b/lib/tar/read_sparse_map.c
new file mode 100644
index 0000000..77876f5
--- /dev/null
+++ b/lib/tar/read_sparse_map.c
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "internal.h"
+
+sparse_map_t *read_sparse_map(const char *line)
+{
+	sparse_map_t *last = NULL, *list = NULL, *ent = NULL;
+
+	do {
+		ent = calloc(1, sizeof(*ent));
+		if (ent == NULL)
+			goto fail_errno;
+
+		if (pax_read_decimal(line, &ent->offset))
+			goto fail_format;
+
+		while (isdigit(*line))
+			++line;
+
+		if (*(line++) != ',')
+			goto fail_format;
+
+		if (pax_read_decimal(line, &ent->count))
+			goto fail_format;
+
+		while (isdigit(*line))
+			++line;
+
+		if (last == NULL) {
+			list = last = ent;
+		} else {
+			last->next = ent;
+			last = ent;
+		}
+	} while (*(line++) == ',');
+
+	return list;
+fail_errno:
+	perror("parsing GNU pax sparse file record");
+	goto fail;
+fail_format:
+	fputs("malformed GNU pax sparse file record\n", stderr);
+	goto fail;
+fail:
+	free_sparse_list(list);
+	free(ent);
+	return NULL;
+}