patterns: add WebP pattern

README.md

@@ -140,6 +140,7 @@ Everything will immediately show up in ImHex's Content Store and gets bundled wi
 | WAV  | `audio/x-wav`  | [`patterns/wav.hexpat`](patterns/wav.hexpat)  | RIFF header, WAVE header, PCM header |
 | WAS | | [`patterns\was_oskasoftware.hexpat`](patterns\was_oskasoftware.hexpat) | Oska Software DeskMates WAS/WA3 (WAVE/MP3 Set) file
 | WAD | | [`patterns/wad.hexpat`](patterns/wad.hexpat) | DOOM WAD Archive |
+| WebP | `image/webp` | [`patterns/webp.hexpat`](patterns/webp.hexpat) | Google WebP image |
 | XBEH | `audio/x-xbox-executable` | [`patterns/xbeh.hexpat`](patterns/xbeh.hexpat) | Xbox executable |
 | XCI | | [`patterns/xci.hexpat`](patterns/xci.hexpat) | Nintendo Switch XCI cartridge ROM |
 | XGT | | [`patterns/xgt.hexpat`](patterns/xgstexture.hexpat) | Exient XGS Engine Texture |

patterns/webp.hexpat

@@ -0,0 +1,122 @@
+#pragma author applecuckoo
+#pragma description Google WebP
+
+#pragma endian little
+#pragma MIME image/webp
+
+// based off of ttf.hexpat by Rebuild and wav.hexpat by WerWolv
+
+import std.mem;
+import std.core;
+import type.magic;
+
+struct RiffHeader {
+    char ckID[4] [[comment("Container Signature"), name("RIFF Header Signature")]];
+    u32  ckSize [[comment("Size of RIFF Header"), name("RIFF Chunk Size")]];
+    char format[4] [[comment("RIFF format"), name("WAVE Header Signature")]];
+};
+
+struct WebPChunk {
+    char chunkId[4];
+    u32  chunkSize;
+};
+
+bitfield VP8XFlags {
+    padding : 1;
+    A : 1;
+    X : 1;
+    E : 1;
+    L : 1;
+    I : 1;
+    padding : 2;
+};
+
+struct OneBase {
+    u24 value;
+} [[sealed, format("format_onebase")]];
+
+fn format_onebase(OneBase onebase) {
+    return onebase.value + 1;
+};
+
+struct WebPVP8XData {
+    VP8XFlags flags;
+    padding[3];
+    OneBase canvasWidth;
+    OneBase canvasHeight;
+};
+
+struct WebPANIMData {
+    u32 backgroundColor;
+    u16 loopCount;
+};
+
+bitfield ANMFFlags {
+    D : 1;
+    B : 1;
+    padding : 6;
+};
+
+bitfield WebPVP8LHeader {
+    widthMinusOne : 14;
+    heightMinusOne : 14;
+    alphaUsed : 1;
+    version : 3;
+};
+
+struct WebPVP8LData {
+    type::Magic<"\x2f"> id;
+    WebPVP8LHeader header;
+};
+
+u32 frameSize;
+
+struct WebPANMFData {
+    u24 frameX;
+    u24 frameY;
+    OneBase frameWidth;
+    OneBase frameHeight;
+    u24 frameDuration;
+    ANMFFlags flags;
+    u8 data[parent.chunkHeader.chunkSize - 16]; // lazy fix - can't be bothered implementing subchunks
+
+};
+
+bitfield ALPHFlags {
+    C : 2;
+    F : 2;
+    P : 2;
+    padding : 2;
+};
+
+u32 paddedChunkSize;
+
+struct WebPData {
+    WebPChunk chunkHeader;
+    paddedChunkSize = (chunkHeader.chunkSize + 1) >> 1 << 1;
+    match (chunkHeader.chunkId) {
+        ("VP8X"): WebPVP8XData VP8XData;
+        ("ANIM"): WebPANIMData ANIMData;
+        ("ANMF"): { 
+            WebPANMFData ANMFData;
+            padding[paddedChunkSize - sizeof(ANMFData)];
+        }
+        ("VP8L"): {
+        WebPVP8LHeader VP8LData;
+        u8 image[chunkHeader.chunkSize-3];
+        padding[paddedChunkSize - sizeof(VP8LData) - sizeof(image)];
+        }
+        ("ALPH"): {
+            ALPHFlags flags;
+            u8 ALPHData[chunkHeader.chunkSize-1];
+            padding[paddedChunkSize - sizeof(ALPHData) - sizeof(flags)];
+        }
+        (_): {
+            u8 data[chunkHeader.chunkSize];
+            padding[paddedChunkSize - sizeof(data)];
+        }
+    }
+} [[name(std::format("Chunk ({})", chunkHeader.chunkId))]];;
+
+RiffHeader header @0x00;
+WebPData data[while (!std::mem::eof())] @ $;