pdf: add pdf_from_ucs2 to encode a unicode string in pdfdocencoding.

For use by SumatraPDF to check passwords.

1 files changed, 45 insertions, 2 deletions

diff --git a/pdf/pdf_parse.c b/pdf/pdf_parse.c
index 9f9d33b1..31a2bd0c 100644
--- a/pdf/pdf_parse.c
+++ b/pdf/pdf_parse.c
@@ -1,7 +1,8 @@
 #include "fitz.h"
 #include "mupdf.h"
 
-fz_rect pdf_to_rect(fz_obj *array)
+fz_rect
+pdf_to_rect(fz_obj *array)
 {
 	fz_rect r;
 	float a = fz_to_real(fz_array_get(array, 0));
@@ -15,7 +16,8 @@ fz_rect pdf_to_rect(fz_obj *array)
 	return r;
 }
 
-fz_matrix pdf_to_matrix(fz_obj *array)
+fz_matrix
+pdf_to_matrix(fz_obj *array)
 {
 	fz_matrix m;
 	m.a = fz_to_real(fz_array_get(array, 0));
@@ -27,6 +29,7 @@ fz_matrix pdf_to_matrix(fz_obj *array)
 	return m;
 }
 
+/* Convert Unicode/PdfDocEncoding string into utf-8 */
 char *
 pdf_to_utf8(fz_obj *src)
 {
@@ -72,6 +75,7 @@ pdf_to_utf8(fz_obj *src)
 	return dst;
 }
 
+/* Convert Unicode/PdfDocEncoding string into ucs-2 */
 unsigned short *
 pdf_to_ucs2(fz_obj *src)
 {
@@ -98,6 +102,45 @@ pdf_to_ucs2(fz_obj *src)
 	return dst;
 }
 
+/* Convert UCS-2 string into PdfDocEncoding for authentication */
+char *
+pdf_from_ucs2(unsigned short *src)
+{
+	int i, j, len;
+	char *docstr;
+
+	len = 0;
+	while (src[len])
+		len++;
+
+	docstr = fz_malloc(len + 1);
+
+	for (i = 0; i < len; i++)
+	{
+		/* shortcut: check if the character has the same code point in both encodings */
+		if (0 < src[i] && src[i] < 256 && pdf_doc_encoding[src[i]] == src[i]) {
+			docstr[i] = src[i];
+			continue;
+		}
+
+		/* search through pdf_docencoding for the character's code point */
+		for (j = 0; j < 256; j++)
+			if (pdf_doc_encoding[j] == src[i])
+				break;
+		docstr[i] = j;
+
+		/* fail, if a character can't be encoded */
+		if (!docstr[i])
+		{
+			fz_free(docstr);
+			return NULL;
+		}
+	}
+	docstr[len] = '\0';
+
+	return docstr;
+}
+
 fz_obj *
 pdf_to_utf8_name(fz_obj *src)
 {