Add QPDFWriter method to output to FILE*

ChangeLog

@@ -1,3 +1,9 @@
+2012-07-05  Jay Berkenbilt  <ejb@ql.org>
+
+	* Add QPDFWriter methods to write to an already open stdio FILE*.
+	Implementation and idea area based on contributions from Tobias
+	Hoffmann.
+
 2012-07-04  Jay Berkenbilt  <ejb@ql.org>
 
 	* Accept changes from Tobias Hoffmann: add public method

include/qpdf/QPDFWriter.hh

@@ -49,6 +49,14 @@ class QPDFWriter
     // setOutputFilename() for details.
     QPDF_DLL
     QPDFWriter(QPDF& pdf, char const* filename);
+
+    // Create a QPDFWriter object that writes its output to an already
+    // open FILE*.  This is equivalent to calling the first
+    // constructor and then calling setOutputFile().  See
+    // setOutputFile() for details.
+    QPDF_DLL
+    QPDFWriter(QPDF& pdf, char const* description, FILE* file, bool close_file);
+
     QPDF_DLL
     ~QPDFWriter();
 
@@ -66,6 +74,14 @@ class QPDFWriter
     QPDF_DLL
     void setOutputFilename(char const* filename);
 
+    // Write to the given FILE*, which must be opened by the caller.
+    // If close_file is true, QPDFWriter will close the file.
+    // Otherwise, the caller must close the file.  The file does not
+    // need to be seekable; it will be written to in a single pass.
+    // It must be open in binary mode.
+    QPDF_DLL
+    void setOutputFile(char const* description, FILE* file, bool close_file);
+
     // Indicate that QPDFWriter should create a memory buffer to
     // contain the final PDF file.  Obtain the memory by calling
     // getBuffer().

libqpdf/QPDFWriter.cc

@@ -34,6 +34,14 @@ QPDFWriter::QPDFWriter(QPDF& pdf, char const* filename) :
     setOutputFilename(filename);
 }
 
+QPDFWriter::QPDFWriter(QPDF& pdf, char const* description,
+                       FILE *file, bool close_file) :
+    pdf(pdf)
+{
+    init();
+    setOutputFile(description, file, close_file);
+}
+
 void
 QPDFWriter::init()
 {
@@ -79,21 +87,31 @@ QPDFWriter::~QPDFWriter()
 void
 QPDFWriter::setOutputFilename(char const* filename)
 {
-    this->filename = filename;
+    char const* description = filename;
+    FILE* f = 0;
     if (filename == 0)
     {
-	this->filename = "standard output";
+	description = "standard output";
 	QTC::TC("qpdf", "QPDFWriter write to stdout");
-	file = stdout;
+	f = stdout;
 	QUtil::binary_stdout();
     }
     else
     {
 	QTC::TC("qpdf", "QPDFWriter write to file");
-	file = QUtil::fopen_wrapper(std::string("open ") + filename,
-				    fopen(filename, "wb+"));
+	f = QUtil::fopen_wrapper(std::string("open ") + filename,
+                                 fopen(filename, "wb+"));
 	close_file = true;
     }
+    setOutputFile(description, f, close_file);
+}
+
+void
+QPDFWriter::setOutputFile(char const* description, FILE* file, bool close_file)
+{
+    this->filename = description;
+    this->file = file;
+    this->close_file = close_file;
     Pipeline* p = new Pl_StdioFile("qpdf output", file);
     to_delete.push_back(p);
     initializePipelineStack(p);

qpdf/test_driver.cc

@@ -728,7 +728,10 @@ void runtest(int n, char const* filename)
         checkPageContents(pages[11], "New page 11");
         checkPageContents(pages[12], "New page 12");
 
-	QPDFWriter w(pdf, "a.pdf");
+        // Exercise writing to FILE*
+        FILE* out =  QUtil::fopen_wrapper(std::string("open a.pdf"),
+                                          fopen("a.pdf", "wb"));
+	QPDFWriter w(pdf, "FILE* a.pdf", out, true);
 	w.setStaticID(true);
 	w.setStreamDataMode(qpdf_s_preserve);
 	w.write();