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#include "mupdf/pdf.h"
/*
* Check if an object is a stream or not.
*/
int
pdf_is_stream(pdf_document *doc, int num, int gen)
{
pdf_xref_entry *entry;
if (num < 0 || num >= pdf_xref_len(doc))
return 0;
pdf_cache_object(doc, num, gen);
entry = pdf_get_xref_entry(doc, num);
return entry->stm_ofs != 0 || entry->stm_buf;
}
/*
* Scan stream dictionary for an explicit /Crypt filter
*/
static int
pdf_stream_has_crypt(fz_context *ctx, pdf_obj *stm)
{
pdf_obj *filters;
pdf_obj *obj;
int i;
filters = pdf_dict_getsa(stm, "Filter", "F");
if (filters)
{
if (!strcmp(pdf_to_name(filters), "Crypt"))
return 1;
if (pdf_is_array(filters))
{
int n = pdf_array_len(filters);
for (i = 0; i < n; i++)
{
obj = pdf_array_get(filters, i);
if (!strcmp(pdf_to_name(obj), "Crypt"))
return 1;
}
}
}
return 0;
}
static fz_jbig2_globals *
pdf_load_jbig2_globals(pdf_document *doc, pdf_obj *dict)
{
fz_jbig2_globals *globals;
fz_context *ctx = doc->ctx;
fz_buffer *buf = NULL;
fz_var(buf);
if ((globals = pdf_find_item(ctx, fz_free_jbig2_globals_imp, dict)) != NULL)
{
return globals;
}
fz_try(ctx)
{
buf = pdf_load_stream(doc, pdf_to_num(dict), pdf_to_gen(dict));
globals = fz_load_jbig2_globals(ctx, buf->data, buf->len);
pdf_store_item(ctx, dict, globals, buf->len);
}
fz_always(ctx)
{
fz_drop_buffer(ctx, buf);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
return globals;
}
/*
* Create a filter given a name and param dictionary.
*/
static fz_stream *
build_filter(fz_stream *chain, pdf_document *doc, pdf_obj *f, pdf_obj *p, int num, int gen, fz_compression_params *params)
{
fz_context *ctx = chain->ctx;
char *s = pdf_to_name(f);
int predictor = pdf_to_int(pdf_dict_gets(p, "Predictor"));
pdf_obj *columns_obj = pdf_dict_gets(p, "Columns");
int columns = pdf_to_int(columns_obj);
int colors = pdf_to_int(pdf_dict_gets(p, "Colors"));
int bpc = pdf_to_int(pdf_dict_gets(p, "BitsPerComponent"));
if (!strcmp(s, "ASCIIHexDecode") || !strcmp(s, "AHx"))
return fz_open_ahxd(chain);
else if (!strcmp(s, "ASCII85Decode") || !strcmp(s, "A85"))
return fz_open_a85d(chain);
else if (!strcmp(s, "CCITTFaxDecode") || !strcmp(s, "CCF"))
{
pdf_obj *k = pdf_dict_gets(p, "K");
pdf_obj *eol = pdf_dict_gets(p, "EndOfLine");
pdf_obj *eba = pdf_dict_gets(p, "EncodedByteAlign");
pdf_obj *rows = pdf_dict_gets(p, "Rows");
pdf_obj *eob = pdf_dict_gets(p, "EndOfBlock");
pdf_obj *bi1 = pdf_dict_gets(p, "BlackIs1");
if (params)
{
/* We will shortstop here */
params->type = FZ_IMAGE_FAX;
params->u.fax.k = (k ? pdf_to_int(k) : 0);
params->u.fax.end_of_line = (eol ? pdf_to_bool(eol) : 0);
params->u.fax.encoded_byte_align = (eba ? pdf_to_bool(eba) : 0);
params->u.fax.columns = (columns_obj ? columns : 1728);
params->u.fax.rows = (rows ? pdf_to_int(rows) : 0);
params->u.fax.end_of_block = (eob ? pdf_to_bool(eob) : 1);
params->u.fax.black_is_1 = (bi1 ? pdf_to_bool(bi1) : 0);
return chain;
}
return fz_open_faxd(chain,
k ? pdf_to_int(k) : 0,
eol ? pdf_to_bool(eol) : 0,
eba ? pdf_to_bool(eba) : 0,
columns_obj ? columns : 1728,
rows ? pdf_to_int(rows) : 0,
eob ? pdf_to_bool(eob) : 1,
bi1 ? pdf_to_bool(bi1) : 0);
}
else if (!strcmp(s, "DCTDecode") || !strcmp(s, "DCT"))
{
pdf_obj *ct = pdf_dict_gets(p, "ColorTransform");
if (params)
{
/* We will shortstop here */
params->type = FZ_IMAGE_JPEG;
params->u.jpeg.color_transform = (ct ? pdf_to_int(ct) : -1);
return chain;
}
return fz_open_dctd(chain, ct ? pdf_to_int(ct) : -1, 0, NULL);
}
else if (!strcmp(s, "RunLengthDecode") || !strcmp(s, "RL"))
{
if (params)
{
/* We will shortstop here */
params->type = FZ_IMAGE_RLD;
return chain;
}
return fz_open_rld(chain);
}
else if (!strcmp(s, "FlateDecode") || !strcmp(s, "Fl"))
{
if (params)
{
/* We will shortstop here */
params->type = FZ_IMAGE_FLATE;
params->u.flate.predictor = predictor;
params->u.flate.columns = columns;
params->u.flate.colors = colors;
params->u.flate.bpc = bpc;
return chain;
}
chain = fz_open_flated(chain);
if (predictor > 1)
chain = fz_open_predict(chain, predictor, columns, colors, bpc);
return chain;
}
else if (!strcmp(s, "LZWDecode") || !strcmp(s, "LZW"))
{
pdf_obj *ec = pdf_dict_gets(p, "EarlyChange");
if (params)
{
/* We will shortstop here */
params->type = FZ_IMAGE_LZW;
params->u.lzw.predictor = predictor;
params->u.lzw.columns = columns;
params->u.lzw.colors = colors;
params->u.lzw.bpc = bpc;
params->u.lzw.early_change = (ec ? pdf_to_int(ec) : 1);
return chain;
}
chain = fz_open_lzwd(chain, ec ? pdf_to_int(ec) : 1);
if (predictor > 1)
chain = fz_open_predict(chain, predictor, columns, colors, bpc);
return chain;
}
else if (!strcmp(s, "JBIG2Decode"))
{
fz_jbig2_globals *globals = NULL;
pdf_obj *obj = pdf_dict_gets(p, "JBIG2Globals");
if (pdf_is_indirect(obj))
globals = pdf_load_jbig2_globals(doc, obj);
/* fz_open_jbig2d takes possession of globals */
return fz_open_jbig2d(chain, globals);
}
else if (!strcmp(s, "JPXDecode"))
return chain; /* JPX decoding is special cased in the image loading code */
else if (!strcmp(s, "Crypt"))
{
pdf_obj *name;
if (!doc->crypt)
{
fz_warn(ctx, "crypt filter in unencrypted document");
return chain;
}
name = pdf_dict_gets(p, "Name");
if (pdf_is_name(name))
return pdf_open_crypt_with_filter(chain, doc->crypt, pdf_to_name(name), num, gen);
return chain;
}
fz_warn(ctx, "unknown filter name (%s)", s);
return chain;
}
/*
* Build a chain of filters given filter names and param dicts.
* If head is given, start filter chain with it.
* Assume ownership of head.
*/
static fz_stream *
build_filter_chain(fz_stream *chain, pdf_document *doc, pdf_obj *fs, pdf_obj *ps, int num, int gen, fz_compression_params *params)
{
pdf_obj *f;
pdf_obj *p;
int i, n;
n = pdf_array_len(fs);
for (i = 0; i < n; i++)
{
f = pdf_array_get(fs, i);
p = pdf_array_get(ps, i);
chain = build_filter(chain, doc, f, p, num, gen, (i == n-1 ? params : NULL));
}
return chain;
}
/*
* Build a filter for reading raw stream data.
* This is a null filter to constrain reading to the stream length (and to
* allow for other people accessing the file), followed by a decryption
* filter.
*
* orig_num and orig_gen are used purely to seed the encryption.
*/
static fz_stream *
pdf_open_raw_filter(fz_stream *chain, pdf_document *doc, pdf_obj *stmobj, int num, int orig_num, int orig_gen, int offset)
{
fz_context *ctx = chain->ctx;
int hascrypt;
int len;
if (num > 0 && num < pdf_xref_len(doc))
{
pdf_xref_entry *entry = pdf_get_xref_entry(doc, num);
if (entry->stm_buf)
return fz_open_buffer(ctx, entry->stm_buf);
}
/* don't close chain when we close this filter */
fz_keep_stream(chain);
len = pdf_to_int(pdf_dict_gets(stmobj, "Length"));
chain = fz_open_null(chain, len, offset);
hascrypt = pdf_stream_has_crypt(ctx, stmobj);
if (doc->crypt && !hascrypt)
chain = pdf_open_crypt(chain, doc->crypt, orig_num, orig_gen);
return chain;
}
/*
* Construct a filter to decode a stream, constraining
* to stream length and decrypting.
*/
static fz_stream *
pdf_open_filter(fz_stream *chain, pdf_document *doc, pdf_obj *stmobj, int num, int gen, int offset, fz_compression_params *imparams)
{
pdf_obj *filters;
pdf_obj *params;
filters = pdf_dict_getsa(stmobj, "Filter", "F");
params = pdf_dict_getsa(stmobj, "DecodeParms", "DP");
chain = pdf_open_raw_filter(chain, doc, stmobj, num, num, gen, offset);
fz_var(chain);
fz_try(doc->ctx)
{
if (pdf_is_name(filters))
{
fz_stream *chain2 = chain;
chain = NULL;
chain = build_filter(chain2, doc, filters, params, num, gen, imparams);
}
else if (pdf_array_len(filters) > 0)
{
fz_stream *chain2 = chain;
chain = NULL;
chain = build_filter_chain(chain2, doc, filters, params, num, gen, imparams);
}
}
fz_catch(doc->ctx)
{
fz_close(chain);
fz_rethrow(doc->ctx);
}
return chain;
}
/*
* Construct a filter to decode a stream, without
* constraining to stream length, and without decryption.
*/
fz_stream *
pdf_open_inline_stream(pdf_document *doc, pdf_obj *stmobj, int length, fz_stream *chain, fz_compression_params *imparams)
{
pdf_obj *filters;
pdf_obj *params;
filters = pdf_dict_getsa(stmobj, "Filter", "F");
params = pdf_dict_getsa(stmobj, "DecodeParms", "DP");
/* don't close chain when we close this filter */
fz_keep_stream(chain);
if (pdf_is_name(filters))
return build_filter(chain, doc, filters, params, 0, 0, imparams);
if (pdf_array_len(filters) > 0)
return build_filter_chain(chain, doc, filters, params, 0, 0, imparams);
return fz_open_null(chain, length, fz_tell(chain));
}
/*
* Open a stream for reading the raw (compressed but decrypted) data.
*/
fz_stream *
pdf_open_raw_stream(pdf_document *doc, int num, int gen)
{
return pdf_open_raw_renumbered_stream(doc, num, gen, num, gen);
}
fz_stream *
pdf_open_raw_renumbered_stream(pdf_document *doc, int num, int gen, int orig_num, int orig_gen)
{
pdf_xref_entry *x;
if (num < 0 || num >= pdf_xref_len(doc))
fz_throw(doc->ctx, FZ_ERROR_GENERIC, "object id out of range (%d %d R)", num, gen);
pdf_cache_object(doc, num, gen);
x = pdf_get_xref_entry(doc, num);
if (x->stm_ofs == 0)
fz_throw(doc->ctx, FZ_ERROR_GENERIC, "object is not a stream");
return pdf_open_raw_filter(doc->file, doc, x->obj, num, orig_num, orig_gen, x->stm_ofs);
}
static fz_stream *
pdf_open_image_stream(pdf_document *doc, int num, int gen, int orig_num, int orig_gen, fz_compression_params *params)
{
pdf_xref_entry *x;
if (num < 0 || num >= pdf_xref_len(doc))
fz_throw(doc->ctx, FZ_ERROR_GENERIC, "object id out of range (%d %d R)", num, gen);
pdf_cache_object(doc, num, gen);
x = pdf_get_xref_entry(doc, num);
if (x->stm_ofs == 0 && x->stm_buf == NULL)
fz_throw(doc->ctx, FZ_ERROR_GENERIC, "object is not a stream");
return pdf_open_filter(doc->file, doc, x->obj, orig_num, orig_gen, x->stm_ofs, params);
}
/*
* Open a stream for reading uncompressed data.
* Put the opened file in doc->stream.
* Using doc->file while a stream is open is a Bad idea.
*/
fz_stream *
pdf_open_stream(pdf_document *doc, int num, int gen)
{
return pdf_open_image_stream(doc, num, gen, num, gen, NULL);
}
fz_stream *
pdf_open_stream_with_offset(pdf_document *doc, int num, int gen, pdf_obj *dict, int stm_ofs)
{
if (stm_ofs == 0)
fz_throw(doc->ctx, FZ_ERROR_GENERIC, "object is not a stream");
return pdf_open_filter(doc->file, doc, dict, num, gen, stm_ofs, NULL);
}
/*
* Load raw (compressed but decrypted) contents of a stream into buf.
*/
fz_buffer *
pdf_load_raw_stream(pdf_document *doc, int num, int gen)
{
return pdf_load_raw_renumbered_stream(doc, num, gen, num, gen);
}
fz_buffer *
pdf_load_raw_renumbered_stream(pdf_document *doc, int num, int gen, int orig_num, int orig_gen)
{
fz_stream *stm;
pdf_obj *dict;
int len;
fz_buffer *buf;
if (num > 0 && num < pdf_xref_len(doc))
{
pdf_xref_entry *entry = pdf_get_xref_entry(doc, num);
if (entry->stm_buf)
return fz_keep_buffer(doc->ctx, entry->stm_buf);
}
dict = pdf_load_object(doc, num, gen);
len = pdf_to_int(pdf_dict_gets(dict, "Length"));
pdf_drop_obj(dict);
stm = pdf_open_raw_renumbered_stream(doc, num, gen, orig_num, orig_gen);
buf = fz_read_all(stm, len);
fz_close(stm);
return buf;
}
static int
pdf_guess_filter_length(int len, char *filter)
{
if (!strcmp(filter, "ASCIIHexDecode"))
return len / 2;
if (!strcmp(filter, "ASCII85Decode"))
return len * 4 / 5;
if (!strcmp(filter, "FlateDecode"))
return len * 3;
if (!strcmp(filter, "RunLengthDecode"))
return len * 3;
if (!strcmp(filter, "LZWDecode"))
return len * 2;
return len;
}
static fz_buffer *
pdf_load_image_stream(pdf_document *doc, int num, int gen, int orig_num, int orig_gen, fz_compression_params *params, int *truncated)
{
fz_context *ctx = doc->ctx;
fz_stream *stm = NULL;
pdf_obj *dict, *obj;
int i, len, n;
fz_buffer *buf;
fz_var(buf);
if (num > 0 && num < pdf_xref_len(doc))
{
pdf_xref_entry *entry = pdf_get_xref_entry(doc, num);
if (entry->stm_buf)
return fz_keep_buffer(doc->ctx, entry->stm_buf);
}
dict = pdf_load_object(doc, num, gen);
len = pdf_to_int(pdf_dict_gets(dict, "Length"));
obj = pdf_dict_gets(dict, "Filter");
len = pdf_guess_filter_length(len, pdf_to_name(obj));
n = pdf_array_len(obj);
for (i = 0; i < n; i++)
len = pdf_guess_filter_length(len, pdf_to_name(pdf_array_get(obj, i)));
pdf_drop_obj(dict);
stm = pdf_open_image_stream(doc, num, gen, orig_num, orig_gen, params);
fz_try(ctx)
{
if (truncated)
buf = fz_read_best(stm, len, truncated);
else
buf = fz_read_all(stm, len);
}
fz_always(ctx)
{
fz_close(stm);
}
fz_catch(ctx)
{
fz_rethrow_message(ctx, "cannot read raw stream (%d %d R)", num, gen);
}
return buf;
}
/*
* Load uncompressed contents of a stream into buf.
*/
fz_buffer *
pdf_load_stream(pdf_document *doc, int num, int gen)
{
return pdf_load_image_stream(doc, num, gen, num, gen, NULL, NULL);
}
fz_buffer *
pdf_load_renumbered_stream(pdf_document *doc, int num, int gen, int orig_num, int orig_gen, int *truncated)
{
return pdf_load_image_stream(doc, num, gen, orig_num, orig_gen, NULL, truncated);
}
fz_compressed_buffer *
pdf_load_compressed_stream(pdf_document *doc, int num, int gen)
{
fz_context *ctx = doc->ctx;
fz_compressed_buffer *bc = fz_malloc_struct(ctx, fz_compressed_buffer);
fz_try(ctx)
{
bc->buffer = pdf_load_image_stream(doc, num, gen, num, gen, &bc->params, NULL);
}
fz_catch(ctx)
{
fz_free(ctx, bc);
fz_rethrow(ctx);
}
return bc;
}
static fz_stream *
pdf_open_object_array(pdf_document *doc, pdf_obj *list)
{
int i, n;
fz_context *ctx = doc->ctx;
fz_stream *stm;
n = pdf_array_len(list);
stm = fz_open_concat(ctx, n, 1);
fz_var(i); /* Workaround Mac compiler bug */
for (i = 0; i < n; i++)
{
pdf_obj *obj = pdf_array_get(list, i);
fz_try(ctx)
{
fz_concat_push(stm, pdf_open_stream(doc, pdf_to_num(obj), pdf_to_gen(obj)));
}
fz_catch(ctx)
{
fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
fz_warn(ctx, "cannot load content stream part %d/%d", i + 1, n);
continue;
}
}
return stm;
}
fz_stream *
pdf_open_contents_stream(pdf_document *doc, pdf_obj *obj)
{
fz_context *ctx = doc->ctx;
int num, gen;
if (pdf_is_array(obj))
return pdf_open_object_array(doc, obj);
num = pdf_to_num(obj);
gen = pdf_to_gen(obj);
if (pdf_is_stream(doc, num, gen))
return pdf_open_image_stream(doc, num, gen, num, gen, NULL);
fz_warn(ctx, "pdf object stream missing (%d %d R)", num, gen);
return NULL;
}
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