qoi_pipe decoding support

external/solanaceae_tox

@@ -1 +1 @@
-Subproject commit ec926dcb95be38e22a4b2ddc0c5cd5d14eb3a6b7
+Subproject commit 178f08ee9617bd89e12bb16163a56ec4cafcf012

src/image_loader_qoi.cpp

@@ -1,10 +1,72 @@
 #include "./image_loader_qoi.hpp"
 
-#include <cstdint>
 #include <qoi/qoi.h>
 
+#include <cstdint>
+#include <cassert>
+
 #include <iostream>
 
+#define QOI_HEADER_SIZE 14
+
+// true if data looks like qoi
+static bool probe_qoi(const uint8_t* data, int64_t data_size) {
+	// smallest possible qoi
+	// magic
+	// dims (w h)
+	// chan
+	// col
+	if (data_size < QOI_HEADER_SIZE+8) {
+		return false;
+	}
+
+	if (
+		data[0] != 'q' ||
+		data[1] != 'o' ||
+		data[2] != 'i' ||
+		data[3] != 'f'
+	) {
+		return false;
+	}
+
+	return true;
+}
+
+// every qoi ends with 0,0,0,0,0,0,0,1
+// returns the index for the first byte after padding (aka the size of the qoi)
+static int64_t probe_qoi_padding(const uint8_t* data, int64_t data_size) {
+	assert(data);
+	assert(data_size >= 8);
+
+	// loop checks if 0x00 or 0x01, otherwise skips 2
+	// we start at the last possible first position
+	for (int64_t pos = 7; pos < data_size;) {
+		if (data[pos] == 0x00) {
+			pos += 1; // not last char in padding, but we might be in the padding
+		} else if (data[pos] == 0x01) {
+			// last char from padding
+			if (
+				data[pos-7] == 0x00 &&
+				data[pos-6] == 0x00 &&
+				data[pos-5] == 0x00 &&
+				data[pos-4] == 0x00 &&
+				data[pos-3] == 0x00 &&
+				data[pos-2] == 0x00 &&
+				data[pos-1] == 0x00
+			) {
+				//return pos - 7; // first byte of padding
+				return pos+1;
+			} else {
+				pos += 8; // cant be last byte for another 7
+			}
+		} else {
+			pos += 2;
+		}
+	}
+
+	return -1; // not found
+}
+
 ImageLoaderQOI::ImageInfo ImageLoaderQOI::loadInfoFromMemory(const uint8_t* data, uint64_t data_size) {
 	ImageInfo res;
 
@@ -26,24 +88,46 @@ ImageLoaderQOI::ImageInfo ImageLoaderQOI::loadInfoFromMemory(const uint8_t* data
 ImageLoaderQOI::ImageResult ImageLoaderQOI::loadFromMemoryRGBA(const uint8_t* data, uint64_t data_size) {
 	ImageResult res;
 
-	qoi_desc desc;
-
-	uint8_t* img_data = static_cast<uint8_t*>(
-		qoi_decode(data, data_size, &desc, 4)
-	);
-	if (img_data == nullptr) {
-		// not readable
+	if (!probe_qoi(data, data_size)) {
 		return res;
 	}
 
-	res.width = desc.width;
-	res.height = desc.height;
+	for (size_t data_pos = 0; data_pos < data_size;) {
+		const auto qoi_size = probe_qoi_padding(data+data_pos, data_size-data_pos);
+		if (qoi_size < QOI_HEADER_SIZE+8) {
+			// too small
+			break;
+		}
 
-	auto& new_frame = res.frames.emplace_back();
-	new_frame.ms = 0;
-	new_frame.data = {img_data, img_data+(desc.width*desc.height*4)};
+		qoi_desc desc;
+
+		uint8_t* img_data = static_cast<uint8_t*>(
+			qoi_decode(data + data_pos, qoi_size, &desc, 4)
+		);
+		if (img_data == nullptr) {
+			// not readable
+			return res;
+		}
+
+		if (res.width == 0 || res.height == 0) {
+			res.width = desc.width;
+			res.height = desc.height;
+		}
+
+		if (res.width == desc.width && res.height == desc.height) {
+			auto& new_frame = res.frames.emplace_back();
+			new_frame.ms = 25; // ffmpeg default
+			new_frame.data = {img_data, img_data+(desc.width*desc.height*4)};
+		} else {
+			// dim mismatch, what do we do? abort, continue?
+			data_pos = data_size; // force exit loop
+		}
+
+		free(img_data);
+
+		data_pos += qoi_size;
+	}
 
-	free(img_data);
 	return res;
 }