Support ZSTD compression method for reading (#256)

Cargo.toml

@@ -20,10 +20,14 @@ exclude = ["tests/images/*", "tests/fuzz_images/*"]
 weezl = "0.1.0"
 jpeg = { package = "jpeg-decoder", version = "0.3.0", default-features = false }
 flate2 = "1.0.20"
+zstd = { version = "0.13", optional = true }
 
 [dev-dependencies]
 criterion = "0.3.1"
 
+[features]
+zstd = ["dep:zstd"]
+
 [[bench]]
 name = "lzw"
 harness = false

README.md

@@ -36,6 +36,7 @@ This table lists photometric interpretations and sample formats which are suppor
 | Deflate  | ✓        | ✓        |
 | PackBits | ✓        | ✓        |
 | JPEG     | ✓        | not yet  |
+| ZSTD     | ✓        | not yet  |
 
 
 ## Not yet supported

src/decoder/image.rs

@@ -378,7 +378,11 @@ impl Image {
             CompressionMethod::None => Box::new(reader),
             CompressionMethod::LZW => {
                 Box::new(LZWReader::new(reader, usize::try_from(compressed_length)?))
-            }
+            },
+            #[cfg(feature = "zstd")]
+            CompressionMethod::ZSTD => {
+                Box::new(zstd::Decoder::new(reader)?)
+            },
             CompressionMethod::PackBits => Box::new(PackBitsReader::new(reader, compressed_length)),
             CompressionMethod::Deflate | CompressionMethod::OldDeflate => {
                 Box::new(DeflateReader::new(reader))

src/tags.rs

@@ -184,6 +184,9 @@ pub enum CompressionMethod(u16) unknown("A custom compression method") {
     Deflate = 8,
     OldDeflate = 0x80B2,
     PackBits = 0x8005,
+
+    // Self-assigned by libtiff
+    ZSTD = 0xC350,
 }
 }
 

tests/decode_images.rs

@@ -515,3 +515,10 @@ fn test_predictor_3_rgb_f32() {
 fn test_predictor_3_gray_f32() {
     test_image_sum_f32("predictor-3-gray-f32.tif", ColorType::Gray(32), 20008.275);
 }
+
+#[test]
+#[cfg(feature = "zstd")]
+fn test_zstd_compression() {
+    // gdal_translate -co COMPRESS=ZSTD -co ZSTD_LEVEL=20 int16.tif int16_zstd.tif
+    test_image_sum_i16("int16_zstd.tif", ColorType::Gray(16), 354396);
+}