From d8173c5209396aad14621859fdf8d572ef88319e Mon Sep 17 00:00:00 2001
From: handa <handa>
Date: Fri, 12 Oct 2007 05:31:51 +0000
Subject: [PATCH] (Mexist): New variable. (enum FontLayoutCmdRuleSrcType): New
 enum SRC_EXIST. (FontLayoutCmdRule): New member src.exist.
 (load_category_table): Use isalnum, not isalpha.
 (load_command): Check the command "exist". (run_rule):
 Hande the case SRC_EXIST. (run_command): Check the range of
 FROM. (mfont__flt_init): Initialize Mexist.

---
 src/font-flt.c |   55 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 4 deletions(-)

diff --git a/src/font-flt.c b/src/font-flt.c
index 6f05fbe..882463b 100644
--- a/src/font-flt.c
+++ b/src/font-flt.c
@@ -257,7 +257,7 @@ static MPlist *flt_list;
 #define CMD_ID_TO_INDEX(id) (CMD_ID_OFFSET_INDEX - (id))
 #define INDEX_TO_CMD_ID(idx) (CMD_ID_OFFSET_INDEX - (idx))
 
-static MSymbol Mcond, Mrange;
+static MSymbol Mcond, Mrange, Mexist;
 
 #define GLYPH_CODE_P(code)	\
   ((code) >= GLYPH_CODE_MIN && (code) <= GLYPH_CODE_MAX)
@@ -280,7 +280,8 @@ enum FontLayoutCmdRuleSrcType
     SRC_REGEX,
     SRC_INDEX,
     SRC_SEQ,
-    SRC_RANGE
+    SRC_RANGE,
+    SRC_EXIST
   };
 
 typedef struct
@@ -299,6 +300,9 @@ typedef struct
     struct {
       int from, to;
     } range;
+    struct {
+      int c;
+    } exist;
   } src;
 
   int n_cmds;
@@ -383,7 +387,7 @@ load_category_table (MPlist *plist)
 	    MERROR (MERROR_FONT, NULL);
 	  category_code = MPLIST_INTEGER (elt);
 	}
-      if (! isalpha (category_code))
+      if (! isalnum (category_code))
 	MERROR (MERROR_FONT, NULL);
 
       if (from == to)
@@ -687,6 +691,21 @@ load_command (FontLayoutStage *stage, MPlist *plist,
 		  cmd->body.rule.src.range.to
 		    = (unsigned) MPLIST_INTEGER (pl);
 		}
+	      else if (MPLIST_SYMBOL_P (pl) && size <= 2)
+		{
+		  if (MPLIST_SYMBOL (pl) != Mexist)
+		    MERROR (MERROR_FLT, INVALID_CMD_ID);
+		  cmd->body.rule.src_type = SRC_EXIST;
+		  if (size == 1)
+		    cmd->body.rule.src.exist.c = -1;
+		  else
+		    {
+		      pl = MPLIST_NEXT (pl);
+		      if (! MPLIST_INTEGER_P (pl))
+			MERROR (MERROR_DRAW, INVALID_CMD_ID);
+		      cmd->body.rule.src.exist.c = MPLIST_INTEGER (pl);
+		    }
+		}
 	      else
 		MERROR (MERROR_DRAW, INVALID_CMD_ID);
 	    }
@@ -1064,6 +1083,33 @@ run_rule (int depth,
       if (MDEBUG_FLAG () > 2)
 	MDEBUG_PRINT3 ("\n [FLT] %*s(INDEX %d", depth, "", rule->src.match_idx);
     }
+  else if (rule->src_type == SRC_EXIST)
+    {
+      MGlyph *g = MGLYPH (from);
+      int encoded = g->otf_encoded;
+      unsigned code;
+
+      if (rule->src.exist.c < 0)
+	{
+	  if (from >= to)
+	    return 0;
+	  code = g->code;
+	  to = from + 1;
+	}
+      else
+	{
+	  code = rule->src.exist.c;
+	  to = from;
+	  encoded = 0;
+	}
+      if (! encoded)
+	{
+	  code = (g->rface->rfont->driver->encode_char
+		  (NULL, (MFont *) g->rface->rfont, NULL, code));
+	  if (code == MCHAR_INVALID_CODE)
+	    return 0;
+	}
+    }
 
   consumed = 0;
   depth++;
@@ -1157,7 +1203,7 @@ run_command (int depth, int id, MGlyphString *gstring, int from, int to,
 
       /* Direct code (== id + ctx->code_offset) output.
 	 The source is not consumed.  */
-      if (from < to)
+      if (from < to || from == 1)
 	g = *(MGLYPH (from));
       else
 	g = *(MGLYPH (from - 1));
@@ -1307,6 +1353,7 @@ mfont__flt_init (void)
   Mcond = msymbol ("cond");
   Mrange = msymbol ("range");
   Mlayouter = msymbol ("layouter");
+  Mexist = msymbol ("exist");
   flt_list = mplist ();
   return 0;
 }
-- 
1.7.10.4