Add missing pdfioPageGetNumStreams and pdfioPageOpenStream functions.

Add initial version of pdfiototext text extraction utility.

pdfio-page.c

@@ -1,7 +1,7 @@
 //
 // PDF page functions for PDFio.
 //
-// Copyright © 2021 by Michael R Sweet.
+// Copyright © 2021-2022 by Michael R Sweet.
 //
 // Licensed under Apache License v2.0.  See the file "LICENSE" for more
 // information.
@@ -14,6 +14,13 @@
 #include "pdfio-private.h"
 
 
+//
+// Local functions...
+//
+
+static _pdfio_value_t	*get_contents(pdfio_obj_t *page);
+
+
 //
 // 'pdfioPageCopy()' - Copy a page to a PDF file.
 //
@@ -47,3 +54,74 @@ pdfioPageCopy(pdfio_file_t *pdf,	// I - PDF file
   else
     return (_pdfioFileAddPage(pdf, dstpage));
 }
+
+
+//
+// 'pdfioPageGetNumStreams()' - Get the number of content streams for a page object.
+//
+
+size_t					// O - Number of streams
+pdfioPageGetNumStreams(
+    pdfio_obj_t *page)			// I - Page object
+{
+  _pdfio_value_t *contents = get_contents(page);
+					// Contents value
+
+
+  if (!contents)
+    return (0);
+  else if (contents->type == PDFIO_VALTYPE_ARRAY)
+    return (pdfioArrayGetSize(contents->value.array));
+  else
+    return (1);
+}
+
+
+//
+// 'pdfioPageOpenStream()' - Open a content stream for a page.
+//
+
+pdfio_stream_t *			// O - Stream
+pdfioPageOpenStream(
+    pdfio_obj_t *page,			// I - Page object
+    size_t      n,			// I - Stream index (0-based)
+    bool        decode)			// I - `true` to decode/decompress stream
+{
+  _pdfio_value_t *contents = get_contents(page);
+					// Contents value
+
+
+  if (!contents)
+    return (NULL);
+  else if (contents->type == PDFIO_VALTYPE_ARRAY && n < pdfioArrayGetSize(contents->value.array))
+    return (pdfioObjOpenStream(pdfioArrayGetObj(contents->value.array, n), decode));
+  else if (n)
+    return (NULL);
+  else
+    return (pdfioObjOpenStream(pdfioFileFindObj(page->pdf, contents->value.indirect.number), decode));
+}
+
+
+//
+// 'get_contents()' - Get a page's Contents value.
+//
+
+static _pdfio_value_t *			// O - Value or NULL on error
+get_contents(pdfio_obj_t *page)		// I - Page object
+{
+  // Range check input...
+  if (!page)
+    return (NULL);
+
+  // Load the page object as needed...
+  if (page->value.type == PDFIO_VALTYPE_NONE)
+  {
+    if (!_pdfioObjLoad(page))
+      return (NULL);
+  }
+
+  if (page->value.type != PDFIO_VALTYPE_DICT)
+    return (NULL);
+
+  return (_pdfioDictGetValue(page->value.value.dict, "Contents"));
+}