shithub: pdffs

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add and use flate filter

--- /dev/null

+++ b/buffer.c

@@ -1,0 +1,121 @@

+#include <u.h>

+#include <libc.h>

+#include <bio.h>

+#include "pdf.h"

+

+static int

+bufgrow(Buffer *b, int sz)

+{

+	uchar *r;

+	int maxsz;

+

+	if(b->maxsz < 1){

+		if((b->b = mallocz(128, 1)) == nil)

+			return -1;

+		b->maxsz = 128;

+	}

+	for(maxsz = b->maxsz; b->sz+sz > maxsz; maxsz *= 2);

+	if(maxsz != b->maxsz){

+		if((r = realloc(b->b, maxsz)) == nil)

+			return -1;

+		memset(r+b->maxsz, 0, maxsz-b->maxsz);

+		b->b = r;

+		b->maxsz = maxsz;

+	}

+

+	return 0;

+}

+

+void

+bufinit(Buffer *b, uchar *d, int sz)

+{

+	memset(b, 0, sizeof(*b));

+	if(d != nil){

+		b->b = d;

+		b->sz = sz;

+		b->ro = 1;

+	}

+}

+

+void

+buffree(Buffer *b)

+{

+	if(b->ro == 0)

+		free(b->b);

+}

+

+int

+bufeof(Buffer *b)

+{

+	return b->off == b->sz;

+}

+

+uchar *

+bufdata(Buffer *b, int *sz)

+{

+	*sz = b->sz;

+	return b->b;

+}

+

+int

+bufreadn(Buffer *b, void *bio, int sz)

+{

+	int n, end;

+

+	if(bufgrow(b, sz) != 0)

+		return -1;

+	for(end = b->sz+sz; b->sz < end; b->sz += n){

+		if((n = Bread(bio, b->b+b->sz, sz)) < 1)

+			return -1;

+		sz -= n;

+	}

+	return 0;

+}

+

+int

+bufput(Buffer *b, uchar *d, int sz)

+{

+	if(b->ro)

+		sysfatal("bufferput on readonly buffer");

+	if(bufgrow(b, sz) != 0)

+		return -1;

+

+	memmove(b->b+b->sz, d, sz);

+	b->sz += sz;

+

+	return sz;

+}

+

+int

+bufget(Buffer *b, uchar *d, int sz)

+{

+	if(sz == 0)

+		return 0;

+

+	if(b->off > b->sz)

+		sysfatal("buffer: off(%d) > sz(%d)", b->off, b->sz);

+	if(sz > b->sz - b->off)

+		sz = b->sz - b->off;

+	memmove(d, b->b+b->off, sz);

+	b->off += sz;

+	b->eof = sz == 0;

+

+	return sz;

+}

+

+void

+bufdump(Buffer *b)

+{

+	Biobuf bio;

+	int i, j;

+

+	Binit(&bio, 2, OWRITE);

+	Bprint(&bio, "%d bytes:\n", b->sz);

+	for(i = 0; i < b->sz;){

+		Bprint(&bio, "%04x\t", i);

+		for(j = 0; i < b->sz && j < 16; j++, i++)

+			Bprint(&bio, "%02x%s", b->b[i], (j+1)&7 ? " " : "  ");

+		Bprint(&bio, "\n");

+	}

+	Bterm(&bio);

+}

--- a/dict.c

+++ b/dict.c

@@ -69,7 +69,7 @@

 {

 	int i;

-	if(o == nil || o->type != Odict || name == nil)

+	if(o == nil || (o->type != Ostream && o->type != Odict) || name == nil)

 		return nil;

 	for(i = 0; i < o->dict.nkv && strcmp(name, o->dict.kv[i].key) != 0; i++);

--- /dev/null

+++ b/f_flate.c

@@ -1,0 +1,38 @@

+#include <u.h>

+#include <libc.h>

+#include <bio.h>

+#include <flate.h>

+#include "pdf.h"

+

+static int

+bw(void *aux, void *d, int n)

+{

+	return bufput(aux, d, n);

+}

+

+static int

+bget(void *aux)

+{

+	uchar c;

+

+	return bufget(aux, &c, 1) == 1 ? c : -1;

+}

+

+int

+fFlate(void *aux, Buffer *bi, Buffer *bo)

+{

+	int r;

+

+	USED(aux);

+

+	do{

+		r = inflatezlib(bo, bw, bi, bget);

+	}while(r == FlateOk && !bufeof(bi));

+

+	if(r != FlateOk){

+		werrstr("%s", flateerr(r));

+		return -1;

+	}

+

+	return 0;

+}

--- a/filter.c

+++ b/filter.c

@@ -3,17 +3,72 @@

 #include <bio.h>

 #include "pdf.h"

-/*

-7.4

+/* 7.4 Filters */

-ASCIIHex

-ASCII85

-LZW

-Flate

-RunLength

-CCITTFax

-JBIG2

-DCT

-JPX

-Crypt

-*/

+struct Filter {

+	char *name;

+	int (*readall)(void *aux, Buffer *bi, Buffer *bo);

+	int (*open)(Filter *f, Object *o);

+	void (*close)(Filter *f);

+	void *aux;

+};

+

+int fFlate(void *aux, Buffer *bi, Buffer *bo);

+

+static Filter filters[] = {

+	{"ASCII85Decode", nil, nil, nil},

+	{"ASCIIHexDecode", nil, nil, nil},

+	{"CCITTFaxDecode", nil, nil, nil},

+	{"CryptDecode", nil, nil, nil},

+	{"DCTDecode", nil, nil, nil},

+	{"FlateDecode", fFlate},

+	{"JBIG2Decode", nil, nil, nil},

+	{"JPXDecode", nil, nil, nil},

+	{"LZWDecode", nil, nil, nil},

+	{"RunLengthDecode", nil, nil, nil},

+};

+

+Filter *

+filteropen(char *name, Object *o)

+{

+	int i;

+	Filter *f;

+

+	for(i = 0; i < nelem(filters) && strcmp(filters[i].name, name) != 0; i++);

+	if(i >= nelem(filters)){

+		werrstr("no such filter %q", name);

+		return nil;

+	}

+	if(filters[i].readall == nil){

+		werrstr("filter %q not implemented", name);

+		return nil;

+	}

+	if((f = malloc(sizeof(*f))) == nil)

+		return nil;

+	memmove(f, &filters[i], sizeof(*f));

+	if(f->open != nil && f->open(f, o) != 0){

+		free(f);

+		return nil;

+	}

+

+	return f;

+}

+

+int

+filterrun(Filter *f, Buffer *bi, Buffer *bo)

+{

+	if(f->readall(f->aux, bi, bo) != 0){

+		werrstr("filter[%s]: %r", f->name);

+		return -1;

+	}

+	fprint(2, "filter[%s]: %d → %d %d\n", f->name, bi->sz, bo->sz, bo->off);

+	return 0;

+}

+

+void

+filterclose(Filter *f)

+{

+	if(f->close != nil)

+		f->close(f);

+	free(f);

+}

--- a/main.c

+++ b/main.c

@@ -22,7 +22,7 @@

 	Object *v;

 	quotefmtinstall();

-	deflateinit();

+	inflateinit();

 	ARGBEGIN{

 	default:

--- a/mkfile

+++ b/mkfile

@@ -5,8 +5,10 @@

 OFILES=\

 	array.$O\

+	buffer.$O\

 	dict.$O\

 	eval.$O\

+	f_flate.$O\

 	filter.$O\

 	main.$O\

 	misc.$O\

@@ -14,6 +16,7 @@

 	object.$O\

 	pdf.$O\

 	pdfs.$O\

+	stream.$O\

 	string.$O\

 HFILES=\

--- a/object.c

+++ b/object.c

@@ -13,6 +13,31 @@

 	.type = Onull,

 };

+static char *otypes[] = {

+	[Obool] = "bool",

+	[Onum] = "num",

+	[Ostr] = "str",

+	[Oname] = "name",

+	[Oarray] = "array",

+	[Odict] = "dict",

+	[Ostream] = "stream",

+	[Onull] = "null",

+	[Oindir] = "indir",

+};

+

+int

+Tfmt(Fmt *f)

+{

+	Object *o;

+

+	o = va_arg(f->args, Object*);

+	if(o == nil || o == &null)

+		return fmtprint(f, "null");

+	if(o->type < 0 || o->type >= nelem(otypes))

+		return fmtprint(f, "????");

+	return fmtprint(f, "%s", otypes[o->type]);

+}

+

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

 Object *

 pdfobj(Pdf *pdf, void *b)

@@ -49,8 +74,8 @@

 						goto err;

 					}

 					o->type = Ostream;

-					o->stream.length = m->num;

-					o->stream.offset = Boffset(b);

+					o->stream.len = m->num;

+					o->stream.off = Boffset(b);

 					return o;

 				}

 				Bseek(b, off, 0);

--- a/pdf.c

+++ b/pdf.c

@@ -75,9 +75,7 @@

 static int

 trailerread(Pdf *pdf)

 {

-	int i;

 	Object *o;

-	KeyValue *kv;

 	if((o = pdfobj(pdf, pdf->bio)) == nil)

 		goto err;

@@ -87,12 +85,8 @@

 		goto err;

 	}

-	for(i = 0, kv = o->dict.kv; i < o->dict.nkv; i++, kv++){

-		if(strcmp(kv->key, "Root") == 0)

-			pdf->root = kv->value;

-		else if(strcmp(kv->key, "Info") == 0)

-			pdf->info = kv->value;

-	}

+	pdf->root = pdfdictget(o, "Root");

+	pdf->info = pdfdictget(o, "Info");

 	pdfobjfree(o);

 	o = nil;

@@ -101,8 +95,6 @@

 		werrstr("no root");

 		goto err;

 	}

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

-		goto err;

 	return 0;

 err:

@@ -121,7 +113,10 @@

 	int nxref; /* 7.5.4 xref subsection number of objects */

 	int xreftb; /* 7.5.4 xref table offset from the beginning of the file */

 	int i, n, off;

+	Stream *stream;

+	fmtinstall('T', Tfmt);

+

 	b = nil;

 	o = nil;

 	if((pdf = calloc(1, sizeof(*pdf))) == nil || (b = Bfdopen(fd, OREAD)) == nil)

@@ -196,10 +191,16 @@

 		}

 	}else if(isdigit(tmp[0])){ /* could be 7.5.8 xref stream (since PDF 1.5) */

 		Bseek(b, xreftb, 0);

-		if((o = pdfobj(pdf, b)) == nil || pdfeval(pdf, o) != 0)

-			goto err;

-		

+		if((o = pdfobj(pdf, b)) == nil || (stream = streamopen(pdf, o)) == nil)

+			goto badxref;

+		streamclose(stream);

+		pdf->root = pdfdictget(o, "Root");

+		pdf->info = pdfdictget(o, "Info");

 	}

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

+		goto err;

+	fprint(2, "root %T\n", pdf->root);

+	fprint(2, "info %T\n", pdf->info);

 	return pdf;

 err:

--- a/pdf.h

+++ b/pdf.h

@@ -10,12 +10,24 @@

 	Oindir,  /* 7.3.10 */

 };

+typedef struct Buffer Buffer;

+typedef struct Filter Filter;

 typedef struct KeyValue KeyValue;

 typedef struct Object Object;

 typedef struct Pdf Pdf;

-typedef struct Xref Xref;

 typedef struct Stream Stream;

+typedef struct Xref Xref;

+#pragma incomplete Filter

+struct Buffer {

+	uchar *b;

+	int ro;

+	int maxsz;

+	int sz;

+	int off;

+	int eof;

+};

+

 struct Object {

 	int type;

 	union {

@@ -45,8 +57,8 @@

 		struct {

 			KeyValue *kv;

 			int nkv;

-			u32int length; /* packed */

-			u32int offset;

+			u32int len; /* packed */

+			u32int off;

 		}stream;

 	};

 };

@@ -72,9 +84,8 @@

 };

 struct Stream {

-	Biobuf;

-	Object *o;

-	u32int offset;

+	Buffer buf;

+	void *bio;

 };

 Pdf *pdfopen(int fd);

@@ -96,3 +107,19 @@

 Stream *streamopen(Pdf *pdf, Object *o);

 void streamclose(Stream *s);

+

+Filter *filteropen(char *name, Object *o);

+int filterrun(Filter *f, Buffer *bi, Buffer *bo);

+void filterclose(Filter *f);

+

+void bufinit(Buffer *b, uchar *d, int sz);

+void buffree(Buffer *b);

+int bufeof(Buffer *b);

+uchar *bufdata(Buffer *b, int *sz);

+int bufreadn(Buffer *b, void *bio, int sz);

+int bufput(Buffer *b, uchar *d, int sz);

+int bufget(Buffer *b, uchar *d, int sz);

+void bufdump(Buffer *b);

+

+#pragma varargck type "T" Object *

+int Tfmt(Fmt *f);

--- /dev/null

+++ b/stream.c

@@ -1,0 +1,93 @@

+#include <u.h>

+#include <libc.h>

+#include <bio.h>

+#include "pdf.h"

+

+static int

+bufiof(Biobufhdr *b, void *data, long n)

+{

+	Stream *s;

+

+	s = (void*)((char*)b - sizeof(*s));

+

+	return bufget(&s->buf, data, n);

+}

+

+Stream *

+streamopen(Pdf *pdf, Object *o)

+{

+	Stream *s;

+	Buffer b, x;

+	Object *of, **flts;

+	Filter *f;

+	int i, nflts;

+

+	s = nil;

+	if(pdfeval(pdf, o) != 0 || o == nil || o->type != Ostream) /* FIXME open a string object as a stream as well? */

+		return nil;

+

+	bufinit(&b, nil, 0);

+	if(Bseek(pdf->bio, o->stream.off, 0) != o->stream.off)

+		return nil;

+	if(bufreadn(&b, pdf->bio, o->stream.len) < 0)

+		goto err;

+	bufdump(&b);

+

+	/* see if there are any filters */

+	if((of = pdfdictget(o, "Filter")) != nil){

+		if(pdfeval(pdf, of) != 0)

+			goto err;

+		if(of->type == Oname){ /* one filter */

+			flts = &of;

+			nflts = 1;

+		}else if(of->type == Oarray){ /* array of filters */

+			flts = of->array.e;

+			nflts = of->array.ne;

+		}else{

+			werrstr("filters type invalid (%T)", of);

+			goto err;

+		}

+

+		for(i = nflts-1; i >= 0; i--){

+			if(flts[i]->type != Oname){

+				werrstr("filter type invalid (%T)", flts[i]);

+				goto err;

+			}

+			if((f = filteropen(flts[i]->name, o)) == nil)

+				goto err;

+			bufinit(&x, nil, 0);

+			if(filterrun(f, &b, &x) != 0){

+				buffree(&x);

+				goto err;

+			}

+			buffree(&b);

+			b = x;

+		}

+	}

+

+	if((s = calloc(1, sizeof(*s)+sizeof(Biobuf))) == nil){

+		buffree(&b);

+		return nil;

+	}

+	s->bio = (uchar*)(s+1);

+	s->buf = b;

+	Binit(s->bio, Bfildes(pdf->bio), OREAD);

+	Biofn(s->bio, bufiof);

+

+	bufdump(&s->buf);

+

+	return s;

+err:

+	werrstr("stream: %r");

+	buffree(&b);

+	free(s);

+	return nil;

+}

+

+void

+streamclose(Stream *s)

+{

+	buffree(&s->buf);

+	Bterm(s->bio);

+	free(s);

+}