/* 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 GPLv2 or later, see file LICENSE in this source tree.
 */
/* 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 */

//config:config PRINTF
//config:       bool "printf (3.8 kb)"
//config:       default y
//config:       help
//config:       printf is used to format and print specified strings.
//config:       It's similar to 'echo' except it has more options.

//applet:IF_PRINTF(APPLET_NOFORK(printf, printf, BB_DIR_USR_BIN, BB_SUID_DROP, printf))

//kbuild:lib-$(CONFIG_PRINTF) += printf.o
//kbuild:lib-$(CONFIG_ASH_PRINTF)  += printf.o
//kbuild:lib-$(CONFIG_HUSH_PRINTF) += printf.o

//usage:#define printf_trivial_usage
//usage:       "FORMAT [ARG]..."
//usage:#define printf_full_usage "\n\n"
//usage:       "Format and print ARG(s) according to FORMAT (a-la C printf)"
//usage:
//usage:#define printf_example_usage
//usage:       "$ printf \"Val=%d\\n\" 5\n"
//usage:       "Val=5\n"

#include "libbb.h"

/* A note on bad input: neither bash 3.2 nor coreutils 6.10 stop on it.
 * They report it:
 *  bash: printf: XXX: invalid number
 *  printf: XXX: expected a numeric value
 *  bash: printf: 123XXX: invalid number
 *  printf: 123XXX: value not completely converted
 * but then they use 0 (or partially converted numeric prefix) as a value
 * and continue. They exit with 1 in this case.
 * Both accept insane field width/precision (e.g. %9999999999.9999999999d).
 * Both print error message and assume 0 if %*.*f width/precision is "bad"
 *  (but negative numbers are not "bad").
 * Both accept negative numbers for %u specifier.
 *
 * We try to be compatible.
 */

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

static int multiconvert(const char *arg, void *result, converter convert)
{
        if (*arg == '"' || *arg == '\'') {
                arg = utoa((unsigned char)arg[1]);
        }
        errno = 0;
        convert(arg, result);
        if (errno) {
                bb_error_msg("invalid number '%s'", arg);
                return 1;
        }
        return 0;
}

static void FAST_FUNC conv_strtoull(const char *arg, void *result)
{
        /* Allow leading '+' - bb_strtoull() by itself does not allow it,
         * and probably shouldn't (other callers might require purely numeric
         * inputs to be allowed.
         */
        if (arg[0] == '+')
                arg++;
        *(unsigned long long*)result = bb_strtoull(arg, NULL, 0);
        /* both coreutils 6.10 and bash 3.2:
         * $ printf '%x\n' -2
         * fffffffffffffffe
         * Mimic that:
         */
        if (errno) {
                *(unsigned long long*)result = bb_strtoll(arg, NULL, 0);
        }
}
static void FAST_FUNC conv_strtoll(const char *arg, void *result)
{
        if (arg[0] == '+')
                arg++;
        *(long long*)result = bb_strtoll(arg, NULL, 0);
}
static void FAST_FUNC conv_strtod(const char *arg, void *result)
{
        char *end;
        /* Well, this one allows leading whitespace... so what? */
        /* What I like much less is that "-" accepted too! :( */
        *(double*)result = strtod(arg, &end);
        if (end[0]) {
                errno = ERANGE;
                *(double*)result = 0;
        }
}

/* Callers should check errno to detect errors */
static unsigned long long my_xstrtoull(const char *arg)
{
        unsigned long long result;
        if (multiconvert(arg, &result, conv_strtoull))
                result = 0;
        return result;
}
static long long my_xstrtoll(const char *arg)
{
        long long result;
        if (multiconvert(arg, &result, conv_strtoll))
                result = 0;
        return result;
}
static double my_xstrtod(const char *arg)
{
        double result;
        multiconvert(arg, &result, conv_strtod);
        return result;
}

/* Handles %b; return 1 if output is to be short-circuited by \c */
static int print_esc_string(const char *str)
{
        char c;
        while ((c = *str) != '\0') {
                str++;
                if (c == '\\') {
                        /* %b also accepts 4-digit octals of the form \0### */
                        if (*str == '0') {
                                if ((unsigned char)(str[1] - '0') < 8) {
                                        /* 2nd char is 0..7: skip leading '0' */
                                        str++;
                                }
                        }
                        else if (*str == 'c') {
                                return 1;
                        }
                        {
                                /* optimization: don't force arg to be on-stack,
                                 * use another variable for that. */
                                const char *z = str;
                                c = bb_process_escape_sequence(&z);
                                str = z;
                        }
                }
                putchar(c);
        }

        return 0;
}

static void print_direc(char *format, unsigned fmt_length,
                int field_width, int precision,
                const char *argument)
{
        long long llv;
        double dv;
        char saved;
        char *have_prec, *have_width;

        saved = format[fmt_length];
        format[fmt_length] = '\0';

        have_prec = strstr(format, ".*");
        have_width = strchr(format, '*');
        if (have_width - 1 == have_prec)
                have_width = NULL;

        /* multiconvert sets errno = 0, but %s needs it cleared */
        errno = 0;

        switch (format[fmt_length - 1]) {
        case 'c':
                printf(format, *argument);
                break;
        case 'd':
        case 'i':
                llv = my_xstrtoll(skip_whitespace(argument));
 print_long:
                if (!have_width) {
                        if (!have_prec)
                                printf(format, llv);
                        else
                                printf(format, precision, llv);
                } else {
                        if (!have_prec)
                                printf(format, field_width, llv);
                        else
                                printf(format, field_width, precision, llv);
                }
                break;
        case 'o':
        case 'u':
        case 'x':
        case 'X':
                llv = my_xstrtoull(skip_whitespace(argument));
                /* cheat: unsigned long and long have same width, so... */
                goto print_long;
        case 's':
                /* Are char* and long long the same? */
                if (sizeof(argument) == sizeof(llv)) {
                        llv = (long long)(ptrdiff_t)argument;
                        goto print_long;
                } else {
                        /* Hope compiler will optimize it out by moving call
                         * instruction after the ifs... */
                        if (!have_width) {
                                if (!have_prec)
                                        printf(format, argument, /*unused:*/ argument, argument);
                                else
                                        printf(format, precision, argument, /*unused:*/ argument);
                        } else {
                                if (!have_prec)
                                        printf(format, field_width, argument, /*unused:*/ argument);
                                else
                                        printf(format, field_width, precision, argument);
                        }
                        break;
                }
        case 'f':
        case 'e':
        case 'E':
        case 'g':
        case 'G':
                dv = my_xstrtod(argument);
                if (!have_width) {
                        if (!have_prec)
                                printf(format, dv);
                        else
                                printf(format, precision, dv);
                } else {
                        if (!have_prec)
                                printf(format, field_width, dv);
                        else
                                printf(format, field_width, precision, dv);
                }
                break;
        } /* switch */

        format[fmt_length] = saved;
}

/* Handle params for "%*.*f". Negative numbers are ok (compat). */
static int get_width_prec(const char *str)
{
        int v = bb_strtoi(str, NULL, 10);
        if (errno) {
                bb_error_msg("invalid number '%s'", str);
                v = 0;
        }
        return v;
}

/* Print the text in FORMAT, using ARGV for arguments to any '%' directives.
   Return advanced ARGV.  */
static char **print_formatted(char *f, char **argv, int *conv_err)
{
        char *direc_start;      /* Start of % directive.  */
        unsigned direc_length;  /* Length of % directive.  */
        int field_width;        /* Arg to first '*' */
        int precision;          /* Arg to second '*' */
        char **saved_argv = argv;

        for (; *f; ++f) {
                switch (*f) {
                case '%':
                        direc_start = f++;
                        direc_length = 1;
                        field_width = precision = 0;
                        if (*f == '%') {
                                bb_putchar('%');
                                break;
                        }
                        if (*f == 'b') {
                                if (*argv) {
                                        if (print_esc_string(*argv))
                                                return saved_argv; /* causes main() to exit */
                                        ++argv;
                                }
                                break;
                        }
                        if (*f && strchr("-+ #", *f)) {
                                ++f;
                                ++direc_length;
                        }
                        if (*f == '*') {
                                ++f;
                                ++direc_length;
                                if (*argv)
                                        field_width = get_width_prec(*argv++);
                        } else {
                                while (isdigit(*f)) {
                                        ++f;
                                        ++direc_length;
                                }
                        }
                        if (*f == '.') {
                                ++f;
                                ++direc_length;
                                if (*f == '*') {
                                        ++f;
                                        ++direc_length;
                                        if (*argv)
                                                precision = get_width_prec(*argv++);
                                } else {
                                        while (isdigit(*f)) {
                                                ++f;
                                                ++direc_length;
                                        }
                                }
                        }

                        /* Remove "lLhz" size modifiers, repeatedly.
                         * bash does not like "%lld", but coreutils
                         * happily takes even "%Llllhhzhhzd"!
                         * We are permissive like coreutils */
                        while ((*f | 0x20) == 'l' || *f == 'h' || *f == 'z') {
                                overlapping_strcpy(f, f + 1);
                        }
                        /* Add "ll" if integer modifier, then print */
                        {
                                static const char format_chars[] ALIGN1 = "diouxXfeEgGcs";
                                char *p = strchr(format_chars, *f);
                                /* needed - try "printf %" without it */
                                if (p == NULL || *f == '\0') {
                                        bb_error_msg("%s: invalid format", direc_start);
                                        /* causes main() to exit with error */
                                        return saved_argv - 1;
                                }
                                ++direc_length;
                                if (p - format_chars <= 5) {
                                        /* it is one of "diouxX" */
                                        p = xmalloc(direc_length + 3);
                                        memcpy(p, direc_start, direc_length);
                                        p[direc_length + 1] = p[direc_length - 1];
                                        p[direc_length - 1] = 'l';
                                        p[direc_length] = 'l';
                                        //bb_error_msg("<%s>", p);
                                        direc_length += 2;
                                        direc_start = p;
                                } else {
                                        p = NULL;
                                }
                                if (*argv) {
                                        print_direc(direc_start, direc_length, field_width,
                                                                precision, *argv++);
                                } else {
                                        print_direc(direc_start, direc_length, field_width,
                                                                precision, "");
                                }
                                *conv_err |= errno;
                                free(p);
                        }
                        break;
                case '\\':
                        if (*++f == 'c') {
                                return saved_argv; /* causes main() to exit */
                        }
                        bb_putchar(bb_process_escape_sequence((const char **)&f));
                        f--;
                        break;
                default:
                        putchar(*f);
                }
        }

        return argv;
}

int printf_main(int argc UNUSED_PARAM, char **argv)
{
        int conv_err;
        char *format;
        char **argv2;

        /* We must check that stdout is not closed.
         * The reason for this is highly non-obvious.
         * printf_main is used from shell.
         * Shell must correctly handle 'printf "%s" foo'
         * if stdout is closed. With stdio, output gets shoveled into
         * stdout buffer, and even fflush cannot clear it out. It seems that
         * even if libc receives EBADF on write attempts, it feels determined
         * to output data no matter what. So it will try later,
         * and possibly will clobber future output. Not good. */
// TODO: check fcntl() & O_ACCMODE == O_WRONLY or O_RDWR?
        if (fcntl(1, F_GETFL) == -1)
                return 1; /* match coreutils 6.10 (sans error msg to stderr) */
        //if (dup2(1, 1) != 1) - old way
        //      return 1;

        /* bash builtin errors out on "printf '-%s-\n' foo",
         * coreutils-6.9 works. Both work with "printf -- '-%s-\n' foo".
         * We will mimic coreutils. */
        if (argv[1] && argv[1][0] == '-' && argv[1][1] == '-' && !argv[1][2])
                argv++;
        if (!argv[1]) {
                if (ENABLE_ASH_PRINTF
                 && applet_name[0] != 'p'
                ) {
                        bb_error_msg("usage: printf FORMAT [ARGUMENT...]");
                        return 2; /* bash compat */
                }
                bb_show_usage();
        }

        format = argv[1];
        argv2 = argv + 2;

        conv_err = 0;
        do {
                argv = argv2;
                argv2 = print_formatted(format, argv, &conv_err);
        } while (argv2 > argv && *argv2);

        /* coreutils compat (bash doesn't do this):
        if (*argv)
                fprintf(stderr, "excess args ignored");
        */

        return (argv2 < argv) /* if true, print_formatted errored out */
                || conv_err; /* print_formatted saw invalid number */
}