apr_snprintf.c

linux subdivision ying gai ke yi le ba

/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
 * applicable.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "apr.h"
#include "apr_private.h"

#include "apr_lib.h"
#include "apr_strings.h"
#include "apr_network_io.h"
#include "apr_portable.h"
#include <math.h>
#if APR_HAVE_CTYPE_H
#include <ctype.h>
#endif
#if APR_HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if APR_HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if APR_HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#if APR_HAVE_LIMITS_H
#include <limits.h>
#endif
#if APR_HAVE_STRING_H
#include <string.h>
#endif

typedef enum {
    NO = 0, YES = 1
} boolean_e;

#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif
#define NUL '\0'
#define WIDE_INT long

typedef WIDE_INT wide_int;
typedef unsigned WIDE_INT u_wide_int;
typedef apr_int64_t widest_int;
#ifdef __TANDEM
/* Although Tandem supports "long long" there is no unsigned variant. */
typedef unsigned long       u_widest_int;
#else
typedef apr_uint64_t u_widest_int;
#endif
typedef int bool_int;

#define S_NULL "(null)"
#define S_NULL_LEN 6

#define FLOAT_DIGITS 6
#define EXPONENT_LENGTH 10

/*
 * NUM_BUF_SIZE is the size of the buffer used for arithmetic conversions
 *
 * NOTICE: this is a magic number; do not decrease it
 */
#define NUM_BUF_SIZE 512

/*
 * cvt.c - IEEE floating point formatting routines for FreeBSD
 * from GNU libc-4.6.27.  Modified to be thread safe.
 */

/*
 *    apr_ecvt converts to decimal
 *      the number of digits is specified by ndigit
 *      decpt is set to the position of the decimal point
 *      sign is set to 0 for positive, 1 for negative
 */

#define NDIG 80

/* buf must have at least NDIG bytes */
static char *apr_cvt(double arg, int ndigits, int *decpt, int *sign, 
                     int eflag, char *buf)
{
    register int r2;
    double fi, fj;
    register char *p, *p1;
    
    if (ndigits >= NDIG - 1)
        ndigits = NDIG - 2;
    r2 = 0;
    *sign = 0;
    p = &buf[0];
    if (arg < 0) {
        *sign = 1;
        arg = -arg;
    }
    arg = modf(arg, &fi);
    p1 = &buf[NDIG];
    /*
     * Do integer part
     */
    if (fi != 0) {
        p1 = &buf[NDIG];
        while (p1 > &buf[0] && fi != 0) {
            fj = modf(fi / 10, &fi);
            *--p1 = (int) ((fj + .03) * 10) + '0';
            r2++;
        }
        while (p1 < &buf[NDIG])
            *p++ = *p1++;
    }
    else if (arg > 0) {
        while ((fj = arg * 10) < 1) {
            arg = fj;
            r2--;
        }
    }
    p1 = &buf[ndigits];
    if (eflag == 0)
        p1 += r2;
    if (p1 < &buf[0]) {
        *decpt = -ndigits;
        buf[0] = '\0';
        return (buf);
    }
    *decpt = r2;
    while (p <= p1 && p < &buf[NDIG]) {
        arg *= 10;
        arg = modf(arg, &fj);
        *p++ = (int) fj + '0';
    }
    if (p1 >= &buf[NDIG]) {
        buf[NDIG - 1] = '\0';
        return (buf);
    }
    p = p1;
    *p1 += 5;
    while (*p1 > '9') {
        *p1 = '0';
        if (p1 > buf)
            ++ * --p1;
        else {
            *p1 = '1';
            (*decpt)++;
            if (eflag == 0) {
                if (p > buf)
                    *p = '0';
                p++;
            }
        }
    }
    *p = '\0';
    return (buf);
}

static char *apr_ecvt(double arg, int ndigits, int *decpt, int *sign, char *buf)
{
    return (apr_cvt(arg, ndigits, decpt, sign, 1, buf));
}

static char *apr_fcvt(double arg, int ndigits, int *decpt, int *sign, char *buf)
{
    return (apr_cvt(arg, ndigits, decpt, sign, 0, buf));
}

/*
 * apr_gcvt  - Floating output conversion to
 * minimal length string
 */

static char *apr_gcvt(double number, int ndigit, char *buf, boolean_e altform)
{
    int sign, decpt;
    register char *p1, *p2;
    register int i;
    char buf1[NDIG];

    p1 = apr_ecvt(number, ndigit, &decpt, &sign, buf1);
    p2 = buf;
    if (sign)
        *p2++ = '-';
    for (i = ndigit - 1; i > 0 && p1[i] == '0'; i--)
        ndigit--;
    if ((decpt >= 0 && decpt - ndigit > 4)
        || (decpt < 0 && decpt < -3)) {                /* use E-style */
        decpt--;
        *p2++ = *p1++;
        *p2++ = '.';
        for (i = 1; i < ndigit; i++)
            *p2++ = *p1++;
        *p2++ = 'e';
        if (decpt < 0) {
            decpt = -decpt;
            *p2++ = '-';
        }
        else
            *p2++ = '+';
        if (decpt / 100 > 0)
            *p2++ = decpt / 100 + '0';
        if (decpt / 10 > 0)
            *p2++ = (decpt % 100) / 10 + '0';
        *p2++ = decpt % 10 + '0';
    }
    else {
        if (decpt <= 0) {
            if (*p1 != '0')
                *p2++ = '.';
            while (decpt < 0) {
                decpt++;
                *p2++ = '0';
            }
        }
        for (i = 1; i <= ndigit; i++) {
            *p2++ = *p1++;
            if (i == decpt)
                *p2++ = '.';
        }
        if (ndigit < decpt) {
            while (ndigit++ < decpt)
                *p2++ = '0';
            *p2++ = '.';
        }
    }
    if (p2[-1] == '.' && !altform)
        p2--;
    *p2 = '\0';
    return (buf);
}

/*
 * The INS_CHAR macro inserts a character in the buffer and writes
 * the buffer back to disk if necessary
 * It uses the char pointers sp and bep:
 *      sp points to the next available character in the buffer
 *      bep points to the end-of-buffer+1
 * While using this macro, note that the nextb pointer is NOT updated.
 *
 * NOTE: Evaluation of the c argument should not have any side-effects
 */
#define INS_CHAR(c, sp, bep, cc)                    \
{                                                   \
    if (sp) {                                       \
        if (sp >= bep) {                            \
            vbuff->curpos = sp;                     \
            if (flush_func(vbuff))                  \
                return -1;                          \
            sp = vbuff->curpos;                     \
            bep = vbuff->endpos;                    \
        }                                           \
        *sp++ = (c);                                \
    }                                               \
    cc++;                                           \
}

#define NUM(c) (c - '0')

#define STR_TO_DEC(str, num)                        \
    num = NUM(*str++);                              \
    while (apr_isdigit(*str))                       \
    {                                               \
        num *= 10 ;                                 \
        num += NUM(*str++);                         \
    }

/*
 * This macro does zero padding so that the precision
 * requirement is satisfied. The padding is done by
 * adding '0's to the left of the string that is going
 * to be printed. We don't allow precision to be large
 * enough that we continue past the start of s.
 *
 * NOTE: this makes use of the magic info that s is
 * always based on num_buf with a size of NUM_BUF_SIZE.
 */
#define FIX_PRECISION(adjust, precision, s, s_len)  \
    if (adjust) {                                   \
        int p = precision < NUM_BUF_SIZE - 1 ? precision : NUM_BUF_SIZE - 1; \
        while (s_len < p)                           \
        {                                           \
            *--s = '0';                             \
            s_len++;                                \
        }                                           \
    }

/*
 * Macro that does padding. The padding is done by printing
 * the character ch.
 */
#define PAD(width, len, ch)                         \
do                                                  \
{                                                   \
    INS_CHAR(ch, sp, bep, cc);                      \
    width--;                                        \
}                                                   \
while (width > len)

/*
 * Prefix the character ch to the string str
 * Increase length
 * Set the has_prefix flag
 */
#define PREFIX(str, length, ch)                     \
    *--str = ch;                                    \
    length++;                                       \
    has_prefix=YES;


/*
 * Convert num to its decimal format.
 * Return value:
 *   - a pointer to a string containing the number (no sign)
 *   - len contains the length of the string
 *   - is_negative is set to TRUE or FALSE depending on the sign
 *     of the number (always set to FALSE if is_unsigned is TRUE)
 *
 * The caller provides a buffer for the string: that is the buf_end argument
 * which is a pointer to the END of the buffer + 1 (i.e. if the buffer
 * is declared as buf[ 100 ], buf_end should be &buf[ 100 ])
 *
 * Note: we have 2 versions. One is used when we need to use quads
 * (conv_10_quad), the other when we don't (conv_10). We're assuming the
 * latter is faster.
 */
static char *conv_10(register wide_int num, register bool_int is_unsigned,
                     register bool_int *is_negative, char *buf_end,
                     register int *len)
{
    register char *p = buf_end;
    register u_wide_int magnitude;

    if (is_unsigned) {
        magnitude = (u_wide_int) num;
        *is_negative = FALSE;
    }
    else {
        *is_negative = (num < 0);

        /*
         * On a 2's complement machine, negating the most negative integer 
         * results in a number that cannot be represented as a signed integer.
         * Here is what we do to obtain the number's magnitude:
         *      a. add 1 to the number
         *      b. negate it (becomes positive)
         *      c. convert it to unsigned
         *      d. add 1
         */
        if (*is_negative) {
            wide_int t = num + 1;

            magnitude = ((u_wide_int) -t) + 1;
        }
        else
            magnitude = (u_wide_int) num;
    }

    /*
     * We use a do-while loop so that we write at least 1 digit 
     */
    do {
        register u_wide_int new_magnitude = magnitude / 10;

        *--p = (char) (magnitude - new_magnitude * 10 + '0');
        magnitude = new_magnitude;
    }
    while (magnitude);

    *len = buf_end - p;
    return (p);
}

static char *conv_10_quad(widest_int num, register bool_int is_unsigned,
                     register bool_int *is_negative, char *buf_end,
                     register int *len)
{
    register char *p = buf_end;
    u_widest_int magnitude;

    /*
     * We see if we can use the faster non-quad version by checking the
     * number against the largest long value it can be. If <=, we
     * punt to the quicker version.
     */
    if ((num <= ULONG_MAX && is_unsigned) 
        || (num <= LONG_MAX && num >= LONG_MIN && !is_unsigned))
            return(conv_10( (wide_int)num, is_unsigned, is_negative,
               buf_end, len));

    if (is_unsigned) {
        magnitude = (u_widest_int) num;
        *is_negative = FALSE;
    }
    else {
        *is_negative = (num < 0);

        /*
         * On a 2's complement machine, negating the most negative integer 
         * results in a number that cannot be represented as a signed integer.
         * Here is what we do to obtain the number's magnitude:
         *      a. add 1 to the number
         *      b. negate it (becomes positive)
         *      c. convert it to unsigned
         *      d. add 1
         */
        if (*is_negative) {
            widest_int t = num + 1;

            magnitude = ((u_widest_int) -t) + 1;
        }
        else
            magnitude = (u_widest_int) num;
    }

    /*
     * We use a do-while loop so that we write at least 1 digit 
     */
    do {
        u_widest_int new_magnitude = magnitude / 10;

        *--p = (char) (magnitude - new_magnitude * 10 + '0');
        magnitude = new_magnitude;
    }
    while (magnitude);