ash: code shrink around varvalue

Based on commit c989d72 from git://git.kernel.org/pub/scm/utils/dash/dash.git
by Herbert Xu

function                                             old     new   delta
strtodest                                              -      40     +40
memtodest                                            123     147     +24
parse_command                                       1443    1440      -3
readtoken1                                          3205    3199      -6
argstr                                              1203    1180     -23
varvalue                                             788     660    -128
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/4 up/down: 64/-160)           Total: -96 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 38 insertions, 46 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 7af8842bb..a81922add 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -5539,6 +5539,11 @@ ash_arith(const char *s)
 #define RMESCAPE_GROW   0x8     /* Grow strings instead of stalloc */
 #define RMESCAPE_HEAP   0x10    /* Malloc strings instead of stalloc */
 
+/* Add CTLESC when necessary. */
+#define QUOTES_ESC     (EXP_FULL | EXP_CASE | EXP_REDIR)
+/* Do not skip NUL characters. */
+#define QUOTES_KEEPNUL EXP_TILDE
+
 /*
  * Structure specifying which parts of the string should be searched
  * for IFS characters.
@@ -5695,29 +5700,34 @@ preglob(const char *pattern, int quoted, int flag)
 static void
 memtodest(const char *p, size_t len, int syntax, int quotes)
 {
-        char *q = expdest;
+        char *q;
+
+        if (!len)
+                return;
 
-        q = makestrspace(quotes ? len * 2 : len, q);
+        q = makestrspace((quotes & QUOTES_ESC) ? len * 2 : len, expdest);
 
-        while (len--) {
+        do {
                 unsigned char c = *p++;
-                if (c == '\0')
-                        continue;
-                if (quotes) {
+                if (c) {
                         int n = SIT(c, syntax);
-                        if (n == CCTL || n == CBACK)
+                        if ((quotes & QUOTES_ESC) &&
+                                        (n == CCTL || n == CBACK))
                                 USTPUTC(CTLESC, q);
-                }
+                } else if (!(quotes & QUOTES_KEEPNUL))
+                        continue;
                 USTPUTC(c, q);
-        }
+        } while (--len);
 
         expdest = q;
 }
 
-static void
+static size_t
 strtodest(const char *p, int syntax, int quotes)
 {
-        memtodest(p, strlen(p), syntax, quotes);
+        size_t len = strlen(p);
+        memtodest(p, len, syntax, quotes);
+        return len;
 }
 
 /*
@@ -5790,7 +5800,7 @@ exptilde(char *startp, char *p, int flags)
         char *name;
         struct passwd *pw;
         const char *home;
-        int quotes = flags & (EXP_FULL | EXP_CASE | EXP_REDIR);
+        int quotes = flags & QUOTES_ESC;
 
         name = p + 1;
 
@@ -6043,7 +6053,7 @@ argstr(char *p, int flags, struct strlist *var_str_list)
                 '\0'
         };
         const char *reject = spclchars;
-        int quotes = flags & (EXP_FULL | EXP_CASE | EXP_REDIR); /* do CTLESC */
+        int quotes = flags & QUOTES_ESC;
         int breakall = flags & EXP_WORD;
         int inquotes;
         size_t length;
@@ -6608,13 +6618,16 @@ varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
         const char *p;
         int num;
         int i;
-        int sepq = 0;
         ssize_t len = 0;
-        int subtype = varflags & VSTYPE;
-        int quotes = flags & (EXP_FULL | EXP_CASE | EXP_REDIR);
+        int sep;
         int quoted = varflags & VSQUOTE;
+        int subtype = varflags & VSTYPE;
+        int discard = subtype == VSPLUS || subtype == VSLENGTH;
+        int quotes = (discard ? 0 : (flags & QUOTES_ESC)) | QUOTES_KEEPNUL;
         int syntax = quoted ? DQSYNTAX : BASESYNTAX;
 
+        sep = quoted ? ((flags & EXP_FULL) << CHAR_BIT) : 0;
+
         switch (*name) {
         case '$':
                 num = rootpid;
@@ -6649,7 +6662,7 @@ varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
                 break;
         case '@': {
                 char **ap;
-                int sep;
+                char sepc;
 
                 if (quoted && (flags & EXP_FULL)) {
                         /* note: this is not meant as PEOF value */
@@ -6659,39 +6672,20 @@ varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
                 /* fall through */
         case '*':
                 sep = ifsset() ? (unsigned char)(ifsval()[0]) : ' ';
-                i = SIT(sep, syntax);
-                if (quotes && (i == CCTL || i == CBACK))
-                        sepq = 1;
  param:
                 ap = shellparam.p;
+                sepc = sep;
                 if (!ap)
                         return -1;
                 while ((p = *ap++) != NULL) {
-                        size_t partlen;
-
-                        partlen = strlen(p);
-                        len += partlen;
-
-                        if (!(subtype == VSPLUS || subtype == VSLENGTH))
-                                memtodest(p, partlen, syntax, quotes);
+                        len += strtodest(p, syntax, quotes);
 
                         if (*ap && sep) {
-                                char *q;
-
                                 len++;
-                                if (subtype == VSPLUS || subtype == VSLENGTH) {
-                                        continue;
-                                }
-                                q = expdest;
-                                if (sepq)
-                                        STPUTC(CTLESC, q);
-                                /* note: may put NUL despite sep != 0
-                                 * (see sep = 1 << CHAR_BIT above) */
-                                STPUTC(sep, q);
-                                expdest = q;
+                                memtodest(&sepc, 1, syntax, quotes);
                         }
                 }
-                return len;
+                break;
         } /* case '@' and '*' */
         case '0':
         case '1':
@@ -6740,9 +6734,7 @@ varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
                 if (!p)
                         return -1;
 
-                len = strlen(p);
-                if (!(subtype == VSPLUS || subtype == VSLENGTH))
-                        memtodest(p, len, syntax, quotes);
+                len = strtodest(p, syntax, quotes);
 #if ENABLE_UNICODE_SUPPORT
                 if (subtype == VSLENGTH && len > 0) {
                         reinit_unicode_for_ash();
@@ -6751,10 +6743,10 @@ varvalue(char *name, int varflags, int flags, struct strlist *var_str_list)
                         }
                 }
 #endif
-                return len;
+                break;
         }
 
-        if (subtype == VSPLUS || subtype == VSLENGTH)
+        if (discard)
                 STADJUST(-len, expdest);
         return len;
 }
@@ -6870,7 +6862,7 @@ evalvar(char *p, int flags, struct strlist *var_str_list)
                 patloc = expdest - (char *)stackblock();
                 if (NULL == subevalvar(p, /* varname: */ NULL, patloc, subtype,
                                 startloc, varflags,
-                                /* quotes: */ flags & (EXP_FULL | EXP_CASE | EXP_REDIR),
+                                /* quotes: */ flags & QUOTES_ESC,
                                 var_str_list)
                 ) {
                         int amount = expdest - (