diff options
Diffstat (limited to 'Build/source/texk/dvipdfm-x/pdfobj.c')
| -rw-r--r-- | Build/source/texk/dvipdfm-x/pdfobj.c | 191 |
1 files changed, 160 insertions, 31 deletions
diff --git a/Build/source/texk/dvipdfm-x/pdfobj.c b/Build/source/texk/dvipdfm-x/pdfobj.c index 2c6d09f6ffe..fa7e3cae7da 100644 --- a/Build/source/texk/dvipdfm-x/pdfobj.c +++ b/Build/source/texk/dvipdfm-x/pdfobj.c @@ -2818,8 +2818,8 @@ backup_line (FILE *pdf_input_file) static int find_xref (FILE *pdf_input_file) { - int xref_pos; - int tries = 10; + int xref_pos = 0; + int len, tries = 10; do { int currentpos; @@ -2840,14 +2840,15 @@ find_xref (FILE *pdf_input_file) /* Skip rest of this line */ mfgets(work_buffer, WORK_BUFFER_SIZE, pdf_input_file); /* Next line of input file should contain actual xref location */ - mfgets(work_buffer, WORK_BUFFER_SIZE, pdf_input_file); - - { + len = mfreadln(work_buffer, WORK_BUFFER_SIZE, pdf_input_file); + if (len <= 0) + WARN("Reading xref location data failed... Not a PDF file?"); + else { const char *start, *end; char *number; start = work_buffer; - end = start + strlen(work_buffer); + end = start + len; skip_white(&start, end); number = parse_number(&start, end); xref_pos = (int) atof(number); @@ -3227,38 +3228,65 @@ extend_xref (pdf_file *pf, int new_size) pf->num_obj = new_size; } +/* Returns < 0 for error, 1 for success, and 0 when xref stream found. */ static int parse_xref_table (pdf_file *pf, int xref_pos) { - FILE *pdf_input_file = pf->file; - unsigned int first, size; - unsigned int i, offset; - unsigned int obj_gen; - char flag; - int r; + FILE *pdf_input_file = pf->file; + const char *p, *endptr; + char buf[256]; /* See, PDF ref. v.1.7, p.91 for "255+1" here. */ + int len; /* * This routine reads one xref segment. It may be called multiple times * on the same file. xref tables sometimes come in pieces. */ - seek_absolute(pf->file, xref_pos); - - mfgets(work_buffer, WORK_BUFFER_SIZE, pdf_input_file); - if (memcmp(work_buffer, "xref", strlen("xref"))) { + len = mfreadln(buf, 255, pdf_input_file); + /* We should have already checked that "startxref" section exists. + * So, EOF here (len = -1) is impossible. We don't treat too long line + * case seriously. + */ + if (len < 0) { + WARN("Something went wrong while reading xref table...giving up."); + return -1; + } + p = buf; + endptr = buf + len; + /* No skip_white() here. There should not be any white-spaces here. */ + if (memcmp(p, "xref", strlen("xref"))) { /* Might be an xref stream and not an xref table */ return 0; } + p += strlen("xref"); + skip_white(&p, endptr); + if (p != endptr) { + WARN("Garbage after \"xref\" keyword found."); + return -1; + } + /* Next line in file has first item and size of table */ for (;;) { + char flag; unsigned int current_pos; + int i; + uint32_t first, size, offset, obj_gen; current_pos = tell_position(pdf_input_file); - if (mfgets(work_buffer, WORK_BUFFER_SIZE, pdf_input_file) == NULL) { - WARN("Premature end of PDF file while parsing xref table."); + len = mfreadln(buf, 255, pdf_input_file); + if (len == 0) /* empty line... just skip. */ + continue; + else if (len < 0) { + WARN("Reading a line failed in xref table."); return -1; } - if (!strncmp(work_buffer, "trailer", strlen ("trailer"))) { + + p = buf; + endptr = buf + len; + skip_white(&p, endptr); + if (p == endptr) { /* Only white-spaces and/or comment found. */ + continue; + } else if (!strncmp(p, "trailer", strlen ("trailer"))) { /* * Backup... This is ugly, but it seems like the safest thing to * do. It is possible the trailer dictionary starts on the same @@ -3266,37 +3294,138 @@ parse_xref_table (pdf_file *pf, int xref_pos) * call might have started to read the trailer dictionary and * parse_trailer would fail. */ + current_pos += p - buf; /* Jump to the beginning of "trailer" keyword. */ seek_absolute(pdf_input_file, current_pos); break; } - sscanf(work_buffer, "%u %u", &first, &size); + /* Line containing something other than white-space characters found. + * + * Start reading xref subsection + * + * This section just reads two nusigned integers, namely, the object number + * of first object and the size of the xref subsection. PDF reference says + * that only "a space" is allowed between those two numbers but we allow + * more white-space characters. + */ + { + char *q; + + /* Object number of the first object whithin this xref subsection. */ + q = parse_unsigned(&p, endptr); + if (!q) { + WARN("An unsigned integer expected but counld not find. (xref)"); + return -1; + } + first = atoi(q); + RELEASE(q); + skip_white(&p, endptr); + + /* Nnumber of objects in this xref subsection. */ + q = parse_unsigned(&p, endptr); + if (!q) { + WARN("An unsigned integer expected but counld not find. (xref)"); + return -1; + } + size = atoi(q); + RELEASE(q); + skip_white(&p, endptr); + + /* Check for unrecognized tokens */ + if (p != endptr) { + WARN("Unexpected token found in xref table."); + return -1; + } + } + + /* The first line of a xref subsection OK. */ if (pf->num_obj < first + size) { extend_xref(pf, first + size); } - for (i = first; i < first + size; i++) { - fread(work_buffer, sizeof(char), 20, pdf_input_file); + /* Start parsing xref subsection body... */ + for (i = first; i < first + size; ) { + /* PDF spec. requires each xref subsection lines being exactly 20 bytes + * long [including end-of-line marker(s)], offset 10 decimal digits, + * generation number being 5 decimal digits, and each entries delimitted + * by "a single space". However, we don't srtictly follow this rule: + * More than one "white-spaces" allowed, can be ended with a comment, + * and so on. + */ + len = mfreadln(buf, 255, pdf_input_file); + if (len == 0) /* empty line...just skip. */ + continue; + else if (len < 0) { + WARN("Something went wrong while reading xref subsection..."); + return -1; + } + p = buf; + endptr = buf + len; + skip_white(&p, endptr); + if (p == endptr) /* Only white-spaces and/or comment. */ + continue; + /* * Don't overwrite positions that have already been set by a * modified xref table. We are working our way backwards * through the reference table, so we only set "position" * if it hasn't been set yet. */ - work_buffer[19] = 0; offset = 0UL; obj_gen = 0; flag = 0; - r = sscanf(work_buffer, "%010u %05u %c", &offset, &obj_gen, &flag); - if ( r != 3 || - ((flag != 'n' && flag != 'f') || - (flag == 'n' && - (offset >= pf->file_size || (offset > 0 && offset < 4))))) { + { + char *q; + + /* Offset value -- 10 digits (0 padded) */ + q = parse_unsigned(&p, endptr); + if (!q) { + WARN("An unsigned integer expected but counld not find. (xref)"); + return -1; + } else if (strlen(q) != 10) { /* exactly 10 digits */ + WARN(("Offset must be a 10 digits number. (xref)")); + return -1; + } + /* FIXME: Possible overflow here. Consider using strtoll(). */ + offset = atoi(q); + RELEASE(q); + skip_white(&p, endptr); + + /* Generation number -- 5 digits (0 padded) */ + q = parse_unsigned(&p, endptr); + if (!q) { + WARN("An unsigned integer expected but counld not find. (xref)"); + return -1; + } else if (strlen(q) != 5) { /* exactly 5 digits */ + WARN(("Expecting a 5 digits number. (xref)")); + return -1; + } + obj_gen = atoi(q); + RELEASE(q); + skip_white(&p, endptr); + } + if (p == endptr) { + WARN("Unexpected EOL reached while reading a xref subsection entry."); + return -1; + } + + /* Flag -- a char */ + flag = *p; p++; + skip_white(&p, endptr); + if (p < endptr) { + WARN("Garbage in xref subsection entry found..."); + return -1; + } else if (((flag != 'n' && flag != 'f') || + (flag == 'n' && + (offset >= pf->file_size || (offset > 0 && offset < 4))))) { WARN("Invalid xref table entry [%lu]. PDF file is corrupt...", i); return -1; } + + /* Everything seems to be OK. */ if (!pf->xref_table[i].field2) { - pf->xref_table[i].type = (flag == 'n'); - pf->xref_table[i].field2 = offset; - pf->xref_table[i].field3 = obj_gen; + pf->xref_table[i].type = (flag == 'n'); + pf->xref_table[i].field2 = offset; + pf->xref_table[i].field3 = obj_gen; } + i++; } } |