busybox/coreutils/printf.c

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/* vi: set sw=4 ts=4: */
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/* printf - format and print data
Copyright 1999 Dave Cinege
Portions copyright (C) 1990-1996 Free Software Foundation, Inc.
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Licensed under GPL v2 or later, see file LICENSE in this tarball for details.
*/
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/* Usage: printf format [argument...]
A front end to the printf function that lets it be used from the shell.
Backslash escapes:
\" = double quote
\\ = backslash
\a = alert (bell)
\b = backspace
\c = produce no further output
\f = form feed
\n = new line
\r = carriage return
\t = horizontal tab
\v = vertical tab
\0ooo = octal number (ooo is 0 to 3 digits)
\xhhh = hexadecimal number (hhh is 1 to 3 digits)
Additional directive:
%b = print an argument string, interpreting backslash escapes
The `format' argument is re-used as many times as necessary
to convert all of the given arguments.
David MacKenzie <djm@gnu.ai.mit.edu> */
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// 19990508 Busy Boxed! Dave Cinege
#include "busybox.h"
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static int print_formatted(char *format, int argc, char **argv);
static void print_direc(char *start, size_t length,
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int field_width, int precision, char *argument);
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typedef int (*converter)(char *arg, void *result);
static void multiconvert(char *arg, void *result, converter convert)
{
char s[16];
if (*arg == '"' || *arg == '\'') {
sprintf(s, "%d", (unsigned)arg[1]);
arg = s;
}
if (convert(arg, result))
fputs(arg, stderr);
}
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static unsigned long xstrtoul(char *arg)
{
unsigned long result;
multiconvert(arg, &result, (converter)safe_strtoul);
return result;
}
static long xstrtol(char *arg)
{
long result;
multiconvert(arg, &result, (converter)safe_strtol);
return result;
}
static double xstrtod(char *arg)
{
double result;
multiconvert(arg, &result, (converter)safe_strtod);
return result;
}
static void print_esc_string(char *str)
{
for (; *str; str++) {
if (*str == '\\') {
str++;
putchar(bb_process_escape_sequence((const char **)&str));
} else {
putchar(*str);
}
}
}
int printf_main(int argc, char **argv)
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{
char *format;
int args_used;
if (argc <= 1 || argv[1][0] == '-') {
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bb_show_usage();
}
format = argv[1];
argc -= 2;
argv += 2;
do {
args_used = print_formatted(format, argc, argv);
argc -= args_used;
argv += args_used;
}
while (args_used > 0 && argc > 0);
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/* if (argc > 0)
fprintf(stderr, "excess args ignored");
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*/
return EXIT_SUCCESS;
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}
/* Print the text in FORMAT, using ARGV (with ARGC elements) for
arguments to any `%' directives.
Return the number of elements of ARGV used. */
static int print_formatted(char *format, int argc, char **argv)
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{
int save_argc = argc; /* Preserve original value. */
char *f; /* Pointer into `format'. */
char *direc_start; /* Start of % directive. */
size_t direc_length; /* Length of % directive. */
int field_width; /* Arg to first '*', or -1 if none. */
int precision; /* Arg to second '*', or -1 if none. */
for (f = format; *f; ++f) {
switch (*f) {
case '%':
direc_start = f++;
direc_length = 1;
field_width = precision = -1;
if (*f == '%') {
putchar('%');
break;
}
if (*f == 'b') {
if (argc > 0) {
print_esc_string(*argv);
++argv;
--argc;
}
break;
}
if (strchr("-+ #", *f)) {
++f;
++direc_length;
}
if (*f == '*') {
++f;
++direc_length;
if (argc > 0) {
field_width = xstrtoul(*argv);
++argv;
--argc;
} else
field_width = 0;
} else
while (isdigit(*f)) {
++f;
++direc_length;
}
if (*f == '.') {
++f;
++direc_length;
if (*f == '*') {
++f;
++direc_length;
if (argc > 0) {
precision = xstrtoul(*argv);
++argv;
--argc;
} else
precision = 0;
} else
while (isdigit(*f)) {
++f;
++direc_length;
}
}
if (*f == 'l' || *f == 'L' || *f == 'h') {
++f;
++direc_length;
}
/*
if (!strchr ("diouxXfeEgGcs", *f))
fprintf(stderr, "%%%c: invalid directive", *f);
*/
++direc_length;
if (argc > 0) {
print_direc(direc_start, direc_length, field_width,
precision, *argv);
++argv;
--argc;
} else
print_direc(direc_start, direc_length, field_width,
precision, "");
break;
case '\\':
if (*++f == 'c')
exit(0);
putchar(bb_process_escape_sequence((const char **)&f));
f--;
break;
default:
putchar(*f);
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}
}
return save_argc - argc;
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}
static void
print_direc(char *start, size_t length, int field_width, int precision,
char *argument)
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{
char *p; /* Null-terminated copy of % directive. */
p = xmalloc((unsigned) (length + 1));
strncpy(p, start, length);
p[length] = 0;
switch (p[length - 1]) {
case 'd':
case 'i':
if (field_width < 0) {
if (precision < 0)
printf(p, xstrtol(argument));
else
printf(p, precision, xstrtol(argument));
} else {
if (precision < 0)
printf(p, field_width, xstrtol(argument));
else
printf(p, field_width, precision, xstrtol(argument));
}
break;
case 'o':
case 'u':
case 'x':
case 'X':
if (field_width < 0) {
if (precision < 0)
printf(p, xstrtoul(argument));
else
printf(p, precision, xstrtoul(argument));
} else {
if (precision < 0)
printf(p, field_width, xstrtoul(argument));
else
printf(p, field_width, precision, xstrtoul(argument));
}
break;
case 'f':
case 'e':
case 'E':
case 'g':
case 'G':
if (field_width < 0) {
if (precision < 0)
printf(p, xstrtod(argument));
else
printf(p, precision, xstrtod(argument));
} else {
if (precision < 0)
printf(p, field_width, xstrtod(argument));
else
printf(p, field_width, precision, xstrtod(argument));
}
break;
case 'c':
printf(p, *argument);
break;
case 's':
if (field_width < 0) {
if (precision < 0)
printf(p, argument);
else
printf(p, precision, argument);
} else {
if (precision < 0)
printf(p, field_width, argument);
else
printf(p, field_width, precision, argument);
}
break;
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}
free(p);
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}