LibGfx+LibPDF: Use LibCompress' implementation of the PackBits decoder

No need to have these three copies :^)

Userland/Libraries/LibGfx/ImageFormats/ILBMLoader.cpp

@@ -9,6 +9,7 @@
 #include <AK/Endian.h>
 #include <AK/FixedArray.h>
 #include <AK/IntegralMath.h>
+#include <LibCompress/PackBitsDecoder.h>
 #include <LibGfx/FourCC.h>
 #include <LibGfx/ImageFormats/ILBMLoader.h>
 
@@ -246,39 +247,7 @@ static ErrorOr<ByteBuffer> uncompress_byte_run(ReadonlyBytes data, ILBMLoadingCo
     if (plane_data_size > NumericLimits<u32>::max() || ceil_div(plane_data_size, 127ul) > length)
         return Error::from_string_literal("Uncompressed data size too large");
 
-    auto plane_data = TRY(ByteBuffer::create_uninitialized(plane_data_size));
+    auto plane_data = TRY(Compress::PackBits::decode_all(data, plane_data_size));
-
-    u32 index = 0;
-    u32 read_bytes = 0;
-    // Uncompressing is done once we've read all buffer or plane buffer has been fully filled
-    while (read_bytes < length && index < plane_data_size) {
-        auto const byte = static_cast<i8>(data[read_bytes++]);
-        if (byte >= -127 && byte <= -1) {
-            // read next byte
-            if (read_bytes == data.size())
-                return Error::from_string_literal("Malformed compressed data");
-
-            u8 next_byte = data[read_bytes++];
-            if (index + -byte >= plane_data.size())
-                return Error::from_string_literal("Malformed compressed data");
-
-            for (u16 i = 0; i < -byte + 1; ++i) {
-                plane_data[index++] = next_byte;
-            }
-        } else if (byte >= 0) {
-            if (index + byte >= plane_data_size || read_bytes + byte >= length)
-                return Error::from_string_literal("Malformed compressed data");
-
-            for (u16 i = 0; i < byte + 1; ++i) {
-                plane_data[index] = data[read_bytes];
-                read_bytes++;
-                index++;
-            }
-        }
-    }
-
-    if (index != plane_data_size)
-        return Error::from_string_literal("Unexpected end of chunk while decompressing data");
 
     return plane_data;
 }

Userland/Libraries/LibGfx/ImageFormats/TIFFLoader.cpp

@@ -9,6 +9,7 @@
 #include <AK/Endian.h>
 #include <AK/String.h>
 #include <LibCompress/LZWDecoder.h>
+#include <LibCompress/PackBitsDecoder.h>
 #include <LibGfx/ImageFormats/CCITTDecoder.h>
 #include <LibGfx/ImageFormats/TIFFMetadata.h>
 
@@ -284,44 +285,8 @@ private:
             ByteBuffer decoded_bytes {};
 
             auto decode_packbits_strip = [&](u32 num_bytes) -> ErrorOr<ReadonlyBytes> {
-                auto strip_stream = make<FixedMemoryStream>(TRY(m_stream->read_in_place<u8 const>(num_bytes)));
+                auto const encoded_bytes = TRY(m_stream->read_in_place<u8 const>(num_bytes));
-
+                decoded_bytes = TRY(Compress::PackBits::decode_all(encoded_bytes));
-                decoded_bytes.clear();
-
-                Optional<i8> n {};
-                Optional<u8> saved_byte {};
-
-                while (strip_stream->remaining() > 0 || saved_byte.has_value()) {
-                    if (!n.has_value())
-                        n = TRY(strip_stream->read_value<i8>());
-
-                    if (n.value() >= 0 && !saved_byte.has_value()) {
-                        n.value() = n.value() - 1;
-                        if (n.value() == -1)
-                            n.clear();
-
-                        decoded_bytes.append(TRY(strip_stream->read_value<u8>()));
-                        continue;
-                    }
-
-                    if (n.value() == -128) {
-                        n.clear();
-                        continue;
-                    }
-
-                    if (!saved_byte.has_value())
-                        saved_byte = TRY(strip_stream->read_value<u8>());
-
-                    n.value() = n.value() + 1;
-
-                    decoded_bytes.append(*saved_byte);
-
-                    if (n == 1) {
-                        saved_byte.clear();
-                        n.clear();
-                    }
-                }
-
                 return decoded_bytes;
             };
 

Userland/Libraries/LibPDF/Filter.cpp

@@ -8,6 +8,7 @@
 #include <AK/Hex.h>
 #include <LibCompress/Deflate.h>
 #include <LibCompress/LZWDecoder.h>
+#include <LibCompress/PackBitsDecoder.h>
 #include <LibGfx/ImageFormats/JPEGLoader.h>
 #include <LibGfx/ImageFormats/PNGLoader.h>
 #include <LibPDF/CommonNames.h>
@@ -210,30 +211,7 @@ PDFErrorOr<ByteBuffer> Filter::decode_flate(ReadonlyBytes bytes, int predictor,
 
 PDFErrorOr<ByteBuffer> Filter::decode_run_length(ReadonlyBytes bytes)
 {
-    constexpr size_t END_OF_DECODING = 128;
+    return TRY(Compress::PackBits::decode_all(bytes, OptionalNone {}, Compress::PackBits::CompatibilityMode::PDF));
-    ByteBuffer buffer {};
-    while (true) {
-        VERIFY(bytes.size() > 0);
-        auto length = bytes[0];
-        bytes = bytes.slice(1);
-        if (length == END_OF_DECODING) {
-            VERIFY(bytes.is_empty());
-            break;
-        }
-        if (length < 128) {
-            TRY(buffer.try_append(bytes.slice(0, length + 1)));
-            bytes = bytes.slice(length + 1);
-        } else {
-            VERIFY(bytes.size() > 1);
-            auto byte_to_append = bytes[0];
-            bytes = bytes.slice(1);
-            size_t n_chars = 257 - length;
-            for (size_t i = 0; i < n_chars; ++i) {
-                TRY(buffer.try_append(byte_to_append));
-            }
-        }
-    }
-    return buffer;
 }
 
 PDFErrorOr<ByteBuffer> Filter::decode_ccitt(ReadonlyBytes)