libbb: introduce and use strcpy_and_process_escape_sequences

function                                             old     new   delta
strcpy_and_process_escape_sequences                    -      50     +50
bb_process_escape_sequence                           148     138     -10
printf_main                                          789     776     -13
getty_main                                          1897    1831     -66
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/3 up/down: 50/-89)            Total: -39 bytes

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

6 files changed, 44 insertions, 61 deletions

diff --git a/coreutils/printf.c b/coreutils/printf.c
index 2cc238439..c8395fa89 100644
--- a/coreutils/printf.c
+++ b/coreutils/printf.c
@@ -122,16 +122,14 @@ static double my_xstrtod(const char *arg)
         return result;
 }
 
-static void print_esc_string(char *str)
+static void print_esc_string(const char *str)
 {
-        while (*str) {
-                if (*str == '\\') {
-                        str++;
-                        bb_putchar(bb_process_escape_sequence((const char **)&str));
-                } else {
-                        bb_putchar(*str);
-                        str++;
-                }
+        char c;
+        while ((c = *str) != '\0') {
+                str++;
+                if (c == '\\')
+                        c = bb_process_escape_sequence(&str);
+                putchar(c);
         }
 }
 
@@ -344,7 +342,7 @@ static char **print_formatted(char *f, char **argv, int *conv_err)
                         f--;
                         break;
                 default:
-                        bb_putchar(*f);
+                        putchar(*f);
                 }
         }
 
diff --git a/e2fsprogs/old_e2fsprogs/fsck.c b/e2fsprogs/old_e2fsprogs/fsck.c
index 524b84652..3a0743bb1 100644
--- a/e2fsprogs/old_e2fsprogs/fsck.c
+++ b/e2fsprogs/old_e2fsprogs/fsck.c
@@ -349,15 +349,7 @@ static void parse_escape(char *word)
         if (!word)
                 return;
 
-        for (p = q = word; *p; q++) {
-                c = *p++;
-                if (c != '\\') {
-                        *q = c;
-                } else {
-                        *q = bb_process_escape_sequence(&p);
-                }
-        }
-        *q = 0;
+        strcpy_and_process_escape_sequences(word, word);
 }
 
 static void free_instance(struct fsck_instance *i)
diff --git a/include/libbb.h b/include/libbb.h
index 409c434cb..c85dab282 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -324,6 +324,7 @@ extern void bb_copyfd_exact_size(int fd1, int fd2, off_t size) FAST_FUNC;
 /* this helper yells "short read!" if param is not -1 */
 extern void complain_copyfd_and_die(off_t sz) NORETURN FAST_FUNC;
 extern char bb_process_escape_sequence(const char **ptr) FAST_FUNC;
+char* strcpy_and_process_escape_sequences(char *dst, const char *src) FAST_FUNC;
 /* xxxx_strip version can modify its parameter:
  * "/"        -> "/"
  * "abc"      -> "abc"
diff --git a/libbb/parse_config.c b/libbb/parse_config.c
index 3fff9f212..9dbfaf5d7 100644
--- a/libbb/parse_config.c
+++ b/libbb/parse_config.c
@@ -187,19 +187,7 @@ again:
 
 #if 0 /* unused so far */
                 if (flags & PARSE_ESCAPE) {
-                        const char *from;
-                        char *to;
-
-                        from = to = tokens[t];
-                        while (*from) {
-                                if (*from == '\\') {
-                                        from++;
-                                        *to++ = bb_process_escape_sequence(&from);
-                                } else {
-                                        *to++ = *from++;
-                                }
-                        }
-                        *to = '\0';
+                        strcpy_and_process_escape_sequences(tokens[t], tokens[t]);
                 }
 #endif
                 /* Skip possible delimiters */
diff --git a/libbb/process_escape_sequence.c b/libbb/process_escape_sequence.c
index 82cbe10dc..dd6e076b0 100644
--- a/libbb/process_escape_sequence.c
+++ b/libbb/process_escape_sequence.c
@@ -31,14 +31,13 @@ char FAST_FUNC bb_process_escape_sequence(const char **ptr)
         unsigned num_digits;
         unsigned r;
         unsigned n;
-        unsigned d;
         unsigned base;
 
         num_digits = n = 0;
         base = 8;
         q = *ptr;
 
-#ifdef WANT_HEX_ESCAPES
+#if WANT_HEX_ESCAPES
         if (*q == 'x') {
                 ++q;
                 base = 16;
@@ -50,20 +49,21 @@ char FAST_FUNC bb_process_escape_sequence(const char **ptr)
          * \02 works, \2 does not (prints \ and 2).
          * We treat \2 as a valid octal escape sequence. */
         do {
-                d = (unsigned char)(*q) - '0';
-#ifdef WANT_HEX_ESCAPES
-                if (d >= 10) {
-                        d = (unsigned char)(_tolower(*q)) - 'a' + 10;
-                }
+#if !WANT_HEX_ESCAPES
+                unsigned d = (unsigned char)(*q) - '0';
+#else
+                unsigned d = (unsigned char)_tolower(*q) - '0';
+                if (d >= 10)
+                        d += ('0' - 'a' + 10);
 #endif
-
                 if (d >= base) {
-#ifdef WANT_HEX_ESCAPES
-                        if ((base == 16) && (!--num_digits)) {
-/*                              return '\\'; */
-                                --q;
+                        if (WANT_HEX_ESCAPES && base == 16) {
+                                --num_digits;
+                                if (num_digits == 0) {
+                                        /* \x<bad_char> */
+                                        --q; /* go back to x */
+                                }
                         }
-#endif
                         break;
                 }
 
@@ -85,7 +85,9 @@ char FAST_FUNC bb_process_escape_sequence(const char **ptr)
                         }
                 } while (*++p);
                 /* p points to found escape char or NUL,
-                 * advance it and find what it translates to */
+                 * advance it and find what it translates to.
+                 * Note that unrecognized sequence \z returns '\'
+                 * and leaves ptr pointing to z. */
                 p += sizeof(charmap) / 2;
                 n = *p;
         }
@@ -94,3 +96,17 @@ char FAST_FUNC bb_process_escape_sequence(const char **ptr)
 
         return (char) n;
 }
+
+char* FAST_FUNC strcpy_and_process_escape_sequences(char *dst, const char *src)
+{
+        while (1) {
+                char c, c1;
+                c = c1 = *src++;
+                if (c1 == '\\')
+                        c1 = bb_process_escape_sequence(&src);
+                *dst = c1;
+                if (c == '\0')
+                        return dst;
+                dst++;
+        }
+}
diff --git a/loginutils/getty.c b/loginutils/getty.c
index b1cd235fb..ab55ea4b0 100644
--- a/loginutils/getty.c
+++ b/loginutils/getty.c
@@ -188,21 +188,9 @@ static void parse_args(char **argv, struct options *op, char **fakehost_p)
                 &(op->login), &op->timeout);
         argv += optind;
         if (op->flags & F_INITSTRING) {
-                const char *p = op->initstring;
-                char *q;
-
-                op->initstring = q = xstrdup(p);
-                /* copy optarg into op->initstring decoding \ddd
-                   octal codes into chars */
-                while (*p) {
-                        if (*p == '\\') {
-                                p++;
-                                *q++ = bb_process_escape_sequence(&p);
-                        } else {
-                                *q++ = *p++;
-                        }
-                }
-                *q = '\0';
+                op->initstring = xstrdup(op->initstring);
+                /* decode \ddd octal codes into chars */
+                strcpy_and_process_escape_sequences((char*)op->initstring, op->initstring);
         }
         op->flags ^= F_ISSUE;           /* invert flag "show /etc/issue" */
         debug("after getopt\n");