Add libziparchive-based unzip.

Bug: N/A
Test: new toybox unzip.test
Change-Id: I00be388578be9a0a0390a9e2ecfac664c6ab39ca
diff --git a/libziparchive/zip_archive.cc b/libziparchive/zip_archive.cc
index 246575f..6860c4e 100644
--- a/libziparchive/zip_archive.cc
+++ b/libziparchive/zip_archive.cc
@@ -27,6 +27,7 @@
 #include <limits.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <unistd.h>
 
 #include <memory>
@@ -589,6 +590,13 @@
     data->has_data_descriptor = 1;
   }
 
+  // 4.4.2.1: the upper byte of `version_made_by` gives the source OS. Unix is 3.
+  if ((cdr->version_made_by >> 8) == 3) {
+    data->unix_mode = (cdr->external_file_attributes >> 16) & 0xffff;
+  } else {
+    data->unix_mode = 0777;
+  }
+
   // Check that the local file header name matches the declared
   // name in the central directory.
   if (lfh->file_name_length == nameLen) {
@@ -1227,3 +1235,17 @@
   }
   return true;
 }
+
+tm ZipEntry::GetModificationTime() const {
+  tm t = {};
+
+  t.tm_hour = (mod_time >> 11) & 0x1f;
+  t.tm_min = (mod_time >> 5) & 0x3f;
+  t.tm_sec = (mod_time & 0x1f) << 1;
+
+  t.tm_year = ((mod_time >> 25) & 0x7f) + 80;
+  t.tm_mon = ((mod_time >> 21) & 0xf) - 1;
+  t.tm_mday = (mod_time >> 16) & 0x1f;
+
+  return t;
+}