Fix json serialization for {x | -1 < x < 1} (fixes #308)

JSON serialization was preserving the value as presented, but JSON
doesn't accept decimal values without a 0 before the decimal point.

1 files changed, 24 insertions, 1 deletions

diff --git a/libqpdf/QPDF_Real.cc b/libqpdf/QPDF_Real.cc
index b28c2f70..b4c8283f 100644
--- a/libqpdf/QPDF_Real.cc
+++ b/libqpdf/QPDF_Real.cc
@@ -25,7 +25,30 @@ QPDF_Real::unparse()
 JSON
 QPDF_Real::getJSON()
 {
-    return JSON::makeNumber(this->val);
+    // While PDF allows .x or -.x, JSON does not. Rather than
+    // convering from string to double and back, just handle this as a
+    // special case for JSON.
+    std::string result;
+    if (this->val.length() == 0)
+    {
+        // Can't really happen...
+        result = "0";
+    }
+    else if (this->val.at(0) == '.')
+    {
+        result = "0" + this->val;
+    }
+    else if ((this->val.length() >= 2) &&
+             (this->val.at(0) == '-') &&
+             (this->val.at(1) == '.'))
+    {
+        result = "-0." + this->val.substr(2);
+    }
+    else
+    {
+        result = this->val;
+    }
+    return JSON::makeNumber(result);
 }
 
 QPDFObject::object_type_e