QUtil::double_to_string: trim trailing zeroes with option to disable

4 files changed, 36 insertions, 7 deletions

diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index 15907f6e..94875e13 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -2422,7 +2422,16 @@ QPDFObjectHandle::newReal(std::string const& value)
 QPDFObjectHandle
 QPDFObjectHandle::newReal(double value, int decimal_places)
 {
-    return QPDFObjectHandle(new QPDF_Real(value, decimal_places));
+    return QPDFObjectHandle(
+        new QPDF_Real(value, decimal_places, true));
+}
+
+QPDFObjectHandle
+QPDFObjectHandle::newReal(double value, int decimal_places,
+                          bool trim_trailing_zeroes)
+{
+    return QPDFObjectHandle(
+        new QPDF_Real(value, decimal_places, trim_trailing_zeroes));
 }
 
 QPDFObjectHandle
diff --git a/libqpdf/QPDF_Real.cc b/libqpdf/QPDF_Real.cc
index 396ea25f..55f61b35 100644
--- a/libqpdf/QPDF_Real.cc
+++ b/libqpdf/QPDF_Real.cc
@@ -7,8 +7,9 @@ QPDF_Real::QPDF_Real(std::string const& val) :
 {
 }
 
-QPDF_Real::QPDF_Real(double value, int decimal_places) :
-    val(QUtil::double_to_string(value, decimal_places))
+QPDF_Real::QPDF_Real(double value, int decimal_places,
+                     bool trim_trailing_zeroes) :
+    val(QUtil::double_to_string(value, decimal_places, trim_trailing_zeroes))
 {
 }
 
diff --git a/libqpdf/QUtil.cc b/libqpdf/QUtil.cc
index 4b86c0d4..a3fa94f4 100644
--- a/libqpdf/QUtil.cc
+++ b/libqpdf/QUtil.cc
@@ -324,10 +324,17 @@ QUtil::uint_to_string_base(unsigned long long num, int base, int length)
 std::string
 QUtil::double_to_string(double num, int decimal_places)
 {
+    return double_to_string(num, decimal_places, true);
+}
+
+std::string
+QUtil::double_to_string(double num, int decimal_places,
+                        bool trim_trailing_zeroes)
+{
     // Backward compatibility -- this code used to use sprintf and
     // treated decimal_places <= 0 to mean to use the default, which
-    // was six decimal places.  Also sprintf with %*.f interprets the
-    // length as fixed point rather than significant figures.
+    // was six decimal places. Starting in 10.2, we trim trailing
+    // zeroes by default.
     if (decimal_places <= 0)
     {
         decimal_places = 6;
@@ -335,7 +342,19 @@ QUtil::double_to_string(double num, int decimal_places)
     std::ostringstream buf;
     buf.imbue(std::locale::classic());
     buf << std::setprecision(decimal_places) << std::fixed << num;
-    return buf.str();
+    std::string result = buf.str();
+    if (trim_trailing_zeroes)
+    {
+        while ((result.length() > 1) && (result.back() == '0'))
+        {
+            result.pop_back();
+        }
+        if ((result.length() > 1) && (result.back() == '.'))
+        {
+            result.pop_back();
+        }
+    }
+    return result;
 }
 
 long long
diff --git a/libqpdf/qpdf/QPDF_Real.hh b/libqpdf/qpdf/QPDF_Real.hh
index dbc03de6..793990c0 100644
--- a/libqpdf/qpdf/QPDF_Real.hh
+++ b/libqpdf/qpdf/QPDF_Real.hh
@@ -7,7 +7,7 @@ class QPDF_Real: public QPDFObject
 {
   public:
     QPDF_Real(std::string const& val);
-    QPDF_Real(double value, int decimal_places = 0);
+    QPDF_Real(double value, int decimal_places, bool trim_trailing_zeroes);
     virtual ~QPDF_Real();
     virtual std::string unparse();
     virtual JSON getJSON();