fix: simplify ImageSpec::set_cicp from string method

Signed-off-by: Zach Lewis <zachcanbereached@gmail.com>

Author: zachlewis

src/libOpenImageIO/formatspec.cpp

@@ -1288,11 +1288,12 @@ ImageSpec::set_cicp(string_view cicp)
         erase_attribute("oiio:CICP");
         return;
     }
-    auto vals = Strutil::extract_from_list_string<int>("0,0,0,1", 4, 0);
-    auto p    = find_attribute("oiio:CICP", TypeDesc(TypeDesc::UINT8, 4));
-    if (p) {
-        string_view existing_vals = metadata_val(*p);
-        Strutil::extract_from_list_string<int>(vals, existing_vals);
+    std::vector<int> vals { 0, 0, 0, 1 };
+    auto p = find_attribute("oiio:CICP", TypeDesc(TypeDesc::UINT8, 4));
+    if (p && p->type() == TypeDesc(TypeDesc::UINT8, 4) && p->nvalues() == 4) {
+        const uint8_t* existing = static_cast<const uint8_t*>(p->data());
+        for (int i = 0; i < 4; ++i)
+            vals[i] = existing[i];
     }
     Strutil::extract_from_list_string<int>(vals, cicp);
     set_cicp(vals[0], vals[1], vals[2], vals[3]);

testsuite/png/ref/out-libpng15.txt

@@ -93,7 +93,7 @@ smallalpha.png       :    1 x    1, 4 channel, uint8 png
 cicp:
   16 x   16, 4 channel, float png
     channel list: R, G, B, A
-    Software: "OpenImageIO 3.1.1.0dev : DC4B1085141AF19019744DC43B156DE981E3B465"
+    Software: "OpenImageIO 3.1.2.0dev : DC4B1085141AF19019744DC43B156DE981E3B465"
     oiio:ColorSpace: "sRGB"
 Comparing "test16.png" and "ref/test16.png"
 PASS

testsuite/png/ref/out.txt

@@ -93,7 +93,7 @@ smallalpha.png       :    1 x    1, 4 channel, uint8 png
 cicp:
   16 x   16, 4 channel, float png
     channel list: R, G, B, A
-    Software: "OpenImageIO 3.1.1.0dev : DC4B1085141AF19019744DC43B156DE981E3B465"
+    Software: "OpenImageIO 3.1.2.0dev : DC4B1085141AF19019744DC43B156DE981E3B465"
     oiio:CICP: 1, 13, 0, 1
     oiio:ColorSpace: "sRGB"
 Comparing "test16.png" and "ref/test16.png"