builtin_printf.cpp

/* printf - format and print data
   Copyright (C) 1990-2007 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

/* 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
   \e = escape
   \f = form feed
   \n = new line
   \r = carriage return
   \t = horizontal tab
   \v = vertical tab
   \ooo = octal number (ooo is 1 to 3 digits)
   \xhh = hexadecimal number (hhh is 1 to 2 digits)
   \uhhhh = 16-bit Unicode character (hhhh is 4 digits)
   \Uhhhhhhhh = 32-bit Unicode character (hhhhhhhh is 8 digits)

   Additional directive:

   %b = print an argument string, interpreting backslash escapes,
     except that octal escapes are of the form \0 or \0ooo.

   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> */

/* This file has been imported from source code of printf command in GNU Coreutils version 6.9 */

#include <stdio.h>
#include <sys/types.h>
#include <inttypes.h>

#include "common.h"

struct builtin_printf_state_t
{
    /* The status of the operation */
    int exit_code;

    /* Whether we should stop outputting. This gets set in the case of an error, and also with the \c escape. */
    bool early_exit;

    builtin_printf_state_t() : exit_code(0), early_exit(false)
    {
    }

    void verify_numeric(const wchar_t *s, const wchar_t *end, int errcode);

    void print_direc(const wchar_t *start, size_t length, wchar_t conversion,
                     bool have_field_width, int field_width,
                     bool have_precision, int precision,
                     wchar_t const *argument);

    int print_formatted(const wchar_t *format, int argc, wchar_t **argv);

    void fatal_error(const wchar_t *format, ...);

    long print_esc(const wchar_t *escstart, bool octal_0);
    void print_esc_string(const wchar_t *str);
    void print_esc_char(wchar_t c);

    void append_output(wchar_t c);
    void append_output(const wchar_t *c);
    void append_format_output(const wchar_t *fmt, ...);
};

static bool is_octal_digit(wchar_t c)
{
    return c != L'\0' && wcschr(L"01234567", c) != NULL;
}

static bool is_hex_digit(wchar_t c)
{
    return c != L'\0' && wcschr(L"0123456789ABCDEFabcdef", c) != NULL;
}

static int hex_to_bin(const wchar_t &c)
{
    switch (c)
    {
        case L'0':
            return 0;
        case L'1':
            return 1;
        case L'2':
            return 2;
        case L'3':
            return 3;
        case L'4':
            return 4;
        case L'5':
            return 5;
        case L'6':
            return 6;
        case L'7':
            return 7;
        case L'8':
            return 8;
        case L'9':
            return 9;
        case L'a':
        case L'A':
            return 10;
        case L'b':
        case L'B':
            return 11;
        case L'c':
        case L'C':
            return 12;
        case L'd':
        case L'D':
            return 13;
        case L'e':
        case L'E':
            return 14;
        case L'f':
        case L'F':
            return 15;
        default:
            return -1;
    }
}

static int octal_to_bin(wchar_t c)
{
    switch (c)
    {
        case L'0':
            return 0;
        case L'1':
            return 1;
        case L'2':
            return 2;
        case L'3':
            return 3;
        case L'4':
            return 4;
        case L'5':
            return 5;
        case L'6':
            return 6;
        case L'7':
            return 7;
        default:
            return -1;
    }
}

/* This message appears in N_() here rather than just in _() below because
   the sole use would have been in a #define.  */
static wchar_t const *const cfcc_msg =
    N_(L"warning: %ls: character(s) following character constant have been ignored");

double C_STRTOD(wchar_t const *nptr, wchar_t **endptr)
{
    double r;

    const wcstring saved_locale = wsetlocale(LC_NUMERIC, NULL);

    if (!saved_locale.empty())
    {
        wsetlocale(LC_NUMERIC, L"C");
    }

    r = wcstod(nptr, endptr);

    if (!saved_locale.empty())
    {
        wsetlocale(LC_NUMERIC, saved_locale.c_str());
    }

    return r;
}

void builtin_printf_state_t::fatal_error(const wchar_t *fmt, ...)
{
    // Don't error twice
    if (early_exit)
        return;

    va_list va;
    va_start(va, fmt);
    wcstring errstr = vformat_string(fmt, va);
    va_end(va);
    stderr_buffer.append(errstr);
    if (! string_suffixes_string(L"\n", errstr))
        stderr_buffer.push_back(L'\n');

    this->exit_code = STATUS_BUILTIN_ERROR;
    this->early_exit = true;
}

void builtin_printf_state_t::append_output(wchar_t c)
{
    // Don't output if we're done
    if (early_exit)
        return;

    stdout_buffer.push_back(c);
}

void builtin_printf_state_t::append_output(const wchar_t *c)
{
    // Don't output if we're done
    if (early_exit)
        return;

    stdout_buffer.append(c);
}

void builtin_printf_state_t::append_format_output(const wchar_t *fmt, ...)
{
    // Don't output if we're done
    if (early_exit)
        return;

    va_list va;
    va_start(va, fmt);
    append_formatv(stdout_buffer, fmt, va);
    va_end(va);
}


void builtin_printf_state_t::verify_numeric(const wchar_t *s, const wchar_t *end, int errcode)
{
    if (errcode != 0)
    {
        this->fatal_error(L"%ls: %s", s, strerror(errcode));
    }
    else if (*end)
    {
        if (s == end)
            this->fatal_error(_(L"%ls: expected a numeric value"), s);
        else
            this->fatal_error(_(L"%ls: value not completely converted"), s);
    }
}

template<typename T>
static T raw_string_to_scalar_type(const wchar_t *s, wchar_t ** end);

// we use wcstoll instead of wcstoimax because FreeBSD 8 has busted wcstoumax and wcstoimax - see #626
template<>
intmax_t raw_string_to_scalar_type(const wchar_t *s, wchar_t ** end)
{
    return wcstoll(s, end, 0);
}

template<>
uintmax_t raw_string_to_scalar_type(const wchar_t *s, wchar_t ** end)
{
    return wcstoull(s, end, 0);
}

template<>
long double raw_string_to_scalar_type(const wchar_t *s, wchar_t ** end)
{
    return C_STRTOD(s, end);
}

template<typename T>
static T string_to_scalar_type(const wchar_t *s, builtin_printf_state_t *state)
{
    T val;
    if (*s == L'\"' || *s == L'\'')
    {
        wchar_t ch = *++s;
        val = ch;
    }
    else
    {
        wchar_t *end = NULL;
        errno = 0;
        val = raw_string_to_scalar_type<T>(s, &end);
        state->verify_numeric(s, end, errno);
    }
    return val;
}

/* Output a single-character \ escape.  */

void builtin_printf_state_t::print_esc_char(wchar_t c)
{
    switch (c)
    {
        case L'a':			/* Alert. */
            this->append_output(L'\a');
            break;
        case L'b':			/* Backspace. */
            this->append_output(L'\b');
            break;
        case L'c':			/* Cancel the rest of the output. */
            this->early_exit = true;
            break;
        case L'e':			/* Escape */
            this->append_output(L'\x1B');
            break;
        case L'f':			/* Form feed. */
            this->append_output(L'\f');
            break;
        case L'n':			/* New line. */
            this->append_output(L'\n');
            break;
        case L'r':			/* Carriage return. */
            this->append_output(L'\r');
            break;
        case L't':			/* Horizontal tab. */
            this->append_output(L'\t');
            break;
        case L'v':			/* Vertical tab. */
            this->append_output(L'\v');
            break;
        default:
            this->append_output(c);
            break;
    }
}

/* Print a \ escape sequence starting at ESCSTART.
   Return the number of characters in the escape sequence
   besides the backslash.
   If OCTAL_0 is nonzero, octal escapes are of the form \0ooo, where o
   is an octal digit; otherwise they are of the form \ooo.  */
long builtin_printf_state_t::print_esc(const wchar_t *escstart, bool octal_0)
{
    const wchar_t *p = escstart + 1;
    int esc_value = 0;		/* Value of \nnn escape. */
    int esc_length;		/* Length of \nnn escape. */

    if (*p == L'x')
    {
        /* A hexadecimal \xhh escape sequence must have 1 or 2 hex. digits.  */
        for (esc_length = 0, ++p; esc_length < 2 && is_hex_digit(*p); ++esc_length, ++p)
            esc_value = esc_value * 16 + hex_to_bin(*p);
        if (esc_length == 0)
            this->fatal_error(_(L"missing hexadecimal number in escape"));
        this->append_output(ENCODE_DIRECT_BASE + esc_value % 256);
    }
    else if (is_octal_digit(*p))
    {
        /* Parse \0ooo (if octal_0 && *p == L'0') or \ooo (otherwise).
        Allow \ooo if octal_0 && *p != L'0'; this is an undocumented
        extension to POSIX that is compatible with Bash 2.05b.  */
        /* Wrap mod 256, which matches historic behavior */
        for (esc_length = 0, p += octal_0 && *p == L'0'; esc_length < 3 && is_octal_digit(*p); ++esc_length, ++p)
            esc_value = esc_value * 8 + octal_to_bin(*p);
        this->append_output(ENCODE_DIRECT_BASE + esc_value % 256);
    }
    else if (*p && wcschr(L"\"\\abcefnrtv", *p))
    {
        print_esc_char(*p++);
    }
    else if (*p == L'u' || *p == L'U')
    {
        wchar_t esc_char = *p;
        p++;
        uint32_t uni_value = 0;
        for (size_t esc_length = 0; esc_length < (esc_char == L'u' ? 4 : 8); esc_length++)
        {
            if (! is_hex_digit(*p))
            {
                /* Escape sequence must be done. Complain if we didn't get anything */
                if (esc_length == 0)
                {
                    this->fatal_error(_(L"Missing hexadecimal number in Unicode escape"));
                }
                break;
            }
            uni_value = uni_value * 16 + hex_to_bin(*p);
            p++;
        }

        /* PCA GNU printf respects the limitations described in ISO N717, about which universal characters "shall not" be specified. I believe this limitation is for the benefit of compilers; I see no reason to impose it in builtin_printf.

          If __STDC_ISO_10646__ is defined, then it means wchar_t can and does hold Unicode code points, so just use that. If not defined, use the %lc printf conversion; this probably won't do anything good if your wide character set is not Unicode, but such platforms are exceedingly rare.
        */
        if (uni_value > 0x10FFFF)
        {
            this->fatal_error(_(L"Unicode character out of range: \\%c%0*x"), esc_char, (esc_char == L'u' ? 4 : 8), uni_value);
        }
        else
        {
#if defined(__STDC_ISO_10646__)
            this->append_output(uni_value);
#else
            this->append_format_output(L"%lc", uni_value);
#endif
        }
    }
    else
    {
        this->append_output(L'\\');
        if (*p)
        {
            this->append_output(*p);
            p++;
        }
    }
    return p - escstart - 1;
}

/* Print string STR, evaluating \ escapes. */

void builtin_printf_state_t::print_esc_string(const wchar_t *str)
{
    for (; *str; str++)
        if (*str == L'\\')
            str += print_esc(str, true);
        else
            this->append_output(*str);
}

/* Evaluate a printf conversion specification.  START is the start of
   the directive, LENGTH is its length, and CONVERSION specifies the
   type of conversion.  LENGTH does not include any length modifier or
   the conversion specifier itself.  FIELD_WIDTH and PRECISION are the
   field width and precision for '*' values, if HAVE_FIELD_WIDTH and
   HAVE_PRECISION are true, respectively.  ARGUMENT is the argument to
   be formatted.  */

void builtin_printf_state_t::print_direc(const wchar_t *start, size_t length, wchar_t conversion,
        bool have_field_width, int field_width,
        bool have_precision, int precision,
        wchar_t const *argument)
{
    // Start with everything except the conversion specifier
    wcstring fmt(start, length);

    /*  Create a copy of the % directive, with an intmax_t-wide width modifier substituted for any existing integer length modifier. */
    switch (conversion)
    {
        case L'd':
        case L'i':
        case L'u':
            fmt.append(L"ll");
            break;
        case L'a':
        case L'e':
        case L'f':
        case L'g':
        case L'A':
        case L'E':
        case L'F':
        case L'G':
            fmt.append(L"L");
            break;
        case L's':
        case L'c':
            fmt.append(L"l");
            break;
        default:
            break;
    }

    // Append the conversion itself
    fmt.push_back(conversion);

    switch (conversion)
    {
        case L'd':
        case L'i':
        {
            intmax_t arg = string_to_scalar_type<intmax_t>(argument, this);
            if (! have_field_width)
            {
                if (! have_precision)
                    this->append_format_output(fmt.c_str(), arg);
                else
                    this->append_format_output(fmt.c_str(), precision, arg);
            }
            else
            {
                if (! have_precision)
                    this->append_format_output(fmt.c_str(), field_width, arg);
                else
                    this->append_format_output(fmt.c_str(), field_width, precision, arg);
            }
        }
        break;

        case L'o':
        case L'u':
        case L'x':
        case L'X':
        {
            uintmax_t arg = string_to_scalar_type<uintmax_t>(argument, this);
            if (!have_field_width)
            {
                if (!have_precision)
                    this->append_format_output(fmt.c_str(), arg);
                else
                    this->append_format_output(fmt.c_str(), precision, arg);
            }
            else
            {
                if (!have_precision)
                    this->append_format_output(fmt.c_str(), field_width, arg);
                else
                    this->append_format_output(fmt.c_str(), field_width, precision, arg);
            }
        }
        break;

        case L'a':
        case L'A':
        case L'e':
        case L'E':
        case L'f':
        case L'F':
        case L'g':
        case L'G':
        {
            long double arg = string_to_scalar_type<long double>(argument, this);
            if (!have_field_width)
            {
                if (!have_precision)
                    this->append_format_output(fmt.c_str(), arg);
                else
                    this->append_format_output(fmt.c_str(), precision, arg);
            }
            else
            {
                if (!have_precision)
                    this->append_format_output(fmt.c_str(), field_width, arg);
                else
                    this->append_format_output(fmt.c_str(), field_width, precision, arg);
            }
        }
        break;

        case L'c':
            if (!have_field_width)
                this->append_format_output(fmt.c_str(), *argument);
            else
                this->append_format_output(fmt.c_str(), field_width, *argument);
            break;
        case L's':
            if (!have_field_width)
            {
                if (!have_precision)
                {
                    this->append_format_output(fmt.c_str(), argument);
                }
                else
                    this->append_format_output(fmt.c_str(), precision, argument);
            }
            else
            {
                if (!have_precision)
                    this->append_format_output(fmt.c_str(), field_width, argument);
                else
                    this->append_format_output(fmt.c_str(), field_width, precision, argument);
            }
            break;
    }
}

/* For each character in str, set the corresponding boolean in the array to the given flag */
static inline void modify_allowed_format_specifiers(bool ok[UCHAR_MAX + 1], const char *str, bool flag)
{
    for (const char *c  = str; *c != '\0'; c++)
    {
        unsigned char idx = static_cast<unsigned char>(*c);
        ok[idx] = flag;
    }
}

/* Print the text in FORMAT, using ARGV (with ARGC elements) for
   arguments to any `%' directives.
   Return the number of elements of ARGV used.  */

int builtin_printf_state_t::print_formatted(const wchar_t *format, int argc, wchar_t **argv)
{
    int save_argc = argc;		/* Preserve original value.  */
    const wchar_t *f;		/* Pointer into `format'.  */
    const wchar_t *direc_start;	/* Start of % directive.  */
    size_t direc_length;		/* Length of % directive.  */
    bool have_field_width;	/* True if FIELD_WIDTH is valid.  */
    int field_width = 0;		/* Arg to first '*'.  */
    bool have_precision;		/* True if PRECISION is valid.  */
    int precision = 0;		/* Arg to second '*'.  */
    bool ok[UCHAR_MAX + 1] = { };	/* ok['x'] is true if %x is allowed.  */

    for (f = format; *f != L'\0'; ++f)
    {
        switch (*f)
        {
            case L'%':
                direc_start = f++;
                direc_length = 1;
                have_field_width = have_precision = false;
                if (*f == L'%')
                {
                    this->append_output(L'%');
                    break;
                }
                if (*f == L'b')
                {
                    /* FIXME: Field width and precision are not supported
                    for %b, even though POSIX requires it.  */
                    if (argc > 0)
                    {
                        print_esc_string(*argv);
                        ++argv;
                        --argc;
                    }
                    break;
                }

                modify_allowed_format_specifiers(ok, "aAcdeEfFgGiosuxX", true);

                for (;; f++, direc_length++)
                {
                    switch (*f)
                    {
                        case L'I':
                        case L'\'':
                            modify_allowed_format_specifiers(ok, "aAceEosxX", false);
                            break;
                        case '-':
                        case '+':
                        case ' ':
                            break;
                        case L'#':
                            modify_allowed_format_specifiers(ok, "cdisu", false);
                            break;
                        case '0':
                            modify_allowed_format_specifiers(ok, "cs", false);
                            break;
                        default:
                            goto no_more_flag_characters;
                    }
                }
no_more_flag_characters:
                ;

                if (*f == L'*')
                {
                    ++f;
                    ++direc_length;
                    if (argc > 0)
                    {
                        intmax_t width = string_to_scalar_type<intmax_t>(*argv, this);
                        if (INT_MIN <= width && width <= INT_MAX)
                            field_width = static_cast<int>(width);
                        else
                            this->fatal_error(_(L"invalid field width: %ls"), *argv);
                        ++argv;
                        --argc;
                    }
                    else
                    {
                        field_width = 0;
                    }
                    have_field_width = true;
                }
                else
                {
                    while (iswdigit(*f))
                    {
                        ++f;
                        ++direc_length;
                    }
                }
                if (*f == L'.')
                {
                    ++f;
                    ++direc_length;
                    modify_allowed_format_specifiers(ok, "c", false);
                    if (*f == L'*')
                    {
                        ++f;
                        ++direc_length;
                        if (argc > 0)
                        {
                            intmax_t prec = string_to_scalar_type<intmax_t>(*argv, this);
                            if (prec < 0)
                            {
                                /* A negative precision is taken as if the
                                precision were omitted, so -1 is safe
                                here even if prec < INT_MIN.  */
                                precision = -1;
                            }
                            else if (INT_MAX < prec)
                                this->fatal_error(_(L"invalid precision: %ls"), *argv);
                            else
                            {
                                precision = static_cast<int>(prec);
                            }
                            ++argv;
                            --argc;
                        }
                        else
                        {
                            precision = 0;
                        }
                        have_precision = true;
                    }
                    else
                    {
                        while (iswdigit(*f))
                        {
                            ++f;
                            ++direc_length;
                        }
                    }
                }

                while (*f == L'l' || *f == L'L' || *f == L'h' || *f == L'j' || *f == L't' || *f == L'z')
                    ++f;

                {
                    wchar_t conversion = *f;
                    if (conversion > 0xFF || ! ok[conversion])
                    {
                        this->fatal_error(_(L"%.*ls: invalid conversion specification"), (int)(f + 1 - direc_start), direc_start);
                        return 0;
                    }
                }

                print_direc(direc_start, direc_length, *f,
                            have_field_width, field_width,
                            have_precision, precision,
                            (argc <= 0 ? L"" : (argc--, *argv++)));
                break;

            case L'\\':
                f += print_esc(f, false);
                break;

            default:
                this->append_output(*f);
        }
    }
    return save_argc - argc;
}

static int builtin_printf(parser_t &parser, wchar_t **argv)
{
    builtin_printf_state_t state;

    wchar_t *format;
    int args_used;
    int argc = builtin_count_args(argv);

    if (argc <= 1)
    {
        state.fatal_error(_(L"printf: not enough arguments"));
        return STATUS_BUILTIN_ERROR;
    }

    format = argv[1];
    argc -= 2;
    argv += 2;

    do
    {
        args_used = state.print_formatted(format, argc, argv);
        argc -= args_used;
        argv += args_used;
    }
    while (args_used > 0 && argc > 0 && ! state.early_exit);
    return state.exit_code;
}