From 3b21eda9ad3b2ece9c6e5472eb419fb4d88424bd Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Thu, 17 Sep 2020 19:20:36 +0200
Subject: Add image upscaling with waifu2x-ncnn-vulkan, async load images in
 scroll image view mode

---
 src/ImageUtils.cpp | 114 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 src/ImageUtils.cpp

(limited to 'src/ImageUtils.cpp')

diff --git a/src/ImageUtils.cpp b/src/ImageUtils.cpp
new file mode 100644
index 0000000..d160450
--- /dev/null
+++ b/src/ImageUtils.cpp
@@ -0,0 +1,114 @@
+#include "../include/ImageUtils.hpp"
+#include <string.h>
+#include <arpa/inet.h>
+
+namespace QuickMedia {
+    static bool gif_get_size(unsigned char *data, size_t data_size, int *width, int *height) {
+        if(data_size >= 10 && memcmp(data, "GIF", 3) == 0) {
+            *width = ((int)data[7] << 8) | data[6];
+            *height = ((int)data[9] << 8) | data[8];
+            return true;
+        }
+        return false;
+    }
+
+    static bool png_get_size(unsigned char *data, size_t data_size, int *width, int *height) {
+        if(data_size >= 24 && memcmp(data, "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A", 8) == 0) {
+            memcpy(width, data + 16, sizeof(int));
+            memcpy(height, data + 16 + sizeof(int), sizeof(int));
+            *width = htonl(*width);
+            *height = htonl(*height);
+            return true;
+        }
+        return false;
+    }
+
+    static bool is_cpu_little_endian() {
+        unsigned short i;
+        memcpy(&i, "LE", sizeof(i));
+        return (i & 0xF) == 'E';
+    }
+
+    static unsigned short read_uint16(unsigned char *data, bool cpu_little_endian, bool file_little_endian) {
+        unsigned short result;
+        memcpy(&result, data, sizeof(result));
+        if(cpu_little_endian != file_little_endian)
+            result = __builtin_bswap16(result);
+        return result;
+    }
+
+    static unsigned int read_uint32(unsigned char *data, bool cpu_little_endian, bool file_little_endian) {
+        unsigned int result;
+        memcpy(&result, data, sizeof(result));
+        if(cpu_little_endian != file_little_endian)
+            result = __builtin_bswap32(result);
+        return result;
+    }
+#if 0
+    static bool tiff_get_size(unsigned char *data, size_t data_size, int *width, int *height) {
+        if(data_size < 8)
+            return false;
+
+        bool cpu_little_endian = is_cpu_little_endian();
+        bool file_little_endian = true;
+        if(memcmp(data, "II", 2) == 0)
+            file_little_endian = true;
+        else if(memcmp(data, "MM", 2) == 0)
+            file_little_endian = false;
+        else
+            return false;
+
+        unsigned short id = read_uint16(data, cpu_little_endian, file_little_endian);
+        if(id != 42)
+            return false;
+
+        unsigned int offset_to_ifd = read_uint32(data, cpu_little_endian, file_little_endian);
+        if(offset_to_ifd )
+    }
+#endif
+
+    static bool jpeg_get_size(unsigned char *data, size_t data_size, int *width, int *height) {
+        if(data_size < 11 || memcmp(data, "\xFF\xD8\xFF\xE0", 4) != 0)
+            return false;
+
+        unsigned short block_length = ((int)data[4] << 8) | data[5];
+        if(memcmp(data + 6, "JFIF\0", 5) != 0)
+            return false;
+
+        size_t index = 4;
+        while(index < data_size) {
+            index += block_length;
+            if(index + 1 >= data_size) return false;
+            if(data[index] != 0xFF) return false; // Check if start of block
+            if((data[index + 1] == 0xC0 || data[index + 1] == 0xC2) && index + 8 < data_size) { // Start of frame marker
+                *height = ((int)data[index + 5] << 8) | data[index + 6];
+                *width = ((int)data[index + 7] << 8) | data[index + 8];
+                return true;
+            } else {
+                if(index + 2 >= data_size) return false;
+                index += 2;
+                block_length = ((int)data[index] << 8) | data[index + 1];
+            }
+        }
+
+        return false;
+    }
+
+    bool image_get_resolution(const Path &path, int *width, int *height) {
+        FILE *file = fopen(path.data.c_str(), "rb");
+        if(!file)
+            return false;
+
+        unsigned char data[512];
+        size_t bytes_read = fread(data, 1, sizeof(data), file);
+        fclose(file);
+
+        if(png_get_size(data, bytes_read, width, height))
+            return true;
+        else if(gif_get_size(data, bytes_read, width, height))
+            return true;
+        else if(jpeg_get_size(data, bytes_read, width, height))
+            return true;
+        return false;
+    }
+}
\ No newline at end of file
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