commit 75392c60408c1692c34c2f4c72452273f0a02625
parent 347d1650195f971d155e95fa55b36c6c2c4b5ff0
Author: Christian Grothoff <christian@grothoff.org>
Date: Fri, 24 Mar 2006 17:22:46 +0000
pdfstart
Diffstat:
1 file changed, 256 insertions(+), 0 deletions(-)
diff --git a/src/plugins/pdfextractor.c b/src/plugins/pdfextractor.c
@@ -0,0 +1,256 @@
+/*
+ This file is part of libextractor.
+ (C) 2006 Vidyut Samanta and Christian Grothoff
+
+ libextractor is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published
+ by the Free Software Foundation; either version 2, or (at your
+ option) any later version.
+
+ libextractor is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with libextractor; see the file COPYING. If not, write to the
+ Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.
+ */
+
+#include "platform.h"
+#include "extractor.h"
+#include <zlib.h>
+#include "convert.h"
+
+static char * stndup(const char * str,
+ size_t n) {
+ char * tmp;
+ tmp = malloc(n+1);
+ tmp[n] = '\0';
+ memcpy(tmp, str, n);
+ return tmp;
+}
+
+/**
+ * strnlen is GNU specific, let's redo it here to be
+ * POSIX compliant.
+ */
+static size_t stnlen(const char * str,
+ size_t maxlen) {
+ size_t ret;
+ ret = 0;
+ while ( (ret < maxlen) &&
+ (str[ret] != '\0') )
+ ret++;
+ return ret;
+}
+
+static struct EXTRACTOR_Keywords *
+addKeyword(EXTRACTOR_KeywordType type,
+ const char * keyword,
+ struct EXTRACTOR_Keywords * next) {
+ EXTRACTOR_KeywordList * result;
+
+ if (keyword == NULL)
+ return next;
+ result = malloc(sizeof(EXTRACTOR_KeywordList));
+ result->next = next;
+ result->keyword = strdup(keyword);
+ result->keywordType = type;
+ return result;
+}
+
+static struct {
+ char * name;
+ EXTRACTOR_KeywordType type;
+} tagmap[] = {
+ { "Author" , EXTRACTOR_AUTHOR},
+ { "Description" , EXTRACTOR_DESCRIPTION},
+ { "Comment", EXTRACTOR_COMMENT},
+ { "Copyright", EXTRACTOR_COPYRIGHT},
+ { "Source", EXTRACTOR_SOURCE},
+ { "Creation Time", EXTRACTOR_DATE},
+ { "Title", EXTRACTOR_TITLE},
+ { "Software", EXTRACTOR_SOFTWARE},
+ { "Disclaimer", EXTRACTOR_DISCLAIMER},
+ { "Warning", EXTRACTOR_WARNING},
+ { "Signature", EXTRACTOR_RESOURCE_IDENTIFIER},
+ { NULL, EXTRACTOR_UNKNOWN},
+};
+
+#define PDF_HEADER "%PDF"
+#define PDF_EOF "%%EOF"
+#define PDF_SXR "startxref"
+#define PDF_XREF "xref"
+#define PDF_INFO "/Info "
+#define PDF_TRAILER "trailer"
+#define MAX_STEPS 256
+
+#define IS_NL(c) ((c == '\n') || (c == '\r'))
+#define MIN(a,b) ((a) < (b) ? (a) : (b))
+#define SKIP(k,p,b,s) while ( (p<s) && (NULL != strchr(k, b[p])) ) p++;
+
+struct EXTRACTOR_Keywords *
+libextractor_pdf_extract(const char * filename,
+ const char * data,
+ size_t size,
+ struct EXTRACTOR_Keywords * prev) {
+ size_t pos;
+ size_t steps;
+ unsigned int xstart;
+ unsigned int xcount;
+ unsigned int xinfo;
+ unsigned long long startxref;
+ unsigned long long xrefpos;
+ int haveValidXref;
+ unsigned long long info_offset;
+ char buf[MAX_STEPS+1];
+ int i;
+
+ while ( (size > 0) && (IS_NL(data[size-1])) )
+ size--;
+ if (size < strlen(PDF_HEADER) + strlen(PDF_EOF) + strlen(PDF_SXR) + 3)
+ return prev;
+ if (0 != memcmp(data, PDF_HEADER, strlen(PDF_HEADER)))
+ return prev;
+ if (0 != memcmp(&data[size - strlen(PDF_EOF)], PDF_EOF, strlen(PDF_EOF)))
+ return prev;
+
+ pos = size - strlen(PDF_EOF) - strlen(PDF_SXR);
+ steps = 0;
+ while ( (steps++ < MAX_STEPS) &&
+ (pos > 0) &&
+ (0 != memcmp(&data[pos], PDF_SXR, strlen(PDF_SXR))) )
+ pos--;
+ printf("pos: %u\n", pos);
+ if (0 != memcmp(&data[pos], PDF_SXR, strlen(PDF_SXR)))
+ return prev;
+ memcpy(buf, &data[pos + strlen(PDF_SXR)], steps);
+ buf[steps] = '\0';
+ if (1 != sscanf(buf, "%llu", &startxref))
+ return prev;
+ printf("startxref: %llu\n", startxref);
+ if (startxref >= size - strlen(PDF_XREF))
+ return prev;
+ if (0 != memcmp(&data[startxref], PDF_XREF, strlen(PDF_XREF)))
+ return prev;
+ haveValidXref = 0;
+ xrefpos = startxref + strlen(PDF_XREF);
+
+ while (1) {
+ pos = xrefpos;
+ while ( (pos < size) && (IS_NL(data[pos])) )
+ pos++;
+ memcpy(buf, &data[pos], MIN(MAX_STEPS, size - pos));
+ buf[MIN(MAX_STEPS,size-pos)] = '\0';
+ if (2 != sscanf(buf, "%u %u", &xstart, &xcount))
+ break;
+ printf("xstart: %u - xcount: %u - pos %u\n",
+ xstart,
+ xcount,
+ pos);
+ while ( (pos < size) && (! IS_NL(data[pos])) )
+ pos++;
+ if ( (pos < size) && IS_NL(data[pos]))
+ pos++;
+ xrefpos = 20 * xcount + pos;
+ if ( (xrefpos >= size) || (xrefpos < pos) )
+ return prev; /* invalid xref size */
+ haveValidXref = 1;
+ printf("xref portion ends at %llu\n",
+ xrefpos);
+ }
+ if (! haveValidXref)
+ return prev;
+ if (size - pos < strlen(PDF_TRAILER))
+ return prev;
+ if (0 != memcmp(&data[pos],
+ PDF_TRAILER,
+ strlen(PDF_TRAILER)))
+ return prev;
+ pos += strlen(PDF_TRAILER);
+ SKIP("<< \n\r", pos, data, size);
+ while ( (pos < size) &&
+ (pos + strlen(PDF_INFO) < size) &&
+ (0 != memcmp(&data[pos],
+ PDF_INFO,
+ strlen(PDF_INFO))) ) {
+ while ( (pos < size) &&
+ (! IS_NL(data[pos]) ) ) {
+ if ( (data[pos] == '>') &&
+ (pos + 1 < size) &&
+ (data[pos+1] == '>') )
+ return prev; /* no info */
+ pos++;
+ }
+ while ( (pos < size) &&
+ (IS_NL(data[pos]) || isspace(data[pos]) ) )
+ pos++;
+ }
+ if ( ! ( (pos < size) &&
+ (pos + strlen(PDF_INFO) < size) &&
+ (0 == memcmp(&data[pos],
+ PDF_INFO,
+ strlen(PDF_INFO))) ) )
+ return prev;
+
+ pos += strlen(PDF_INFO);
+ memcpy(buf,
+ &data[pos],
+ MIN(MAX_STEPS, size - pos));
+ buf[MIN(MAX_STEPS,size-pos)] = '\0';
+ for (i=0;i<MIN(MAX_STEPS,size-pos);i++)
+ if (isspace(buf[i])) {
+ buf[i] = '\0';
+ break;
+ }
+ if (1 != sscanf(buf, "%u", &xinfo))
+ return prev;
+ printf("xinfo: %u\n", xinfo);
+
+ haveValidXref = 0;
+ /* now go find xinfo in xref table */
+ xrefpos = startxref + strlen(PDF_XREF);
+ while (1) {
+ pos = xrefpos;
+ while ( (pos < size) && (IS_NL(data[pos])) )
+ pos++;
+ memcpy(buf, &data[pos], MIN(MAX_STEPS, size - pos));
+ buf[MIN(MAX_STEPS,size-pos)] = '\0';
+ if (2 != sscanf(buf, "%u %u", &xstart, &xcount))
+ break;
+ printf("xstart: %u - xcount: %u - pos %u\n",
+ xstart,
+ xcount,
+ pos);
+ while ( (pos < size) && (! IS_NL(data[pos])) )
+ pos++;
+ if ( (pos < size) && IS_NL(data[pos]))
+ pos++;
+ if ( (xinfo > xstart) &&
+ (xinfo < xstart + xcount) ) {
+ haveValidXref = 1;
+ pos += 20 * xinfo - xstart;
+ memcpy(buf, &data[pos], 20);
+ buf[20] = '\0';
+ sscanf(buf, "%10llu %*5u %*c", &info_offset);
+
+
+ break;
+ }
+ xrefpos = 20 * xcount + pos;
+ if ( (xrefpos >= size) || (xrefpos < pos) )
+ return prev; /* invalid xref size */
+ }
+ if (! haveValidXref)
+ return prev;
+
+ /* read size of xref */
+ /* parse xref */
+ /* find info index */
+ /* parse info */
+
+ return prev;
+}
+
