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/*

 * Copyright (C) 2001-2004 Jakub Jermar

 * Copyright (C) 2006 Josef Cejka

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include <unistd.h>

#include <stdio.h>

#include <io/printf_core.h>

#include <ctype.h>

#include <string.h>

#define __PRINTF_FLAG_PREFIX        0x00000001  /* show prefixes 0x or 0*/

#define __PRINTF_FLAG_SIGNED        0x00000002  /* signed / unsigned number */

#define __PRINTF_FLAG_ZEROPADDED    0x00000004  /* print leading zeroes */

#define __PRINTF_FLAG_LEFTALIGNED   0x00000010  /* align to left */

#define __PRINTF_FLAG_SHOWPLUS      0x00000020  /* always show + sign */

#define __PRINTF_FLAG_SPACESIGN     0x00000040  /* print space instead of plus */

#define __PRINTF_FLAG_BIGCHARS      0x00000080  /* show big characters */

#define __PRINTF_FLAG_NEGATIVE      0x00000100  /* number has - sign */

#define PRINT_NUMBER_BUFFER_SIZE    (64+5)      /* Buffer big enought for 64 bit number

                             * printed in base 2, sign, prefix and

                             * 0 to terminate string.. (last one is only for better testing

                             * end of buffer by zero-filling subroutine)

                             */

typedef enum {

    PrintfQualifierByte = 0,

    PrintfQualifierShort,

    PrintfQualifierInt,

    PrintfQualifierLong,

    PrintfQualifierLongLong,

    PrintfQualifierSizeT,

    PrintfQualifierPointer

} qualifier_t;

static char digits_small[] = "0123456789abcdef";    /* Small hexadecimal characters */

static char digits_big[] = "0123456789ABCDEF";  /* Big hexadecimal characters */

/** Print count chars from buffer without adding newline

 * @param buf Buffer with size at least count bytes - NULL pointer NOT allowed!

 * @param count

 * @param ps output method and its data

 * @return 0 on success, EOF on fail

 */

static int printf_putnchars(const char * buf, size_t count, struct printf_spec *ps)

{

    if (ps->write((void *)buf, count, ps->data) == count) {

        return 0;

    }

    return EOF;

}

/** Print string without added newline

 * @param str string to print

 * @param ps write function specification and support data

 * @return 0 on success or EOF on fail

 */

static int printf_putstr(const char * str, struct printf_spec *ps)

{

    size_t count;

    if (str == NULL) {

        return printf_putnchars("(NULL)", 6, ps);

    }

    for (count = 0; str[count] != 0; count++);

    if (ps->write((void *) str, count, ps->data) == count) {

        return 0;

    }

    return EOF;

}

/** Print one character to output

 * @param c one character

 * @param ps output method

 * @return printed character or EOF

 */

static int printf_putchar(int c, struct printf_spec *ps)

{

    unsigned char ch = c;

    if (ps->write((void *) &ch, 1, ps->data) == 1) {

        return c;

    }

    return EOF;

}

/** Print one formatted character

 * @param c character to print

 * @param width

 * @param flags

 * @return number of printed characters or EOF

 */

static int print_char(char c, int width, uint64_t flags, struct printf_spec *ps)

{

    int counter = 0;

    if (!(flags & __PRINTF_FLAG_LEFTALIGNED)) {

        while (--width > 0) {   /* one space is consumed by character itself hence predecrement */

            /* FIXME: painful slow */

            printf_putchar(' ', ps);   

            ++counter;

        }

    }

    if (printf_putchar(c, ps) == EOF) {

        return EOF;

    }

    while (--width > 0) { /* one space is consumed by character itself hence predecrement */

        printf_putchar(' ', ps);

        ++counter;

    }

    return ++counter;

}

/** Print one string

 * @param s string

 * @param width

 * @param precision

 * @param flags

 * @return number of printed characters or EOF

 */

static int print_string(char *s, int width, int precision, uint64_t flags, struct printf_spec *ps)

{

    int counter = 0;

    size_t size;

    if (s == NULL) {

        return printf_putstr("(NULL)", ps);

    }

    size = strlen(s);

    /* print leading spaces */

    if (precision == 0)

        precision = size;

    width -= precision;

    if (!(flags & __PRINTF_FLAG_LEFTALIGNED)) {

        while (width-- > 0) {  

            printf_putchar(' ', ps);   

            counter++;

        }

    }

    while (precision > size) {

        precision--;

        printf_putchar(' ', ps);   

        ++counter;

    }

    if (printf_putnchars(s, precision, ps) == EOF) {

        return EOF;

    }

    counter += precision;

    while (width-- > 0) {

        printf_putchar(' ', ps);   

        ++counter;

    }

    return ++counter;

}

/** Print number in given base

 *

 * Print significant digits of a number in given

 * base.

 *

 * @param num  Number to print.

 * @param width

 * @param precision

 * @param base Base to print the number in (should

 *             be in range 2 .. 16).

 * @param flags output modifiers

 * @return number of written characters or EOF

 *

 */

static int print_number(uint64_t num, int width, int precision, int base , uint64_t flags, struct printf_spec *ps)

{

    char *digits = digits_small;

    char d[PRINT_NUMBER_BUFFER_SIZE];   /* this is good enough even for base == 2, prefix and sign */

    char *ptr = &d[PRINT_NUMBER_BUFFER_SIZE - 1];

    int size = 0; /* size of number with all prefixes and signs */

    int number_size; /* size of plain number */

    int written = 0;

    char sgn;

    if (flags & __PRINTF_FLAG_BIGCHARS)

        digits = digits_big;   

    *ptr-- = 0; /* Put zero at end of string */

    if (num == 0) {

        *ptr-- = '0';

        size++;

    } else {

        do {

            *ptr-- = digits[num % base];

            size++;

        } while (num /= base);

    }

    number_size = size;

    /* Collect sum of all prefixes/signs/... to calculate padding and leading zeroes */

    if (flags & __PRINTF_FLAG_PREFIX) {

        switch(base) {

            case 2: /* Binary formating is not standard, but usefull */

                size += 2;

                break;

            case 8:

                size++;

                break;

            case 16:

                size += 2;

                break;

        }

    }

    sgn = 0;

    if (flags & __PRINTF_FLAG_SIGNED) {

        if (flags & __PRINTF_FLAG_NEGATIVE) {

            sgn = '-';

            size++;

        } else if (flags & __PRINTF_FLAG_SHOWPLUS) {

                sgn = '+';

                size++;

            } else if (flags & __PRINTF_FLAG_SPACESIGN) {

                    sgn = ' ';

                    size++;

                }

    }

    if (flags & __PRINTF_FLAG_LEFTALIGNED) {

        flags &= ~__PRINTF_FLAG_ZEROPADDED;

    }

    /* if number is leftaligned or precision is specified then zeropadding is ignored */

    if (flags & __PRINTF_FLAG_ZEROPADDED) {

        if ((precision == 0) && (width > size)) {

            precision = width - size + number_size;

        }

    }

    /* print leading spaces */

    if (number_size > precision) /* We must print whole number not only a part */

        precision = number_size;

    width -= precision + size - number_size;

    if (!(flags & __PRINTF_FLAG_LEFTALIGNED)) {

        while (width-- > 0) {  

            printf_putchar(' ', ps);   

            written++;

        }

    }

    /* print sign */

    if (sgn) {

        printf_putchar(sgn, ps);

        written++;

    }

    /* print prefix */

    if (flags & __PRINTF_FLAG_PREFIX) {

        switch(base) {

            case 2: /* Binary formating is not standard, but usefull */

                printf_putchar('0', ps);

                if (flags & __PRINTF_FLAG_BIGCHARS) {

                    printf_putchar('B', ps);

                } else {

                    printf_putchar('b', ps);

                }

                written += 2;

                break;

            case 8:

                printf_putchar('o', ps);

                written++;

                break;

            case 16:

                printf_putchar('0', ps);

                if (flags & __PRINTF_FLAG_BIGCHARS) {

                    printf_putchar('X', ps);

                } else {

                    printf_putchar('x', ps);

                }

                written += 2;

                break;

        }

    }

    /* print leading zeroes */

    precision -= number_size;

    while (precision-- > 0) {  

        printf_putchar('0', ps);   

        written++;

    }

    /* print number itself */

    written += printf_putstr(++ptr, ps);

    /* print ending spaces */

    while (width-- > 0) {  

        printf_putchar(' ', ps);   

        written++;

    }

    return written;

}

/** General formatted text print

 *

 * Print string formatted according the fmt parameter

 * and variant arguments. Each formatting directive

 * must have the following form:

 * % [ flags ] [ width ] [ .precision ] [ type ] conversion

 *

 * FLAGS:

 * #    Force to print prefix. For conversion %o is prefix 0, for %x and %X are prefixes 0x and 0X and for conversion %b is prefix 0b.

 * -    Align to left.

 * +    Print positive sign just as negative.

 *   (space)    If printed number is positive and '+' flag is not set, print space in place of sign.

 * 0    Print 0 as padding instead of spaces. Zeroes are placed between sign and the rest of number. This flag is ignored if '-' flag is specified.

 *

 * WIDTH:

 * Specify minimal width of printed argument. If it is bigger, width is ignored.

 * If width is specified with a '*' character instead of number, width is taken from parameter list.

 * Int parameter expected before parameter for processed conversion specification.

 * If this value is negative it is taken its absolute value and the '-' flag is set.

 *

 * PRECISION:

 * Value precision. For numbers it specifies minimum valid numbers.

 * Smaller numbers are printed with leading zeroes. Bigger numbers are not affected.

 * Strings with more than precision characters are cutted of.

 * Just as width could be '*' used instead a number.

 * A int value is then expected in parameters. When both width and precision are specified using '*',

 * first parameter is used for width and second one for precision.

 *

 * TYPE:

 * hh   signed or unsigned char

 * h    signed or usigned short

 *  signed or usigned int (default value)

 * l    signed or usigned long int

 * ll   signed or usigned long long int

 * z    size_t type

 *

 *

 * CONVERSIONS:

 *

 * %    Print percentage character.

 *

 * c    Print single character.

 *

 * s    Print zero terminated string. If a NULL value is passed as value, "(NULL)" is printed instead.

 *

 * P, p Print value of a pointer. Void * value is expected and it is printed in hexadecimal notation with prefix

 * ( as with %#X or %#x for 32bit or %#X / %#x for 64bit long pointers)

 *

 * b    Print value as unsigned binary number.  Prefix is not printed by default. (Nonstandard extension.)

 *

 * o    Print value as unsigned octal number. Prefix is not printed by default.

 *

 * d,i  Print signed decimal number. There is no difference between d and i conversion.

 *

 * u    Print unsigned decimal number.

 *

 * X, x Print hexadecimal number with upper- or lower-case. Prefix is not printed by default.

 *

 * All other characters from fmt except the formatting directives

 * are printed in verbatim.

 *

 * @param fmt Formatting NULL terminated string.

 * @return count of printed characters or negative value on fail.

 */

int printf_core(const char *fmt, struct printf_spec *ps, va_list ap)

{

    int i = 0, j = 0; /* i is index of currently processed char from fmt, j is index to the first not printed nonformating character */

    int end;

    int counter; /* counter of printed characters */

    int retval; /* used to store return values from called functions */

    char c;

    qualifier_t qualifier;  /* type of argument */

    int base;   /* base in which will be parameter (numbers only) printed */

    uint64_t number; /* argument value */

    size_t  size; /* byte size of integer parameter */

    int width, precision;

    uint64_t flags;

    counter = 0;

    while ((c = fmt[i])) {

        /* control character */

        if (c == '%' ) {

            /* print common characters if any processed */ 

            if (i > j) {

                if ((retval = printf_putnchars(&fmt[j], (size_t)(i - j), ps)) == EOF) { /* error */

                    return -counter;

                }

                counter += retval;

            }

            j = i;

            /* parse modifiers */

            flags = 0;

            end = 0;

            do {

                ++i;

                switch (c = fmt[i]) {

                    case '#': flags |= __PRINTF_FLAG_PREFIX; break;

                    case '-': flags |= __PRINTF_FLAG_LEFTALIGNED; break;

                    case '+': flags |= __PRINTF_FLAG_SHOWPLUS; break;

                    case ' ': flags |= __PRINTF_FLAG_SPACESIGN; break;

                    case '0': flags |= __PRINTF_FLAG_ZEROPADDED; break;

                    default: end = 1;

                }; 

            } while (end == 0);

            /* width & '*' operator */

            width = 0;

            if (isdigit(fmt[i])) {

                while (isdigit(fmt[i])) {

                    width *= 10;

                    width += fmt[i++] - '0';

                }

            } else if (fmt[i] == '*') {

                /* get width value from argument list*/

                i++;

                width = (int)va_arg(ap, int);

                if (width < 0) {

                    /* negative width means to set '-' flag */

                    width *= -1;

                    flags |= __PRINTF_FLAG_LEFTALIGNED;

                }

            }

            /* precision and '*' operator */   

            precision = 0;

            if (fmt[i] == '.') {

                ++i;

                if (isdigit(fmt[i])) {

                    while (isdigit(fmt[i])) {

                        precision *= 10;

                        precision += fmt[i++] - '0';

                    }

                } else if (fmt[i] == '*') {

                    /* get precision value from argument list*/

                    i++;

                    precision = (int)va_arg(ap, int);

                    if (precision < 0) {

                        /* negative precision means to ignore it */

                        precision = 0;

                    }

                }

            }

            switch (fmt[i++]) {

                /** TODO: unimplemented qualifiers:

                 * t ptrdiff_t - ISO C 99

                 */

                case 'h':   /* char or short */

                    qualifier = PrintfQualifierShort;

                    if (fmt[i] == 'h') {

                        i++;

                        qualifier = PrintfQualifierByte;

                    }

                    break;

                case 'l':   /* long or long long*/

                    qualifier = PrintfQualifierLong;

                    if (fmt[i] == 'l') {

                        i++;

                        qualifier = PrintfQualifierLongLong;

                    }

                    break;

                case 'z':   /* size_t */

                    qualifier = PrintfQualifierSizeT;

                    break;

                default:

                    qualifier = PrintfQualifierInt; /* default type */

                    --i;

            }  

            base = 10;

            switch (c = fmt[i]) {

                /*

                * String and character conversions.

                */

                case 's':

                    if ((retval = print_string(va_arg(ap, char*), width, precision, flags, ps)) == EOF) {

                        return -counter;

                    };

                    counter += retval;

                    j = i + 1;

                    goto next_char;

                case 'c':

                    c = va_arg(ap, unsigned int);

                    if ((retval = print_char(c, width, flags, ps)) == EOF) {

                        return -counter;

                    };

                    counter += retval;

                    j = i + 1;

                    goto next_char;

                /*

                 * Integer values

                */

                case 'P': /* pointer */

                        flags |= __PRINTF_FLAG_BIGCHARS;

                case 'p':

                    flags |= __PRINTF_FLAG_PREFIX;

                    base = 16;

                    qualifier = PrintfQualifierPointer;

                    break; 

                case 'b':

                    base = 2;

                    break;

                case 'o':

                    base = 8;

                    break;

                case 'd':

                case 'i':

                    flags |= __PRINTF_FLAG_SIGNED;  

                case 'u':

                    break;

                case 'X':

                    flags |= __PRINTF_FLAG_BIGCHARS;

                case 'x':

                    base = 16;

                    break;

                /* percentile itself */

                case '%':

                    j = i;

                    goto next_char;

                /*

                * Bad formatting.

                */

                default:

                    /* Unknown format

                     *  now, the j is index of '%' so we will

                     * print whole bad format sequence

                     */

                    goto next_char;    

            }

        /* Print integers */

            /* print number */

            switch (qualifier) {

                case PrintfQualifierByte:

                    size = sizeof(unsigned char);

                    number = (uint64_t)va_arg(ap, unsigned int);

                    break;

                case PrintfQualifierShort:

                    size = sizeof(unsigned short);

                    number = (uint64_t)va_arg(ap, unsigned int);

                    break;

                case PrintfQualifierInt:

                    size = sizeof(unsigned int);

                    number = (uint64_t)va_arg(ap, unsigned int);

                    break;

                case PrintfQualifierLong:

                    size = sizeof(unsigned long);

                    number = (uint64_t)va_arg(ap, unsigned long);

                    break;

                case PrintfQualifierLongLong:

                    size = sizeof(unsigned long long);

                    number = (uint64_t)va_arg(ap, unsigned long long);

                    break;

                case PrintfQualifierPointer:

                    size = sizeof(void *);

                    number = (uint64_t)(unsigned long)va_arg(ap, void *);

                    break;

                case PrintfQualifierSizeT:

                    size = sizeof(size_t);

                    number = (uint64_t)va_arg(ap, size_t);

                    break;

                default: /* Unknown qualifier */

                    return -counter;

            }

            if (flags & __PRINTF_FLAG_SIGNED) {

                if (number & (0x1 << (size*8 - 1))) {

                    flags |= __PRINTF_FLAG_NEGATIVE;

                    if (size == sizeof(uint64_t)) {

                        number = -((int64_t)number);

                    } else {

                        number = ~number;

                        number &= (~((0xFFFFFFFFFFFFFFFFll) <<  (size * 8)));

                        number++;

                    }

                }

            }

            if ((retval = print_number(number, width, precision, base, flags, ps)) == EOF ) {

                return -counter;

            };

            counter += retval;

            j = i + 1;

        }  

next_char:

        ++i;

    }

    if (i > j) {

        if ((retval = printf_putnchars(&fmt[j], (size_t)(i - j), ps)) == EOF) { /* error */

            return -counter;

        }

        counter += retval;

    }

    return counter;

}