(PUSH_FAILURE_COUNT): New macro.

(POP_FAILURE_REG_OR_COUNT): Renamed from POP_FAILURE_REG.
Handle popping of a register's or a counter's data.
(POP_FAILURE_POINT): Use the new name.
(re_match_2_internal): Push counter data on the stack for succeed_n,
jump_n and set_number_at and remove misleading dead code in succeed_n.

2 files changed, 58 insertions, 25 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 34c181dc3c2..263d7a4f15e 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2000-08-25  Stefan Monnier  <monnier@cs.yale.edu>
+
+        * regex.c (PUSH_FAILURE_COUNT): New macro.
+        (POP_FAILURE_REG_OR_COUNT): Renamed from POP_FAILURE_REG.
+        Handle popping of a register's or a counter's data.
+        (POP_FAILURE_POINT): Use the new name.
+        (re_match_2_internal): Push counter data on the stack for succeed_n,
+        jump_n and set_number_at and remove misleading dead code in succeed_n.
+
 2000-08-25  Gerd Moellmann  <gerd@gnu.org>
 
         * xdisp.c (redisplay_internal): If considering all windows on all
diff --git a/src/regex.c b/src/regex.c
index 97cc409b545..0ba9d3b8878 100644
--- a/src/regex.c
+++ b/src/regex.c
@@ -21,7 +21,10 @@
 
 /* TODO:
    - structure the opcode space into opcode+flag.
-   - merge with glibc's regex.[ch]
+   - merge with glibc's regex.[ch].
+   - replace succeed_n + jump_n with a combined operation so that the counter
+     can simply be decremented when popping the failure_point without having
+     to stack up failure_count entries.
  */
 
 /* AIX requires this to be the first thing in the file. */
@@ -1416,14 +1419,37 @@ do {									\
   PUSH_FAILURE_INT (num);                                               \
 } while (0)
 
+#define PUSH_FAILURE_COUNT(ptr)                                         \
+do {                                                                    \
+  char *destination;                                                    \
+  int c;                                                                \
+  ENSURE_FAIL_STACK(3);                                                 \
+  EXTRACT_NUMBER (c, ptr);                                              \
+  DEBUG_PRINT3 ("    Push counter %p = %d\n", ptr, c);                  \
+  PUSH_FAILURE_INT (c);                                                 \
+  PUSH_FAILURE_POINTER (ptr);                                           \
+  PUSH_FAILURE_INT (-1);                                                \
+} while (0)
+
 /* Pop a saved register off the stack.  */
-#define POP_FAILURE_REG()                                               \
+#define POP_FAILURE_REG_OR_COUNT()                                      \
 do {                                                                    \
   int reg = POP_FAILURE_INT ();                                         \
-  regend[reg] = POP_FAILURE_POINTER ();                                 \
-  regstart[reg] = POP_FAILURE_POINTER ();                               \
-  DEBUG_PRINT4 ("     Pop reg %d (spanning %p -> %p)\n",                \
-                reg, regstart[reg], regend[reg]);                       \
+  if (reg == -1)                                                        \
+    {                                                                   \
+      /* It's a counter.  */                                            \
+      unsigned char *ptr = (unsigned char*) POP_FAILURE_POINTER ();     \
+      reg = POP_FAILURE_INT ();                                         \
+      STORE_NUMBER (ptr, reg);                                          \
+      DEBUG_PRINT3 ("     Pop counter %p = %d\n", ptr, reg);            \
+    }                                                                   \
+  else                                                                  \
+    {                                                                   \
+      regend[reg] = POP_FAILURE_POINTER ();                             \
+      regstart[reg] = POP_FAILURE_POINTER ();                           \
+      DEBUG_PRINT4 ("     Pop reg %d (spanning %p -> %p)\n",            \
+                    reg, regstart[reg], regend[reg]);                   \
+    }                                                                   \
 } while (0)
 
 /* Check that we are not stuck in an infinite loop.  */
@@ -1517,7 +1543,7 @@ do {									\
                                                                         \
   /* Pop the saved registers.  */                                       \
   while (fail_stack.frame < fail_stack.avail)                           \
-    POP_FAILURE_REG ();                                                 \
+    POP_FAILURE_REG_OR_COUNT ();                                        \
                                                                         \
   pat = (unsigned char *) POP_FAILURE_POINTER ();                       \
   DEBUG_PRINT2 ("  Popping pattern %p: ", pat);                         \
@@ -5217,22 +5243,18 @@ re_match_2_internal (bufp, string1, size1, string2, size2, pos, regs, stop)
           EXTRACT_NUMBER (mcnt, p + 2);
           DEBUG_PRINT2 ("EXECUTING succeed_n %d.\n", mcnt);
 
-          assert (mcnt >= 0);
-          /* Originally, this is how many times we HAVE to succeed.  */
-          if (mcnt > 0)
+          /* Originally, mcnt is how many times we HAVE to succeed.  */
+          if (mcnt != 0)
             {
-               mcnt--;
-               p += 2;
-               STORE_NUMBER_AND_INCR (p, mcnt);
-               DEBUG_PRINT3 ("  Setting %p to %d.\n", p, mcnt);
-            }
-          else if (mcnt == 0)
-            {
-              DEBUG_PRINT2 ("  Setting two bytes from %p to no_op.\n", p+2);
-              p[2] = (unsigned char) no_op;
-              p[3] = (unsigned char) no_op;
-              goto on_failure;
+              mcnt--;
+              p += 2;
+              PUSH_FAILURE_COUNT (p);
+              STORE_NUMBER_AND_INCR (p, mcnt);
+              DEBUG_PRINT3 ("   Setting %p to %d.\n", p, mcnt);
             }
+          else
+            /* The two bytes encoding mcnt == 0 are two no_op opcodes.  */
+            goto on_failure;
           break;
 
         case jump_n:
@@ -5240,11 +5262,12 @@ re_match_2_internal (bufp, string1, size1, string2, size2, pos, regs, stop)
           DEBUG_PRINT2 ("EXECUTING jump_n %d.\n", mcnt);
 
           /* Originally, this is how many times we CAN jump.  */
-          if (mcnt)
+          if (mcnt != 0)
             {
-               mcnt--;
-               STORE_NUMBER (p + 2, mcnt);
-               goto unconditional_jump;
+              mcnt--;
+              PUSH_FAILURE_COUNT (p + 2);
+              STORE_NUMBER (p + 2, mcnt);
+              goto unconditional_jump;
             }
           /* If don't have to jump any more, skip over the rest of command.  */
           else
@@ -5259,6 +5282,7 @@ re_match_2_internal (bufp, string1, size1, string2, size2, pos, regs, stop)
             p1 = p + mcnt;
             EXTRACT_NUMBER_AND_INCR (mcnt, p);
             DEBUG_PRINT3 ("  Setting %p to %d.\n", p1, mcnt);
+            PUSH_FAILURE_COUNT (p1);
             STORE_NUMBER (p1, mcnt);
             break;
           }