QUtil::toUTF16

1 files changed, 35 insertions, 0 deletions

diff --git a/libqpdf/QUtil.cc b/libqpdf/QUtil.cc
index 39118854..e2bc0bac 100644
--- a/libqpdf/QUtil.cc
+++ b/libqpdf/QUtil.cc
@@ -506,6 +506,41 @@ QUtil::toUTF8(unsigned long uval)
     return result;
 }
 
+std::string
+QUtil::toUTF16(unsigned long uval)
+{
+    std::string result;
+    if ((uval >= 0xd800) && (uval <= 0xdfff))
+    {
+        result = "\xff\xfd";
+    }
+    else if (uval <= 0xffff)
+    {
+        char out[2];
+        out[0] = (uval & 0xff00) >> 8;
+        out[1] = (uval & 0xff);
+        result = std::string(out, 2);
+    }
+    else if (uval <= 0x10ffff)
+    {
+        char out[4];
+        uval -= 0x10000;
+        unsigned short high = ((uval & 0xffc00) >> 10) + 0xd800;
+        unsigned short low = (uval & 0x3ff) + 0xdc00;
+        out[0] = (high & 0xff00) >> 8;
+        out[1] = (high & 0xff);
+        out[2] = (low & 0xff00) >> 8;
+        out[3] = (low & 0xff);
+        result = std::string(out, 4);
+    }
+    else
+    {
+        result = "\xff\xfd";
+    }
+
+    return result;
+}
+
 // Random data support
 
 long