Bug 697301: Fix "crash" in epub.

Actually an assert. This is caused by a paragraph separator in the
text. The Unicode Bidirectional Algorithm says we should operate
paragraph by paragraph, and includes code to split paragraphs
at paragraph markers, changing their type to boundary neutrals
as it goes.

The use of this code was left "as an exercise for the reader" in
the example code, so we simply hook it up here.

1 files changed, 29 insertions, 11 deletions

diff --git a/source/fitz/bidi.c b/source/fitz/bidi.c
index 4436b615..b31ca749 100644
--- a/source/fitz/bidi.c
+++ b/source/fitz/bidi.c
@@ -414,9 +414,12 @@ create_levels(fz_context *ctx,
 		int resolveWhiteSpace,
 		int flags)
 {
-	fz_bidi_level *levels;
+	fz_bidi_level *levels , *plevels;
 	fz_bidi_chartype *types = NULL;
+	fz_bidi_chartype *ptypes;
 	fz_bidi_level baseLevel;
+	const uint32_t *ptext;
+	size_t plen, remaining;
 
 	levels = fz_malloc(ctx, len * sizeof(*levels));
 
@@ -463,18 +466,33 @@ create_levels(fz_context *ctx,
 		 */
 		classify_quoted_blocks(text, types, len);
 
-		/* Work out the levels and character types... */
-		(void)fz_bidi_resolve_explicit(baseLevel, BDI_N, types, levels, len, 0);
-		fz_bidi_resolve_weak(ctx, baseLevel, types, levels, len);
-		fz_bidi_resolve_neutrals(baseLevel,types, levels, len);
-		fz_bidi_resolve_implicit(types, levels, len);
+		/* Work one paragraph at a time. */
+		plevels = levels;
+		ptypes = types;
+		ptext = text;
+		remaining = len;
+		while (remaining)
+		{
+			plen = fz_bidi_resolve_paragraphs(ptypes, remaining);
+
+			/* Work out the levels and character types... */
+			(void)fz_bidi_resolve_explicit(baseLevel, BDI_N, ptypes, plevels, plen, 0);
+			fz_bidi_resolve_weak(ctx, baseLevel, ptypes, plevels, plen);
+			fz_bidi_resolve_neutrals(baseLevel, ptypes, plevels, plen);
+			fz_bidi_resolve_implicit(ptypes, plevels, plen);
 
-		classify_characters(text, types, len, BIDI_CLASSIFY_WHITE_SPACE);
+			classify_characters(ptext, ptypes, plen, BIDI_CLASSIFY_WHITE_SPACE);
 
-		if (resolveWhiteSpace)
-		{
-			/* resolve whitespace */
-			fz_bidi_resolve_whitespace(baseLevel, types, levels, len);
+			if (resolveWhiteSpace)
+			{
+				/* resolve whitespace */
+				fz_bidi_resolve_whitespace(baseLevel, ptypes, plevels, plen);
+			}
+
+			plevels += plen;
+			ptypes += plen;
+			ptext += plen;
+			remaining -= plen;
 		}
 
 		/* The levels buffer now has odd and even numbers indicating