mirror of
https://github.com/KolibriOS/kolibrios.git
synced 2024-12-17 04:12:34 +03:00
464 lines
9.1 KiB
C
464 lines
9.1 KiB
C
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#include "fitz.h"
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#include "mupdf.h"
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/* Scan file for objects and reconstruct xref table */
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struct entry
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{
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int num;
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int gen;
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int ofs;
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int stm_ofs;
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int stm_len;
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};
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static fz_error
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pdf_repair_obj(fz_stream *file, char *buf, int cap, int *stmofsp, int *stmlenp, fz_obj **encrypt, fz_obj **id)
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{
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fz_error error;
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int tok;
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int stm_len;
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int len;
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int n;
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*stmofsp = 0;
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*stmlenp = -1;
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stm_len = 0;
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error = pdf_lex(&tok, file, buf, cap, &len);
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if (error)
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return fz_rethrow(error, "cannot parse object");
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if (tok == PDF_TOK_OPEN_DICT)
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{
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fz_obj *dict, *obj;
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/* Send NULL xref so we don't try to resolve references */
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error = pdf_parse_dict(&dict, NULL, file, buf, cap);
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if (error)
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return fz_rethrow(error, "cannot parse object");
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obj = fz_dict_gets(dict, "Type");
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if (fz_is_name(obj) && !strcmp(fz_to_name(obj), "XRef"))
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{
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obj = fz_dict_gets(dict, "Encrypt");
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if (obj)
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{
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if (*encrypt)
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fz_drop_obj(*encrypt);
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*encrypt = fz_keep_obj(obj);
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}
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obj = fz_dict_gets(dict, "ID");
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if (obj)
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{
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if (*id)
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fz_drop_obj(*id);
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*id = fz_keep_obj(obj);
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}
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}
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obj = fz_dict_gets(dict, "Length");
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if (fz_is_int(obj))
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stm_len = fz_to_int(obj);
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fz_drop_obj(dict);
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}
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while ( tok != PDF_TOK_STREAM &&
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tok != PDF_TOK_ENDOBJ &&
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tok != PDF_TOK_ERROR &&
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tok != PDF_TOK_EOF )
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{
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error = pdf_lex(&tok, file, buf, cap, &len);
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if (error)
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return fz_rethrow(error, "cannot scan for endobj or stream token");
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}
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if (tok == PDF_TOK_STREAM)
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{
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int c = fz_read_byte(file);
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if (c == '\r') {
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c = fz_peek_byte(file);
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if (c == '\n')
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fz_read_byte(file);
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}
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*stmofsp = fz_tell(file);
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if (*stmofsp < 0)
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return fz_throw("cannot seek in file");
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if (stm_len > 0)
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{
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fz_seek(file, *stmofsp + stm_len, 0);
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error = pdf_lex(&tok, file, buf, cap, &len);
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if (error)
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fz_catch(error, "cannot find endstream token, falling back to scanning");
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if (tok == PDF_TOK_ENDSTREAM)
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goto atobjend;
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fz_seek(file, *stmofsp, 0);
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}
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n = fz_read(file, (unsigned char *) buf, 9);
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if (n < 0)
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return fz_rethrow(n, "cannot read from file");
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while (memcmp(buf, "endstream", 9) != 0)
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{
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c = fz_read_byte(file);
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if (c == EOF)
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break;
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memmove(buf, buf + 1, 8);
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buf[8] = c;
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}
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*stmlenp = fz_tell(file) - *stmofsp - 9;
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atobjend:
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error = pdf_lex(&tok, file, buf, cap, &len);
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if (error)
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return fz_rethrow(error, "cannot scan for endobj token");
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if (tok != PDF_TOK_ENDOBJ)
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fz_warn("object missing 'endobj' token");
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}
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return fz_okay;
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}
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static fz_error
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pdf_repair_obj_stm(pdf_xref *xref, int num, int gen)
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{
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fz_error error;
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fz_obj *obj;
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fz_stream *stm;
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int tok;
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int i, n, count;
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char buf[256];
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error = pdf_load_object(&obj, xref, num, gen);
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if (error)
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return fz_rethrow(error, "cannot load object stream object (%d %d R)", num, gen);
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count = fz_to_int(fz_dict_gets(obj, "N"));
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fz_drop_obj(obj);
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error = pdf_open_stream(&stm, xref, num, gen);
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if (error)
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return fz_rethrow(error, "cannot open object stream object (%d %d R)", num, gen);
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for (i = 0; i < count; i++)
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{
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error = pdf_lex(&tok, stm, buf, sizeof buf, &n);
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if (error || tok != PDF_TOK_INT)
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{
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fz_close(stm);
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return fz_rethrow(error, "corrupt object stream (%d %d R)", num, gen);
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}
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n = atoi(buf);
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if (n >= xref->len)
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pdf_resize_xref(xref, n + 1);
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xref->table[n].ofs = num;
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xref->table[n].gen = i;
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xref->table[n].stm_ofs = 0;
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xref->table[n].obj = NULL;
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xref->table[n].type = 'o';
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error = pdf_lex(&tok, stm, buf, sizeof buf, &n);
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if (error || tok != PDF_TOK_INT)
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{
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fz_close(stm);
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return fz_rethrow(error, "corrupt object stream (%d %d R)", num, gen);
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}
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}
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fz_close(stm);
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return fz_okay;
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}
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fz_error
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pdf_repair_xref(pdf_xref *xref, char *buf, int bufsize)
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{
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fz_error error;
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fz_obj *dict, *obj;
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fz_obj *length;
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fz_obj *encrypt = NULL;
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fz_obj *id = NULL;
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fz_obj *root = NULL;
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fz_obj *info = NULL;
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struct entry *list = NULL;
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int listlen;
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int listcap;
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int maxnum = 0;
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int num = 0;
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int gen = 0;
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int tmpofs, numofs = 0, genofs = 0;
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int stm_len, stm_ofs = 0;
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int tok;
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int next;
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int i, n, c;
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fz_seek(xref->file, 0, 0);
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listlen = 0;
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listcap = 1024;
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list = fz_calloc(listcap, sizeof(struct entry));
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/* look for '%PDF' version marker within first kilobyte of file */
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n = fz_read(xref->file, (unsigned char *)buf, MAX(bufsize, 1024));
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if (n < 0)
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{
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error = fz_rethrow(n, "cannot read from file");
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goto cleanup;
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}
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fz_seek(xref->file, 0, 0);
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for (i = 0; i < n - 4; i++)
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{
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if (memcmp(buf + i, "%PDF", 4) == 0)
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{
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fz_seek(xref->file, i + 8, 0); /* skip "%PDF-X.Y" */
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break;
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}
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}
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/* skip comment line after version marker since some generators
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* forget to terminate the comment with a newline */
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c = fz_read_byte(xref->file);
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while (c >= 0 && (c == ' ' || c == '%'))
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c = fz_read_byte(xref->file);
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fz_unread_byte(xref->file);
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while (1)
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{
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tmpofs = fz_tell(xref->file);
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if (tmpofs < 0)
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{
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error = fz_throw("cannot tell in file");
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goto cleanup;
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}
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error = pdf_lex(&tok, xref->file, buf, bufsize, &n);
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if (error)
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{
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fz_catch(error, "ignoring the rest of the file");
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break;
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}
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if (tok == PDF_TOK_INT)
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{
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numofs = genofs;
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num = gen;
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genofs = tmpofs;
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gen = atoi(buf);
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}
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else if (tok == PDF_TOK_OBJ)
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{
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error = pdf_repair_obj(xref->file, buf, bufsize, &stm_ofs, &stm_len, &encrypt, &id);
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if (error)
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{
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error = fz_rethrow(error, "cannot parse object (%d %d R)", num, gen);
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goto cleanup;
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}
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if (listlen + 1 == listcap)
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{
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listcap = (listcap * 3) / 2;
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list = fz_realloc(list, listcap, sizeof(struct entry));
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}
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list[listlen].num = num;
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list[listlen].gen = gen;
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list[listlen].ofs = numofs;
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list[listlen].stm_ofs = stm_ofs;
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list[listlen].stm_len = stm_len;
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listlen ++;
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if (num > maxnum)
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maxnum = num;
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}
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/* trailer dictionary */
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else if (tok == PDF_TOK_OPEN_DICT)
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{
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error = pdf_parse_dict(&dict, xref, xref->file, buf, bufsize);
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if (error)
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{
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error = fz_rethrow(error, "cannot parse object");
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goto cleanup;
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}
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obj = fz_dict_gets(dict, "Encrypt");
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if (obj)
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{
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if (encrypt)
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fz_drop_obj(encrypt);
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encrypt = fz_keep_obj(obj);
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}
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obj = fz_dict_gets(dict, "ID");
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if (obj)
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{
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if (id)
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fz_drop_obj(id);
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id = fz_keep_obj(obj);
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}
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obj = fz_dict_gets(dict, "Root");
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if (obj)
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{
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if (root)
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fz_drop_obj(root);
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root = fz_keep_obj(obj);
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}
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obj = fz_dict_gets(dict, "Info");
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if (obj)
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{
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if (info)
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fz_drop_obj(info);
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info = fz_keep_obj(obj);
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}
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fz_drop_obj(dict);
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}
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else if (tok == PDF_TOK_ERROR)
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fz_read_byte(xref->file);
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else if (tok == PDF_TOK_EOF)
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break;
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}
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/* make xref reasonable */
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pdf_resize_xref(xref, maxnum + 1);
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for (i = 0; i < listlen; i++)
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{
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xref->table[list[i].num].type = 'n';
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xref->table[list[i].num].ofs = list[i].ofs;
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xref->table[list[i].num].gen = list[i].gen;
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xref->table[list[i].num].stm_ofs = list[i].stm_ofs;
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/* corrected stream length */
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if (list[i].stm_len >= 0)
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{
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error = pdf_load_object(&dict, xref, list[i].num, list[i].gen);
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if (error)
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{
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error = fz_rethrow(error, "cannot load stream object (%d %d R)", list[i].num, list[i].gen);
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goto cleanup;
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}
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length = fz_new_int(list[i].stm_len);
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fz_dict_puts(dict, "Length", length);
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fz_drop_obj(length);
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fz_drop_obj(dict);
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}
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}
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xref->table[0].type = 'f';
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xref->table[0].ofs = 0;
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xref->table[0].gen = 65535;
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xref->table[0].stm_ofs = 0;
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xref->table[0].obj = NULL;
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next = 0;
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for (i = xref->len - 1; i >= 0; i--)
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{
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if (xref->table[i].type == 'f')
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{
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xref->table[i].ofs = next;
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if (xref->table[i].gen < 65535)
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xref->table[i].gen ++;
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next = i;
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}
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}
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/* create a repaired trailer, Root will be added later */
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xref->trailer = fz_new_dict(5);
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obj = fz_new_int(maxnum + 1);
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fz_dict_puts(xref->trailer, "Size", obj);
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fz_drop_obj(obj);
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if (root)
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{
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fz_dict_puts(xref->trailer, "Root", root);
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fz_drop_obj(root);
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}
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if (info)
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{
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fz_dict_puts(xref->trailer, "Info", info);
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fz_drop_obj(info);
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}
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if (encrypt)
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{
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if (fz_is_indirect(encrypt))
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{
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/* create new reference with non-NULL xref pointer */
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obj = fz_new_indirect(fz_to_num(encrypt), fz_to_gen(encrypt), xref);
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fz_drop_obj(encrypt);
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encrypt = obj;
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}
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fz_dict_puts(xref->trailer, "Encrypt", encrypt);
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fz_drop_obj(encrypt);
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}
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if (id)
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{
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if (fz_is_indirect(id))
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{
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/* create new reference with non-NULL xref pointer */
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obj = fz_new_indirect(fz_to_num(id), fz_to_gen(id), xref);
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fz_drop_obj(id);
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id = obj;
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}
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fz_dict_puts(xref->trailer, "ID", id);
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fz_drop_obj(id);
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}
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fz_free(list);
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return fz_okay;
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cleanup:
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if (encrypt) fz_drop_obj(encrypt);
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if (id) fz_drop_obj(id);
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if (root) fz_drop_obj(root);
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if (info) fz_drop_obj(info);
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fz_free(list);
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return error; /* already rethrown */
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}
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fz_error
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pdf_repair_obj_stms(pdf_xref *xref)
|
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{
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fz_obj *dict;
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int i;
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for (i = 0; i < xref->len; i++)
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{
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||
|
if (xref->table[i].stm_ofs)
|
||
|
{
|
||
|
pdf_load_object(&dict, xref, i, 0);
|
||
|
if (!strcmp(fz_to_name(fz_dict_gets(dict, "Type")), "ObjStm"))
|
||
|
pdf_repair_obj_stm(xref, i, 0);
|
||
|
fz_drop_obj(dict);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
return fz_okay;
|
||
|
}
|