[src/trunk]: src/usr.bin/make make(1): make implementation of the :S modifier...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/cce8aa7b4ab6
branches:  trunk
changeset: 936169:cce8aa7b4ab6
user:      rillig <rillig%NetBSD.org@localhost>
date:      Mon Jul 20 15:10:35 2020 +0000

description:
make(1): make implementation of the :S modifier simpler

diffstat:

 usr.bin/make/var.c |  131 ++++++++++++++++++----------------------------------
 1 files changed, 45 insertions(+), 86 deletions(-)

diffs (165 lines):

diff -r 0c3f8a56d3de -r cce8aa7b4ab6 usr.bin/make/var.c
--- a/usr.bin/make/var.c        Mon Jul 20 14:59:57 2020 +0000
+++ b/usr.bin/make/var.c        Mon Jul 20 15:10:35 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: var.c,v 1.278 2020/07/20 14:50:41 rillig Exp $ */
+/*     $NetBSD: var.c,v 1.279 2020/07/20 15:10:35 rillig Exp $ */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -69,14 +69,14 @@
  */
 
 #ifndef MAKE_NATIVE
-static char rcsid[] = "$NetBSD: var.c,v 1.278 2020/07/20 14:50:41 rillig Exp $";
+static char rcsid[] = "$NetBSD: var.c,v 1.279 2020/07/20 15:10:35 rillig Exp $";
 #else
 #include <sys/cdefs.h>
 #ifndef lint
 #if 0
 static char sccsid[] = "@(#)var.c      8.3 (Berkeley) 3/19/94";
 #else
-__RCSID("$NetBSD: var.c,v 1.278 2020/07/20 14:50:41 rillig Exp $");
+__RCSID("$NetBSD: var.c,v 1.279 2020/07/20 15:10:35 rillig Exp $");
 #endif
 #endif /* not lint */
 #endif
@@ -1351,96 +1351,55 @@
 VarSubstitute(GNode *ctx MAKE_ATTR_UNUSED, const char *word, SepBuf *buf,
              void *data)
 {
-    int wordLen = strlen(word);
-    const char *cp;            /* General pointer */
+    size_t wordLen = strlen(word);
     VarPattern *pattern = data;
-
-    if ((pattern->pflags & (VARP_SUB_ONE | VARP_SUB_MATCHED)) !=
-       (VARP_SUB_ONE | VARP_SUB_MATCHED)) {
-       /*
-        * Still substituting -- break it down into simple anchored cases
-        * and if none of them fits, perform the general substitution case.
-        */
-       if ((pattern->pflags & VARP_MATCH_START) &&
-           (strncmp(word, pattern->lhs, pattern->leftLen) == 0)) {
-           /*
-            * Anchored at start and beginning of word matches pattern
-            */
-           if ((pattern->pflags & VARP_MATCH_END) &&
-               (wordLen == pattern->leftLen)) {
-               /*
-                * Also anchored at end and matches to the end (word
-                * is same length as pattern).
-                */
-               SepBuf_AddBytes(buf, pattern->rhs, pattern->rightLen);
-               pattern->pflags |= VARP_SUB_MATCHED;
-           } else if (pattern->pflags & VARP_MATCH_END) {
-               /*
-                * Doesn't match to end -- copy word wholesale
-                */
-               goto nosub;
-           } else {
-               /*
-                * Matches at start but need to copy in trailing characters
-                */
-               SepBuf_AddBytes(buf, pattern->rhs, pattern->rightLen);
-               SepBuf_AddBytes(buf, word + pattern->leftLen,
-                               wordLen - pattern->leftLen);
-               pattern->pflags |= VARP_SUB_MATCHED;
-           }
-       } else if (pattern->pflags & VARP_MATCH_START) {
-           /*
-            * Had to match at start of word and didn't -- copy whole word.
-            */
+    const VarPatternFlags pflags = pattern->pflags;
+
+    if ((pflags & (VARP_SUB_ONE | VARP_SUB_MATCHED)) ==
+       (VARP_SUB_ONE | VARP_SUB_MATCHED))
+       goto nosub;
+
+    if (pattern->pflags & VARP_MATCH_START) {
+       if (strncmp(word, pattern->lhs, pattern->leftLen) != 0)
            goto nosub;
-       } else if (pattern->pflags & VARP_MATCH_END) {
-           /*
-            * Anchored at end, Find only place match could occur (leftLen
-            * characters from the end of the word) and see if it does. Note
-            * that because the $ will be left at the end of the lhs, we have
-            * to use strncmp.
-            */
-           cp = word + (wordLen - pattern->leftLen);
-           if (cp >= word &&
-               strncmp(cp, pattern->lhs, pattern->leftLen) == 0) {
-               /*
-                * Match found. Stuff in the initial, unmatched part of the
-                * word followed by the right-hand-side.
-                */
-               SepBuf_AddBytes(buf, word, cp - word);
-               SepBuf_AddBytes(buf, pattern->rhs, pattern->rightLen);
-               pattern->pflags |= VARP_SUB_MATCHED;
-           } else {
-               /*
-                * Had to match at end and didn't. Copy entire word.
-                */
+
+       if (pattern->pflags & VARP_MATCH_END) {
+           if (wordLen != (size_t)pattern->leftLen)
                goto nosub;
-           }
+
+           SepBuf_AddBytes(buf, pattern->rhs, pattern->rightLen);
+           pattern->pflags |= VARP_SUB_MATCHED;
        } else {
-           /*
-            * Pattern is unanchored: search for the pattern in the word using
-            * String_FindSubstring, copying unmatched portions and the
-            * right-hand-side for each match found, handling non-global
-            * substitutions correctly, etc. When the loop is done, any
-            * remaining part of the word (word and wordLen are adjusted
-            * accordingly through the loop) is copied straight into the
-            * buffer.
-            */
-           while ((cp = Str_FindSubstring(word, pattern->lhs)) != NULL) {
-               SepBuf_AddBytes(buf, word, cp - word);
-               SepBuf_AddBytes(buf, pattern->rhs, pattern->rightLen);
-               wordLen -= (cp - word) + pattern->leftLen;
-               word = cp + pattern->leftLen;
-               if (wordLen == 0)
-                   break;
-               if ((pattern->pflags & VARP_SUB_GLOBAL) == 0)
-                   break;
-               pattern->pflags |= VARP_SUB_MATCHED;
-           }
-           SepBuf_AddBytes(buf, word, wordLen);
+           SepBuf_AddBytes(buf, pattern->rhs, pattern->rightLen);
+           SepBuf_AddBytes(buf, word + pattern->leftLen,
+                           wordLen - pattern->leftLen);
+           pattern->pflags |= VARP_SUB_MATCHED;
        }
        return;
     }
+
+    if (pattern->pflags & VARP_MATCH_END) {
+       const char *cp = word + (wordLen - pattern->leftLen);
+       if (cp < word || strncmp(cp, pattern->lhs, pattern->leftLen) != 0)
+           goto nosub;
+
+       SepBuf_AddBytes(buf, word, cp - word);
+       SepBuf_AddBytes(buf, pattern->rhs, pattern->rightLen);
+       pattern->pflags |= VARP_SUB_MATCHED;
+       return;
+    }
+
+    /* unanchored */
+    const char *cp;
+    while ((cp = Str_FindSubstring(word, pattern->lhs)) != NULL) {
+       SepBuf_AddBytes(buf, word, cp - word);
+       SepBuf_AddBytes(buf, pattern->rhs, pattern->rightLen);
+       wordLen -= (cp - word) + pattern->leftLen;
+       word = cp + pattern->leftLen;
+       if (wordLen == 0 || !(pattern->pflags & VARP_SUB_GLOBAL))
+           break;
+       pattern->pflags |= VARP_SUB_MATCHED;
+    }
 nosub:
     SepBuf_AddBytes(buf, word, wordLen);
 }