snprintf.c

/*
 * snprintf functions for the ESP Package Manager (EPM).
 *
 * Copyright © 2020 by Jim Jagielski
 * Copyright 1999-2014 by Michael R Sweet
 * Copyright 1999-2005 by Easy Software Products.
 *
 * 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 necessary headers...
 */

#include "epmstring.h"
#include <ctype.h>
#include <stdio.h>

#ifndef HAVE_VSNPRINTF
/*
 * 'vsnprintf()' - Format a string into a fixed size buffer.
 */

int                               /* O - Number of bytes formatted */
epm_vsnprintf(char *buffer,       /* O - Output buffer */
              size_t bufsize,     /* O - Size of output buffer */
              const char *format, /* I - printf-style format string */
              va_list ap)         /* I - Pointer to additional arguments */
{
    char *bufptr,          /* Pointer to position in buffer */
        *bufend,           /* Pointer to end of buffer */
        sign,              /* Sign of format width */
        size,              /* Size character (h, l, L) */
        type;              /* Format type character */
    const char *bufformat; /* Start of format */
    int width,             /* Width of field */
        prec;              /* Number of characters of precision */
    char tformat[100],     /* Temporary format string for sprintf() */
        temp[1024];        /* Buffer for formatted numbers */
    char *s;               /* Pointer to string */
    int slen;              /* Length of string */

    /*
     * Loop through the format string, formatting as needed...
     */

    bufptr = buffer;
    bufend = buffer + bufsize - 1;

    while (*format && bufptr < bufend) {
        if (*format == '%') {
            bufformat = format;
            format++;

            if (*format == '%') {
                *bufptr++ = *format++;
                continue;
            } else if (strchr(" -+#\'", *format))
                sign = *format++;
            else
                sign = 0;

            width = 0;
            while (isdigit(*format))
                width = width * 10 + *format++ - '0';

            if (*format == '.') {
                format++;
                prec = 0;

                while (isdigit(*format))
                    prec = prec * 10 + *format++ - '0';
            } else
                prec = -1;

            if (*format == 'l' && format[1] == 'l') {
                size = 'L';
                format += 2;
            } else if (*format == 'h' || *format == 'l' || *format == 'L')
                size = *format++;

            if (!*format)
                break;

            type = *format++;

            switch (type) {
            case 'E': /* Floating point formats */
            case 'G':
            case 'e':
            case 'f':
            case 'g':
                if ((format - bufformat + 1) > sizeof(tformat) ||
                    (width + 2) > sizeof(temp))
                    break;

                strlcpy(tformat, bufformat, format - bufformat + 1);

                sprintf(temp, tformat, va_arg(ap, double));

                if ((bufptr + strlen(temp)) > bufend) {
                    strncpy(bufptr, temp, bufend - bufptr);
                    bufptr = bufend;
                    break;
                } else {
                    strcpy(bufptr, temp);
                    bufptr += strlen(temp);
                }
                break;

            case 'B': /* Integer formats */
            case 'X':
            case 'b':
            case 'd':
            case 'i':
            case 'o':
            case 'u':
            case 'x':
                if ((format - bufformat + 1) > sizeof(tformat) ||
                    (width + 2) > sizeof(temp))
                    break;

                strlcpy(tformat, bufformat, format - bufformat + 1);

                sprintf(temp, tformat, va_arg(ap, int));

                if ((bufptr + strlen(temp)) > bufend) {
                    strncpy(bufptr, temp, bufend - bufptr);
                    bufptr = bufend;
                    break;
                } else {
                    strcpy(bufptr, temp);
                    bufptr += strlen(temp);
                }
                break;

            case 'p': /* Pointer value */
                if ((format - bufformat + 1) > sizeof(tformat) ||
                    (width + 2) > sizeof(temp))
                    break;

                strlcpy(tformat, bufformat, format - bufformat + 1);

                sprintf(temp, tformat, va_arg(ap, void *));

                strlcpy(bufptr, temp, bufend - bufptr + 1);
                bufptr += strlen(bufptr);
                break;

            case 'c': /* Character or character array */
                if (width <= 1)
                    *bufptr++ = va_arg(ap, int);
                else {
                    if ((bufptr + width) > bufend)
                        width = bufend - bufptr;

                    memcpy(bufptr, va_arg(ap, char *), width);
                    bufptr += width;
                }
                break;

            case 's': /* String */
                if ((s = va_arg(ap, char *)) == NULL)
                    s = "(null)";

                slen = strlen(s);
                if (slen > width && prec != width)
                    width = slen;

                if ((bufptr + width) > bufend)
                    width = bufend - bufptr;

                if (slen > width)
                    slen = width;

                if (sign == '-') {
                    strncpy(bufptr, s, slen);
                    memset(bufptr + slen, ' ', width - slen);
                } else {
                    memset(bufptr, ' ', width - slen);
                    strncpy(bufptr + width - slen, s, slen);
                }

                bufptr += width;
                break;

            case 'n': /* Output number of chars so far */
                if ((format - bufformat + 1) > sizeof(tformat) ||
                    (width + 2) > sizeof(temp))
                    break;

                strlcpy(tformat, bufformat, format - bufformat + 1);

                sprintf(temp, tformat, va_arg(ap, int));

                strlcpy(bufptr, temp, bufend - bufptr + 1);
                bufptr += strlen(bufptr);
                break;
            }
        } else
            *bufptr++ = *format++;
    }

    /*
     * Nul-terminate the string and return the number of characters in it.
     */

    *bufptr = '\0';
    return (bufptr - buffer);
}
#endif /* !HAVE_VSNPRINT */

#ifndef HAVE_SNPRINTF
/*
 * 'epm_snprintf()' - Format a string into a fixed size buffer.
 */

int                              /* O - Number of bytes formatted */
epm_snprintf(char *buffer,       /* O - Output buffer */
             size_t bufsize,     /* O - Size of output buffer */
             const char *format, /* I - printf-style format string */
             ...)                /* I - Additional arguments as needed */
{
    int bytes;  /* Number of bytes formatted */
    va_list ap; /* Pointer to additional arguments */

    va_start(ap, format);
    bytes = vsnprintf(buffer, bufsize, format, ap);
    va_end(ap);

    return (bytes);
}
#endif /* !HAVE_SNPRINTF */