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|
#include "pdf-imp.h"
#include "mupdf/fitz/document.h"
#undef DEBUG_PROGESSIVE_ADVANCE
#ifdef DEBUG_PROGESSIVE_ADVANCE
#define DEBUGMESS(A) do { fz_warn A; } while (0)
#else
#define DEBUGMESS(A) do { } while (0)
#endif
static inline int iswhite(int ch)
{
return
ch == '\000' || ch == '\011' || ch == '\012' ||
ch == '\014' || ch == '\015' || ch == '\040';
}
/*
* xref tables
*/
static void pdf_drop_xref_sections(fz_context *ctx, pdf_document *doc)
{
pdf_unsaved_sig *usig;
int x, e;
for (x = 0; x < doc->num_xref_sections; x++)
{
pdf_xref *xref = &doc->xref_sections[x];
pdf_xref_subsec *sub = xref->subsec;
while (sub != NULL)
{
pdf_xref_subsec *next_sub = sub->next;
for (e = 0; e < sub->len; e++)
{
pdf_xref_entry *entry = &sub->table[e];
if (entry->obj)
{
pdf_drop_obj(ctx, entry->obj);
fz_drop_buffer(ctx, entry->stm_buf);
}
}
fz_free(ctx, sub->table);
fz_free(ctx, sub);
sub = next_sub;
}
pdf_drop_obj(ctx, xref->pre_repair_trailer);
pdf_drop_obj(ctx, xref->trailer);
while ((usig = xref->unsaved_sigs) != NULL)
{
xref->unsaved_sigs = usig->next;
pdf_drop_obj(ctx, usig->field);
pdf_drop_signer(ctx, usig->signer);
fz_free(ctx, usig);
}
}
fz_free(ctx, doc->xref_sections);
doc->xref_sections = NULL;
doc->num_xref_sections = 0;
doc->num_incremental_sections = 0;
}
static void
extend_xref_index(fz_context *ctx, pdf_document *doc, int newlen)
{
int i;
doc->xref_index = fz_resize_array(ctx, doc->xref_index, newlen, sizeof(int));
for (i = doc->max_xref_len; i < newlen; i++)
{
doc->xref_index[i] = 0;
}
doc->max_xref_len = newlen;
}
/* This is only ever called when we already have an incremental
* xref. This means there will only be 1 subsec, and it will be
* a complete subsec. */
static void pdf_resize_xref(fz_context *ctx, pdf_document *doc, int newlen)
{
int i;
pdf_xref *xref = &doc->xref_sections[doc->xref_base];
pdf_xref_subsec *sub;
assert(xref != NULL);
sub = xref->subsec;
assert(sub->next == NULL && sub->start == 0 && sub->len == xref->num_objects);
assert(newlen > xref->num_objects);
sub->table = fz_resize_array(ctx, sub->table, newlen, sizeof(pdf_xref_entry));
for (i = xref->num_objects; i < newlen; i++)
{
sub->table[i].type = 0;
sub->table[i].ofs = 0;
sub->table[i].gen = 0;
sub->table[i].num = 0;
sub->table[i].stm_ofs = 0;
sub->table[i].stm_buf = NULL;
sub->table[i].obj = NULL;
}
xref->num_objects = newlen;
sub->len = newlen;
if (doc->max_xref_len < newlen)
extend_xref_index(ctx, doc, newlen);
}
static void pdf_populate_next_xref_level(fz_context *ctx, pdf_document *doc)
{
pdf_xref *xref;
doc->xref_sections = fz_resize_array(ctx, doc->xref_sections, doc->num_xref_sections + 1, sizeof(pdf_xref));
doc->num_xref_sections++;
xref = &doc->xref_sections[doc->num_xref_sections - 1];
xref->subsec = NULL;
xref->num_objects = 0;
xref->trailer = NULL;
xref->pre_repair_trailer = NULL;
xref->unsaved_sigs = NULL;
xref->unsaved_sigs_end = NULL;
}
pdf_obj *pdf_trailer(fz_context *ctx, pdf_document *doc)
{
/* Return the document's final trailer */
pdf_xref *xref = &doc->xref_sections[0];
return xref->trailer;
}
void pdf_set_populating_xref_trailer(fz_context *ctx, pdf_document *doc, pdf_obj *trailer)
{
/* Update the trailer of the xref section being populated */
pdf_xref *xref = &doc->xref_sections[doc->num_xref_sections - 1];
if (xref->trailer)
{
pdf_drop_obj(ctx, xref->pre_repair_trailer);
xref->pre_repair_trailer = xref->trailer;
}
xref->trailer = pdf_keep_obj(ctx, trailer);
}
int pdf_xref_len(fz_context *ctx, pdf_document *doc)
{
return doc->max_xref_len;
}
/* Ensure that the given xref has a single subsection
* that covers the entire range. */
static void
ensure_solid_xref(fz_context *ctx, pdf_document *doc, int num, int which)
{
pdf_xref *xref = &doc->xref_sections[which];
pdf_xref_subsec *sub = xref->subsec;
pdf_xref_subsec *new_sub;
if (num < xref->num_objects)
num = xref->num_objects;
if (sub != NULL && sub->next == NULL && sub->start == 0 && sub->len >= num)
return;
new_sub = fz_malloc_struct(ctx, pdf_xref_subsec);
fz_try(ctx)
{
new_sub->table = fz_calloc(ctx, num, sizeof(pdf_xref_entry));
new_sub->start = 0;
new_sub->len = num;
new_sub->next = NULL;
}
fz_catch(ctx)
{
fz_free(ctx, new_sub);
fz_rethrow(ctx);
}
/* Move objects over to the new subsection and destroy the old
* ones */
sub = xref->subsec;
while (sub != NULL)
{
pdf_xref_subsec *next = sub->next;
int i;
for (i = 0; i < sub->len; i++)
{
new_sub->table[i+sub->start] = sub->table[i];
}
fz_free(ctx, sub->table);
fz_free(ctx, sub);
sub = next;
}
xref->num_objects = num;
xref->subsec = new_sub;
if (doc->max_xref_len < num)
extend_xref_index(ctx, doc, num);
}
/* Used while reading the individual xref sections from a file */
pdf_xref_entry *pdf_get_populating_xref_entry(fz_context *ctx, pdf_document *doc, int num)
{
/* Return an entry within the xref currently being populated */
pdf_xref *xref;
pdf_xref_subsec *sub;
if (doc->num_xref_sections == 0)
{
doc->xref_sections = fz_malloc_struct(ctx, pdf_xref);
doc->num_xref_sections = 1;
}
/* Prevent accidental heap underflow */
if (num < 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "object number must not be negative (%d)", num);
/* Return the pointer to the entry in the last section. */
xref = &doc->xref_sections[doc->num_xref_sections-1];
for (sub = xref->subsec; sub != NULL; sub = sub->next)
{
if (num >= sub->start && num < sub->start + sub->len)
return &sub->table[num-sub->start];
}
/* We've been asked for an object that's not in a subsec. */
ensure_solid_xref(ctx, doc, num+1, doc->num_xref_sections-1);
xref = &doc->xref_sections[doc->num_xref_sections-1];
sub = xref->subsec;
return &sub->table[num-sub->start];
}
/* Used after loading a document to access entries */
/* This will never throw anything, or return NULL if it is
* only asked to return objects in range within a 'solid'
* xref. */
pdf_xref_entry *pdf_get_xref_entry(fz_context *ctx, pdf_document *doc, int i)
{
pdf_xref *xref = NULL;
pdf_xref_subsec *sub;
int j;
if (i < 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "Negative object number requested");
if (i <= doc->max_xref_len)
j = doc->xref_index[i];
else
j = 0;
/* We may be accessing an earlier version of the document using xref_base
* and j may be an index into a later xref section */
if (doc->xref_base > j)
j = doc->xref_base;
/* Find the first xref section where the entry is defined. */
for (; j < doc->num_xref_sections; j++)
{
xref = &doc->xref_sections[j];
if (i < xref->num_objects)
{
for (sub = xref->subsec; sub != NULL; sub = sub->next)
{
pdf_xref_entry *entry;
if (i < sub->start || i >= sub->start + sub->len)
continue;
entry = &sub->table[i - sub->start];
if (entry->type)
{
/* Don't update xref_index if xref_base may have
* influenced the value of j */
if (doc->xref_base == 0)
doc->xref_index[i] = j;
return entry;
}
}
}
}
/* Didn't find the entry in any section. Return the entry from
* the final section. */
doc->xref_index[i] = 0;
if (xref == NULL || i < xref->num_objects)
{
xref = &doc->xref_sections[doc->xref_base];
for (sub = xref->subsec; sub != NULL; sub = sub->next)
{
if (i >= sub->start && i < sub->start + sub->len)
return &sub->table[i - sub->start];
}
}
/* At this point, we solidify the xref. This ensures that we
* can return a pointer. This is the only case where this function
* might throw an exception, and it will never happen when we are
* working within a 'solid' xref. */
ensure_solid_xref(ctx, doc, i+1, 0);
xref = &doc->xref_sections[0];
sub = xref->subsec;
return &sub->table[i - sub->start];
}
/*
Ensure we have an incremental xref section where we can store
updated versions of indirect objects. This is a new xref section
consisting of a single xref subsection.
*/
static void ensure_incremental_xref(fz_context *ctx, pdf_document *doc)
{
/* If there are as yet no incremental sections, or if the most recent
* one has been used to sign a signature field, then we need a new one.
* After a signing, any further document changes require a new increment */
if ((doc->num_incremental_sections == 0 || doc->xref_sections[0].unsaved_sigs != NULL)
&& !doc->disallow_new_increments)
{
pdf_xref *xref = &doc->xref_sections[0];
pdf_xref *pxref;
pdf_xref_entry *new_table = fz_calloc(ctx, xref->num_objects, sizeof(pdf_xref_entry));
pdf_xref_subsec *sub;
pdf_obj *trailer = NULL;
int i;
fz_var(trailer);
fz_try(ctx)
{
sub = fz_malloc_struct(ctx, pdf_xref_subsec);
trailer = xref->trailer ? pdf_copy_dict(ctx, xref->trailer) : NULL;
doc->xref_sections = fz_resize_array(ctx, doc->xref_sections, doc->num_xref_sections + 1, sizeof(pdf_xref));
xref = &doc->xref_sections[0];
pxref = &doc->xref_sections[1];
memmove(pxref, xref, doc->num_xref_sections * sizeof(pdf_xref));
/* xref->num_objects is already correct */
xref->subsec = sub;
xref->trailer = trailer;
xref->pre_repair_trailer = NULL;
xref->unsaved_sigs = NULL;
xref->unsaved_sigs_end = NULL;
sub->next = NULL;
sub->len = xref->num_objects;
sub->start = 0;
sub->table = new_table;
doc->num_xref_sections++;
doc->num_incremental_sections++;
}
fz_catch(ctx)
{
fz_free(ctx, new_table);
pdf_drop_obj(ctx, trailer);
fz_rethrow(ctx);
}
/* Update the xref_index */
for (i = 0; i < doc->max_xref_len; i++)
{
doc->xref_index[i]++;
}
}
}
/* Used when altering a document */
static pdf_xref_entry *pdf_get_incremental_xref_entry(fz_context *ctx, pdf_document *doc, int i)
{
pdf_xref *xref;
pdf_xref_subsec *sub;
/* Make a new final xref section if we haven't already */
ensure_incremental_xref(ctx, doc);
xref = &doc->xref_sections[doc->xref_base];
if (i >= xref->num_objects)
pdf_resize_xref(ctx, doc, i + 1);
sub = xref->subsec;
assert(sub != NULL && sub->next == NULL);
assert(i >= sub->start && i < sub->start + sub->len);
doc->xref_index[i] = 0;
return &sub->table[i - sub->start];
}
int pdf_xref_is_incremental(fz_context *ctx, pdf_document *doc, int num)
{
pdf_xref *xref = &doc->xref_sections[doc->xref_base];
pdf_xref_subsec *sub = xref->subsec;
assert(sub != NULL && sub->next == NULL && sub->len == xref->num_objects && sub->start == 0);
return num < xref->num_objects && sub->table[num].type;
}
void pdf_xref_store_unsaved_signature(fz_context *ctx, pdf_document *doc, pdf_obj *field, pdf_signer *signer)
{
pdf_xref *xref = &doc->xref_sections[0];
pdf_unsaved_sig *unsaved_sig;
/* Record details within the document structure so that contents
* and byte_range can be updated with their correct values at
* saving time */
unsaved_sig = fz_malloc_struct(ctx, pdf_unsaved_sig);
unsaved_sig->field = pdf_keep_obj(ctx, field);
unsaved_sig->signer = pdf_keep_signer(ctx, signer);
unsaved_sig->next = NULL;
if (xref->unsaved_sigs_end == NULL)
xref->unsaved_sigs_end = &xref->unsaved_sigs;
*xref->unsaved_sigs_end = unsaved_sig;
xref->unsaved_sigs_end = &unsaved_sig->next;
}
int pdf_xref_obj_is_unsaved_signature(pdf_document *doc, pdf_obj *obj)
{
int i;
for (i = 0; i < doc->num_incremental_sections; i++)
{
pdf_xref *xref = &doc->xref_sections[i];
pdf_unsaved_sig *usig;
for (usig = xref->unsaved_sigs; usig; usig = usig->next)
{
if (usig->field == obj)
return 1;
}
}
return 0;
}
/* Ensure that the current populating xref has a single subsection
* that covers the entire range. */
void pdf_ensure_solid_xref(fz_context *ctx, pdf_document *doc, int num)
{
if (doc->num_xref_sections == 0)
pdf_populate_next_xref_level(ctx, doc);
ensure_solid_xref(ctx, doc, num, doc->num_xref_sections-1);
}
/* Ensure that an object has been cloned into the incremental xref section */
void pdf_xref_ensure_incremental_object(fz_context *ctx, pdf_document *doc, int num)
{
pdf_xref_entry *new_entry, *old_entry;
pdf_xref_subsec *sub = NULL;
int i;
/* Make sure we have created an xref section for incremental updates */
ensure_incremental_xref(ctx, doc);
/* Search for the section that contains this object */
for (i = doc->xref_index[num]; i < doc->num_xref_sections; i++)
{
pdf_xref *xref = &doc->xref_sections[i];
if (num < 0 && num >= xref->num_objects)
break;
for (sub = xref->subsec; sub != NULL; sub = sub->next)
{
if (sub->start <= num && num < sub->start + sub->len && sub->table[num - sub->start].type)
break;
}
if (sub != NULL)
break;
}
/* sub == NULL implies we did not find it */
/* If we don't find it, or it's already in the incremental section, return */
if (i == 0 || sub == NULL)
return;
/* Move the object to the incremental section */
doc->xref_index[num] = 0;
old_entry = &sub->table[num - sub->start];
new_entry = pdf_get_incremental_xref_entry(ctx, doc, num);
*new_entry = *old_entry;
if (i < doc->num_incremental_sections)
{
/* old entry is incremental and may have changes.
* Better keep a copy. We must override the old entry with
* the copy because the caller may be holding a reference to
* the original and expect it to end up in the new entry */
old_entry->obj = pdf_deep_copy_obj(ctx, old_entry->obj);
}
else
{
old_entry->obj = NULL;
}
old_entry->stm_buf = NULL;
}
void pdf_replace_xref(fz_context *ctx, pdf_document *doc, pdf_xref_entry *entries, int n)
{
pdf_xref *xref = NULL;
pdf_xref_subsec *sub;
pdf_obj *trailer = pdf_keep_obj(ctx, pdf_trailer(ctx, doc));
fz_var(xref);
fz_try(ctx)
{
fz_free(ctx, doc->xref_index);
doc->xref_index = NULL; /* In case the calloc fails */
doc->xref_index = fz_calloc(ctx, n, sizeof(int));
xref = fz_malloc_struct(ctx, pdf_xref);
sub = fz_malloc_struct(ctx, pdf_xref_subsec);
/* The new table completely replaces the previous separate sections */
pdf_drop_xref_sections(ctx, doc);
sub->table = entries;
sub->start = 0;
sub->len = n;
xref->subsec = sub;
xref->num_objects = n;
xref->trailer = trailer;
trailer = NULL;
doc->xref_sections = xref;
doc->num_xref_sections = 1;
doc->num_incremental_sections = 0;
doc->xref_base = 0;
doc->disallow_new_increments = 0;
doc->max_xref_len = n;
memset(doc->xref_index, 0, sizeof(int)*doc->max_xref_len);
}
fz_catch(ctx)
{
fz_free(ctx, xref);
pdf_drop_obj(ctx, trailer);
fz_rethrow(ctx);
}
}
/*
* magic version tag and startxref
*/
static void
pdf_load_version(fz_context *ctx, pdf_document *doc)
{
char buf[20];
fz_seek(ctx, doc->file, 0, SEEK_SET);
fz_read_line(ctx, doc->file, buf, sizeof buf);
if (memcmp(buf, "%PDF-", 5) != 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot recognize version marker");
doc->version = 10 * (fz_atof(buf+5) + 0.05);
}
static void
pdf_read_start_xref(fz_context *ctx, pdf_document *doc)
{
unsigned char buf[1024];
size_t i, n;
fz_off_t t;
fz_seek(ctx, doc->file, 0, SEEK_END);
doc->file_size = fz_tell(ctx, doc->file);
t = fz_maxo(0, doc->file_size - (fz_off_t)sizeof buf);
fz_seek(ctx, doc->file, t, SEEK_SET);
n = fz_read(ctx, doc->file, buf, sizeof buf);
if (n < 9)
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot find startxref");
i = n - 9;
do
{
if (memcmp(buf + i, "startxref", 9) == 0)
{
i += 9;
while (i < n && iswhite(buf[i]))
i ++;
doc->startxref = 0;
while (i < n && buf[i] >= '0' && buf[i] <= '9')
{
if (doc->startxref >= FZ_OFF_MAX/10)
fz_throw(ctx, FZ_ERROR_GENERIC, "startxref too large");
doc->startxref = doc->startxref * 10 + (buf[i++] - '0');
}
if (doc->startxref != 0)
return;
break;
}
} while (i-- > 0);
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot find startxref");
}
static void
fz_skip_space(fz_context *ctx, fz_stream *stm)
{
do
{
int c = fz_peek_byte(ctx, stm);
if (c > 32 && c != EOF)
return;
(void)fz_read_byte(ctx, stm);
}
while (1);
}
static int fz_skip_string(fz_context *ctx, fz_stream *stm, const char *str)
{
while (*str)
{
int c = fz_peek_byte(ctx, stm);
if (c == EOF || c != *str++)
return 1;
(void)fz_read_byte(ctx, stm);
}
return 0;
}
/*
* trailer dictionary
*/
static int
pdf_xref_size_from_old_trailer(fz_context *ctx, pdf_document *doc, pdf_lexbuf *buf)
{
fz_off_t len;
char *s;
fz_off_t t;
pdf_token tok;
int c;
int size;
fz_off_t ofs;
pdf_obj *trailer = NULL;
size_t n;
fz_var(trailer);
/* Record the current file read offset so that we can reinstate it */
ofs = fz_tell(ctx, doc->file);
fz_skip_space(ctx, doc->file);
if (fz_skip_string(ctx, doc->file, "xref"))
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot find xref marker");
fz_skip_space(ctx, doc->file);
while (1)
{
c = fz_peek_byte(ctx, doc->file);
if (!(c >= '0' && c <= '9'))
break;
fz_read_line(ctx, doc->file, buf->scratch, buf->size);
s = buf->scratch;
fz_strsep(&s, " "); /* ignore ofs */
if (!s)
fz_throw(ctx, FZ_ERROR_GENERIC, "invalid range marker in xref");
len = fz_atoo(fz_strsep(&s, " "));
if (len < 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "xref range marker must be positive");
/* broken pdfs where the section is not on a separate line */
if (s && *s != '\0')
fz_seek(ctx, doc->file, -(2 + (int)strlen(s)), SEEK_CUR);
t = fz_tell(ctx, doc->file);
if (t < 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot tell in file");
/* Spec says xref entries should be 20 bytes, but it's not infrequent
* to see 19, in particular for some PCLm drivers. Cope. */
if (len > 0)
{
n = fz_read(ctx, doc->file, (unsigned char *)buf->scratch, 20);
if (n < 19)
fz_throw(ctx, FZ_ERROR_GENERIC, "malformed xref table");
if (n == 20 && buf->scratch[19] > 32)
n = 19;
}
else
n = 20;
if (len > (fz_off_t)((FZ_OFF_MAX - t) / n))
fz_throw(ctx, FZ_ERROR_GENERIC, "xref has too many entries");
fz_seek(ctx, doc->file, (fz_off_t)(t + n * len), SEEK_SET);
}
fz_try(ctx)
{
tok = pdf_lex(ctx, doc->file, buf);
if (tok != PDF_TOK_TRAILER)
fz_throw(ctx, FZ_ERROR_GENERIC, "expected trailer marker");
tok = pdf_lex(ctx, doc->file, buf);
if (tok != PDF_TOK_OPEN_DICT)
fz_throw(ctx, FZ_ERROR_GENERIC, "expected trailer dictionary");
trailer = pdf_parse_dict(ctx, doc, doc->file, buf);
size = pdf_to_int(ctx, pdf_dict_get(ctx, trailer, PDF_NAME_Size));
if (!size)
fz_throw(ctx, FZ_ERROR_GENERIC, "trailer missing Size entry");
}
fz_always(ctx)
{
pdf_drop_obj(ctx, trailer);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
fz_seek(ctx, doc->file, ofs, SEEK_SET);
return size;
}
static pdf_xref_entry *
pdf_xref_find_subsection(fz_context *ctx, pdf_document *doc, fz_off_t ofs, int len)
{
pdf_xref *xref = &doc->xref_sections[doc->num_xref_sections-1];
pdf_xref_subsec *sub;
int new_max;
/* Different cases here. Case 1) We might be asking for a
* subsection (or a subset of a subsection) that we already
* have - Just return it. Case 2) We might be asking for a
* completely new subsection - Create it and return it.
* Case 3) We might have an overlapping one - Create a 'solid'
* subsection and return that. */
/* Sanity check */
for (sub = xref->subsec; sub != NULL; sub = sub->next)
{
if (ofs >= sub->start && ofs + len <= sub->start + sub->len)
return &sub->table[ofs-sub->start]; /* Case 1 */
if (ofs + len > sub->start && ofs <= sub->start + sub->len)
break; /* Case 3 */
}
new_max = xref->num_objects;
if (new_max < ofs + len)
new_max = ofs + len;
if (sub == NULL)
{
/* Case 2 */
sub = fz_malloc_struct(ctx, pdf_xref_subsec);
fz_try(ctx)
{
sub->table = fz_calloc(ctx, len, sizeof(pdf_xref_entry));
sub->start = ofs;
sub->len = len;
sub->next = xref->subsec;
xref->subsec = sub;
}
fz_catch(ctx)
{
fz_free(ctx, sub);
fz_rethrow(ctx);
}
xref->num_objects = new_max;
if (doc->max_xref_len < new_max)
extend_xref_index(ctx, doc, new_max);
}
else
{
/* Case 3 */
ensure_solid_xref(ctx, doc, new_max, doc->num_xref_sections-1);
xref = &doc->xref_sections[doc->num_xref_sections-1];
sub = xref->subsec;
}
return &sub->table[ofs-sub->start];
}
static pdf_obj *
pdf_read_old_xref(fz_context *ctx, pdf_document *doc, pdf_lexbuf *buf)
{
fz_stream *file = doc->file;
fz_off_t ofs;
int len;
char *s;
size_t n;
pdf_token tok;
fz_off_t i;
int c;
int xref_len = pdf_xref_size_from_old_trailer(ctx, doc, buf);
pdf_xref_entry *table;
int carried;
fz_skip_space(ctx, doc->file);
if (fz_skip_string(ctx, doc->file, "xref"))
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot find xref marker");
fz_skip_space(ctx, doc->file);
while (1)
{
c = fz_peek_byte(ctx, file);
if (!(c >= '0' && c <= '9'))
break;
fz_read_line(ctx, file, buf->scratch, buf->size);
s = buf->scratch;
ofs = fz_atoo(fz_strsep(&s, " "));
len = fz_atoi(fz_strsep(&s, " "));
/* broken pdfs where the section is not on a separate line */
if (s && *s != '\0')
{
fz_warn(ctx, "broken xref section. proceeding anyway.");
fz_seek(ctx, file, -(2 + (int)strlen(s)), SEEK_CUR);
}
if (ofs < 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "out of range object num in xref: %d", (int)ofs);
/* broken pdfs where size in trailer undershoots entries in xref sections */
if (ofs + len > xref_len)
{
fz_warn(ctx, "broken xref section, proceeding anyway.");
}
table = pdf_xref_find_subsection(ctx, doc, ofs, len);
/* Xref entries SHOULD be 20 bytes long, but we see 19 byte
* ones more frequently than we'd like (e.g. PCLm drivers).
* Cope with this by 'carrying' data forward. */
carried = 0;
for (i = ofs; i < ofs + len; i++)
{
pdf_xref_entry *entry = &table[i-ofs];
n = fz_read(ctx, file, (unsigned char *) buf->scratch + carried, 20-carried);
if (n != 20-carried)
fz_throw(ctx, FZ_ERROR_GENERIC, "unexpected EOF in xref table");
n += carried;
if (!entry->type)
{
s = buf->scratch;
/* broken pdfs where line start with white space */
while (*s != '\0' && iswhite(*s))
s++;
entry->ofs = fz_atoo(s);
entry->gen = fz_atoi(s + 11);
entry->num = (int)i;
entry->type = s[17];
if (s[17] != 'f' && s[17] != 'n' && s[17] != 'o')
fz_throw(ctx, FZ_ERROR_GENERIC, "unexpected xref type: %#x (%d %d R)", s[17], entry->num, entry->gen);
/* If the last byte of our buffer isn't an EOL (or space), carry one byte forward */
carried = s[19] > 32;
if (carried)
s[0] = s[19];
}
}
if (carried)
fz_unread_byte(ctx, file);
}
tok = pdf_lex(ctx, file, buf);
if (tok != PDF_TOK_TRAILER)
fz_throw(ctx, FZ_ERROR_GENERIC, "expected trailer marker");
tok = pdf_lex(ctx, file, buf);
if (tok != PDF_TOK_OPEN_DICT)
fz_throw(ctx, FZ_ERROR_GENERIC, "expected trailer dictionary");
return pdf_parse_dict(ctx, doc, file, buf);
}
static void
pdf_read_new_xref_section(fz_context *ctx, pdf_document *doc, fz_stream *stm, fz_off_t i0, int i1, int w0, int w1, int w2)
{
pdf_xref_entry *table;
int i, n;
if (i0 < 0 || i1 < 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "negative xref stream entry index");
//if (i0 + i1 > pdf_xref_len(ctx, doc))
// fz_throw(ctx, FZ_ERROR_GENERIC, "xref stream has too many entries");
table = pdf_xref_find_subsection(ctx, doc, i0, i1);
for (i = i0; i < i0 + i1; i++)
{
pdf_xref_entry *entry = &table[i-i0];
int a = 0;
fz_off_t b = 0;
int c = 0;
if (fz_is_eof(ctx, stm))
fz_throw(ctx, FZ_ERROR_GENERIC, "truncated xref stream");
for (n = 0; n < w0; n++)
a = (a << 8) + fz_read_byte(ctx, stm);
for (n = 0; n < w1; n++)
b = (b << 8) + fz_read_byte(ctx, stm);
for (n = 0; n < w2; n++)
c = (c << 8) + fz_read_byte(ctx, stm);
if (!entry->type)
{
int t = w0 ? a : 1;
entry->type = t == 0 ? 'f' : t == 1 ? 'n' : t == 2 ? 'o' : 0;
entry->ofs = w1 ? b : 0;
entry->gen = w2 ? c : 0;
entry->num = i;
}
}
doc->has_xref_streams = 1;
}
/* Entered with file locked, remains locked throughout. */
static pdf_obj *
pdf_read_new_xref(fz_context *ctx, pdf_document *doc, pdf_lexbuf *buf)
{
fz_stream *stm = NULL;
pdf_obj *trailer = NULL;
pdf_obj *index = NULL;
pdf_obj *obj = NULL;
int num, gen;
fz_off_t ofs, stm_ofs;
int size, w0, w1, w2;
int t;
fz_var(trailer);
fz_var(stm);
fz_try(ctx)
{
ofs = fz_tell(ctx, doc->file);
trailer = pdf_parse_ind_obj(ctx, doc, doc->file, buf, &num, &gen, &stm_ofs, NULL);
}
fz_catch(ctx)
{
pdf_drop_obj(ctx, trailer);
fz_rethrow(ctx);
}
fz_try(ctx)
{
pdf_xref_entry *entry;
obj = pdf_dict_get(ctx, trailer, PDF_NAME_Size);
if (!obj)
fz_throw(ctx, FZ_ERROR_GENERIC, "xref stream missing Size entry (%d 0 R)", num);
size = pdf_to_int(ctx, obj);
obj = pdf_dict_get(ctx, trailer, PDF_NAME_W);
if (!obj)
fz_throw(ctx, FZ_ERROR_GENERIC, "xref stream missing W entry (%d R)", num);
w0 = pdf_to_int(ctx, pdf_array_get(ctx, obj, 0));
w1 = pdf_to_int(ctx, pdf_array_get(ctx, obj, 1));
w2 = pdf_to_int(ctx, pdf_array_get(ctx, obj, 2));
if (w0 < 0)
fz_warn(ctx, "xref stream objects have corrupt type");
if (w1 < 0)
fz_warn(ctx, "xref stream objects have corrupt offset");
if (w2 < 0)
fz_warn(ctx, "xref stream objects have corrupt generation");
w0 = w0 < 0 ? 0 : w0;
w1 = w1 < 0 ? 0 : w1;
w2 = w2 < 0 ? 0 : w2;
index = pdf_dict_get(ctx, trailer, PDF_NAME_Index);
stm = pdf_open_stream_with_offset(ctx, doc, num, trailer, stm_ofs);
if (!index)
{
pdf_read_new_xref_section(ctx, doc, stm, 0, size, w0, w1, w2);
}
else
{
int n = pdf_array_len(ctx, index);
for (t = 0; t < n; t += 2)
{
int i0 = pdf_to_int(ctx, pdf_array_get(ctx, index, t + 0));
int i1 = pdf_to_int(ctx, pdf_array_get(ctx, index, t + 1));
pdf_read_new_xref_section(ctx, doc, stm, i0, i1, w0, w1, w2);
}
}
entry = pdf_get_populating_xref_entry(ctx, doc, num);
entry->ofs = ofs;
entry->gen = gen;
entry->num = num;
entry->stm_ofs = stm_ofs;
pdf_drop_obj(ctx, entry->obj);
entry->obj = pdf_keep_obj(ctx, trailer);
entry->type = 'n';
}
fz_always(ctx)
{
fz_drop_stream(ctx, stm);
}
fz_catch(ctx)
{
pdf_drop_obj(ctx, trailer);
fz_rethrow(ctx);
}
return trailer;
}
static pdf_obj *
pdf_read_xref(fz_context *ctx, pdf_document *doc, fz_off_t ofs, pdf_lexbuf *buf)
{
pdf_obj *trailer;
int c;
fz_seek(ctx, doc->file, ofs, SEEK_SET);
while (iswhite(fz_peek_byte(ctx, doc->file)))
fz_read_byte(ctx, doc->file);
c = fz_peek_byte(ctx, doc->file);
if (c == 'x')
trailer = pdf_read_old_xref(ctx, doc, buf);
else if (c >= '0' && c <= '9')
trailer = pdf_read_new_xref(ctx, doc, buf);
else
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot recognize xref format");
return trailer;
}
typedef struct ofs_list_s ofs_list;
struct ofs_list_s
{
int max;
int len;
fz_off_t *list;
};
static fz_off_t
read_xref_section(fz_context *ctx, pdf_document *doc, fz_off_t ofs, pdf_lexbuf *buf, ofs_list *offsets)
{
pdf_obj *trailer = NULL;
fz_off_t xrefstmofs = 0;
fz_off_t prevofs = 0;
fz_var(trailer);
fz_try(ctx)
{
int i;
/* Avoid potential infinite recursion */
for (i = 0; i < offsets->len; i ++)
{
if (offsets->list[i] == ofs)
break;
}
if (i < offsets->len)
{
fz_warn(ctx, "ignoring xref recursion with offset %d", (int)ofs);
break;
}
if (offsets->len == offsets->max)
{
offsets->list = fz_resize_array(ctx, offsets->list, offsets->max*2, sizeof(*offsets->list));
offsets->max *= 2;
}
offsets->list[offsets->len++] = ofs;
trailer = pdf_read_xref(ctx, doc, ofs, buf);
pdf_set_populating_xref_trailer(ctx, doc, trailer);
/* FIXME: do we overwrite free entries properly? */
/* FIXME: Does this work properly with progression? */
xrefstmofs = pdf_to_offset(ctx, pdf_dict_get(ctx, trailer, PDF_NAME_XRefStm));
if (xrefstmofs)
{
if (xrefstmofs < 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "negative xref stream offset");
/*
Read the XRefStm stream, but throw away the resulting trailer. We do not
follow any Prev tag therein, as specified on Page 108 of the PDF reference
1.7
*/
pdf_drop_obj(ctx, pdf_read_xref(ctx, doc, xrefstmofs, buf));
}
/* FIXME: pdf_to_offset? */
prevofs = pdf_to_offset(ctx, pdf_dict_get(ctx, trailer, PDF_NAME_Prev));
if (prevofs < 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "negative xref stream offset for previous xref stream");
}
fz_always(ctx)
{
pdf_drop_obj(ctx, trailer);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
return prevofs;
}
static void
pdf_read_xref_sections(fz_context *ctx, pdf_document *doc, fz_off_t ofs, pdf_lexbuf *buf, int read_previous)
{
ofs_list list;
list.len = 0;
list.max = 10;
list.list = fz_malloc_array(ctx, 10, sizeof(*list.list));
fz_try(ctx)
{
while(ofs)
{
pdf_populate_next_xref_level(ctx, doc);
ofs = read_xref_section(ctx, doc, ofs, buf, &list);
if (!read_previous)
break;
}
}
fz_always(ctx)
{
fz_free(ctx, list.list);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
}
static void
pdf_prime_xref_index(fz_context *ctx, pdf_document *doc)
{
int i, j;
int *idx = doc->xref_index;
for (i = doc->num_xref_sections-1; i >= 0; i--)
{
pdf_xref *xref = &doc->xref_sections[i];
pdf_xref_subsec *subsec = xref->subsec;
while (subsec != NULL)
{
int start = subsec->start;
int end = subsec->start + subsec->len;
for (j = start; j < end; j++)
{
char t = subsec->table[j-start].type;
if (t != 0 && t != 'f')
idx[j] = i;
}
subsec = subsec->next;
}
}
}
/*
* load xref tables from pdf
*
* File locked on entry, throughout and on exit.
*/
static void
pdf_load_xref(fz_context *ctx, pdf_document *doc, pdf_lexbuf *buf)
{
int i;
int xref_len;
pdf_xref_entry *entry;
pdf_read_start_xref(ctx, doc);
pdf_read_xref_sections(ctx, doc, doc->startxref, buf, 1);
if (pdf_xref_len(ctx, doc) == 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "found xref was empty");
pdf_prime_xref_index(ctx, doc);
entry = pdf_get_xref_entry(ctx, doc, 0);
/* broken pdfs where first object is missing */
if (!entry->type)
{
entry->type = 'f';
entry->gen = 65535;
entry->num = 0;
}
/* broken pdfs where first object is not free */
else if (entry->type != 'f')
fz_warn(ctx, "first object in xref is not free");
/* broken pdfs where object offsets are out of range */
xref_len = pdf_xref_len(ctx, doc);
for (i = 0; i < xref_len; i++)
{
pdf_xref_entry *entry = pdf_get_xref_entry(ctx, doc, i);
if (entry->type == 'n')
{
/* Special case code: "0000000000 * n" means free,
* according to some producers (inc Quartz) */
if (entry->ofs == 0)
entry->type = 'f';
else if (entry->ofs <= 0 || entry->ofs >= doc->file_size)
fz_throw(ctx, FZ_ERROR_GENERIC, "object offset out of range: %d (%d 0 R)", (int)entry->ofs, i);
}
if (entry->type == 'o')
{
/* Read this into a local variable here, because pdf_get_xref_entry
* may solidify the xref, hence invalidating "entry", meaning we
* need a stashed value for the throw. */
fz_off_t ofs = entry->ofs;
if (ofs <= 0 || ofs >= xref_len || pdf_get_xref_entry(ctx, doc, ofs)->type != 'n')
fz_throw(ctx, FZ_ERROR_GENERIC, "invalid reference to an objstm that does not exist: %d (%d 0 R)", (int)ofs, i);
}
}
}
static void
pdf_load_linear(fz_context *ctx, pdf_document *doc)
{
pdf_obj *dict = NULL;
pdf_obj *hint = NULL;
pdf_obj *o;
int num, gen, lin, len;
fz_off_t stmofs;
fz_var(dict);
fz_var(hint);
fz_try(ctx)
{
pdf_xref_entry *entry;
dict = pdf_parse_ind_obj(ctx, doc, doc->file, &doc->lexbuf.base, &num, &gen, &stmofs, NULL);
if (!pdf_is_dict(ctx, dict))
fz_throw(ctx, FZ_ERROR_GENERIC, "Failed to read linearized dictionary");
o = pdf_dict_get(ctx, dict, PDF_NAME_Linearized);
if (o == NULL)
fz_throw(ctx, FZ_ERROR_GENERIC, "Failed to read linearized dictionary");
lin = pdf_to_int(ctx, o);
if (lin != 1)
fz_throw(ctx, FZ_ERROR_GENERIC, "Unexpected version of Linearized tag (%d)", lin);
len = pdf_to_int(ctx, pdf_dict_get(ctx, dict, PDF_NAME_L));
if (len != doc->file_length)
fz_throw(ctx, FZ_ERROR_GENERIC, "File has been updated since linearization");
pdf_read_xref_sections(ctx, doc, fz_tell(ctx, doc->file), &doc->lexbuf.base, 0);
doc->page_count = pdf_to_int(ctx, pdf_dict_get(ctx, dict, PDF_NAME_N));
doc->linear_page_refs = fz_resize_array(ctx, doc->linear_page_refs, doc->page_count, sizeof(pdf_obj *));
memset(doc->linear_page_refs, 0, doc->page_count * sizeof(pdf_obj*));
doc->linear_obj = dict;
doc->linear_pos = fz_tell(ctx, doc->file);
doc->linear_page1_obj_num = pdf_to_int(ctx, pdf_dict_get(ctx, dict, PDF_NAME_O));
doc->linear_page_refs[0] = pdf_new_indirect(ctx, doc, doc->linear_page1_obj_num, 0);
doc->linear_page_num = 0;
hint = pdf_dict_get(ctx, dict, PDF_NAME_H);
doc->hint_object_offset = pdf_to_int(ctx, pdf_array_get(ctx, hint, 0));
doc->hint_object_length = pdf_to_int(ctx, pdf_array_get(ctx, hint, 1));
entry = pdf_get_populating_xref_entry(ctx, doc, 0);
entry->type = 'f';
}
fz_catch(ctx)
{
pdf_drop_obj(ctx, dict);
fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
/* Drop back to non linearized reading mode */
doc->file_reading_linearly = 0;
}
}
/*
* Initialize and load xref tables.
* If password is not null, try to decrypt.
*/
static void
pdf_init_document(fz_context *ctx, pdf_document *doc)
{
pdf_obj *encrypt, *id;
pdf_obj *dict = NULL;
pdf_obj *obj;
pdf_obj *nobj = NULL;
int i, repaired = 0;
fz_var(dict);
fz_var(nobj);
fz_try(ctx)
{
pdf_load_version(ctx, doc);
doc->file_length = fz_stream_meta(ctx, doc->file, FZ_STREAM_META_LENGTH, 0, NULL);
if (doc->file_length < 0)
doc->file_length = 0;
/* Check to see if we should work in progressive mode */
if (fz_stream_meta(ctx, doc->file, FZ_STREAM_META_PROGRESSIVE, 0, NULL) > 0)
doc->file_reading_linearly = 1;
/* Try to load the linearized file if we are in progressive
* mode. */
if (doc->file_reading_linearly)
pdf_load_linear(ctx, doc);
/* If we aren't in progressive mode (or the linear load failed
* and has set us back to non-progressive mode), load normally.
*/
if (!doc->file_reading_linearly)
pdf_load_xref(ctx, doc, &doc->lexbuf.base);
}
fz_catch(ctx)
{
pdf_drop_xref_sections(ctx, doc);
fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
fz_warn(ctx, "trying to repair broken xref");
repaired = 1;
}
fz_try(ctx)
{
int hasroot, hasinfo;
if (repaired)
{
/* pdf_repair_xref may access xref_index, so reset it properly */
memset(doc->xref_index, 0, sizeof(int) * doc->max_xref_len);
pdf_repair_xref(ctx, doc);
pdf_prime_xref_index(ctx, doc);
}
encrypt = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME_Encrypt);
id = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME_ID);
if (pdf_is_dict(ctx, encrypt))
doc->crypt = pdf_new_crypt(ctx, encrypt, id);
/* Allow lazy clients to read encrypted files with a blank password */
pdf_authenticate_password(ctx, doc, "");
if (repaired)
{
int xref_len = pdf_xref_len(ctx, doc);
pdf_repair_obj_stms(ctx, doc);
hasroot = (pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME_Root) != NULL);
hasinfo = (pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME_Info) != NULL);
for (i = 1; i < xref_len; i++)
{
pdf_xref_entry *entry = pdf_get_xref_entry(ctx, doc, i);
if (entry->type == 0 || entry->type == 'f')
continue;
fz_try(ctx)
{
dict = pdf_load_object(ctx, doc, i);
}
fz_catch(ctx)
{
fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
fz_warn(ctx, "ignoring broken object (%d 0 R)", i);
continue;
}
if (!hasroot)
{
obj = pdf_dict_get(ctx, dict, PDF_NAME_Type);
if (pdf_name_eq(ctx, obj, PDF_NAME_Catalog))
{
nobj = pdf_new_indirect(ctx, doc, i, 0);
pdf_dict_put(ctx, pdf_trailer(ctx, doc), PDF_NAME_Root, nobj);
pdf_drop_obj(ctx, nobj);
nobj = NULL;
}
}
if (!hasinfo)
{
if (pdf_dict_get(ctx, dict, PDF_NAME_Creator) || pdf_dict_get(ctx, dict, PDF_NAME_Producer))
{
nobj = pdf_new_indirect(ctx, doc, i, 0);
pdf_dict_put(ctx, pdf_trailer(ctx, doc), PDF_NAME_Info, nobj);
pdf_drop_obj(ctx, nobj);
nobj = NULL;
}
}
pdf_drop_obj(ctx, dict);
dict = NULL;
}
/* ensure that strings are not used in their repaired, non-decrypted form */
if (doc->crypt)
pdf_clear_xref(ctx, doc);
}
}
fz_catch(ctx)
{
pdf_drop_obj(ctx, dict);
pdf_drop_obj(ctx, nobj);
fz_rethrow(ctx);
}
fz_try(ctx)
{
pdf_read_ocg(ctx, doc);
}
fz_catch(ctx)
{
fz_warn(ctx, "Ignoring Broken Optional Content");
}
fz_try(ctx)
{
char *version_str;
obj = pdf_dict_getl(ctx, pdf_trailer(ctx, doc), PDF_NAME_Root, PDF_NAME_Version, NULL);
version_str = pdf_to_name(ctx, obj);
if (*version_str)
{
int version = 10 * (fz_atof(version_str) + 0.05);
if (version > doc->version)
doc->version = version;
}
}
fz_catch(ctx) { }
}
static void
pdf_drop_document_imp(fz_context *ctx, pdf_document *doc)
{
int i;
fz_try(ctx)
{
fz_defer_reap_start(ctx);
/* Type3 glyphs in the glyph cache can contain pdf_obj pointers
* that we are about to destroy. Simplest solution is to bin the
* glyph cache at this point. */
fz_purge_glyph_cache(ctx);
pdf_drop_js(ctx, doc->js);
pdf_drop_xref_sections(ctx, doc);
fz_free(ctx, doc->xref_index);
pdf_drop_obj(ctx, doc->focus_obj);
fz_drop_stream(ctx, doc->file);
pdf_drop_crypt(ctx, doc->crypt);
pdf_drop_obj(ctx, doc->linear_obj);
if (doc->linear_page_refs)
{
for (i=0; i < doc->page_count; i++)
pdf_drop_obj(ctx, doc->linear_page_refs[i]);
fz_free(ctx, doc->linear_page_refs);
}
fz_free(ctx, doc->hint_page);
fz_free(ctx, doc->hint_shared_ref);
fz_free(ctx, doc->hint_shared);
fz_free(ctx, doc->hint_obj_offsets);
for (i=0; i < doc->num_type3_fonts; i++)
{
fz_decouple_type3_font(ctx, doc->type3_fonts[i], (void *)doc);
fz_drop_font(ctx, doc->type3_fonts[i]);
}
fz_free(ctx, doc->type3_fonts);
pdf_drop_ocg(ctx, doc);
pdf_drop_portfolio(ctx, doc);
pdf_empty_store(ctx, doc);
pdf_lexbuf_fin(ctx, &doc->lexbuf.base);
pdf_drop_resource_tables(ctx, doc);
for (i = 0; i < doc->orphans_count; i++)
pdf_drop_obj(ctx, doc->orphans[i]);
fz_free(ctx, doc->orphans);
}
fz_always(ctx)
{
fz_defer_reap_end(ctx);
}
fz_catch(ctx)
fz_rethrow(ctx);
}
void
pdf_drop_document(fz_context *ctx, pdf_document *doc)
{
fz_drop_document(ctx, &doc->super);
}
void
pdf_print_xref(fz_context *ctx, pdf_document *doc)
{
int i;
int xref_len = pdf_xref_len(ctx, doc);
printf("xref\n0 %d\n", xref_len);
for (i = 0; i < xref_len; i++)
{
pdf_xref_entry *entry = pdf_get_xref_entry(ctx, doc, i);
printf("%05d: %010d %05d %c (stm_ofs=%d; stm_buf=%p)\n", i,
(int)entry->ofs,
entry->gen,
entry->type ? entry->type : '-',
(int)entry->stm_ofs,
entry->stm_buf);
}
}
/*
* compressed object streams
*/
static pdf_xref_entry *
pdf_load_obj_stm(fz_context *ctx, pdf_document *doc, int num, pdf_lexbuf *buf, int target)
{
fz_stream *stm = NULL;
pdf_obj *objstm = NULL;
int *numbuf = NULL;
fz_off_t *ofsbuf = NULL;
pdf_obj *obj;
fz_off_t first;
int count;
int i;
pdf_token tok;
pdf_xref_entry *ret_entry = NULL;
fz_var(numbuf);
fz_var(ofsbuf);
fz_var(objstm);
fz_var(stm);
fz_try(ctx)
{
objstm = pdf_load_object(ctx, doc, num);
count = pdf_to_int(ctx, pdf_dict_get(ctx, objstm, PDF_NAME_N));
first = pdf_to_int(ctx, pdf_dict_get(ctx, objstm, PDF_NAME_First));
if (count < 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "negative number of objects in object stream");
if (first < 0)
fz_throw(ctx, FZ_ERROR_GENERIC, "first object in object stream resides outside stream");
numbuf = fz_calloc(ctx, count, sizeof(*numbuf));
ofsbuf = fz_calloc(ctx, count, sizeof(*ofsbuf));
stm = pdf_open_stream_number(ctx, doc, num);
for (i = 0; i < count; i++)
{
tok = pdf_lex(ctx, stm, buf);
if (tok != PDF_TOK_INT)
fz_throw(ctx, FZ_ERROR_GENERIC, "corrupt object stream (%d 0 R)", num);
numbuf[i] = buf->i;
tok = pdf_lex(ctx, stm, buf);
if (tok != PDF_TOK_INT)
fz_throw(ctx, FZ_ERROR_GENERIC, "corrupt object stream (%d 0 R)", num);
ofsbuf[i] = buf->i;
}
fz_seek(ctx, stm, first, SEEK_SET);
for (i = 0; i < count; i++)
{
int xref_len = pdf_xref_len(ctx, doc);
pdf_xref_entry *entry;
fz_seek(ctx, stm, first + ofsbuf[i], SEEK_SET);
obj = pdf_parse_stm_obj(ctx, doc, stm, buf);
if (numbuf[i] <= 0 || numbuf[i] >= xref_len)
{
pdf_drop_obj(ctx, obj);
fz_throw(ctx, FZ_ERROR_GENERIC, "object id (%d 0 R) out of range (0..%d)", numbuf[i], xref_len - 1);
}
entry = pdf_get_xref_entry(ctx, doc, numbuf[i]);
pdf_set_obj_parent(ctx, obj, numbuf[i]);
if (entry->type == 'o' && entry->ofs == num)
{
/* If we already have an entry for this object,
* we'd like to drop it and use the new one -
* but this means that anyone currently holding
* a pointer to the old one will be left with a
* stale pointer. Instead, we drop the new one
* and trust that the old one is correct. */
if (entry->obj)
{
if (pdf_objcmp(ctx, entry->obj, obj))
fz_warn(ctx, "Encountered new definition for object %d - keeping the original one", numbuf[i]);
pdf_drop_obj(ctx, obj);
}
else
{
entry->obj = obj;
fz_drop_buffer(ctx, entry->stm_buf);
entry->stm_buf = NULL;
}
if (numbuf[i] == target)
ret_entry = entry;
}
else
{
pdf_drop_obj(ctx, obj);
}
}
}
fz_always(ctx)
{
fz_drop_stream(ctx, stm);
fz_free(ctx, ofsbuf);
fz_free(ctx, numbuf);
pdf_drop_obj(ctx, objstm);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
return ret_entry;
}
/*
* object loading
*/
static int
pdf_obj_read(fz_context *ctx, pdf_document *doc, fz_off_t *offset, int *nump, pdf_obj **page)
{
pdf_lexbuf *buf = &doc->lexbuf.base;
int num, gen, tok;
fz_off_t numofs, genofs, stmofs, tmpofs, newtmpofs;
int xref_len;
pdf_xref_entry *entry;
numofs = *offset;
fz_seek(ctx, doc->file, numofs, SEEK_SET);
/* We expect to read 'num' here */
tok = pdf_lex(ctx, doc->file, buf);
genofs = fz_tell(ctx, doc->file);
if (tok != PDF_TOK_INT)
{
/* Failed! */
DEBUGMESS((ctx, "skipping unexpected data (tok=%d) at %d", tok, *offset));
*offset = genofs;
return tok == PDF_TOK_EOF;
}
*nump = num = buf->i;
/* We expect to read 'gen' here */
tok = pdf_lex(ctx, doc->file, buf);
tmpofs = fz_tell(ctx, doc->file);
if (tok != PDF_TOK_INT)
{
/* Failed! */
DEBUGMESS((ctx, "skipping unexpected data after \"%d\" (tok=%d) at %d", num, tok, *offset));
*offset = tmpofs;
return tok == PDF_TOK_EOF;
}
gen = buf->i;
/* We expect to read 'obj' here */
do
{
tmpofs = fz_tell(ctx, doc->file);
tok = pdf_lex(ctx, doc->file, buf);
if (tok == PDF_TOK_OBJ)
break;
if (tok != PDF_TOK_INT)
{
DEBUGMESS((ctx, "skipping unexpected data (tok=%d) at %d", tok, tmpofs));
*offset = fz_tell(ctx, doc->file);
return tok == PDF_TOK_EOF;
}
DEBUGMESS((ctx, "skipping unexpected int %d at %d", num, numofs));
*nump = num = gen;
numofs = genofs;
gen = buf->i;
genofs = tmpofs;
}
while (1);
/* Now we read the actual object */
xref_len = pdf_xref_len(ctx, doc);
/* When we are reading a progressive file, we typically see:
* File Header
* obj m (Linearization params)
* xref #1 (refers to objects m-n)
* obj m+1
* ...
* obj n
* obj 1
* ...
* obj n-1
* xref #2
*
* The linearisation params are read elsewhere, hence
* whenever we read an object it should just go into the
* previous xref.
*/
tok = pdf_repair_obj(ctx, doc, buf, &stmofs, NULL, NULL, NULL, page, &newtmpofs, NULL);
do /* So we can break out of it */
{
if (num <= 0 || num >= xref_len)
{
fz_warn(ctx, "Not a valid object number (%d %d obj)", num, gen);
break;
}
if (gen != 0)
{
fz_warn(ctx, "Unexpected non zero generation number in linearized file");
}
entry = pdf_get_populating_xref_entry(ctx, doc, num);
if (entry->type != 0)
{
DEBUGMESS((ctx, "Duplicate object found (%d %d obj)", num, gen));
break;
}
if (page && *page)
{
DEBUGMESS((ctx, "Successfully read object %d @ %d - and found page %d!", num, numofs, doc->linear_page_num));
if (!entry->obj)
entry->obj = pdf_keep_obj(ctx, *page);
if (doc->linear_page_refs[doc->linear_page_num] == NULL)
doc->linear_page_refs[doc->linear_page_num] = pdf_new_indirect(ctx, doc, num, gen);
}
else
{
DEBUGMESS((ctx, "Successfully read object %d @ %d", num, numofs));
}
entry->type = 'n';
entry->gen = gen; // XXX: was 0
entry->num = num;
entry->ofs = numofs;
entry->stm_ofs = stmofs;
}
while (0);
if (page && *page)
doc->linear_page_num++;
if (tok == PDF_TOK_ENDOBJ)
{
*offset = fz_tell(ctx, doc->file);
}
else
{
*offset = newtmpofs;
}
return 0;
}
static void
pdf_load_hinted_page(fz_context *ctx, pdf_document *doc, int pagenum)
{
if (!doc->hints_loaded || !doc->linear_page_refs)
return;
if (doc->linear_page_refs[pagenum])
return;
fz_try(ctx)
{
int num = doc->hint_page[pagenum].number;
pdf_obj *page = pdf_load_object(ctx, doc, num);
if (pdf_name_eq(ctx, PDF_NAME_Page, pdf_dict_get(ctx, page, PDF_NAME_Type)))
{
/* We have found the page object! */
DEBUGMESS((ctx, "LoadHintedPage pagenum=%d num=%d", pagenum, num));
doc->linear_page_refs[pagenum] = pdf_new_indirect(ctx, doc, num, 0);
}
pdf_drop_obj(ctx, page);
}
fz_catch(ctx)
{
fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
/* Silently swallow the error and proceed as normal */
}
}
static int
read_hinted_object(fz_context *ctx, pdf_document *doc, int num)
{
/* Try to find the object using our hint table. Find the closest
* object <= the one we want that has a hint and read forward from
* there. */
int expected = num;
int curr_pos;
fz_off_t start, offset;
while (doc->hint_obj_offsets[expected] == 0 && expected > 0)
expected--;
if (expected != num)
DEBUGMESS((ctx, "object %d is unhinted, will search forward from %d", expected, num));
if (expected == 0) /* No hints found, just bail */
return 0;
curr_pos = fz_tell(ctx, doc->file);
offset = doc->hint_obj_offsets[expected];
fz_var(expected);
fz_try(ctx)
{
int found;
/* Try to read forward from there */
do
{
start = offset;
DEBUGMESS((ctx, "Searching for object %d @ %d", expected, offset));
pdf_obj_read(ctx, doc, &offset, &found, 0);
DEBUGMESS((ctx, "Found object %d - next will be @ %d", found, offset));
if (found <= expected)
{
/* We found the right one (or one earlier than
* we expected). Update the hints. */
doc->hint_obj_offsets[expected] = offset;
doc->hint_obj_offsets[found] = start;
doc->hint_obj_offsets[found+1] = offset;
/* Retry with the next one */
expected = found+1;
}
else
{
/* We found one later than we expected. */
doc->hint_obj_offsets[expected] = 0;
doc->hint_obj_offsets[found] = start;
doc->hint_obj_offsets[found+1] = offset;
while (doc->hint_obj_offsets[expected] == 0 && expected > 0)
expected--;
if (expected == 0) /* No hints found, we give up */
break;
}
}
while (found != num);
}
fz_always(ctx)
{
fz_seek(ctx, doc->file, curr_pos, SEEK_SET);
}
fz_catch(ctx)
{
fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
/* FIXME: Currently we ignore the hint. Perhaps we should
* drop back to non-hinted operation here. */
doc->hint_obj_offsets[expected] = 0;
fz_rethrow(ctx);
}
return expected != 0;
}
pdf_xref_entry *
pdf_cache_object(fz_context *ctx, pdf_document *doc, int num)
{
pdf_xref_entry *x;
int rnum, rgen, try_repair;
fz_var(try_repair);
if (num <= 0 || num >= pdf_xref_len(ctx, doc))
fz_throw(ctx, FZ_ERROR_GENERIC, "object out of range (%d 0 R); xref size %d", num, pdf_xref_len(ctx, doc));
object_updated:
try_repair = 0;
rnum = num;
x = pdf_get_xref_entry(ctx, doc, num);
if (x->obj != NULL)
return x;
if (x->type == 'f')
{
x->obj = pdf_new_null(ctx, doc);
}
else if (x->type == 'n')
{
fz_seek(ctx, doc->file, x->ofs, SEEK_SET);
fz_try(ctx)
{
x->obj = pdf_parse_ind_obj(ctx, doc, doc->file, &doc->lexbuf.base,
&rnum, &rgen, &x->stm_ofs, &try_repair);
}
fz_catch(ctx)
{
if (!try_repair || fz_caught(ctx) == FZ_ERROR_TRYLATER)
fz_rethrow(ctx);
}
if (!try_repair && rnum != num)
{
pdf_drop_obj(ctx, x->obj);
x->type = 'f';
x->ofs = -1;
x->gen = 0;
x->num = 0;
x->stm_ofs = 0;
x->obj = NULL;
try_repair = (doc->repair_attempted == 0);
}
if (try_repair)
{
fz_try(ctx)
{
pdf_repair_xref(ctx, doc);
pdf_prime_xref_index(ctx, doc);
}
fz_catch(ctx)
{
if (rnum == num)
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot parse object (%d 0 R)", num);
else
fz_throw(ctx, FZ_ERROR_GENERIC, "found object (%d 0 R) instead of (%d 0 R)", rnum, num);
}
goto object_updated;
}
if (doc->crypt)
pdf_crypt_obj(ctx, doc->crypt, x->obj, x->num, x->gen);
}
else if (x->type == 'o')
{
if (!x->obj)
{
x = pdf_load_obj_stm(ctx, doc, x->ofs, &doc->lexbuf.base, num);
if (x == NULL)
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot load object stream containing object (%d 0 R)", num);
if (!x->obj)
fz_throw(ctx, FZ_ERROR_GENERIC, "object (%d 0 R) was not found in its object stream", num);
}
}
else if (doc->hint_obj_offsets && read_hinted_object(ctx, doc, num))
{
goto object_updated;
}
else if (doc->file_length && doc->linear_pos < doc->file_length)
{
fz_throw(ctx, FZ_ERROR_TRYLATER, "cannot find object in xref (%d 0 R) - not loaded yet?", num);
}
else
{
fz_throw(ctx, FZ_ERROR_GENERIC, "cannot find object in xref (%d 0 R)", num);
}
pdf_set_obj_parent(ctx, x->obj, num);
return x;
}
pdf_obj *
pdf_load_object(fz_context *ctx, pdf_document *doc, int num)
{
pdf_xref_entry *entry = pdf_cache_object(ctx, doc, num);
assert(entry->obj != NULL);
return pdf_keep_obj(ctx, entry->obj);
}
pdf_obj *
pdf_resolve_indirect(fz_context *ctx, pdf_obj *ref)
{
if (pdf_is_indirect(ctx, ref))
{
pdf_document *doc = pdf_get_indirect_document(ctx, ref);
int num = pdf_to_num(ctx, ref);
pdf_xref_entry *entry;
if (!doc)
return NULL;
if (num <= 0)
{
fz_warn(ctx, "invalid indirect reference (%d 0 R)", num);
return NULL;
}
fz_try(ctx)
entry = pdf_cache_object(ctx, doc, num);
fz_catch(ctx)
{
fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
fz_warn(ctx, "cannot load object (%d 0 R) into cache", num);
return NULL;
}
ref = entry->obj;
}
return ref;
}
pdf_obj *
pdf_resolve_indirect_chain(fz_context *ctx, pdf_obj *ref)
{
int sanity = 10;
while (pdf_is_indirect(ctx, ref))
{
if (--sanity == 0)
{
fz_warn(ctx, "too many indirections (possible indirection cycle involving %d 0 R)", pdf_to_num(ctx, ref));
return NULL;
}
ref = pdf_resolve_indirect(ctx, ref);
}
return ref;
}
int
pdf_count_objects(fz_context *ctx, pdf_document *doc)
{
return pdf_xref_len(ctx, doc);
}
int
pdf_create_object(fz_context *ctx, pdf_document *doc)
{
/* TODO: reuse free object slots by properly linking free object chains in the ofs field */
pdf_xref_entry *entry;
int num = pdf_xref_len(ctx, doc);
entry = pdf_get_incremental_xref_entry(ctx, doc, num);
entry->type = 'f';
entry->ofs = -1;
entry->gen = 0;
entry->num = num;
entry->stm_ofs = 0;
entry->stm_buf = NULL;
entry->obj = NULL;
return num;
}
void
pdf_delete_object(fz_context *ctx, pdf_document *doc, int num)
{
pdf_xref_entry *x;
if (num <= 0 || num >= pdf_xref_len(ctx, doc))
{
fz_warn(ctx, "object out of range (%d 0 R); xref size %d", num, pdf_xref_len(ctx, doc));
return;
}
x = pdf_get_incremental_xref_entry(ctx, doc, num);
fz_drop_buffer(ctx, x->stm_buf);
pdf_drop_obj(ctx, x->obj);
x->type = 'f';
x->ofs = 0;
x->gen += 1;
x->num = 0;
x->stm_ofs = 0;
x->stm_buf = NULL;
x->obj = NULL;
}
void
pdf_update_object(fz_context *ctx, pdf_document *doc, int num, pdf_obj *newobj)
{
pdf_xref_entry *x;
if (num <= 0 || num >= pdf_xref_len(ctx, doc))
{
fz_warn(ctx, "object out of range (%d 0 R); xref size %d", num, pdf_xref_len(ctx, doc));
return;
}
x = pdf_get_incremental_xref_entry(ctx, doc, num);
pdf_drop_obj(ctx, x->obj);
x->type = 'n';
x->ofs = 0;
x->obj = pdf_keep_obj(ctx, newobj);
pdf_set_obj_parent(ctx, newobj, num);
}
void
pdf_update_stream(fz_context *ctx, pdf_document *doc, pdf_obj *obj, fz_buffer *newbuf, int compressed)
{
int num;
pdf_xref_entry *x;
if (pdf_is_indirect(ctx, obj))
num = pdf_to_num(ctx, obj);
else
num = pdf_obj_parent_num(ctx, obj);
if (num <= 0 || num >= pdf_xref_len(ctx, doc))
{
fz_warn(ctx, "object out of range (%d 0 R); xref size %d", num, pdf_xref_len(ctx, doc));
return;
}
x = pdf_get_xref_entry(ctx, doc, num);
fz_drop_buffer(ctx, x->stm_buf);
x->stm_buf = fz_keep_buffer(ctx, newbuf);
pdf_dict_puts_drop(ctx, obj, "Length", pdf_new_int(ctx, doc, (int)fz_buffer_storage(ctx, newbuf, NULL)));
if (!compressed)
{
pdf_dict_dels(ctx, obj, "Filter");
pdf_dict_dels(ctx, obj, "DecodeParms");
}
}
int
pdf_lookup_metadata(fz_context *ctx, pdf_document *doc, const char *key, char *buf, int size)
{
if (!strcmp(key, "format"))
return (int)fz_snprintf(buf, size, "PDF %d.%d", doc->version/10, doc->version % 10);
if (!strcmp(key, "encryption"))
{
if (doc->crypt)
return (int)fz_snprintf(buf, size, "Standard V%d R%d %d-bit %s",
pdf_crypt_version(ctx, doc),
pdf_crypt_revision(ctx, doc),
pdf_crypt_length(ctx, doc),
pdf_crypt_method(ctx, doc));
else
return (int)fz_strlcpy(buf, "None", size);
}
if (strstr(key, "info:") == key)
{
pdf_obj *info;
char *s;
int n;
info = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME_Info);
if (!info)
return -1;
info = pdf_dict_gets(ctx, info, key + 5);
if (!info)
return -1;
s = pdf_to_utf8(ctx, info);
n = (int)fz_strlcpy(buf, s, size);
fz_free(ctx, s);
return n;
}
return -1;
}
/*
Initializers for the fz_document interface.
The functions are split across two files to allow calls to a
version of the constructor that does not link in the interpreter.
The interpreter references the built-in font and cmap resources
which are quite big. Not linking those into the mutool binary
saves roughly 6MB of space.
*/
static pdf_document *
pdf_new_document(fz_context *ctx, fz_stream *file)
{
pdf_document *doc = fz_new_document(ctx, pdf_document);
doc->super.drop_document = (fz_document_drop_fn *)pdf_drop_document_imp;
doc->super.needs_password = (fz_document_needs_password_fn *)pdf_needs_password;
doc->super.authenticate_password = (fz_document_authenticate_password_fn *)pdf_authenticate_password;
doc->super.has_permission = (fz_document_has_permission_fn *)pdf_has_permission;
doc->super.load_outline = (fz_document_load_outline_fn *)pdf_load_outline;
doc->super.resolve_link = (fz_document_resolve_link_fn *)pdf_resolve_link;
doc->super.count_pages = (fz_document_count_pages_fn *)pdf_count_pages;
doc->super.load_page = (fz_document_load_page_fn *)pdf_load_page;
doc->super.lookup_metadata = (fz_document_lookup_metadata_fn *)pdf_lookup_metadata;
doc->update_appearance = pdf_update_appearance;
pdf_lexbuf_init(ctx, &doc->lexbuf.base, PDF_LEXBUF_LARGE);
doc->file = fz_keep_stream(ctx, file);
return doc;
}
pdf_document *
pdf_open_document_with_stream(fz_context *ctx, fz_stream *file)
{
pdf_document *doc = pdf_new_document(ctx, file);
fz_try(ctx)
{
pdf_init_document(ctx, doc);
}
fz_catch(ctx)
{
fz_drop_document(ctx, &doc->super);
fz_rethrow(ctx);
}
return doc;
}
pdf_document *
pdf_open_document(fz_context *ctx, const char *filename)
{
fz_stream *file = NULL;
pdf_document *doc = NULL;
fz_var(file);
fz_var(doc);
fz_try(ctx)
{
file = fz_open_file(ctx, filename);
doc = pdf_new_document(ctx, file);
pdf_init_document(ctx, doc);
}
fz_always(ctx)
{
fz_drop_stream(ctx, file);
}
fz_catch(ctx)
{
fz_drop_document(ctx, &doc->super);
fz_rethrow(ctx);
}
return doc;
}
static void
pdf_load_hints(fz_context *ctx, pdf_document *doc, int objnum)
{
fz_stream *stream = NULL;
pdf_obj *dict;
fz_var(stream);
fz_var(dict);
fz_try(ctx)
{
int i, j, least_num_page_objs, page_obj_num_bits;
int least_page_len, page_len_num_bits, shared_hint_offset;
/* int least_page_offset, page_offset_num_bits; */
/* int least_content_stream_len, content_stream_len_num_bits; */
int num_shared_obj_num_bits, shared_obj_num_bits;
/* int numerator_bits, denominator_bits; */
int shared;
int shared_obj_num, shared_obj_offset, shared_obj_count_page1;
int shared_obj_count_total;
int least_shared_group_len, shared_group_len_num_bits;
int max_object_num = pdf_xref_len(ctx, doc);
stream = pdf_open_stream_number(ctx, doc, objnum);
dict = pdf_get_xref_entry(ctx, doc, objnum)->obj;
if (dict == NULL || !pdf_is_dict(ctx, dict))
fz_throw(ctx, FZ_ERROR_GENERIC, "malformed hint object");
shared_hint_offset = pdf_to_int(ctx, pdf_dict_get(ctx, dict, PDF_NAME_S));
/* Malloc the structures (use realloc to cope with the fact we
* may try this several times before enough data is loaded) */
doc->hint_page = fz_resize_array(ctx, doc->hint_page, doc->page_count+1, sizeof(*doc->hint_page));
memset(doc->hint_page, 0, sizeof(*doc->hint_page) * (doc->page_count+1));
doc->hint_obj_offsets = fz_resize_array(ctx, doc->hint_obj_offsets, max_object_num, sizeof(*doc->hint_obj_offsets));
memset(doc->hint_obj_offsets, 0, sizeof(*doc->hint_obj_offsets) * max_object_num);
doc->hint_obj_offsets_max = max_object_num;
/* Read the page object hints table: Header first */
least_num_page_objs = fz_read_bits(ctx, stream, 32);
/* The following is sometimes a lie, but we read this version,
* as other table values are built from it. In
* pdf_reference17.pdf, this points to 2 objects before the
* first pages page object. */
doc->hint_page[0].offset = fz_read_bits(ctx, stream, 32);
if (doc->hint_page[0].offset > doc->hint_object_offset)
doc->hint_page[0].offset += doc->hint_object_length;
page_obj_num_bits = fz_read_bits(ctx, stream, 16);
least_page_len = fz_read_bits(ctx, stream, 32);
page_len_num_bits = fz_read_bits(ctx, stream, 16);
/* least_page_offset = */ (void) fz_read_bits(ctx, stream, 32);
/* page_offset_num_bits = */ (void) fz_read_bits(ctx, stream, 16);
/* least_content_stream_len = */ (void) fz_read_bits(ctx, stream, 32);
/* content_stream_len_num_bits = */ (void) fz_read_bits(ctx, stream, 16);
num_shared_obj_num_bits = fz_read_bits(ctx, stream, 16);
shared_obj_num_bits = fz_read_bits(ctx, stream, 16);
/* numerator_bits = */ (void) fz_read_bits(ctx, stream, 16);
/* denominator_bits = */ (void) fz_read_bits(ctx, stream, 16);
/* Item 1: Page object numbers */
doc->hint_page[0].number = doc->linear_page1_obj_num;
/* We don't care about the number of objects in the first page */
(void)fz_read_bits(ctx, stream, page_obj_num_bits);
j = 1;
for (i = 1; i < doc->page_count; i++)
{
int delta_page_objs = fz_read_bits(ctx, stream, page_obj_num_bits);
doc->hint_page[i].number = j;
j += least_num_page_objs + delta_page_objs;
}
doc->hint_page[i].number = j; /* Not a real page object */
fz_sync_bits(ctx, stream);
/* Item 2: Page lengths */
j = doc->hint_page[0].offset;
for (i = 0; i < doc->page_count; i++)
{
int delta_page_len = fz_read_bits(ctx, stream, page_len_num_bits);
int old = j;
doc->hint_page[i].offset = j;
j += least_page_len + delta_page_len;
if (old <= doc->hint_object_offset && j > doc->hint_object_offset)
j += doc->hint_object_length;
}
doc->hint_page[i].offset = j;
fz_sync_bits(ctx, stream);
/* Item 3: Shared references */
shared = 0;
for (i = 0; i < doc->page_count; i++)
{
int num_shared_objs = fz_read_bits(ctx, stream, num_shared_obj_num_bits);
doc->hint_page[i].index = shared;
shared += num_shared_objs;
}
doc->hint_page[i].index = shared;
doc->hint_shared_ref = fz_resize_array(ctx, doc->hint_shared_ref, shared, sizeof(*doc->hint_shared_ref));
memset(doc->hint_shared_ref, 0, sizeof(*doc->hint_shared_ref) * shared);
fz_sync_bits(ctx, stream);
/* Item 4: Shared references */
for (i = 0; i < shared; i++)
{
int ref = fz_read_bits(ctx, stream, shared_obj_num_bits);
doc->hint_shared_ref[i] = ref;
}
/* Skip items 5,6,7 as we don't use them */
fz_seek(ctx, stream, shared_hint_offset, SEEK_SET);
/* Read the shared object hints table: Header first */
shared_obj_num = fz_read_bits(ctx, stream, 32);
shared_obj_offset = fz_read_bits(ctx, stream, 32);
if (shared_obj_offset > doc->hint_object_offset)
shared_obj_offset += doc->hint_object_length;
shared_obj_count_page1 = fz_read_bits(ctx, stream, 32);
shared_obj_count_total = fz_read_bits(ctx, stream, 32);
shared_obj_num_bits = fz_read_bits(ctx, stream, 16);
least_shared_group_len = fz_read_bits(ctx, stream, 32);
shared_group_len_num_bits = fz_read_bits(ctx, stream, 16);
/* Sanity check the references in Item 4 above to ensure we
* don't access out of range with malicious files. */
for (i = 0; i < shared; i++)
{
if (doc->hint_shared_ref[i] >= shared_obj_count_total)
{
fz_throw(ctx, FZ_ERROR_GENERIC, "malformed hint stream (shared refs)");
}
}
doc->hint_shared = fz_resize_array(ctx, doc->hint_shared, shared_obj_count_total+1, sizeof(*doc->hint_shared));
memset(doc->hint_shared, 0, sizeof(*doc->hint_shared) * (shared_obj_count_total+1));
/* Item 1: Shared references */
j = doc->hint_page[0].offset;
for (i = 0; i < shared_obj_count_page1; i++)
{
int off = fz_read_bits(ctx, stream, shared_group_len_num_bits);
int old = j;
doc->hint_shared[i].offset = j;
j += off + least_shared_group_len;
if (old <= doc->hint_object_offset && j > doc->hint_object_offset)
j += doc->hint_object_length;
}
/* FIXME: We would have problems recreating the length of the
* last page 1 shared reference group. But we'll never need
* to, so ignore it. */
j = shared_obj_offset;
for (; i < shared_obj_count_total; i++)
{
int off = fz_read_bits(ctx, stream, shared_group_len_num_bits);
int old = j;
doc->hint_shared[i].offset = j;
j += off + least_shared_group_len;
if (old <= doc->hint_object_offset && j > doc->hint_object_offset)
j += doc->hint_object_length;
}
doc->hint_shared[i].offset = j;
fz_sync_bits(ctx, stream);
/* Item 2: Signature flags: read these just so we can skip */
for (i = 0; i < shared_obj_count_total; i++)
{
doc->hint_shared[i].number = fz_read_bits(ctx, stream, 1);
}
fz_sync_bits(ctx, stream);
/* Item 3: Signatures: just skip */
for (i = 0; i < shared_obj_count_total; i++)
{
if (doc->hint_shared[i].number)
{
(void) fz_read_bits(ctx, stream, 128);
}
}
fz_sync_bits(ctx, stream);
/* Item 4: Shared object object numbers */
j = doc->linear_page1_obj_num; /* FIXME: This is a lie! */
for (i = 0; i < shared_obj_count_page1; i++)
{
doc->hint_shared[i].number = j;
j += fz_read_bits(ctx, stream, shared_obj_num_bits) + 1;
}
j = shared_obj_num;
for (; i < shared_obj_count_total; i++)
{
doc->hint_shared[i].number = j;
j += fz_read_bits(ctx, stream, shared_obj_num_bits) + 1;
}
doc->hint_shared[i].number = j;
/* Now, actually use the data we have gathered. */
for (i = 0 /*shared_obj_count_page1*/; i < shared_obj_count_total; i++)
{
doc->hint_obj_offsets[doc->hint_shared[i].number] = doc->hint_shared[i].offset;
}
for (i = 0; i < doc->page_count; i++)
{
doc->hint_obj_offsets[doc->hint_page[i].number] = doc->hint_page[i].offset;
}
}
fz_always(ctx)
{
fz_drop_stream(ctx, stream);
}
fz_catch(ctx)
{
fz_rethrow_if(ctx, FZ_ERROR_TRYLATER);
/* Don't try to load hints again */
doc->hints_loaded = 1;
/* We won't use the linearized object any more. */
doc->file_reading_linearly = 0;
/* Any other error becomes a TRYLATER */
fz_throw(ctx, FZ_ERROR_TRYLATER, "malformed hints object");
}
doc->hints_loaded = 1;
}
static void
pdf_load_hint_object(fz_context *ctx, pdf_document *doc)
{
pdf_lexbuf *buf = &doc->lexbuf.base;
fz_off_t curr_pos;
curr_pos = fz_tell(ctx, doc->file);
fz_seek(ctx, doc->file, doc->hint_object_offset, SEEK_SET);
fz_try(ctx)
{
while (1)
{
pdf_obj *page = NULL;
fz_off_t tmpofs;
int num, tok;
tok = pdf_lex(ctx, doc->file, buf);
if (tok != PDF_TOK_INT)
break;
num = buf->i;
tok = pdf_lex(ctx, doc->file, buf);
if (tok != PDF_TOK_INT)
break;
/* Ignore gen = buf->i */
tok = pdf_lex(ctx, doc->file, buf);
if (tok != PDF_TOK_OBJ)
break;
(void)pdf_repair_obj(ctx, doc, buf, &tmpofs, NULL, NULL, NULL, &page, &tmpofs, NULL);
pdf_load_hints(ctx, doc, num);
}
}
fz_always(ctx)
{
fz_seek(ctx, doc->file, curr_pos, SEEK_SET);
}
fz_catch(ctx)
{
fz_rethrow(ctx);
}
}
pdf_obj *pdf_progressive_advance(fz_context *ctx, pdf_document *doc, int pagenum)
{
pdf_lexbuf *buf = &doc->lexbuf.base;
int curr_pos;
pdf_obj *page;
pdf_load_hinted_page(ctx, doc, pagenum);
if (pagenum < 0 || pagenum >= doc->page_count)
fz_throw(ctx, FZ_ERROR_GENERIC, "page load out of range (%d of %d)", pagenum, doc->page_count);
if (doc->linear_pos == doc->file_length)
return doc->linear_page_refs[pagenum];
/* Only load hints once, and then only after we have got page 0 */
if (pagenum > 0 && !doc->hints_loaded && doc->hint_object_offset > 0 && doc->linear_pos >= doc->hint_object_offset)
{
/* Found hint object */
pdf_load_hint_object(ctx, doc);
}
DEBUGMESS((ctx, "continuing to try to advance from %d", doc->linear_pos));
curr_pos = fz_tell(ctx, doc->file);
fz_var(page);
fz_try(ctx)
{
int eof;
do
{
int num;
page = NULL;
eof = pdf_obj_read(ctx, doc, &doc->linear_pos, &num, &page);
pdf_drop_obj(ctx, page);
page = NULL;
}
while (!eof);
{
pdf_obj *catalog;
pdf_obj *pages;
doc->linear_pos = doc->file_length;
pdf_load_xref(ctx, doc, buf);
catalog = pdf_dict_get(ctx, pdf_trailer(ctx, doc), PDF_NAME_Root);
pages = pdf_dict_get(ctx, catalog, PDF_NAME_Pages);
if (!pdf_is_dict(ctx, pages))
fz_throw(ctx, FZ_ERROR_GENERIC, "missing page tree");
break;
}
}
fz_always(ctx)
{
fz_seek(ctx, doc->file, curr_pos, SEEK_SET);
}
fz_catch(ctx)
{
pdf_drop_obj(ctx, page);
if (fz_caught(ctx) == FZ_ERROR_TRYLATER)
{
if (doc->linear_page_refs[pagenum] == NULL)
{
/* Still not got a page */
fz_rethrow(ctx);
}
}
else
fz_rethrow(ctx);
}
return doc->linear_page_refs[pagenum];
}
pdf_document *pdf_document_from_fz_document(fz_context *ctx, fz_document *ptr)
{
return (pdf_document *)((ptr && ptr->count_pages == (void*)pdf_count_pages) ? ptr : NULL);
}
pdf_page *pdf_page_from_fz_page(fz_context *ctx, fz_page *ptr)
{
return (pdf_page *)((ptr && ptr->bound_page == (void*)pdf_bound_page) ? ptr : NULL);
}
pdf_annot *pdf_annot_from_fz_annot(fz_context *ctx, fz_annot *ptr)
{
return (pdf_annot *)((ptr && ptr->bound_annot == (void*)pdf_bound_annot) ? ptr : NULL);
}
pdf_document *pdf_specifics(fz_context *ctx, fz_document *doc)
{
return pdf_document_from_fz_document(ctx, doc);
}
pdf_obj *
pdf_add_object(fz_context *ctx, pdf_document *doc, pdf_obj *obj)
{
pdf_document *orig_doc;
int num;
orig_doc = pdf_get_bound_document(ctx, obj);
if (orig_doc && orig_doc != doc)
fz_throw(ctx, FZ_ERROR_GENERIC, "tried to add an object belonging to a different document");
if (pdf_is_indirect(ctx, obj))
return pdf_keep_obj(ctx, obj);
num = pdf_create_object(ctx, doc);
pdf_update_object(ctx, doc, num, obj);
return pdf_new_indirect(ctx, doc, num, 0);
}
pdf_obj *
pdf_add_object_drop(fz_context *ctx, pdf_document *doc, pdf_obj *obj)
{
pdf_obj *ind;
fz_try(ctx)
ind = pdf_add_object(ctx, doc, obj);
fz_always(ctx)
pdf_drop_obj(ctx, obj);
fz_catch(ctx)
fz_rethrow(ctx);
return ind;
}
pdf_obj *
pdf_add_stream(fz_context *ctx, pdf_document *doc, fz_buffer *buf, pdf_obj *obj, int compressed)
{
pdf_obj *ind;
if (!obj)
ind = pdf_add_object_drop(ctx, doc, pdf_new_dict(ctx, doc, 4));
else
ind = pdf_add_object(ctx, doc, obj);
fz_try(ctx)
pdf_update_stream(ctx, doc, ind, buf, compressed);
fz_catch(ctx)
{
pdf_drop_obj(ctx, ind);
fz_rethrow(ctx);
}
return ind;
}
pdf_document *pdf_create_document(fz_context *ctx)
{
pdf_document *doc;
pdf_obj *o = NULL;
pdf_obj *root;
pdf_obj *pages;
pdf_obj *trailer = NULL;
fz_var(o);
fz_var(trailer);
doc = pdf_new_document(ctx, NULL);
fz_try(ctx)
{
doc->version = 14;
doc->file_size = 0;
doc->startxref = 0;
doc->num_xref_sections = 0;
doc->num_incremental_sections = 0;
doc->xref_base = 0;
doc->disallow_new_increments = 0;
pdf_get_populating_xref_entry(ctx, doc, 0);
trailer = pdf_new_dict(ctx, doc, 2);
pdf_dict_put_drop(ctx, trailer, PDF_NAME_Size, pdf_new_int(ctx, doc, 3));
o = root = pdf_new_dict(ctx, doc, 2);
pdf_dict_put_drop(ctx, trailer, PDF_NAME_Root, pdf_add_object(ctx, doc, o));
pdf_drop_obj(ctx, o);
o = NULL;
pdf_dict_put_drop(ctx, root, PDF_NAME_Type, PDF_NAME_Catalog);
o = pages = pdf_new_dict(ctx, doc, 3);
pdf_dict_put_drop(ctx, root, PDF_NAME_Pages, pdf_add_object(ctx, doc, o));
pdf_drop_obj(ctx, o);
o = NULL;
pdf_dict_put_drop(ctx, pages, PDF_NAME_Type, PDF_NAME_Pages);
pdf_dict_put_drop(ctx, pages, PDF_NAME_Count, pdf_new_int(ctx, doc, 0));
pdf_dict_put_drop(ctx, pages, PDF_NAME_Kids, pdf_new_array(ctx, doc, 1));
/* Set the trailer of the final xref section. */
doc->xref_sections[0].trailer = trailer;
}
fz_catch(ctx)
{
pdf_drop_obj(ctx, trailer);
pdf_drop_obj(ctx, o);
fz_rethrow(ctx);
}
return doc;
}
int
pdf_recognize(fz_context *doc, const char *magic)
{
char *ext = strrchr(magic, '.');
if (ext)
{
if (!fz_strcasecmp(ext, ".pdf"))
return 100;
}
if (!strcmp(magic, "pdf") || !strcmp(magic, "application/pdf"))
return 100;
return 1;
}
fz_document_handler pdf_document_handler =
{
(fz_document_recognize_fn *)&pdf_recognize,
(fz_document_open_fn *)&pdf_open_document,
(fz_document_open_with_stream_fn *)&pdf_open_document_with_stream
};
void pdf_mark_xref(fz_context *ctx, pdf_document *doc)
{
int x, e;
for (x = 0; x < doc->num_xref_sections; x++)
{
pdf_xref *xref = &doc->xref_sections[x];
pdf_xref_subsec *sub;
for (sub = xref->subsec; sub != NULL; sub = sub->next)
{
for (e = 0; e < sub->len; e++)
{
pdf_xref_entry *entry = &sub->table[e];
if (entry->obj)
{
entry->flags |= PDF_OBJ_FLAG_MARK;
}
}
}
}
}
void pdf_clear_xref(fz_context *ctx, pdf_document *doc)
{
int x, e;
for (x = 0; x < doc->num_xref_sections; x++)
{
pdf_xref *xref = &doc->xref_sections[x];
pdf_xref_subsec *sub;
for (sub = xref->subsec; sub != NULL; sub = sub->next)
{
for (e = 0; e < sub->len; e++)
{
pdf_xref_entry *entry = &sub->table[e];
/* We cannot drop objects if the stream
* buffer has been updated */
if (entry->obj != NULL && entry->stm_buf == NULL)
{
if (pdf_obj_refs(ctx, entry->obj) == 1)
{
pdf_drop_obj(ctx, entry->obj);
entry->obj = NULL;
}
}
}
}
}
}
void pdf_clear_xref_to_mark(fz_context *ctx, pdf_document *doc)
{
int x, e;
for (x = 0; x < doc->num_xref_sections; x++)
{
pdf_xref *xref = &doc->xref_sections[x];
pdf_xref_subsec *sub;
for (sub = xref->subsec; sub != NULL; sub = sub->next)
{
for (e = 0; e < sub->len; e++)
{
pdf_xref_entry *entry = &sub->table[e];
/* We cannot drop objects if the stream buffer has
* been updated */
if (entry->obj != NULL && entry->stm_buf == NULL)
{
if ((entry->flags & PDF_OBJ_FLAG_MARK) == 0 && pdf_obj_refs(ctx, entry->obj) == 1)
{
pdf_drop_obj(ctx, entry->obj);
entry->obj = NULL;
}
}
}
}
}
}
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