libbb: shrink sump.c

function                                             old     new   delta
dot_flags_width_chars                                  -      16     +16
int_convs                                              -       7      +7
lcc                                                    7       -      -7
index_str                                             16       -     -16
rewrite                                             1013     937     -76
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 0/1 up/down: 23/-99)            Total: -76 bytes

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

1 files changed, 80 insertions, 79 deletions

diff --git a/libbb/dump.c b/libbb/dump.c
index e9ac0c673..87c1dce13 100644
--- a/libbb/dump.c
+++ b/libbb/dump.c
@@ -14,12 +14,12 @@
 #include "libbb.h"
 #include "dump.h"
 
-static const char index_str[] ALIGN1 = ".#-+ 0123456789";
+static const char dot_flags_width_chars[] ALIGN1 = ".#-+ 0123456789";
 
 static const char size_conv_str[] ALIGN1 =
 "\x1\x4\x4\x4\x4\x4\x4\x8\x8\x8\x8\010cdiouxXeEfgG";
 
-static const char lcc[] ALIGN1 = "diouxX";
+static const char int_convs[] ALIGN1 = "diouxX";
 
 
 typedef struct priv_dumper_t {
@@ -71,7 +71,7 @@ static NOINLINE int bb_dump_size(FS *fs)
                          * skip any special chars -- save precision in
                          * case it's a %s format.
                          */
-                        while (strchr(index_str + 1, *++fmt))
+                        while (strchr(dot_flags_width_chars + 1, *++fmt))
                                 continue;
                         if (*fmt == '.' && isdigit(*++fmt)) {
                                 prec = atoi(fmt);
@@ -82,14 +82,15 @@ static NOINLINE int bb_dump_size(FS *fs)
                         if (!p) {
                                 if (*fmt == 's') {
                                         bcnt += prec;
-                                } else if (*fmt == '_') {
+                                }
+                                if (*fmt == '_') {
                                         ++fmt;
                                         if ((*fmt == 'c') || (*fmt == 'p') || (*fmt == 'u')) {
                                                 bcnt += 1;
                                         }
                                 }
                         } else {
-                                bcnt += size_conv_str[p - (size_conv_str + 12)];
+                                bcnt += p[-12];
                         }
                 }
                 cur_size += bcnt * fu->reps;
@@ -99,32 +100,30 @@ static NOINLINE int bb_dump_size(FS *fs)
 
 static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
 {
-        enum { NOTOKAY, USEBCNT, USEPREC } sokay;
         FU *fu;
-        PR *pr;
-        char *p1, *p2, *p3;
-        char savech, *fmtp;
-        const char *byte_count_str;
-        int nconv, prec = 0;
 
         for (fu = fs->nextfu; fu; fu = fu->nextfu) {
+                PR *pr;
+                char *p1, *p2, *p3;
+                char *fmtp;
+                int nconv = 0;
                 /*
                  * break each format unit into print units; each
                  * conversion character gets its own.
                  */
-                for (nconv = 0, fmtp = fu->fmt; *fmtp; ) {
-                        /* NOSTRICT */
-                        /* DBU:[dvae@cray.com] zalloc so that forward ptrs start out NULL*/
-                        pr = xzalloc(sizeof(PR));
+                for (fmtp = fu->fmt; *fmtp; ) {
+                        unsigned len;
+                        const char *prec;
+                        const char *byte_count_str;
+
+                        /* DBU:[dvae@cray.com] zalloc so that forward ptrs start out NULL */
+                        pr = xzalloc(sizeof(*pr));
                         if (!fu->nextpr)
                                 fu->nextpr = pr;
 
                         /* skip preceding text and up to the next % sign */
-                        for (p1 = fmtp; *p1 && *p1 != '%'; ++p1)
-                                continue;
-
-                        /* only text in the string */
-                        if (!*p1) {
+                        p1 = strchr(fmtp, '%');
+                        if (!p1) { /* only text in the string */
                                 pr->fmt = fmtp;
                                 pr->flags = F_TEXT;
                                 break;
@@ -134,22 +133,20 @@ static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
                          * get precision for %s -- if have a byte count, don't
                          * need it.
                          */
+                        prec = NULL;
                         if (fu->bcnt) {
-                                sokay = USEBCNT;
                                 /* skip to conversion character */
-                                for (++p1; strchr(index_str, *p1); ++p1)
+                                while (strchr(dot_flags_width_chars, *++p1))
                                         continue;
                         } else {
                                 /* skip any special chars, field width */
-                                while (strchr(index_str + 1, *++p1))
+                                while (strchr(dot_flags_width_chars + 1, *++p1))
                                         continue;
                                 if (*p1 == '.' && isdigit(*++p1)) {
-                                        sokay = USEPREC;
-                                        prec = atoi(p1);
+                                        prec = p1;
                                         while (isdigit(*++p1))
                                                 continue;
-                                } else
-                                        sokay = NOTOKAY;
+                                }
                         }
 
                         p2 = p1 + 1; /* set end pointer */
@@ -174,63 +171,63 @@ static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
                                 }
                                 /* Unlike the original, output the remainder of the format string. */
                                 pr->bcnt = *byte_count_str;
-                        } else if (*p1 == 'l') {
+                        } else
+                        if (*p1 == 'l') { /* %ld etc */
+                                const char *e;
+
                                 ++p2;
                                 ++p1;
  DO_INT_CONV:
-                                {
-                                        const char *e;
-                                        e = strchr(lcc, *p1);
-                                        if (!e) {
-                                                goto DO_BAD_CONV_CHAR;
-                                        }
-                                        pr->flags = F_INT;
-                                        if (e > lcc + 1) {
-                                                pr->flags = F_UINT;
-                                        }
-                                        byte_count_str = "\004\002\001";
-                                        goto DO_BYTE_COUNT;
-                                }
-                                /* NOTREACHED */
-                        } else if (strchr(lcc, *p1)) {
+                                e = strchr(int_convs, *p1); /* "diouxX"? */
+                                if (!e)
+                                        goto DO_BAD_CONV_CHAR;
+                                pr->flags = F_INT;
+                                if (e > int_convs + 1) /* not d or i? */
+                                        pr->flags = F_UINT;
+                                byte_count_str = "\004\002\001";
+                                goto DO_BYTE_COUNT;
+                        } else
+                        if (strchr(int_convs, *p1)) { /* %d etc */
                                 goto DO_INT_CONV;
-                        } else if (strchr("eEfgG", *p1)) {
+                        } else
+                        if (strchr("eEfgG", *p1)) { /* floating point */
                                 pr->flags = F_DBL;
                                 byte_count_str = "\010\004";
                                 goto DO_BYTE_COUNT;
-                        } else if (*p1 == 's') {
+                        } else
+                        if (*p1 == 's') {
                                 pr->flags = F_STR;
-                                if (sokay == USEBCNT) {
-                                        pr->bcnt = fu->bcnt;
-                                } else if (sokay == USEPREC) {
-                                        pr->bcnt = prec;
-                                } else {   /* NOTOKAY */
-                                        bb_error_msg_and_die("%%s requires a precision or a byte count");
+                                pr->bcnt = fu->bcnt;
+                                if (fu->bcnt == 0) {
+                                        if (!prec)
+                                                bb_error_msg_and_die("%%s needs precision or byte count");
+                                        pr->bcnt = atoi(prec);
                                 }
-                        } else if (*p1 == '_') {
-                                ++p2;
+                        } else
+                        if (*p1 == '_') {
+                                p2++;  /* move past a in "%_a" */
                                 switch (p1[1]) {
-                                case 'A':
+                                case 'A':       /* %_A[dox]: print address and the end */
                                         dumper->endfu = fu;
                                         fu->flags |= F_IGNORE;
                                         /* FALLTHROUGH */
-                                case 'a':
+                                case 'a':       /* %_a[dox]: current address */
                                         pr->flags = F_ADDRESS;
-                                        ++p2;
+                                        p2++;  /* move past x in "%_ax" */
                                         if ((p1[2] != 'd') && (p1[2] != 'o') && (p1[2] != 'x')) {
                                                 goto DO_BAD_CONV_CHAR;
                                         }
                                         *p1 = p1[2];
                                         break;
-                                case 'c':
+                                case 'c':       /* %_c: chars, \ooo, \n \r \t etc */
                                         pr->flags = F_C;
                                         /* *p1 = 'c';   set in conv_c */
                                         goto DO_BYTE_COUNT_1;
-                                case 'p':
+                                case 'p':       /* %_p: chars, dots for nonprintable */
                                         pr->flags = F_P;
                                         *p1 = 'c';
                                         goto DO_BYTE_COUNT_1;
-                                case 'u':
+                                case 'u':       /* %_p: chars, 'nul', 'esc' etc for nonprintable */
                                         pr->flags = F_U;
                                         /* *p1 = 'c';   set in conv_u */
                                         goto DO_BYTE_COUNT_1;
@@ -246,13 +243,8 @@ static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
                          * copy to PR format string, set conversion character
                          * pointer, update original.
                          */
-                        savech = *p2;
-                        p1[1] = '\0';
-                        pr->fmt = xstrdup(fmtp);
-                        *p2 = savech;
-                        //Too early! xrealloc can move pr->fmt!
-                        //pr->cchar = pr->fmt + (p1 - fmtp);
-
+                        len = (p1 - fmtp) + 1;
+                        pr->fmt = xstrndup(fmtp, len);
                         /* DBU:[dave@cray.com] w/o this, trailing fmt text, space is lost.
                          * Skip subsequent text and up to the next % sign and tack the
                          * additional text onto fmt: eg. if fmt is "%x is a HEX number",
@@ -260,16 +252,17 @@ static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
                          */
                         for (p3 = p2; *p3 && *p3 != '%'; p3++)
                                 continue;
-                        if (p3 > p2) {
-                                savech = *p3;
-                                *p3 = '\0';
-                                pr->fmt = xrealloc(pr->fmt, strlen(pr->fmt) + (p3-p2) + 1);
-                                strcat(pr->fmt, p2);
-                                *p3 = savech;
-                                p2 = p3;
+                        if ((p3 - p2) != 0) {
+                                char *d;
+                                pr->fmt = d = xrealloc(pr->fmt, len + (p3 - p2) + 1);
+                                d += len;
+                                do {
+                                        *d++ = *p2++;
+                                } while (p2 != p3);
+                                *d = '\0';
+                                /* now p2 = p3 */
                         }
-
-                        pr->cchar = pr->fmt + (p1 - fmtp);
+                        pr->cchar = pr->fmt + len - 1; /* must be after realloc! */
                         fmtp = p2;
 
                         /* only one conversion character if byte count */
@@ -281,7 +274,7 @@ static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
                  * if format unit byte count not specified, figure it out
                  * so can adjust rep count later.
                  */
-                if (!fu->bcnt)
+                if (fu->bcnt == 0)
                         for (pr = fu->nextpr; pr; pr = pr->nextpr)
                                 fu->bcnt += pr->bcnt;
         }
@@ -303,16 +296,18 @@ static NOINLINE void rewrite(priv_dumper_t *dumper, FS *fs)
                         fu->reps += (dumper->blocksize - fs->bcnt) / fu->bcnt;
                 }
                 if (fu->reps > 1 && fu->nextpr) {
+                        PR *pr;
+                        char *p1, *p2;
+
                         for (pr = fu->nextpr;; pr = pr->nextpr)
                                 if (!pr->nextpr)
                                         break;
-                        for (p1 = pr->fmt, p2 = NULL; *p1; ++p1)
+                        p2 = NULL;
+                        for (p1 = pr->fmt; *p1; ++p1)
                                 p2 = isspace(*p1) ? p1 : NULL;
                         if (p2)
                                 pr->nospace = p2;
                 }
-                if (!fu->nextfu)
-                        break;
         }
 }
 
@@ -356,6 +351,7 @@ static NOINLINE int next(priv_dumper_t *dumper)
                         if (dumper->next__done)
                                 return 0; /* no next file */
                         dumper->next__done = 1;
+//why stat of stdin is specially prohibited?
                         statok = 0;
                 }
                 if (dumper->pub.dump_skip)
@@ -760,6 +756,11 @@ void FAST_FUNC bb_dump_add(dumper_t* pub_dumper, const char *fmt)
                         if (!isspace(*p)) {
                                 bb_error_msg_and_die("bad format {%s}", fmt);
                         }
+// Above check prohibits formats such as '/1"%02x"' - it requires space after 1.
+// Other than this, formats can be pretty much jammed together:
+// "%07_ax:"8/2 "%04x|""\n"
+// but this space is required. The check *can* be removed, but
+// keeping it to stay compat with util-linux hexdump.
                         tfu->bcnt = atoi(savep);
                         /* skip trailing white space */
                         p = skip_whitespace(p + 1);