1 files changed, 35 insertions, 1 deletions

diff --git a/findutils/grep.c b/findutils/grep.c
index f2ed01e74..9d38ef912 100644
--- a/findutils/grep.c
+++ b/findutils/grep.c
@@ -87,7 +87,11 @@ enum {
 
 struct globals {
         int max_matches;
+#if !ENABLE_EXTRA_COMPAT
         int reflags;
+#else
+        RE_TRANSLATE_TYPE case_fold; /* RE_TRANSLATE_TYPE is [[un]signed] char* */
+#endif
         smalluint invert_search;
         smalluint print_filename;
         smalluint open_errors;
@@ -110,7 +114,19 @@ struct globals {
         }; \
 } while (0)
 #define max_matches       (G.max_matches         )
+#if !ENABLE_EXTRA_COMPAT
 #define reflags           (G.reflags             )
+#else
+#define case_fold         (G.case_fold           )
+/* http://www.delorie.com/gnu/docs/regex/regex_46.html */
+#define reflags           re_syntax_options
+#undef REG_NOSUB
+#undef REG_EXTENDED
+#undef REG_ICASE
+#define REG_NOSUB    bug:is:here /* should not be used */
+#define REG_EXTENDED RE_SYNTAX_EGREP
+#define REG_ICASE    bug:is:here /* should not be used */
+#endif
 #define invert_search     (G.invert_search       )
 #define print_filename    (G.print_filename      )
 #define open_errors       (G.open_errors         )
@@ -240,6 +256,7 @@ static int grep_file(FILE *file)
                                         xregcomp(&gl->compiled_regex, gl->pattern, reflags);
 #else
                                         memset(&gl->compiled_regex, 0, sizeof(gl->compiled_regex));
+                                        gl->compiled_regex.translate = case_fold; /* for -i */
                                         if (re_compile_pattern(gl->pattern, strlen(gl->pattern), &gl->compiled_regex))
                                                 bb_error_msg_and_die("bad regex '%s'", gl->pattern);
 #endif
@@ -532,17 +549,34 @@ int grep_main(int argc, char **argv)
         if (ENABLE_FEATURE_GREP_FGREP_ALIAS && applet_name[0] == 'f')
                 option_mask32 |= OPT_F;
 
+#if !ENABLE_EXTRA_COMPAT
         if (!(option_mask32 & (OPT_o | OPT_w)))
                 reflags = REG_NOSUB;
+#endif
 
         if (ENABLE_FEATURE_GREP_EGREP_ALIAS
          && (applet_name[0] == 'e' || (option_mask32 & OPT_E))
         ) {
                 reflags |= REG_EXTENDED;
         }
+#if ENABLE_EXTRA_COMPAT
+        else {
+                reflags = RE_SYNTAX_GREP;
+        }
+#endif
 
-        if (option_mask32 & OPT_i)
+        if (option_mask32 & OPT_i) {
+#if !ENABLE_EXTRA_COMPAT
                 reflags |= REG_ICASE;
+#else
+                int i;
+                case_fold = xmalloc(256);
+                for (i = 0; i < 256; i++)
+                        case_fold[i] = (unsigned char)i;
+                for (i = 'a'; i <= 'z'; i++)
+                        case_fold[i] = (unsigned char)(i - ('a' - 'A'));
+#endif
+        }
 
         argv += optind;
         argc -= optind;