CPIO support

Author: Lynnesbian

src/map.rs

@@ -564,6 +564,12 @@ matcher_map!(
         "msi",
         matchers::archive::is_msi
     ),
+    (
+        MatcherType::Archive,
+        "application/x-cpio",
+        "cpio",
+        matchers::archive::is_cpio
+    ),
     // Text
     (
         MatcherType::Text,

src/matchers/archive.rs

@@ -216,3 +216,17 @@ pub fn is_msi(buf: &[u8]) -> bool {
         && buf[6] == 0x1A
         && buf[7] == 0xE1
 }
+
+/// Returns whether a buffer is a CPIO archive.
+pub fn is_cpio(buf: &[u8]) -> bool {
+    (buf.len() > 1
+        && ((buf[0] == 0xC7 && buf[1] == 0x71) // little endian, old format
+        || (buf[0] == 0x71 && buf[1] == 0xC7))) // big endian, old format
+    || (buf.len() > 6
+        && buf[0] == 0x30
+        && buf[1] == 0x37
+        && buf[2] == 0x30
+        && buf[3] == 0x37
+        && buf[4] == 0x30
+        && buf[5] == 0x31) // newc format
+}

testdata/sample.cpio

@@ -9,3 +9,5 @@ test_format!(
 );
 
 test_format!(Archive, "application/zstd", "zst", zst, "sample.tar.zst");
+
+test_format!(Archive, "application/x-cpio", "cpio", cpio, "sample.cpio");