Move guts of pdfclean into new pdf_write function.

Expose pdf_write function through the document interface.

1 files changed, 662 insertions, 0 deletions

diff --git a/pdf/pdf_write.c b/pdf/pdf_write.c
new file mode 100644
index 00000000..e14cfa28
--- /dev/null
+++ b/pdf/pdf_write.c
@@ -0,0 +1,662 @@
+#include "fitz.h"
+#include "mupdf-internal.h"
+
+typedef struct pdf_write_options_s pdf_write_options;
+
+struct pdf_write_options_s
+{
+	FILE *out;
+	int doascii;
+	int doexpand;
+	int dogarbage;
+	char *uselist;
+	int *ofslist;
+	int *genlist;
+	int *renumbermap;
+};
+
+/*
+ * Garbage collect objects not reachable from the trailer.
+ */
+
+static pdf_obj *sweepref(pdf_document *xref, pdf_write_options *opts, pdf_obj *obj)
+{
+	int num = pdf_to_num(obj);
+	int gen = pdf_to_gen(obj);
+	fz_context *ctx = xref->ctx;
+
+	if (num < 0 || num >= xref->len)
+		return NULL;
+	if (opts->uselist[num])
+		return NULL;
+
+	opts->uselist[num] = 1;
+
+	/* Bake in /Length in stream objects */
+	fz_try(ctx)
+	{
+		if (pdf_is_stream(xref, num, gen))
+		{
+			pdf_obj *len = pdf_dict_gets(obj, "Length");
+			if (pdf_is_indirect(len))
+			{
+				opts->uselist[pdf_to_num(len)] = 0;
+				len = pdf_resolve_indirect(len);
+				pdf_dict_puts(obj, "Length", len);
+			}
+		}
+	}
+	fz_catch(ctx)
+	{
+		/* Leave broken */
+	}
+
+	return pdf_resolve_indirect(obj);
+}
+
+static void sweepobj(pdf_document *xref, pdf_write_options *opts, pdf_obj *obj)
+{
+	int i;
+
+	if (pdf_is_indirect(obj))
+		obj = sweepref(xref, opts, obj);
+
+	if (pdf_is_dict(obj))
+	{
+		int n = pdf_dict_len(obj);
+		for (i = 0; i < n; i++)
+			sweepobj(xref, opts, pdf_dict_get_val(obj, i));
+	}
+
+	else if (pdf_is_array(obj))
+	{
+		int n = pdf_array_len(obj);
+		for (i = 0; i < n; i++)
+			sweepobj(xref, opts, pdf_array_get(obj, i));
+	}
+}
+
+/*
+ * Scan for and remove duplicate objects (slow)
+ */
+
+static void removeduplicateobjs(pdf_document *xref, pdf_write_options *opts)
+{
+	int num, other;
+	fz_context *ctx = xref->ctx;
+
+	for (num = 1; num < xref->len; num++)
+	{
+		/* Only compare an object to objects preceding it */
+		for (other = 1; other < num; other++)
+		{
+			pdf_obj *a, *b;
+			int match;
+
+			if (num == other || !opts->uselist[num] || !opts->uselist[other])
+				continue;
+
+			/*
+			 * Comparing stream objects data contents would take too long.
+			 *
+			 * pdf_is_stream calls pdf_cache_object and ensures
+			 * that the xref table has the objects loaded.
+			 */
+			fz_try(ctx)
+			{
+				match = (pdf_is_stream(xref, num, 0) || pdf_is_stream(xref, other, 0));
+			}
+			fz_catch(ctx)
+			{
+				/* Assume different */
+				match = 0;
+			}
+			if (match)
+				continue;
+
+			a = xref->table[num].obj;
+			b = xref->table[other].obj;
+
+			a = pdf_resolve_indirect(a);
+			b = pdf_resolve_indirect(b);
+
+			if (pdf_objcmp(a, b))
+				continue;
+
+			/* Keep the lowest numbered object */
+			opts->renumbermap[num] = MIN(num, other);
+			opts->renumbermap[other] = MIN(num, other);
+			opts->uselist[MAX(num, other)] = 0;
+
+			/* One duplicate was found, do not look for another */
+			break;
+		}
+	}
+}
+
+/*
+ * Renumber objects sequentially so the xref is more compact
+ */
+
+static void compactxref(pdf_document *xref, pdf_write_options *opts)
+{
+	int num, newnum;
+
+	/*
+	 * Update renumbermap in-place, clustering all used
+	 * objects together at low object ids. Objects that
+	 * already should be renumbered will have their new
+	 * object ids be updated to reflect the compaction.
+	 */
+
+	newnum = 1;
+	for (num = 1; num < xref->len; num++)
+	{
+		if (opts->uselist[num] && opts->renumbermap[num] == num)
+			opts->renumbermap[num] = newnum++;
+		else if (opts->renumbermap[num] != num)
+			opts->renumbermap[num] = opts->renumbermap[opts->renumbermap[num]];
+	}
+}
+
+/*
+ * Update indirect objects according to renumbering established when
+ * removing duplicate objects and compacting the xref.
+ */
+
+static void renumberobj(pdf_document *xref, pdf_write_options *opts, pdf_obj *obj)
+{
+	int i;
+	fz_context *ctx = xref->ctx;
+
+	if (pdf_is_dict(obj))
+	{
+		int n = pdf_dict_len(obj);
+		for (i = 0; i < n; i++)
+		{
+			pdf_obj *key = pdf_dict_get_key(obj, i);
+			pdf_obj *val = pdf_dict_get_val(obj, i);
+			if (pdf_is_indirect(val))
+			{
+				val = pdf_new_indirect(ctx, opts->renumbermap[pdf_to_num(val)], 0, xref);
+				fz_dict_put(obj, key, val);
+				pdf_drop_obj(val);
+			}
+			else
+			{
+				renumberobj(xref, opts, val);
+			}
+		}
+	}
+
+	else if (pdf_is_array(obj))
+	{
+		int n = pdf_array_len(obj);
+		for (i = 0; i < n; i++)
+		{
+			pdf_obj *val = pdf_array_get(obj, i);
+			if (pdf_is_indirect(val))
+			{
+				val = pdf_new_indirect(ctx, opts->renumbermap[pdf_to_num(val)], 0, xref);
+				pdf_array_put(obj, i, val);
+				pdf_drop_obj(val);
+			}
+			else
+			{
+				renumberobj(xref, opts, val);
+			}
+		}
+	}
+}
+
+static void renumberobjs(pdf_document *xref, pdf_write_options *opts)
+{
+	pdf_xref_entry *oldxref;
+	int newlen;
+	int num;
+	fz_context *ctx = xref->ctx;
+
+	/* Apply renumber map to indirect references in all objects in xref */
+	renumberobj(xref, opts, xref->trailer);
+	for (num = 0; num < xref->len; num++)
+	{
+		pdf_obj *obj = xref->table[num].obj;
+
+		if (pdf_is_indirect(obj))
+		{
+			obj = pdf_new_indirect(ctx, opts->renumbermap[pdf_to_num(obj)], 0, xref);
+			pdf_update_object(xref, num, 0, obj);
+			pdf_drop_obj(obj);
+		}
+		else
+		{
+			renumberobj(xref, opts, obj);
+		}
+	}
+
+	/* Create new table for the reordered, compacted xref */
+	oldxref = xref->table;
+	xref->table = fz_malloc_array(xref->ctx, xref->len, sizeof(pdf_xref_entry));
+	xref->table[0] = oldxref[0];
+
+	/* Move used objects into the new compacted xref */
+	newlen = 0;
+	for (num = 1; num < xref->len; num++)
+	{
+		if (opts->uselist[num])
+		{
+			if (newlen < opts->renumbermap[num])
+				newlen = opts->renumbermap[num];
+			xref->table[opts->renumbermap[num]] = oldxref[num];
+		}
+		else
+		{
+			if (oldxref[num].obj)
+				pdf_drop_obj(oldxref[num].obj);
+		}
+	}
+
+	fz_free(xref->ctx, oldxref);
+
+	/* Update the used objects count in compacted xref */
+	xref->len = newlen + 1;
+
+	/* Update list of used objects to fit with compacted xref */
+	for (num = 1; num < xref->len; num++)
+		opts->uselist[num] = 1;
+}
+
+/*
+ * Make sure we have loaded objects from object streams.
+ */
+
+static void preloadobjstms(pdf_document *xref)
+{
+	pdf_obj *obj;
+	int num;
+
+	for (num = 0; num < xref->len; num++)
+	{
+		if (xref->table[num].type == 'o')
+		{
+			obj = pdf_load_object(xref, num, 0);
+			pdf_drop_obj(obj);
+		}
+	}
+}
+
+/*
+ * Save streams and objects to the output
+ */
+
+static inline int isbinary(int c)
+{
+	if (c == '\n' || c == '\r' || c == '\t')
+		return 0;
+	return c < 32 || c > 127;
+}
+
+static int isbinarystream(fz_buffer *buf)
+{
+	int i;
+	for (i = 0; i < buf->len; i++)
+		if (isbinary(buf->data[i]))
+			return 1;
+	return 0;
+}
+
+static fz_buffer *hexbuf(fz_context *ctx, unsigned char *p, int n)
+{
+	static const char hex[16] = "0123456789abcdef";
+	fz_buffer *buf;
+	int x = 0;
+
+	buf = fz_new_buffer(ctx, n * 2 + (n / 32) + 2);
+
+	while (n--)
+	{
+		buf->data[buf->len++] = hex[*p >> 4];
+		buf->data[buf->len++] = hex[*p & 15];
+		if (++x == 32)
+		{
+			buf->data[buf->len++] = '\n';
+			x = 0;
+		}
+		p++;
+	}
+
+	buf->data[buf->len++] = '>';
+	buf->data[buf->len++] = '\n';
+
+	return buf;
+}
+
+static void addhexfilter(pdf_document *xref, pdf_obj *dict)
+{
+	pdf_obj *f, *dp, *newf, *newdp;
+	pdf_obj *ahx, *nullobj;
+	fz_context *ctx = xref->ctx;
+
+	ahx = fz_new_name(ctx, "ASCIIHexDecode");
+	nullobj = pdf_new_null(ctx);
+	newf = newdp = NULL;
+
+	f = pdf_dict_gets(dict, "Filter");
+	dp = pdf_dict_gets(dict, "DecodeParms");
+
+	if (pdf_is_name(f))
+	{
+		newf = pdf_new_array(ctx, 2);
+		pdf_array_push(newf, ahx);
+		pdf_array_push(newf, f);
+		f = newf;
+		if (pdf_is_dict(dp))
+		{
+			newdp = pdf_new_array(ctx, 2);
+			pdf_array_push(newdp, nullobj);
+			pdf_array_push(newdp, dp);
+			dp = newdp;
+		}
+	}
+	else if (pdf_is_array(f))
+	{
+		pdf_array_insert(f, ahx);
+		if (pdf_is_array(dp))
+			pdf_array_insert(dp, nullobj);
+	}
+	else
+		f = ahx;
+
+	pdf_dict_puts(dict, "Filter", f);
+	if (dp)
+		pdf_dict_puts(dict, "DecodeParms", dp);
+
+	pdf_drop_obj(ahx);
+	pdf_drop_obj(nullobj);
+	if (newf)
+		pdf_drop_obj(newf);
+	if (newdp)
+		pdf_drop_obj(newdp);
+}
+
+static void copystream(pdf_document *xref, pdf_write_options *opts, pdf_obj *obj, int num, int gen)
+{
+	fz_buffer *buf, *tmp;
+	pdf_obj *newlen;
+	fz_context *ctx = xref->ctx;
+
+	buf = pdf_load_raw_stream(xref, num, gen);
+
+	if (opts->doascii && isbinarystream(buf))
+	{
+		tmp = hexbuf(ctx, buf->data, buf->len);
+		fz_drop_buffer(ctx, buf);
+		buf = tmp;
+
+		addhexfilter(xref, obj);
+
+		newlen = pdf_new_int(ctx, buf->len);
+		pdf_dict_puts(obj, "Length", newlen);
+		pdf_drop_obj(newlen);
+	}
+
+	fprintf(opts->out, "%d %d obj\n", num, gen);
+	pdf_fprint_obj(opts->out, obj, opts->doexpand == 0);
+	fprintf(opts->out, "stream\n");
+	fwrite(buf->data, 1, buf->len, opts->out);
+	fprintf(opts->out, "endstream\nendobj\n\n");
+
+	fz_drop_buffer(ctx, buf);
+}
+
+static void expandstream(pdf_document *xref, pdf_write_options *opts, pdf_obj *obj, int num, int gen)
+{
+	fz_buffer *buf, *tmp;
+	pdf_obj *newlen;
+	fz_context *ctx = xref->ctx;
+
+	buf = pdf_load_stream(xref, num, gen);
+
+	pdf_dict_dels(obj, "Filter");
+	pdf_dict_dels(obj, "DecodeParms");
+
+	if (opts->doascii && isbinarystream(buf))
+	{
+		tmp = hexbuf(ctx, buf->data, buf->len);
+		fz_drop_buffer(ctx, buf);
+		buf = tmp;
+
+		addhexfilter(xref, obj);
+	}
+
+	newlen = pdf_new_int(ctx, buf->len);
+	pdf_dict_puts(obj, "Length", newlen);
+	pdf_drop_obj(newlen);
+
+	fprintf(opts->out, "%d %d obj\n", num, gen);
+	pdf_fprint_obj(opts->out, obj, opts->doexpand == 0);
+	fprintf(opts->out, "stream\n");
+	fwrite(buf->data, 1, buf->len, opts->out);
+	fprintf(opts->out, "endstream\nendobj\n\n");
+
+	fz_drop_buffer(ctx, buf);
+}
+
+static void writeobject(pdf_document *xref, pdf_write_options *opts, int num, int gen)
+{
+	pdf_obj *obj;
+	pdf_obj *type;
+	fz_context *ctx = xref->ctx;
+
+	obj = pdf_load_object(xref, num, gen);
+
+	/* skip ObjStm and XRef objects */
+	if (pdf_is_dict(obj))
+	{
+		type = pdf_dict_gets(obj, "Type");
+		if (pdf_is_name(type) && !strcmp(pdf_to_name(type), "ObjStm"))
+		{
+			opts->uselist[num] = 0;
+			pdf_drop_obj(obj);
+			return;
+		}
+		if (pdf_is_name(type) && !strcmp(pdf_to_name(type), "XRef"))
+		{
+			opts->uselist[num] = 0;
+			pdf_drop_obj(obj);
+			return;
+		}
+	}
+
+	if (!pdf_is_stream(xref, num, gen))
+	{
+		fprintf(opts->out, "%d %d obj\n", num, gen);
+		pdf_fprint_obj(opts->out, obj, opts->doexpand == 0);
+		fprintf(opts->out, "endobj\n\n");
+	}
+	else
+	{
+		int dontexpand = 0;
+		if (opts->doexpand != 0 && opts->doexpand != fz_expand_all)
+		{
+			pdf_obj *o;
+
+			if ((o = pdf_dict_gets(obj, "Type"), !strcmp(pdf_to_name(o), "XObject")) &&
+				(o = pdf_dict_gets(obj, "Subtype"), !strcmp(pdf_to_name(o), "Image")))
+				dontexpand = !(opts->doexpand & fz_expand_images);
+			if (o = pdf_dict_gets(obj, "Type"), !strcmp(pdf_to_name(o), "Font"))
+				dontexpand = !(opts->doexpand & fz_expand_fonts);
+			if (o = pdf_dict_gets(obj, "Type"), !strcmp(pdf_to_name(o), "FontDescriptor"))
+				dontexpand = !(opts->doexpand & fz_expand_fonts);
+			if ((o = pdf_dict_gets(obj, "Length1")) != NULL)
+				dontexpand = !(opts->doexpand & fz_expand_fonts);
+			if ((o = pdf_dict_gets(obj, "Length2")) != NULL)
+				dontexpand = !(opts->doexpand & fz_expand_fonts);
+			if ((o = pdf_dict_gets(obj, "Length3")) != NULL)
+				dontexpand = !(opts->doexpand & fz_expand_fonts);
+			if (o = pdf_dict_gets(obj, "Subtype"), !strcmp(pdf_to_name(o), "Type1C"))
+				dontexpand = !(opts->doexpand & fz_expand_fonts);
+			if (o = pdf_dict_gets(obj, "Subtype"), !strcmp(pdf_to_name(o), "CIDFontType0C"))
+				dontexpand = !(opts->doexpand & fz_expand_fonts);
+		}
+		if (opts->doexpand && !dontexpand && !pdf_is_jpx_image(ctx, obj))
+			expandstream(xref, opts, obj, num, gen);
+		else
+			copystream(xref, opts, obj, num, gen);
+	}
+
+	pdf_drop_obj(obj);
+}
+
+static void writexref(pdf_document *xref, pdf_write_options *opts)
+{
+	pdf_obj *trailer;
+	pdf_obj *obj;
+	int startxref;
+	int num;
+	fz_context *ctx = xref->ctx;
+
+	startxref = ftell(opts->out);
+
+	fprintf(opts->out, "xref\n0 %d\n", xref->len);
+	for (num = 0; num < xref->len; num++)
+	{
+		if (opts->uselist[num])
+			fprintf(opts->out, "%010d %05d n \n", opts->ofslist[num], opts->genlist[num]);
+		else
+			fprintf(opts->out, "%010d %05d f \n", opts->ofslist[num], opts->genlist[num]);
+	}
+	fprintf(opts->out, "\n");
+
+	trailer = pdf_new_dict(ctx, 5);
+
+	obj = pdf_new_int(ctx, xref->len);
+	pdf_dict_puts(trailer, "Size", obj);
+	pdf_drop_obj(obj);
+
+	obj = pdf_dict_gets(xref->trailer, "Info");
+	if (obj)
+		pdf_dict_puts(trailer, "Info", obj);
+
+	obj = pdf_dict_gets(xref->trailer, "Root");
+	if (obj)
+		pdf_dict_puts(trailer, "Root", obj);
+
+	obj = pdf_dict_gets(xref->trailer, "ID");
+	if (obj)
+		pdf_dict_puts(trailer, "ID", obj);
+
+	fprintf(opts->out, "trailer\n");
+	pdf_fprint_obj(opts->out, trailer, opts->doexpand == 0);
+	fprintf(opts->out, "\n");
+
+	pdf_drop_obj(trailer);
+
+	fprintf(opts->out, "startxref\n%d\n%%%%EOF\n", startxref);
+}
+
+void pdf_write(pdf_document *xref, char *filename, fz_write_options *fz_opts)
+{
+	int lastfree;
+	int num;
+	pdf_write_options opts = { 0 };
+	fz_context *ctx;
+
+	if (!xref || !fz_opts)
+		return;
+
+	ctx = xref->ctx;
+
+	opts.out = fopen(filename, "wb");
+	if (!opts.out)
+		fz_throw(ctx, "cannot open output file '%s'", filename);
+
+	fz_try(ctx)
+	{
+		opts.doexpand = fz_opts ? fz_opts->doexpand : 0;
+		opts.dogarbage = fz_opts ? fz_opts->dogarbage : 0;
+		opts.doascii = fz_opts ? fz_opts->doascii: 0;
+		opts.uselist = fz_malloc_array(ctx, xref->len + 1, sizeof(char));
+		opts.ofslist = fz_malloc_array(ctx, xref->len + 1, sizeof(int));
+		opts.genlist = fz_malloc_array(ctx, xref->len + 1, sizeof(int));
+		opts.renumbermap = fz_malloc_array(ctx, xref->len + 1, sizeof(int));
+
+		fprintf(opts.out, "%%PDF-%d.%d\n", xref->version / 10, xref->version % 10);
+		fprintf(opts.out, "%%\316\274\341\277\246\n\n");
+
+		for (num = 0; num < xref->len; num++)
+		{
+			opts.uselist[num] = 0;
+			opts.ofslist[num] = 0;
+			opts.renumbermap[num] = num;
+		}
+
+		/* Make sure any objects hidden in compressed streams have been loaded */
+		preloadobjstms(xref);
+
+		/* Sweep & mark objects from the trailer */
+		if (opts.dogarbage >= 1)
+			sweepobj(xref, &opts, xref->trailer);
+
+		/* Coalesce and renumber duplicate objects */
+		if (opts.dogarbage >= 3)
+			removeduplicateobjs(xref, &opts);
+
+		/* Compact xref by renumbering and removing unused objects */
+		if (opts.dogarbage >= 2)
+			compactxref(xref, &opts);
+
+		/* Make renumbering affect all indirect references and update xref */
+		/* Do not renumber objects if encryption is in use, as the object
+		 * numbers are baked into the streams/strings, and we can't currently
+		 * cope with moving them. See bug 692627. */
+		if (opts.dogarbage >= 2 && !xref->crypt)
+			renumberobjs(xref, &opts);
+
+		for (num = 0; num < xref->len; num++)
+		{
+			if (xref->table[num].type == 'f')
+				opts.genlist[num] = xref->table[num].gen;
+			if (xref->table[num].type == 'n')
+				opts.genlist[num] = xref->table[num].gen;
+			if (xref->table[num].type == 'o')
+				opts.genlist[num] = 0;
+
+			if (opts.dogarbage && !opts.uselist[num])
+				continue;
+
+			if (xref->table[num].type == 'n' || xref->table[num].type == 'o')
+			{
+				opts.uselist[num] = 1;
+				opts.ofslist[num] = ftell(opts.out);
+				writeobject(xref, &opts, num, opts.genlist[num]);
+			}
+		}
+
+		/* Construct linked list of free object slots */
+		lastfree = 0;
+		for (num = 0; num < xref->len; num++)
+		{
+			if (!opts.uselist[num])
+			{
+				opts.genlist[num]++;
+				opts.ofslist[lastfree] = num;
+				lastfree = num;
+			}
+		}
+
+		writexref(xref, &opts);
+	}
+	fz_always(ctx)
+	{
+		fz_free(ctx, opts.uselist);
+		fz_free(ctx, opts.ofslist);
+		fz_free(ctx, opts.genlist);
+		fz_free(ctx, opts.renumbermap);
+		fclose(opts.out);
+	}
+	fz_catch(ctx)
+	{
+		fz_rethrow(ctx);
+	}
+}