Merge pull request #398 from Shnatsel/safe-rust-zstd-2

Add safe Rust zstd decoding backend

Cargo.toml

@@ -25,6 +25,7 @@ fax34 = { package = "fax", version = "0.2.6", optional = true }
 flate2 = { version = "1.0.20", optional = true }
 weezl = { version = "0.2.1", optional = true }
 zstd = { version = "0.13", optional = true }
+zrip-decode = { version = "0.8.2", features = ["paranoid"], optional = true }
 zune-jpeg = { version = "0.5.1", optional = true }
 image-webp = {version = "0.2.4", optional = true }
 
@@ -45,6 +46,9 @@ jpeg = ["dep:zune-jpeg"]
 lzw = ["dep:weezl"]
 webp = ["dep:image-webp"]
 zstd = ["dep:zstd"]
+# Fully safe Rust but somewhat slower Zstd decoding.
+# When both zstd and zstd-safe-rust are enabled, zstd takes precedence.
+zstd-safe-rust = ["dep:zrip-decode"]
 
 [[bench]]
 name = "lzw"