Add new methods QPDF::newStream

m-holger · Jay Berkenbilt
1 parent 0a3c5331
Showing 3 changed files with 66 additions and 12 deletions
include/qpdf/QPDF.hh
libqpdf/QPDF.cc
libqpdf/QPDFObjectHandle.cc
@@ -382,6 +382,36 @@ class QPDF
     QPDF_DLL
     std::map<QPDFObjGen, QPDFXRefEntry> getXRefTable();
  
+    // Public factory methods
+
+    // Create a new stream.  A subsequent call must be made to
+    // replaceStreamData() to provide data for the stream.  The stream's
+    // dictionary may be retrieved by calling getDict(), and the resulting
+    // dictionary may be modified.  Alternatively, you can create a new
+    // dictionary and call replaceDict to install it.
+    QPDF_DLL
+    QPDFObjectHandle newStream();
+
+    // Create a new stream.  Use the given buffer as the stream data.  The
+    // stream dictionary's /Length key will automatically be set to the size of
+    // the data buffer.  If additional keys are required, the stream's
+    // dictionary may be retrieved by calling getDict(), and the resulting
+    // dictionary may be modified.  This method is just a convenient wrapper
+    // around the newStream() and replaceStreamData().  It is a convenience
+    // methods for streams that require no parameters beyond the stream length.
+    // Note that you don't have to deal with compression yourself if you use
+    // QPDFWriter.  By default, QPDFWriter will automatically compress
+    // uncompressed stream data.  Example programs are provided that
+    // illustrate this.
+    QPDF_DLL
+    QPDFObjectHandle newStream(std::shared_ptr<Buffer> data);
+
+    // Create new stream with data from string.  This method will
+    // create a copy of the data rather than using the user-provided
+    // buffer as in the std::shared_ptr<Buffer> version of newStream.
+    QPDF_DLL
+    QPDFObjectHandle newStream(std::string const& data);
+
     // Install this object handle as an indirect object and return an
     // indirect reference to it.
     QPDF_DLL
@@ -2002,6 +2002,31 @@ QPDF::makeIndirectObject(QPDFObjectHandle oh)
 }
  
 QPDFObjectHandle
+QPDF::newStream()
+{
+    return makeIndirectObject(QPDF_Stream::create(
+        this, nextObjGen(), QPDFObjectHandle::newDictionary(), 0, 0));
+}
+
+QPDFObjectHandle
+QPDF::newStream(std::shared_ptr<Buffer> data)
+{
+    auto result = newStream();
+    result.replaceStreamData(
+        data, QPDFObjectHandle::newNull(), QPDFObjectHandle::newNull());
+    return result;
+}
+
+QPDFObjectHandle
+QPDF::newStream(std::string const& data)
+{
+    auto result = newStream();
+    result.replaceStreamData(
+        data, QPDFObjectHandle::newNull(), QPDFObjectHandle::newNull());
+    return result;
+}
+
+QPDFObjectHandle
 QPDF::reserveObjectIfNotExists(QPDFObjGen const& og)
 {
     if (!isCached(og) && m->xref_table.count(og) == 0) {
@@ -2165,30 +2165,29 @@ QPDFObjectHandle::newStream(QPDF* qpdf)
             "attempt to create stream in null qpdf object");
     }
     QTC::TC("qpdf", "QPDFObjectHandle newStream");
-    QPDFObjectHandle stream_dict = newDictionary();
-    QPDFObjectHandle result = qpdf->makeIndirectObject(QPDFObjectHandle(
-        QPDF_Stream::create(qpdf, QPDFObjGen(), stream_dict, 0, 0)));
-    auto stream = result.asStream();
-    stream->setObjGen(result.getObjGen());
-    return result;
+    return qpdf->newStream();
 }
  
 QPDFObjectHandle
 QPDFObjectHandle::newStream(QPDF* qpdf, std::shared_ptr<Buffer> data)
 {
+    if (qpdf == nullptr) {
+        throw std::runtime_error(
+            "attempt to create stream in null qpdf object");
+    }
     QTC::TC("qpdf", "QPDFObjectHandle newStream with data");
-    QPDFObjectHandle result = newStream(qpdf);
-    result.replaceStreamData(data, newNull(), newNull());
-    return result;
+    return qpdf->newStream(data);
 }
  
 QPDFObjectHandle
 QPDFObjectHandle::newStream(QPDF* qpdf, std::string const& data)
 {
+    if (qpdf == nullptr) {
+        throw std::runtime_error(
+            "attempt to create stream in null qpdf object");
+    }
     QTC::TC("qpdf", "QPDFObjectHandle newStream with string");
-    QPDFObjectHandle result = newStream(qpdf);
-    result.replaceStreamData(data, newNull(), newNull());
-    return result;
+    return qpdf->newStream(data);
 }
  
 QPDFObjectHandle