userland/interface/vcos/generic/vcos_generic_safe_string.c

/*
Copyright (c) 2012, Broadcom Europe Ltd
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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*/
 /*****************************************************************************
 * Copyright 2012 Broadcom Corporation.  All rights reserved.
 *
 * This program is the proprietary software of Broadcom Corporation and/or
 * its licensors, and may only be used, duplicated, modified or distributed
 * pursuant to the terms and conditions of a separate, written license
 * agreement executed between you and Broadcom (an "Authorized License").
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 * THE SOFTWARE.
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 *    all reasonable efforts to protect the confidentiality thereof, and to
 *    use this information only in connection with your use of Broadcom
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#include "interface/vcos/vcos.h"

#if defined( __KERNEL__ )
#include <linux/string.h>
#include <linux/module.h>
#else
#include <string.h>
#endif

#include <stdarg.h>

/** Like vsnprintf, except it places the output at the specified offset.
  * Output is truncated to fit in buflen bytes, and is guaranteed to be NUL-terminated.
  * Returns the string length before/without truncation.
  */
size_t vcos_safe_vsprintf(char *buf, size_t buflen, size_t offset, const char *fmt, va_list ap)
{
   size_t space = (offset < buflen) ? (buflen - offset) : 0;

   offset += vcos_vsnprintf(buf ? (buf + offset) : NULL, space, fmt, ap);

   return offset;
}

/** Like snprintf, except it places the output at the specified offset.
  * Output is truncated to fit in buflen bytes, and is guaranteed to be NUL-terminated.
  * Returns the string length before/without truncation.
  */
size_t vcos_safe_sprintf(char *buf, size_t buflen, size_t offset, const char *fmt, ...)
{
   size_t space = (offset < buflen) ? (buflen - offset) : 0;
   va_list ap;
   
   va_start(ap, fmt);

   offset += vcos_vsnprintf(buf ? (buf + offset) : NULL, space, fmt, ap);

   va_end(ap);

   return offset;
}

/** Copies string src to dst at the specified offset.
  * Output is truncated to fit in dstlen bytes, i.e. the string is at most
  * (buflen - 1) characters long. Unlike strncpy, exactly one NUL is written
  * to dst, which is always NUL-terminated.
  * Returns the string length before/without truncation.
  */
size_t vcos_safe_strcpy(char *dst, const char *src, size_t dstlen, size_t offset)
{
   if (offset < dstlen)
   {
      const char *p = src;
      char *endp = dst + dstlen -1;

      dst += offset;

      for (; *p!='\0' && dst != endp; dst++, p++)
         *dst = *p;
      *dst = '\0';
   }
   offset += strlen(src);

   return offset;
}