xargs: add support for -I and -i. Closes 493

function                                             old     new   delta
process_stdin_with_replace                             -     195    +195
xmalloc_substitute_string                              -     145    +145
xargs_main                                           808     884     +76
count_strstr                                           -      45     +45
packed_usage                                       29580   29571      -9
parse_params                                        1445    1416     -29
func_exec                                            285     138    -147
------------------------------------------------------------------------------
(add/remove: 4/0 grow/shrink: 1/3 up/down: 461/-185)          Total: 276 bytes
   text	   data	    bss	    dec	    hex	filename
 922156	    932	  17692	 940780	  e5aec	busybox_old
 922440	    932	  17692	 941064	  e5c08	busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/libbb/replace.c b/libbb/replace.c
new file mode 100644
index 000000000..8711f957d
--- /dev/null
+++ b/libbb/replace.c
@@ -0,0 +1,45 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+
+//kbuild:lib-y += replace.o
+
+#include "libbb.h"
+
+unsigned FAST_FUNC count_strstr(const char *str, const char *sub)
+{
+	size_t sub_len = strlen(sub);
+	unsigned count = 0;
+
+	while ((str = strstr(str, sub)) != NULL) {
+		count++;
+		str += sub_len;
+	}
+	return count;
+}
+
+char* FAST_FUNC xmalloc_substitute_string(const char *src, int count, const char *sub, const char *repl)
+{
+	char *buf, *dst, *end;
+	size_t sub_len = strlen(sub);
+	size_t repl_len = strlen(repl);
+
+	//dbg_msg("subst(s:'%s',count:%d,sub:'%s',repl:'%s'", src, count, sub, repl);
+
+	buf = dst = xmalloc(strlen(src) + count * ((int)repl_len - (int)sub_len) + 1);
+	/* we replace each sub with repl */
+	while ((end = strstr(src, sub)) != NULL) {
+		dst = mempcpy(dst, src, end - src);
+		dst = mempcpy(dst, repl, repl_len);
+		/*src = end + 1; - GNU findutils 4.5.10 doesn't do this... */
+		src = end + sub_len; /* but this. Try "xargs -Iaa echo aaa" */
+	}
+	strcpy(dst, src);
+	//dbg_msg("subst9:'%s'", buf);
+	return buf;
+}