ash: shrink on top of previous change

function                                             old     new   delta
readtoken1                                          3201    3221     +20
xxreadtoken                                          306     313      +7
pungetc                                               13      12      -1
ash_main                                            1380    1379      -1
setinputfile                                         196     192      -4
plinno                                                 4       -      -4
parsenleft                                             4       -      -4
parsenextc                                             4       -      -4
parselleft                                             4       -      -4
setinputstring                                        67      62      -5
pushstring                                           123     114      -9
pgetc                                                455     438     -17
pushfile                                              69      31     -38
popfile                                              114      76     -38
------------------------------------------------------------------------------
(add/remove: 0/4 grow/shrink: 2/8 up/down: 27/-129)          Total: -102 bytes
   text    data     bss     dec     hex filename
 798750     564    7756  807070   c509e busybox_old
 798664     560    7748  806972   c503c busybox_unstripped

1 files changed, 128 insertions, 111 deletions

diff --git a/shell/ash.c b/shell/ash.c
index e1df89418..05e2f630d 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -1033,8 +1033,8 @@ struct alias;
 
 struct strpush {
         struct strpush *prev;   /* preceding string on stack */
-        char *prevstring;
-        int prevnleft;
+        char *prev_string;
+        int prev_left_in_line;
 #if ENABLE_ASH_ALIAS
         struct alias *ap;       /* if push was associated with an alias */
 #endif
@@ -1045,9 +1045,9 @@ struct parsefile {
         struct parsefile *prev; /* preceding file on stack */
         int linno;              /* current line */
         int fd;                 /* file descriptor (or -1 if string) */
-        int nleft;              /* number of chars left in this line */
-        int lleft;              /* number of chars left in this buffer */
-        char *nextc;            /* next char in buffer */
+        int left_in_line;       /* number of chars left in this line */
+        int left_in_buffer;     /* number of chars left in this buffer past the line */
+        char *next_to_pgetc;    /* next char in buffer */
         char *buf;              /* input buffer */
         struct strpush *strpush; /* for pushing strings at this level */
         struct strpush basestrpush; /* so pushing one is fast */
@@ -9084,19 +9084,48 @@ enum {
         INPUT_NOFILE_OK = 2,
 };
 
-static int plinno = 1;                  /* input line number */
-/* number of characters left in input buffer */
-static int parsenleft;                  /* copy of parsefile->nleft */
-static int parselleft;                  /* copy of parsefile->lleft */
-/* next character in input buffer */
-static char *parsenextc;                /* copy of parsefile->nextc */
-
 static smallint checkkwd;
 /* values of checkkwd variable */
 #define CHKALIAS        0x1
 #define CHKKWD          0x2
 #define CHKNL           0x4
 
+/*
+ * Push a string back onto the input at this current parsefile level.
+ * We handle aliases this way.
+ */
+#if !ENABLE_ASH_ALIAS
+#define pushstring(s, ap) pushstring(s)
+#endif
+static void
+pushstring(char *s, struct alias *ap)
+{
+        struct strpush *sp;
+        int len;
+
+        len = strlen(s);
+        INT_OFF;
+        if (g_parsefile->strpush) {
+                sp = ckzalloc(sizeof(*sp));
+                sp->prev = g_parsefile->strpush;
+        } else {
+                sp = &(g_parsefile->basestrpush);
+        }
+        g_parsefile->strpush = sp;
+        sp->prev_string = g_parsefile->next_to_pgetc;
+        sp->prev_left_in_line = g_parsefile->left_in_line;
+#if ENABLE_ASH_ALIAS
+        sp->ap = ap;
+        if (ap) {
+                ap->flag |= ALIASINUSE;
+                sp->string = s;
+        }
+#endif
+        g_parsefile->next_to_pgetc = s;
+        g_parsefile->left_in_line = len;
+        INT_ON;
+}
+
 static void
 popstring(void)
 {
@@ -9105,7 +9134,9 @@ popstring(void)
         INT_OFF;
 #if ENABLE_ASH_ALIAS
         if (sp->ap) {
-                if (parsenextc[-1] == ' ' || parsenextc[-1] == '\t') {
+                if (g_parsefile->next_to_pgetc[-1] == ' '
+                 || g_parsefile->next_to_pgetc[-1] == '\t'
+                ) {
                         checkkwd |= CHKALIAS;
                 }
                 if (sp->string != sp->ap->val) {
@@ -9117,8 +9148,8 @@ popstring(void)
                 }
         }
 #endif
-        parsenextc = sp->prevstring;
-        parsenleft = sp->prevnleft;
+        g_parsefile->next_to_pgetc = sp->prev_string;
+        g_parsefile->left_in_line = sp->prev_left_in_line;
         g_parsefile->strpush = sp->prev;
         if (sp != &(g_parsefile->basestrpush))
                 free(sp);
@@ -9130,8 +9161,8 @@ preadfd(void)
 {
         int nr;
         char *buf = g_parsefile->buf;
-        parsenextc = buf;
 
+        g_parsefile->next_to_pgetc = buf;
 #if ENABLE_FEATURE_EDITING
  retry:
         if (!iflag || g_parsefile->fd != STDIN_FILENO)
@@ -9182,8 +9213,9 @@ preadfd(void)
  * Refill the input buffer and return the next input character:
  *
  * 1) If a string was pushed back on the input, pop it;
- * 2) If an EOF was pushed back (parsenleft < -BIGNUM) or we are reading
- *    from a string so we can't refill the buffer, return EOF.
+ * 2) If an EOF was pushed back (g_parsefile->left_in_line < -BIGNUM)
+ *    or we are reading from a string so we can't refill the buffer,
+ *    return EOF.
  * 3) If the is more stuff in this buffer, use it else call read to fill it.
  * 4) Process input up to the next newline, deleting nul characters.
  */
@@ -9197,8 +9229,10 @@ preadbuffer(void)
 
         while (g_parsefile->strpush) {
 #if ENABLE_ASH_ALIAS
-                if (parsenleft == -1 && g_parsefile->strpush->ap
-                 && parsenextc[-1] != ' ' && parsenextc[-1] != '\t'
+                if (g_parsefile->left_in_line == -1
+                 && g_parsefile->strpush->ap
+                 && g_parsefile->next_to_pgetc[-1] != ' '
+                 && g_parsefile->next_to_pgetc[-1] != '\t'
                 ) {
                         pgetc_debug("preadbuffer PEOA");
                         return PEOA;
@@ -9206,43 +9240,51 @@ preadbuffer(void)
 #endif
                 popstring();
                 /* try "pgetc" now: */
-                pgetc_debug("internal pgetc at %d:%p'%s'", parsenleft, parsenextc, parsenextc);
-                if (--parsenleft >= 0)
-                        return signed_char2int(*parsenextc++);
-        }
-        /* on both branches above parsenleft < 0.
+                pgetc_debug("preadbuffer internal pgetc at %d:%p'%s'",
+                                g_parsefile->left_in_line,
+                                g_parsefile->next_to_pgetc,
+                                g_parsefile->next_to_pgetc);
+                if (--g_parsefile->left_in_line >= 0)
+                        return (unsigned char)(*g_parsefile->next_to_pgetc++);
+        }
+        /* on both branches above g_parsefile->left_in_line < 0.
          * "pgetc" needs refilling.
          */
 
         /* -90 is -BIGNUM. Below we use -99 to mark "EOF on read",
-         * pungetc() may decrement it a few times. -90 is enough.
+         * pungetc() may increment it a few times.
+         * Assuming it won't increment it to 0.
          */
-        if (parsenleft < -90 || g_parsefile->buf == NULL) {
+        if (g_parsefile->left_in_line < -90 || g_parsefile->buf == NULL) {
                 pgetc_debug("preadbuffer PEOF1");
-                /* even in failure keep them in lock step,
-                 * for correct pungetc. */
-                parsenextc++;
+                /* even in failure keep left_in_line and next_to_pgetc
+                 * in lock step, for correct multi-layer pungetc.
+                 * left_in_line was decremented before preadbuffer(),
+                 * must inc next_to_pgetc: */
+                g_parsefile->next_to_pgetc++;
                 return PEOF;
         }
 
-        more = parselleft;
+        more = g_parsefile->left_in_buffer;
         if (more <= 0) {
                 flush_stdout_stderr();
  again:
                 more = preadfd();
                 if (more <= 0) {
-                        parselleft = parsenleft = -99;
+                        /* don't try reading again */
+                        g_parsefile->left_in_line = -99;
                         pgetc_debug("preadbuffer PEOF2");
-                        parsenextc++;
+                        g_parsefile->next_to_pgetc++;
                         return PEOF;
                 }
         }
 
         /* Find out where's the end of line.
-         * Set parsenleft/parselleft acordingly.
+         * Set g_parsefile->left_in_line
+         * and g_parsefile->left_in_buffer acordingly.
          * NUL chars are deleted.
          */
-        q = parsenextc;
+        q = g_parsefile->next_to_pgetc;
         for (;;) {
                 char c;
 
@@ -9254,37 +9296,47 @@ preadbuffer(void)
                 } else {
                         q++;
                         if (c == '\n') {
-                                parsenleft = q - parsenextc - 1;
+                                g_parsefile->left_in_line = q - g_parsefile->next_to_pgetc - 1;
                                 break;
                         }
                 }
 
                 if (more <= 0) {
-                        parsenleft = q - parsenextc - 1;
-                        if (parsenleft < 0)
+                        g_parsefile->left_in_line = q - g_parsefile->next_to_pgetc - 1;
+                        if (g_parsefile->left_in_line < 0)
                                 goto again;
                         break;
                 }
         }
-        parselleft = more;
+        g_parsefile->left_in_buffer = more;
 
         if (vflag) {
                 char save = *q;
                 *q = '\0';
-                out2str(parsenextc);
+                out2str(g_parsefile->next_to_pgetc);
                 *q = save;
         }
 
-        pgetc_debug("preadbuffer at %d:%p'%s'", parsenleft, parsenextc, parsenextc);
-        return signed_char2int(*parsenextc++);
+        pgetc_debug("preadbuffer at %d:%p'%s'",
+                        g_parsefile->left_in_line,
+                        g_parsefile->next_to_pgetc,
+                        g_parsefile->next_to_pgetc);
+        return (unsigned char)(*g_parsefile->next_to_pgetc++);
 }
 
-#define pgetc_as_macro() (--parsenleft >= 0 ? signed_char2int(*parsenextc++) : preadbuffer())
+#define pgetc_as_macro() \
+        (--g_parsefile->left_in_line >= 0 \
+        ? (unsigned char)(*g_parsefile->next_to_pgetc++) \
+        : preadbuffer() \
+        )
 
 static int
 pgetc(void)
 {
-        pgetc_debug("pgetc at %d:%p'%s'", parsenleft, parsenextc, parsenextc);
+        pgetc_debug("pgetc_fast at %d:%p'%s'",
+                        g_parsefile->left_in_line,
+                        g_parsefile->next_to_pgetc,
+                        g_parsefile->next_to_pgetc);
         return pgetc_as_macro();
 }
 
@@ -9303,6 +9355,10 @@ pgetc2(void)
 {
         int c;
         do {
+                pgetc_debug("pgetc_fast at %d:%p'%s'",
+                                g_parsefile->left_in_line,
+                                g_parsefile->next_to_pgetc,
+                                g_parsefile->next_to_pgetc);
                 c = pgetc_fast();
         } while (c == PEOA);
         return c;
@@ -9343,45 +9399,12 @@ pfgets(char *line, int len)
 static void
 pungetc(void)
 {
-        parsenleft++;
-        parsenextc--;
-        pgetc_debug("pushed back to %d:%p'%s'", parsenleft, parsenextc, parsenextc);
-}
-
-/*
- * Push a string back onto the input at this current parsefile level.
- * We handle aliases this way.
- */
-#if !ENABLE_ASH_ALIAS
-#define pushstring(s, ap) pushstring(s)
-#endif
-static void
-pushstring(char *s, struct alias *ap)
-{
-        struct strpush *sp;
-        int len;
-
-        len = strlen(s);
-        INT_OFF;
-        if (g_parsefile->strpush) {
-                sp = ckzalloc(sizeof(*sp));
-                sp->prev = g_parsefile->strpush;
-        } else {
-                sp = &(g_parsefile->basestrpush);
-        }
-        g_parsefile->strpush = sp;
-        sp->prevstring = parsenextc;
-        sp->prevnleft = parsenleft;
-#if ENABLE_ASH_ALIAS
-        sp->ap = ap;
-        if (ap) {
-                ap->flag |= ALIASINUSE;
-                sp->string = s;
-        }
-#endif
-        parsenextc = s;
-        parsenleft = len;
-        INT_ON;
+        g_parsefile->left_in_line++;
+        g_parsefile->next_to_pgetc--;
+        pgetc_debug("pushed back to %d:%p'%s'",
+                        g_parsefile->left_in_line,
+                        g_parsefile->next_to_pgetc,
+                        g_parsefile->next_to_pgetc);
 }
 
 /*
@@ -9393,10 +9416,6 @@ pushfile(void)
 {
         struct parsefile *pf;
 
-        g_parsefile->nleft = parsenleft;
-        g_parsefile->lleft = parselleft;
-        g_parsefile->nextc = parsenextc;
-        g_parsefile->linno = plinno;
         pf = ckzalloc(sizeof(*pf));
         pf->prev = g_parsefile;
         pf->fd = -1;
@@ -9418,10 +9437,6 @@ popfile(void)
                 popstring();
         g_parsefile = pf->prev;
         free(pf);
-        parsenleft = g_parsefile->nleft;
-        parselleft = g_parsefile->lleft;
-        parsenextc = g_parsefile->nextc;
-        plinno = g_parsefile->linno;
         INT_ON;
 }
 
@@ -9464,8 +9479,9 @@ setinputfd(int fd, int push)
         g_parsefile->fd = fd;
         if (g_parsefile->buf == NULL)
                 g_parsefile->buf = ckmalloc(IBUFSIZ);
-        parselleft = parsenleft = 0;
-        plinno = 1;
+        g_parsefile->left_in_buffer = 0;
+        g_parsefile->left_in_line = 0;
+        g_parsefile->linno = 1;
 }
 
 /*
@@ -9506,10 +9522,10 @@ setinputstring(char *string)
 {
         INT_OFF;
         pushfile();
-        parsenextc = string;
-        parsenleft = strlen(string);
+        g_parsefile->next_to_pgetc = string;
+        g_parsefile->left_in_line = strlen(string);
         g_parsefile->buf = NULL;
-        plinno = 1;
+        g_parsefile->linno = 1;
         INT_ON;
 }
 
@@ -10653,7 +10669,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
         (void) &prevsyntax;
         (void) &syntax;
 #endif
-        startlinno = plinno;
+        startlinno = g_parsefile->linno;
         bqlist = NULL;
         quotef = 0;
         oldstyle = 0;
@@ -10681,7 +10697,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
                                 if (syntax == BASESYNTAX)
                                         goto endword;   /* exit outer loop */
                                 USTPUTC(c, out);
-                                plinno++;
+                                g_parsefile->linno++;
                                 if (doprompt)
                                         setprompt(2);
                                 c = pgetc();
@@ -10835,7 +10851,7 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
         if (syntax != BASESYNTAX && !parsebackquote && eofmark == NULL)
                 raise_error_syntax("unterminated quoted string");
         if (varnest != 0) {
-                startlinno = plinno;
+                startlinno = g_parsefile->linno;
                 /* { */
                 raise_error_syntax("missing '}'");
         }
@@ -10890,7 +10906,7 @@ checkend: {
                                         continue;
                                 if (*p == '\n' && *q == '\0') {
                                         c = PEOF;
-                                        plinno++;
+                                        g_parsefile->linno++;
                                         needprompt = doprompt;
                                 } else {
                                         pushstring(line, NULL);
@@ -11166,7 +11182,7 @@ parsebackq: {
                         case '\\':
                                 pc = pgetc();
                                 if (pc == '\n') {
-                                        plinno++;
+                                        g_parsefile->linno++;
                                         if (doprompt)
                                                 setprompt(2);
                                         /*
@@ -11189,11 +11205,11 @@ parsebackq: {
 #if ENABLE_ASH_ALIAS
                         case PEOA:
 #endif
-                                startlinno = plinno;
+                                startlinno = g_parsefile->linno;
                                 raise_error_syntax("EOF in backquote substitution");
 
                         case '\n':
-                                plinno++;
+                                g_parsefile->linno++;
                                 needprompt = doprompt;
                                 break;
 
@@ -11334,7 +11350,7 @@ xxreadtoken(void)
         if (needprompt) {
                 setprompt(2);
         }
-        startlinno = plinno;
+        startlinno = g_parsefile->linno;
         for (;;) {                      /* until token or start of word found */
                 c = pgetc_fast();
                 if (c == ' ' || c == '\t' USE_ASH_ALIAS( || c == PEOA))
@@ -11349,7 +11365,7 @@ xxreadtoken(void)
                                 pungetc();
                                 break; /* return readtoken1(...) */
                         }
-                        startlinno = ++plinno;
+                        startlinno = ++g_parsefile->linno;
                         if (doprompt)
                                 setprompt(2);
                 } else {
@@ -11358,7 +11374,7 @@ xxreadtoken(void)
                         p = xxreadtoken_chars + sizeof(xxreadtoken_chars) - 1;
                         if (c != PEOF) {
                                 if (c == '\n') {
-                                        plinno++;
+                                        g_parsefile->linno++;
                                         needprompt = doprompt;
                                 }
 
@@ -11400,7 +11416,7 @@ xxreadtoken(void)
         if (needprompt) {
                 setprompt(2);
         }
-        startlinno = plinno;
+        startlinno = g_parsefile->linno;
         for (;;) {      /* until token or start of word found */
                 c = pgetc_fast();
                 switch (c) {
@@ -11416,7 +11432,7 @@ xxreadtoken(void)
                         continue;
                 case '\\':
                         if (pgetc() == '\n') {
-                                startlinno = ++plinno;
+                                startlinno = ++g_parsefile->linno;
                                 if (doprompt)
                                         setprompt(2);
                                 continue;
@@ -11424,7 +11440,7 @@ xxreadtoken(void)
                         pungetc();
                         goto breakloop;
                 case '\n':
-                        plinno++;
+                        g_parsefile->linno++;
                         needprompt = doprompt;
                         RETURN(TNL);
                 case PEOF:
@@ -13454,7 +13470,7 @@ static void
 init(void)
 {
         /* from input.c: */
-        basepf.nextc = basepf.buf = basebuf;
+        basepf.next_to_pgetc = basepf.buf = basebuf;
 
         /* from trap.c: */
         signal(SIGCHLD, SIG_DFL);
@@ -13575,7 +13591,8 @@ reset(void)
         evalskip = 0;
         loopnest = 0;
         /* from input.c: */
-        parselleft = parsenleft = 0;      /* clear input buffer */
+        g_parsefile->left_in_buffer = 0;
+        g_parsefile->left_in_line = 0;      /* clear input buffer */
         popallfiles();
         /* from parser.c: */
         tokpushback = 0;