Support pdf files larger than 2Gig.

If FZ_LARGEFILE is defined when building, MuPDF uses 64bit offsets
for files; this allows us to open streams larger than 2Gig.

The downsides to this are that:

 * The xref entries are larger.

 * All PDF ints are held as 64bit things rather than 32bit things
   (to cope with /Prev entries, hint stream offsets etc).

 * All file positions are stored as 64bits rather than 32.

The implementation works by detecting FZ_LARGEFILE. Some #ifdeffery
in fitz/system.h sets fz_off_t to either int or int64_t as appropriate,
and sets defines for fz_fopen, fz_fseek, fz_ftell etc as required.

These call the fseeko64 etc functions on linux (and so define
_LARGEFILE64_SOURCE) and the explicit 64bit functions on windows.

1 files changed, 26 insertions, 2 deletions

diff --git a/source/pdf/pdf-object.c b/source/pdf/pdf-object.c
index f6c10b63..f0415e98 100644
--- a/source/pdf/pdf-object.c
+++ b/source/pdf/pdf-object.c
@@ -42,7 +42,7 @@ typedef struct pdf_obj_num_s
 	pdf_obj super;
 	union
 	{
-		int i;
+		fz_off_t i;
 		float f;
 	} u;
 } pdf_obj_num;
@@ -120,6 +120,18 @@ pdf_new_int(fz_context *ctx, pdf_document *doc, int i)
 }
 
 pdf_obj *
+pdf_new_int_offset(fz_context *ctx, pdf_document *doc, fz_off_t i)
+{
+	pdf_obj_num *obj;
+	obj = Memento_label(fz_malloc(ctx, sizeof(pdf_obj_num)), "pdf_obj(offset)");
+	obj->super.refs = 1;
+	obj->super.kind = PDF_INT;
+	obj->super.flags = 0;
+	obj->u.i = i;
+	return &obj->super;
+}
+
+pdf_obj *
 pdf_new_real(fz_context *ctx, pdf_document *doc, float f)
 {
 	pdf_obj_num *obj;
@@ -268,12 +280,24 @@ int pdf_to_int(fz_context *ctx, pdf_obj *obj)
 	if (obj < PDF_OBJ__LIMIT)
 		return 0;
 	if (obj->kind == PDF_INT)
-		return NUM(obj)->u.i;
+		return (int)NUM(obj)->u.i;
 	if (obj->kind == PDF_REAL)
 		return (int)(NUM(obj)->u.f + 0.5f); /* No roundf in MSVC */
 	return 0;
 }
 
+fz_off_t pdf_to_offset(fz_context *ctx, pdf_obj *obj)
+{
+	RESOLVE(obj);
+	if (obj < PDF_OBJ__LIMIT)
+		return 0;
+	if (obj->kind == PDF_INT)
+		return NUM(obj)->u.i;
+	if (obj->kind == PDF_REAL)
+		return (fz_off_t)(NUM(obj)->u.f + 0.5f); /* No roundf in MSVC */
+	return 0;
+}
+
 float pdf_to_real(fz_context *ctx, pdf_obj *obj)
 {
 	RESOLVE(obj);