fix(cineon): validate bit depth against libcineon's supported set

src/cineon.imageio/cineoninput.cpp

@@ -102,8 +102,20 @@ CineonInput::open(const std::string& name, ImageSpec& newspec)
     int maxbits = 0;
     for (int i = 0; i < nchannels; i++) {
         int b(m_cin.header.BitDepth(i));
-        if (b < 1 || b > 32) {
+        // libcineon's ComponentDataSize/ComponentByteCount only know how to
+        // handle these bit depths; anything else asserts (or worse, in a
+        // non-debug build) deep inside the vendored library. Reject bogus
+        // values here so we can give a proper error instead.
+        switch (b) {
+        case 8:
+        case 10:
+        case 12:
+        case 16:
+        case 32:
+        case 64: break;
+        default:
             errorfmt("Invalid bitdepth in channel {}: {} bits", i, b);
+            close();
             return false;
         }
         maxbits = std::max(maxbits, b);

testsuite/cineon/ref/out.txt

@@ -36,3 +36,6 @@ Reading ../oiio-images/cineon/checker.cin
 oiiotool ERROR: read : "src/broken_bitdepth.cin": Invalid number of channels 255 (must be 1-8)
 Full command line was:
 > oiiotool --info --hash src/broken_bitdepth.cin
+oiiotool ERROR: read : "src/broken_bitdepth2.cin": Invalid bitdepth in channel 0: 26 bits
+Full command line was:
+> oiiotool --info --hash src/broken_bitdepth2.cin

testsuite/cineon/run.py

@@ -14,5 +14,8 @@
 
 # Regression tests for broken files
 command += info_command ("src/broken_bitdepth.cin", verbose=False, failureok=True)
+# Regression test for a per-channel bit depth libcineon doesn't recognize
+# (used to assert/abort inside CineonHeader.cpp instead of erroring out).
+command += info_command ("src/broken_bitdepth2.cin", verbose=False, failureok=True)
 
 outputs = [ "out.txt" ]