# HG changeset patch
# User Ryoma SHINYA <shinya@firefly.cr.ie.u-ryukyu.ac.jp>
# Date 1289067043 -32400
# Node ID 56a997f2c1219fd91885293525734caac121e104
# Parent  b02b321d0e062e2e9b37307ee9fc59a054b6ec24
improve codegen. remove needless code (when filter-only, no need to emit dfa-code).

diff -r b02b321d0e06 -r 56a997f2c121 pyrect/translator/grep_translator.py
--- a/pyrect/translator/grep_translator.py	Sun Nov 07 01:48:19 2010 +0900
+++ b/pyrect/translator/grep_translator.py	Sun Nov 07 03:10:43 2010 +0900
@@ -27,6 +27,7 @@
         self.thread_dfa = 1
         self.thread_line = 1
         self.filter = True
+        self.filter_only = False
         self.start = "matcher"
         self.interface = "UCHARP beg, UCHARP buf, UCHARP end"
         self.args = "beg, buf, end"
@@ -50,7 +51,7 @@
         self.emit("#include <fcntl.h>")
         self.emit("#include <string.h>")
 
-        self.emit_skip()
+        #self.emit_skip()
 
         for state in self.cg.map.iterkeys():
             self.emit("void %s(%s);" % (self.state_name(state), self.interface))
@@ -65,6 +66,9 @@
         grepsource = open(self.BASE_DIR + "/template/grep.c")
         self.emit(grepsource.read())
 
+    #TODO: filter is faster than dfa in matching.
+    #but slower than that in compiling.
+    #We have to improve this problem.
     def emit_filter(self, words):
         def longest(s1, s2):
             if len(s1) >= len(s2):
@@ -75,16 +79,15 @@
         key = reduce(longest, words)
 
         if len(words) == 1 and len(key) == self.regexp.min_len:
-            filter_only = True
+            self.filter_only = True
         else:
-            filter_only = False
             filter_prefix = False
 
         def emit_next():
             self.emit("beg = memrchr(buf, '\\n', beg);")
-            if filter_only:
+            if self.filter_only:
                 self.emit("accept(%s);" % self.args)
-            elif filter_prefix:
+            elif self.filter_prefix:
                 self.emit("buf -= %d;" % len(key))
                 self.emit("dfa(%s);" % self.args)
             else:
@@ -106,26 +109,23 @@
         for i in range(l - 1):
             skip[ord(key[i])] = str(l-1-i)
 
-        self.emit('static UCHAR key[] = "%s";' % key)
-        self.emiti(   "static int skip[256] = {")
+        self.emit('static const UCHAR key[] = "%s";' % key)
+
+        self.emiti(   "static const UCHAR skip[256] = {")
         for i in range(8):
             i = i * 32
             self.emit(",".join(skip[i:i+32]) + ",")
         self.emitd(   "};")
 
-        self.emit("UCHARP tmp; register UCHAR c;",  2)
-        self.emit("int i; buf += %d;" % (l-1))
-        self.emiti("while (buf < end) {")
+        self.emit("UCHARP tmp = buf; UCHAR c;",  2)
+        self.emit("int i; buf += %d - skip[c];" % (l-1))
+        self.emiti("while ((buf += skip[c]) < end) {")
         self.emiti(  "if ((c = *buf) == %d /*'%c'*/) {" % (ord(key[l-1]), key[l-1]))
         self.emit(     "i = %d; tmp = buf;" % (l-1))
-        self.emiti(    "while (key[--i] == *(--tmp)) {")
-        self.emiti(       "if (i == 0) {")
-        self.emit(          "beg = memrchr(buf, '\\n', beg);")
-        self.emit(          "goto next;")
-        self.emitd(       "}")
+        self.emit(     "while (key[--i] == *(--tmp)) {")
+        self.emit(       "if (i == 0) goto next;")
         self.emitd(    "}")
         self.emitd(  "}")
-        self.emit(   "buf += skip[c];")
         self.emitd("}")
         self.emit( "return;")
         self.emit( "next:")
@@ -144,8 +144,6 @@
 
     def emit_accept_state(self):
         self.emiti("void accept(%s) {" % self.interface)
-        #self.emit(   "printf(\"*beg = %c, *buf = %c, *end = %c; \\n\", *beg, *buf, *end);")
-        #self.emit(   "printf(\"beg = %x, buf = %x, end = %x; \\n\", beg, buf, end);")
         self.emit(   "buf--;")
         self.emit(   "UCHARP ret = (UCHARP)memchr(buf, '\\n', (buf - end));")
         self.emit(   'if (ret == NULL) {fprintf(stderr, "memchr NULL err!"); exit(0);}')
@@ -180,6 +178,8 @@
         self.emitd("}")
 
     def emit_state(self, cur_state, transition):
+        if self.filter_only: return
+
         self.emiti("void %s(%s) {" % (self.state_name(cur_state), self.interface))
 
         if cur_state in self.cg.accepts: