bc: speed up string printing, fix print ""
function old new delta
static.esc - 9 +9
zxc_program_print 681 683 +2
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/0 up/down: 11/0) Total: 11 bytes
text data bss dec hex filename
979144 485 7296 986925 f0f2d busybox_old
979062 485 7296 986843 f0edb busybox_unstripped
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/miscutils/bc.c b/miscutils/bc.c
index 1b9cdce..bb91216 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -5359,7 +5359,7 @@
static void xc_program_printString(const char *str)
{
#if ENABLE_DC
- if (!str[0]) {
+ if (!str[0] && IS_DC) {
// Example: echo '[]ap' | dc
// should print two bytes: 0x00, 0x0A
bb_putchar('\0');
@@ -5367,46 +5367,25 @@
}
#endif
while (*str) {
- int c = *str++;
- if (c != '\\' || !*str)
- bb_putchar(c);
- else {
+ char c = *str++;
+ if (c == '\\') {
+ static const char esc[] ALIGN1 = "nabfrt""e\\";
+ char *n;
+
c = *str++;
- switch (c) {
- case 'a':
- bb_putchar('\a');
- break;
- case 'b':
- bb_putchar('\b');
- break;
- case '\\':
- case 'e':
- bb_putchar('\\');
- break;
- case 'f':
- bb_putchar('\f');
- break;
- case 'n':
- bb_putchar('\n');
- G.prog.nchars = SIZE_MAX;
- break;
- case 'r':
- bb_putchar('\r');
- break;
- case 'q':
- bb_putchar('"');
- break;
- case 't':
- bb_putchar('\t');
- break;
- default:
- // Just print the backslash and following character.
+ n = strchr(esc, c); // note: c can be NUL
+ if (!n) {
+ // Just print the backslash and following character
bb_putchar('\\');
++G.prog.nchars;
- bb_putchar(c);
- break;
+ } else {
+ if (n - esc == 0) // "\n" ?
+ G.prog.nchars = SIZE_MAX;
+ c = "\n\a\b\f\r\t""\\\\""\\"[n - esc];
+ // n a b f r t e \ \<end of line>
}
}
+ putchar(c);
++G.prog.nchars;
}
}
@@ -5631,16 +5610,15 @@
str = *xc_program_str(idx);
if (inst == XC_INST_PRINT_STR) {
- for (;;) {
- char c = *str++;
- if (c == '\0') break;
- bb_putchar(c);
- ++G.prog.nchars;
- if (c == '\n') G.prog.nchars = 0;
- }
+ char *nl;
+ G.prog.nchars += printf("%s", str);
+ nl = strrchr(str, '\n');
+ if (nl)
+ G.prog.nchars = strlen(nl + 1);
} else {
xc_program_printString(str);
- if (inst == XC_INST_PRINT) bb_putchar('\n');
+ if (inst == XC_INST_PRINT)
+ bb_putchar('\n');
}
}