diff options
Diffstat (limited to 'pdf/pdf_xref.c')
| -rw-r--r-- | pdf/pdf_xref.c | 204 |
1 files changed, 163 insertions, 41 deletions
diff --git a/pdf/pdf_xref.c b/pdf/pdf_xref.c index 2675b0ce..14b8ee5b 100644 --- a/pdf/pdf_xref.c +++ b/pdf/pdf_xref.c @@ -12,11 +12,40 @@ static inline int iswhite(int ch) * xref tables */ -static void pdf_resize_xref(pdf_document *xref, int newlen) +static void pdf_free_xref_sections(pdf_document *doc) +{ + fz_context *ctx = doc->ctx; + int x, e; + + for (x = 0; x < doc->num_xref_sections; x++) + { + pdf_xref *xref = &doc->xref_sections[x]; + + for (e = 0; e < xref->len; e++) + { + pdf_xref_entry *entry = &xref->table[e]; + + if (entry->obj) + { + pdf_drop_obj(entry->obj); + fz_drop_buffer(ctx, entry->stm_buf); + } + } + + fz_free(ctx, xref->table); + pdf_drop_obj(xref->trailer); + } + + fz_free(ctx, doc->xref_sections); + doc->xref_sections = NULL; + doc->num_xref_sections = 0; +} + +static void pdf_resize_xref(fz_context *ctx, pdf_xref *xref, int newlen) { int i; - xref->table = fz_resize_array(xref->ctx, xref->table, newlen, sizeof(pdf_xref_entry)); + xref->table = fz_resize_array(ctx, xref->table, newlen, sizeof(pdf_xref_entry)); for (i = xref->len; i < newlen; i++) { xref->table[i].type = 0; @@ -29,35 +58,140 @@ static void pdf_resize_xref(pdf_document *xref, int newlen) xref->len = newlen; } +static void pdf_populate_next_xref_level(pdf_document *doc) +{ + pdf_xref *xref; + doc->xref_sections = fz_resize_array(doc->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->len = 0; + xref->table = NULL; + xref->trailer = NULL; +} + pdf_obj *pdf_trailer(pdf_document *doc) { - return doc->trailer; + /* Return the document's final trailer */ + pdf_xref *xref = &doc->xref_sections[0]; + + return xref->trailer; } -void pdf_set_xref_trailer(pdf_document *doc, pdf_obj *trailer) +void pdf_set_populating_xref_trailer(pdf_document *doc, pdf_obj *trailer) { - pdf_drop_obj(doc->trailer); - doc->trailer = pdf_keep_obj(trailer); + /* Update the trailer of the xref section being populated */ + pdf_xref *xref = &doc->xref_sections[doc->num_xref_sections - 1]; + pdf_drop_obj(xref->trailer); + xref->trailer = pdf_keep_obj(trailer); } int pdf_xref_len(pdf_document *doc) { - return doc->len; + /* Return the length of the document's final xref section */ + pdf_xref *xref = &doc->xref_sections[0]; + + return xref->len; } +/* Used while reading the individual xref sections from a file */ +pdf_xref_entry *pdf_get_populating_xref_entry(pdf_document *doc, int i) +{ + /* Return an entry within the xref currently being populated */ + pdf_xref *xref; + + if (doc->num_xref_sections == 0) + { + doc->xref_sections = fz_calloc(doc->ctx, 1, sizeof(pdf_xref)); + doc->num_xref_sections = 1; + } + + xref = &doc->xref_sections[doc->num_xref_sections - 1]; + + if (i >= xref->len) + pdf_resize_xref(doc->ctx, xref, i+1); + + return &xref->table[i]; +} + +/* Used after loading a document to access entries */ pdf_xref_entry *pdf_get_xref_entry(pdf_document *doc, int i) { - if (i >= doc->len) - pdf_resize_xref(doc, i+1); + int j; - return &doc->table[i]; + /* Find the first xref section where the entry is defined. */ + for (j = 0; j < doc->num_xref_sections; j++) + { + pdf_xref *xref = &doc->xref_sections[j]; + + if (i >= 0 && i < xref->len) + { + pdf_xref_entry *entry = &xref->table[i]; + + if (entry->type) + return entry; + } + } + + /* + Didn't find the entry in any section. Return the entry from the final + section. + */ + return &doc->xref_sections[0].table[i]; +} + +/* Used when altering a document */ +static pdf_xref_entry *pdf_get_new_xref_entry(pdf_document *doc, int i) +{ + fz_context *ctx = doc->ctx; + pdf_xref *xref; + + /* Make a new final xref section if we haven't already */ + if (!doc->xref_altered) + { + doc->xref_sections = fz_resize_array(ctx, doc->xref_sections, doc->num_xref_sections + 1, sizeof(pdf_xref)); + memmove(&doc->xref_sections[1], &doc->xref_sections[0], doc->num_xref_sections * sizeof(pdf_xref)); + doc->num_xref_sections++; + xref = &doc->xref_sections[0]; + xref->len = 0; + xref->table = NULL; + xref->trailer = pdf_keep_obj(doc->xref_sections[1].trailer); + doc->xref_altered = 1; + } + + xref = &doc->xref_sections[0]; + if (i >= xref->len) + pdf_resize_xref(ctx, xref, i + 1); + + return &xref->table[i]; } void pdf_replace_xref(pdf_document *doc, pdf_xref_entry *entries, int n) { - fz_free(doc->ctx, doc->table); - doc->table = entries; - doc->len = n; + fz_context *ctx = doc->ctx; + pdf_xref *xref; + pdf_obj *trailer = pdf_keep_obj(pdf_trailer(doc)); + + /* The new table completely replaces the previous separate sections */ + pdf_free_xref_sections(doc); + + fz_var(trailer); + fz_try(ctx) + { + xref = fz_calloc(ctx, 1, sizeof(pdf_xref)); + xref->table = entries; + xref->len = n; + xref->trailer = trailer; + trailer = NULL; + + doc->xref_sections = xref; + doc->num_xref_sections = 1; + } + fz_catch(ctx) + { + pdf_drop_obj(trailer); + fz_rethrow(ctx); + } } /* @@ -207,7 +341,7 @@ pdf_read_old_xref(pdf_document *xref, pdf_lexbuf *buf) int xref_len = pdf_xref_size_from_old_trailer(xref, buf); /* Access last entry to ensure xref size up front and avoid reallocs */ - (void)pdf_get_xref_entry(xref, xref_len - 1); + (void)pdf_get_populating_xref_entry(xref, xref_len - 1); fz_read_line(xref->file, buf->scratch, buf->size); if (strncmp(buf->scratch, "xref", 4) != 0) @@ -239,12 +373,12 @@ pdf_read_old_xref(pdf_document *xref, pdf_lexbuf *buf) { fz_warn(xref->ctx, "broken xref section, proceeding anyway."); /* Access last entry to ensure size */ - (void)pdf_get_xref_entry(xref, ofs + len - 1); + (void)pdf_get_populating_xref_entry(xref, ofs + len - 1); } for (i = ofs; i < ofs + len; i++) { - pdf_xref_entry *entry = pdf_get_xref_entry(xref, i); + pdf_xref_entry *entry = pdf_get_populating_xref_entry(xref, i); n = fz_read(xref->file, (unsigned char *) buf->scratch, 20); if (n < 0) fz_throw(xref->ctx, "cannot read xref table"); @@ -296,7 +430,7 @@ pdf_read_new_xref_section(pdf_document *xref, fz_stream *stm, int i0, int i1, in for (i = i0; i < i0 + i1; i++) { - pdf_xref_entry *entry = pdf_get_xref_entry(xref, i); + pdf_xref_entry *entry = pdf_get_populating_xref_entry(xref, i); int a = 0; int b = 0; int c = 0; @@ -342,7 +476,7 @@ pdf_read_new_xref(pdf_document *xref, pdf_lexbuf *buf) pdf_xref_entry *entry; int ofs = fz_tell(xref->file); trailer = pdf_parse_ind_obj(xref, xref->file, buf, &num, &gen, &stm_ofs); - entry = pdf_get_xref_entry(xref, num); + entry = pdf_get_populating_xref_entry(xref, num); entry->ofs = ofs; entry->gen = gen; entry->stm_ofs = stm_ofs; @@ -363,7 +497,7 @@ pdf_read_new_xref(pdf_document *xref, pdf_lexbuf *buf) size = pdf_to_int(obj); /* Access xref entry to assure table size */ - (void)pdf_get_xref_entry(xref, size-1); + (void)pdf_get_populating_xref_entry(xref, size-1); if (num < 0 || num >= pdf_xref_len(xref)) fz_throw(ctx, "object id (%d %d R) out of range (0..%d)", num, gen, pdf_xref_len(xref) - 1); @@ -490,9 +624,7 @@ read_xref_section(pdf_document *xref, int ofs, pdf_lexbuf *buf, ofs_list *offset trailer = pdf_read_xref(xref, ofs, buf); - /* Currently we only store the trailer most recently added to the doc */ - if (!pdf_trailer(xref)) - pdf_set_xref_trailer(xref, trailer); + pdf_set_populating_xref_trailer(xref, trailer); /* FIXME: do we overwrite free entries properly? */ xrefstmofs = pdf_to_int(pdf_dict_gets(trailer, "XRefStm")); @@ -537,7 +669,10 @@ pdf_read_xref_sections(pdf_document *xref, int ofs, pdf_lexbuf *buf) fz_try(ctx) { while(ofs) + { + pdf_populate_next_xref_level(xref); ofs = read_xref_section(xref, ofs, buf, &list); + } } fz_always(ctx) { @@ -775,8 +910,7 @@ pdf_init_document(pdf_document *xref) } fz_catch(ctx) { - pdf_replace_xref(xref, NULL, 0); - pdf_set_xref_trailer(xref, NULL); + pdf_free_xref_sections(xref); fz_warn(xref->ctx, "trying to repair broken xref"); repaired = 1; } @@ -871,7 +1005,7 @@ pdf_init_document(pdf_document *xref) void pdf_close_document(pdf_document *xref) { - int i, xref_len; + int i; fz_context *ctx; if (!xref) @@ -880,18 +1014,7 @@ pdf_close_document(pdf_document *xref) pdf_drop_js(xref->js); - xref_len = pdf_xref_len(xref); - for (i = 0; i < xref_len; i++) - { - pdf_xref_entry *entry = pdf_get_xref_entry(xref, i); - if (entry->obj) - { - pdf_drop_obj(entry->obj); - entry->obj = NULL; - fz_drop_buffer(ctx, entry->stm_buf); - } - } - pdf_replace_xref(xref, NULL, 0); + pdf_free_xref_sections(xref); if (xref->page_objs) { @@ -911,7 +1034,6 @@ pdf_close_document(pdf_document *xref) pdf_drop_obj(xref->focus_obj); if (xref->file) fz_close(xref->file); - pdf_drop_obj(pdf_trailer(xref)); if (xref->crypt) pdf_free_crypt(ctx, xref->crypt); @@ -1192,7 +1314,7 @@ pdf_create_object(pdf_document *xref) /* TODO: reuse free object slots by properly linking free object chains in the ofs field */ pdf_xref_entry *entry; int num = pdf_xref_len(xref); - entry = pdf_get_xref_entry(xref, num); + entry = pdf_get_new_xref_entry(xref, num); entry->type = 'f'; entry->ofs = -1; entry->gen = 0; @@ -1213,7 +1335,7 @@ pdf_delete_object(pdf_document *xref, int num) return; } - x = pdf_get_xref_entry(xref, num); + x = pdf_get_new_xref_entry(xref, num); fz_drop_buffer(xref->ctx, x->stm_buf); pdf_drop_obj(x->obj); @@ -1237,7 +1359,7 @@ pdf_update_object(pdf_document *xref, int num, pdf_obj *newobj) return; } - x = pdf_get_xref_entry(xref, num); + x = pdf_get_new_xref_entry(xref, num); pdf_drop_obj(x->obj); |