From 5c06eff4b50109012842ce408cf0ed846760ed88 Mon Sep 17 00:00:00 2001
From: mattmcw <matt@sixteenmillimeter.com>
Date: Fri, 3 Feb 2023 23:10:50 -0500
Subject: [PATCH] Check image type using a C++ 11 compatible method

---
 example.cpp | 44 ++++++++++++++++++++++++++++++--------------
 1 file changed, 30 insertions(+), 14 deletions(-)

diff --git a/example.cpp b/example.cpp
index d5325f5..879f2bd 100644
--- a/example.cpp
+++ b/example.cpp
@@ -1,29 +1,38 @@
 #include <iostream>
 #include <opencv2/core.hpp>
 #include <sys/stat.h>
-#include <filesystem> // C++17
+#include <string>
+#include <vector>
+#include <algorithm>
 
 namespace fs = std::filesystem;
 
 using namespace std;
 using namespace cv;
 
-string supportedExt[10] = {
-    ".jpg", ".JPG",
-    ".jpeg", ".JPEG",
-    ".png", ".PNG",
-    ".tif", ".TIF",
-    ".tiff", ".tiff"
+std::vector<std::string> supportedExt = {
+    "jpg", "JPG",
+    "jpeg", "JPEG",
+    "png", "PNG",
+    "tif", "TIF",
+    "tiff", "tiff"
 };
 
-inline bool file_exists (const std::string& name) {
-  struct stat buffer;   
-  return (stat (name.c_str(), &buffer) == 0); 
+inline bool in_array(const std::string &value, const std::vector<std::string> &array)
+{
+    return std::find(array.begin(), array.end(), value) != array.end();
 }
 
-inline bool is_image (const std::string& name) {
-    fs::path filePath = name;
-    if (filePath.extension() == ".jpg")
+inline bool file_exists (const std::string& name)
+{
+    struct stat buffer;   
+    return (stat (name.c_str(), &buffer) == 0); 
+}
+
+inline bool is_image (const std::string& name)
+{
+    string ext = name.substr(name.find_last_of(".") + 1);
+    return in_array(ext, supportedExt);
 }
   
 int main(int argc, char** argv)
@@ -40,11 +49,18 @@ int main(int argc, char** argv)
         return -2;
     }
 
-    if (!file_exists(input)) {
+    if (!file_exists(input))
+    {
         cerr << "File " << input << " does not exist." << endl;
         return -3;
     }
 
+    if (!is_image(input))
+    {
+        cerr << "File " << input << " is not a valid image." << endl;
+        return -4;
+    }
+
     cout << "Using image " << input << "." << endl;
   
     return 0;