swf: Support SWZ files

Cargo.lock

@@ -2443,6 +2443,17 @@ dependencies = [
  "minimal-lexical",
 ]
 
+[[package]]
+name = "num-bigint"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "090c7f9998ee0ff65aa5b723e4009f7b217707f1fb5ea551329cc4d6231fb304"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits",
+]
+
 [[package]]
 name = "num-complex"
 version = "0.4.2"
@@ -3507,6 +3518,17 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "43b2853a4d09f215c24cc5489c992ce46052d359b5109343cbafbf26bc62f8a3"
 
+[[package]]
+name = "simple_asn1"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "692ca13de57ce0613a363c8c2f1de925adebc81b04c923ac60c5488bb44abe4b"
+dependencies = [
+ "chrono",
+ "num-bigint",
+ "num-traits",
+]
+
 [[package]]
 name = "slab"
 version = "0.4.7"
@@ -3640,6 +3662,7 @@ dependencies = [
  "lzma-rs",
  "num-derive",
  "num-traits",
+ "simple_asn1",
 ]
 
 [[package]]

core/src/loader.rs

@@ -32,7 +32,7 @@ use ruffle_render::utils::{determine_jpeg_tag_format, JpegTagFormat};
 use std::fmt;
 use std::sync::{Arc, Mutex, Weak};
 use std::time::Duration;
-use swf::read::read_compression_type;
+use swf::read::{extract_swz, read_compression_type};
 use thiserror::Error;
 use url::form_urlencoded;
 
@@ -1270,6 +1270,11 @@ impl<'gc> Loader<'gc> {
         let sniffed_type = ContentType::sniff(data);
         let mut length = data.len();
 
+        if sniffed_type == ContentType::Unknown {
+            if let Ok(data) = extract_swz(data) {
+                return Self::movie_loader_data(handle, player, &data, url, loader_url, in_memory);
+            }
+        }
         player.lock().unwrap().update(|uc| {
             let (clip, event_handler) = match uc.load_manager.get_loader(handle) {
                 Some(Loader::Movie {

swf/Cargo.toml

@@ -21,6 +21,7 @@ log = "0.4"
 flate2 = {version = "1.0", optional = true}
 lzma-rs = {version = "0.2.0", optional = true }
 enum-map = "2.4.0"
+simple_asn1 = "0.4.1"
 
 [features]
 default = ["flate2", "lzma"]

swf/src/read.rs

@@ -7,6 +7,7 @@ use crate::{
 };
 use bitstream_io::BitRead;
 use byteorder::{LittleEndian, ReadBytesExt};
+use simple_asn1::ASN1Block;
 use std::io::{self, Read};
 
 /// Parse a decompressed SWF.
@@ -28,6 +29,28 @@ pub fn parse_swf(swf_buf: &SwfBuf) -> Result<Swf<'_>> {
     })
 }
 
+/// Extracts an SWF inside of an SWZ file.
+pub fn extract_swz(input: &[u8]) -> Result<Vec<u8>> {
+    let asn1_blocks =
+        simple_asn1::from_der(input).map_err(|_| Error::invalid_data("Invalid ASN1 blob"))?;
+    if let Some(ASN1Block::Sequence(_, s)) = asn1_blocks.into_iter().nth(0) {
+        for t in s {
+            if let ASN1Block::Explicit(_, _, _, block) = t {
+                if let ASN1Block::Sequence(_, s) = *block {
+                    if let Some(ASN1Block::Sequence(_, s)) = s.into_iter().nth(2) {
+                        if let Some(ASN1Block::Explicit(_, _, _, octet)) = s.into_iter().nth(1) {
+                            if let ASN1Block::OctetString(_, bytes) = *octet {
+                                return Ok(bytes);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+    Err(Error::invalid_data("Invalid ASN1 blob"))
+}
+
 /// Parses an SWF header and returns a `Reader` that can be used
 /// to read the SWF tags inside the SWF file.
 ///