Change regular-expression searches to treat failure-stack overflow as

a failure to match, and to continue the search.

diff --git a/v7/src/microcode/regex.c b/v7/src/microcode/regex.c
index bd4941ba7e3e167f587cd45a741252e66cdc23c3..889b8ccf8104b687259ad47b08feb6ed31a7bd07 100644 (file)
--- a/v7/src/microcode/regex.c
+++ b/v7/src/microcode/regex.c
@@ -1,8 +1,8 @@
 /* -*-C-*-
 
-$Id: regex.c,v 1.16 1996/03/04 20:37:25 cph Exp $
+$Id: regex.c,v 1.17 1997/06/06 06:56:42 cph Exp $
 
-Copyright (c) 1987-96 Massachusetts Institute of Technology
+Copyright (c) 1987-97 Massachusetts Institute of Technology
 
 This material was developed by the Scheme project at the Massachusetts
 Institute of Technology, Department of Electrical Engineering and
@@ -484,6 +484,12 @@ DEFUN (re_compile_fastmap,
 
 #define RE_MATCH_FAILED (-1)
 
+/* This macro is used by search procedures to decide when a match at a
+   particular place has failed.  If true, the search continues by
+   advancing to the next match point.  */
+#define RE_MATCH_FAILURE_RESULT(result)                                        \
+  (((result) == RE_MATCH_FAILED) || ((result) == (-4)))
+
 #define ADDRESS_TO_INDEX(address)                                      \
   ((((address) > gap_start) ? ((address) - gap_length) : (address))    \
    - (buffer -> text))
@@ -1072,7 +1078,7 @@ DEFUN (name,                                                              \
        continue;                                                       \
                                                                        \
       match_result = (RE_SEARCH_TEST (match_pc - 1));                  \
-      if (match_result == RE_MATCH_FAILED)                             \
+      if (RE_MATCH_FAILURE_RESULT (match_result))                      \
        continue;                                                       \
                                                                        \
       return (match_result);                                           \
@@ -1100,13 +1106,13 @@ DEFINE_RE_SEARCH (re_search_forward)
       while (true)
        {
          match_result = (RE_SEARCH_TEST (match_pc));
-         if (match_result != RE_MATCH_FAILED)
+         if (! (RE_MATCH_FAILURE_RESULT (match_result)))
            return (match_result);
          match_pc += 1;
          if (match_pc == gap_start)
            match_pc = (buffer -> gap_end);
          if (match_pc > match_limit)
-           return (RE_MATCH_FAILED);
+           return (match_result);
        }
     }
 }
@@ -1122,7 +1128,7 @@ DEFINE_RE_SEARCH (re_search_forward)
        continue;                                                       \
                                                                        \
       match_result = (RE_SEARCH_TEST (match_pc));                      \
-      if (match_result == RE_MATCH_FAILED)                             \
+      if (RE_MATCH_FAILURE_RESULT (match_result))                      \
        continue;                                                       \
                                                                        \
       RE_SEARCH_BACKWARD_RETURN (match_pc);                            \
@@ -1159,13 +1165,13 @@ DEFINE_RE_SEARCH (re_search_backward)
       while (true)
        {
          match_result = (RE_SEARCH_TEST (match_pc));
-         if (match_result != RE_MATCH_FAILED)
+         if (! (RE_MATCH_FAILURE_RESULT (match_result)))
            RE_SEARCH_BACKWARD_RETURN (match_pc);
          if (match_pc == gap_end)
            match_pc = (buffer -> gap_start);
          match_pc -= 1;
          if (match_pc < match_limit)
-           return (RE_MATCH_FAILED);
+           RE_SEARCH_BACKWARD_RETURN (match_pc);
        }
     }
 }