source: MondoRescue/branches/stable/mindi-busybox/coreutils/printf.c@ 1770

/* vi: set sw=4 ts=4: */
/* printf - format and print data

   Copyright 1999 Dave Cinege
   Portions copyright (C) 1990-1996 Free Software Foundation, Inc.

   Licensed under GPL v2 or later, see file LICENSE in this tarball for details.
*/

/* 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> */


//   19990508 Busy Boxed! Dave Cinege

#include "libbb.h"

typedef void (*converter)(const char *arg, void *result);

static void multiconvert(const char *arg, void *result, converter convert)
{
    char s[sizeof(int)*3 + 2];

    if (*arg == '"' || *arg == '\'') {
        sprintf(s, "%d", (unsigned char)arg[1]);
        arg = s;
    }
    convert(arg, result);
    /* if there was conversion error, print unconverted string */
    if (errno)
        fputs(arg, stderr);
}

static void conv_strtoul(const char *arg, void *result)
{
    *(unsigned long*)result = bb_strtoul(arg, NULL, 0);
}
static void conv_strtol(const char *arg, void *result)
{
    *(long*)result = bb_strtol(arg, NULL, 0);
}
static void conv_strtod(const char *arg, void *result)
{
    char *end;
    /* Well, this one allows leading whitespace... so what */
    /* What I like much less is that "-" is accepted too! :( */
    *(double*)result = strtod(arg, &end);
    if (end[0]) errno = ERANGE;
}

static unsigned long my_xstrtoul(const char *arg)
{
    unsigned long result;
    multiconvert(arg, &result, conv_strtoul);
    return result;
}

static long my_xstrtol(const char *arg)
{
    long result;
    multiconvert(arg, &result, conv_strtol);
    return result;
}

static double my_xstrtod(const char *arg)
{
    double result;
    multiconvert(arg, &result, conv_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);
        }

    }
}

static void print_direc(char *start, size_t length, int field_width, int precision,
        const char *argument)
{
    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, my_xstrtol(argument));
            else
                printf(p, precision, my_xstrtol(argument));
        } else {
            if (precision < 0)
                printf(p, field_width, my_xstrtol(argument));
            else
                printf(p, field_width, precision, my_xstrtol(argument));
        }
        break;
    case 'o':
    case 'u':
    case 'x':
    case 'X':
        if (field_width < 0) {
            if (precision < 0)
                printf(p, my_xstrtoul(argument));
            else
                printf(p, precision, my_xstrtoul(argument));
        } else {
            if (precision < 0)
                printf(p, field_width, my_xstrtoul(argument));
            else
                printf(p, field_width, precision, my_xstrtoul(argument));
        }
        break;
    case 'f':
    case 'e':
    case 'E':
    case 'g':
    case 'G':
        if (field_width < 0) {
            if (precision < 0)
                printf(p, my_xstrtod(argument));
            else
                printf(p, precision, my_xstrtod(argument));
        } else {
            if (precision < 0)
                printf(p, field_width, my_xstrtod(argument));
            else
                printf(p, field_width, precision, my_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;
    }

    free(p);
}

/* 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)
{
    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 = my_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 = my_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);
        }
    }

    return save_argc - argc;
}

int printf_main(int argc, char **argv);
int printf_main(int argc, char **argv)
{
    char *format;
    int args_used;

    if (argc <= 1 || argv[1][0] == '-') {
        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);

/*  if (argc > 0)
        fprintf(stderr, "excess args ignored");
*/

    return EXIT_SUCCESS;
}