shithub: pdffs

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fix xref parsing and add pdfeval to resolve indirect objects

--- /dev/null

+++ b/eval.c

@@ -1,0 +1,23 @@

+#include <u.h>

+#include <libc.h>

+#include "pdf.h"

+

+int

+pdfeval(Pdf *pdf, Object *o)

+{

+	Xref *x;

+	int i;

+

+	if(o->type != Oindir)

+		return 0;

+

+	for(i = 0; i < pdf->nxref; i++){

+		x = &pdf->xref[i];

+		if(x->id == o->indir.id)

+			return 0;

+	}

+

+	werrstr("no object id %d in xref", o->indir.id);

+

+	return -1;

+}

--- a/mkfile

+++ b/mkfile

@@ -6,6 +6,7 @@

 OFILES=\

 	array.$O\

 	dict.$O\

+	eval.$O\

 	filter.$O\

 	main.$O\

 	misc.$O\

--- a/object.c

+++ b/object.c

@@ -8,7 +8,7 @@

 {

 	Object *o;

 	char *s, *p0;

-	int sz;

+	int sz, gen;

 	o = nil;

 	for(; len > 0 && isws(*p); p++, len--);

@@ -60,7 +60,7 @@

 	default:

 		if(isdigit(*p)){

-			if((o = malloc(sizeof(*o)+sz+1)) != nil){

+			if((o = malloc(sizeof(*o))) != nil){

 				o->type = Onum;

 				o->num = strtod(p, e);

 				sz = len - (*e - p);

@@ -68,16 +68,16 @@

 				s = p0;

 				for(; sz > 0 && isws(*s); s++, sz--);

 				if(sz > 0 && isdigit(*s)){

-					strtod(s, &p);

+					gen = strtod(s, &p);

 					sz -= (p - s);

 					s = p;

 					for(; sz > 0 && isws(*s); s++, sz--);

 					if(sz > 0 && *s == 'R'){ /* indirect object */

-						sz--;

 						s++;

 						o->type = Oindir;

+						o->indir.id = o->num;

+						o->indir.gen = gen;

 						p0 = s;

-						len = sz;

 					}

 				}

 				*e = p0;

--- a/pdf.c

+++ b/pdf.c

@@ -37,7 +37,7 @@

 			werrstr("invalid xref line");

 			goto err;

 		}

-		xref.id = xref0 + nxref;

+		xref.id = xref0 + i;

 		xref.off = strtoul(e, nil, 10);

 		/* search in already existing xrefs, update if found */

@@ -101,13 +101,13 @@

 	freeobject(o);

 	o = nil;

-	/* root is required */

+	/* root is required, info is optional */

 	if(pdf->root == nil){

 		werrstr("no root");

 		goto err;

 	}

-

-	/* info is optional */

+	if(pdfeval(pdf, pdf->root) != 0 || pdfeval(pdf, pdf->info) != 0)

+		goto err;

 	return 0;

 err:

--- a/pdf.h

+++ b/pdf.h

@@ -24,8 +24,8 @@

 		char *name;

 		struct {

-			int id;

-			int gen;

+			u32int id;

+			u16int gen;

 		}indir;

 		struct {

@@ -57,12 +57,17 @@

 struct Xref {

 	u32int id;

 	u32int off;

+	u16int gen;

 };

 Pdf *pdfopen(int fd);

 void pdfclose(Pdf *pdf);

+/*

+ * General function to parse an object of any type.

+ */

 Object *pdfobject(char *p, char **e, int len);

+

 void freeobject(Object *o);

 /*

@@ -91,6 +96,12 @@

  * 7.3.7 Dictionary Objects

  */

 Object *pdfdict(char *p, char **e, int len);

+

+/*

+ * If the object is indirect, resolve it. Operation is not recursive, ie

+ * values of a dictionary won't be resolved automatically.

+ */

+int pdfeval(Pdf *pdf, Object *o);

 int isws(char c);

 int isdelim(char c);