New PDF Engine: Add parameters to only convert a specified set of pages to XML. Useful when trying to extract an ISBN efficiently

src/calibre/ebooks/pdf/input.py

@@ -34,7 +34,7 @@ class PDFInput(InputFormatPlugin):
         from calibre.ebooks.pdf.reflow import PDFDocument
         if pdfreflow_err:
             raise RuntimeError('Failed to load pdfreflow: ' + pdfreflow_err)
-        pdfreflow.reflow(stream.read())
+        pdfreflow.reflow(stream.read(), 1, -1)
         xml = open('index.xml', 'rb').read()
         PDFDocument(xml, self.opts, self.log)
         return os.path.join(os.getcwd(), 'metadata.opf')

src/calibre/ebooks/pdf/main.cpp

@@ -24,13 +24,14 @@ extern "C" {
     pdfreflow_reflow(PyObject *self, PyObject *args) {
         char *pdfdata;
         Py_ssize_t size;
+        int first_page, last_page;
 
-        if (!PyArg_ParseTuple(args, "s#", &pdfdata, &size))
+        if (!PyArg_ParseTuple(args, "s#ii", &pdfdata, &size, &first_page, &last_page))
             return NULL;
 
         try {
             Reflow reflow(pdfdata, static_cast<std::ifstream::pos_type>(size));
-            reflow.render();
+            reflow.render(first_page, last_page);
         } catch (std::exception &e) {
             PyErr_SetString(PyExc_RuntimeError, e.what()); return NULL;
         } catch (...) {
@@ -166,7 +167,7 @@ extern "C" {
     static 
     PyMethodDef pdfreflow_methods[] = {
         {"reflow", pdfreflow_reflow, METH_VARARGS,
-        "reflow(pdf_data)\n\n"
+        "reflow(pdf_data, first_page, last_page)\n\n"
                 "Reflow the specified PDF."
         },
         {"get_metadata", pdfreflow_get_metadata, METH_VARARGS,

src/calibre/ebooks/pdf/reflow.cpp

@@ -713,15 +713,17 @@ Reflow::Reflow(char *pdfdata, size_t sz) :
 }
 
 void
-Reflow::render() {
+Reflow::render(int first_page, int last_page) {
 
     if (!this->doc->okToCopy()) 
         cout << "Warning, this document has the copy protection flag set, ignoring." << endl;
 
     globalParams->setTextEncoding(encoding);
 
-    int first_page = 1;
-    int last_page = doc->getNumPages();
+    int doc_pages = doc->getNumPages();
+    if (last_page < 1 or last_page > doc_pages) last_page = doc_pages;
+    if (first_page < 1) first_page = 1;
+    if (first_page > last_page) first_page = last_page;
 
     XMLOutputDev *xml_out = new XMLOutputDev(this->doc);
     doc->displayPages(xml_out, first_page, last_page,
@@ -733,7 +735,8 @@ Reflow::render() {
               false //Printing
     );
     
-    this->dump_outline();
+    if (last_page - first_page == doc_pages - 1)
+        this->dump_outline();
 
     delete xml_out;
 }

src/calibre/ebooks/pdf/reflow.h

@@ -66,7 +66,7 @@ class Reflow {
         ~Reflow();
         
         /* Convert the PDF to XML. All files are output to the current directory */
-        void render();
+        void render(int first_page, int last_page);
 
         /* Get the PDF Info Dictionary */
         map<string, string> get_info();