Introduce and use _zip_buffer_skip function.

lib/zip_buffer.c

diff --git a/lib/zip_buffer.c b/lib/zip_buffer.c
index 3d79b09..43864f9 100644
--- a/lib/zip_buffer.c
+++ b/lib/zip_buffer.c
@@ -303,6 +303,17 @@
 }
 
 
+int
+_zip_buffer_skip(zip_buffer_t *buffer, zip_uint64_t length) {
+    zip_uint64_t offset = buffer->offset + length;
+    
+    if (offset < buffer->offset) {
+        buffer->ok = false;
+        return -1;
+    }
+    return _zip_buffer_set_offset(buffer, offset);
+}
+
 zip_uint64_t
 _zip_buffer_size(zip_buffer_t *buffer)
 {

lib/zip_dirent.c

diff --git a/lib/zip_dirent.c b/lib/zip_dirent.c
index f787e46..630b6a4 100644
--- a/lib/zip_dirent.c
+++ b/lib/zip_dirent.c
@@ -484,7 +484,7 @@
 	else if (local) {
 	    /* From appnote.txt: This entry in the Local header MUST
 	       include BOTH original and compressed file size fields. */
-	    (void)_zip_buffer_get_64(ef_buffer);
+            (void)_zip_buffer_skip(ef_buffer, 8); /* error is caught by _zip_buffer_eof() call */
 	}
 	if (zde->comp_size == ZIP_UINT32_MAX)
 	    zde->comp_size = _zip_buffer_get_64(ef_buffer);

lib/zipint.h

diff --git a/lib/zipint.h b/lib/zipint.h
index 86edcb3..40f75c4 100644
--- a/lib/zipint.h
+++ b/lib/zipint.h
@@ -478,6 +478,7 @@
 int _zip_buffer_put_32(zip_buffer_t *buffer, zip_uint32_t i);
 int _zip_buffer_put_64(zip_buffer_t *buffer, zip_uint64_t i);
 int _zip_buffer_put_8(zip_buffer_t *buffer, zip_uint8_t i);
+int _zip_buffer_skip(zip_buffer_t *buffer, zip_uint64_t length);
 int _zip_buffer_set_offset(zip_buffer_t *buffer, zip_uint64_t offset);
 zip_uint64_t _zip_buffer_size(zip_buffer_t *buffer);