Switch to reading content streams on the fly during interpretation.

Previously, before interpreting a pages content stream we would
load it entirely into a buffer. Then we would interpret that
buffer. This has a cost in memory use.

Here, we update the code to read from a stream on the fly.

This has required changes in various different parts of the code.

Firstly, we have removed all use of the FILE lock - as stream
reads can now safely be interrupted by resource (or object) reads
from elsewhere in the file, the file lock becomes a very hard
thing to maintain, and doesn't actually benefit us at all. The
choices were to either use a recursive lock, or to remove it
entirely; I opted for the latter.

The file lock enum value remains as a placeholder for future use in
extendable data streams.

Secondly, we add a new 'concat' filter that concatenates a series of
streams together into one, optionally putting whitespace between each
stream (as the pdf parser requires this).

Finally, we change page/xobject/pattern content streams to work
on the fly, but we leave type3 glyphs using buffers (as presumably
these will be run repeatedly).

1 files changed, 3 insertions, 3 deletions

diff --git a/fitz/res_font.c b/fitz/res_font.c
index c279c75b..966cbc6e 100644
--- a/fitz/res_font.c
+++ b/fitz/res_font.c
@@ -692,7 +692,7 @@ static fz_rect
 fz_bound_t3_glyph(fz_context *ctx, fz_font *font, int gid, fz_matrix trm)
 {
 	fz_matrix ctm;
-	fz_buffer *contents;
+	void *contents;
 	fz_rect bounds;
 	fz_bbox bbox;
 	fz_device *dev;
@@ -726,7 +726,7 @@ fz_pixmap *
 fz_render_t3_glyph(fz_context *ctx, fz_font *font, int gid, fz_matrix trm, fz_colorspace *model)
 {
 	fz_matrix ctm;
-	fz_buffer *contents;
+	void *contents;
 	fz_bbox bbox;
 	fz_device *dev;
 	fz_pixmap *glyph;
@@ -786,7 +786,7 @@ void
 fz_render_t3_glyph_direct(fz_context *ctx, fz_device *dev, fz_font *font, int gid, fz_matrix trm, void *gstate)
 {
 	fz_matrix ctm;
-	fz_buffer *contents;
+	void *contents;
 
 	if (gid < 0 || gid > 255)
 		return;