(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.

diff --git a/src/font-flt.c b/src/font-flt.c
index 6f05fbe..882463b 100644 (file)
--- 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;
 }