Subversion Repositories HelenOS-historic

Rev

Rev 1605 | Blame | Compare with Previous | Last modification | View Log | Download | RSS feed

  1. /*
  2.  * Copyright (C) 2006 Josef Cejka
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29.  /** @addtogroup generic   
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #include <print.h>
  36. #include <printf/printf_core.h>
  37. #include <memstr.h>
  38.  
  39. struct vsnprintf_data {
  40.     size_t size; /* total space for string */
  41.     size_t len; /* count of currently used characters */
  42.     char *string; /* destination string */
  43. };
  44.  
  45. int vsnprintf_write(const char *str, size_t count, struct vsnprintf_data *data);
  46.  
  47. /** Write string to given buffer.
  48.  * Write at most data->size characters including trailing zero. According to C99, snprintf() has to return number
  49.  * of characters that would have been written if enough space had been available. Hence the return value is not
  50.  * number of really printed characters but size of the input string. Number of really used characters
  51.  * is stored in data->len.
  52.  * @param str source string to print
  53.  * @param count size of source string
  54.  * @param data structure with destination string, counter of used space and total string size.
  55.  * @return number of characters to print (not characters really printed!)
  56.  */
  57. int vsnprintf_write(const char *str, size_t count, struct vsnprintf_data *data)
  58. {
  59.     size_t i;
  60.     i = data->size - data->len;
  61.  
  62.     if (i == 0) {
  63.         return count;
  64.     }
  65.    
  66.     if (i == 1) {
  67.         /* We have only one free byte left in buffer => write there trailing zero */
  68.         data->string[data->size - 1] = 0;
  69.         data->len = data->size;
  70.         return count;
  71.     }
  72.    
  73.     if (i <= count) {
  74.         /* We have not enought space for whole string with the trailing zero => print only a part of string */
  75.             memcpy((void *)(data->string + data->len), (void *)str, i - 1);
  76.             data->string[data->size - 1] = 0;
  77.             data->len = data->size;
  78.             return count;
  79.     }
  80.    
  81.     /* Buffer is big enought to print whole string */
  82.     memcpy((void *)(data->string + data->len), (void *)str, count);
  83.     data->len += count;
  84.     /* Put trailing zero at end, but not count it into data->len so it could be rewritten next time */
  85.     data->string[data->len] = 0;
  86.  
  87.     return count;  
  88. }
  89.  
  90. int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)
  91. {
  92.     struct vsnprintf_data data = {size, 0, str};
  93.     struct printf_spec ps = {(int(*)(void *, size_t, void *))vsnprintf_write, &data};
  94.  
  95.     /* Print 0 at end of string - fix the case that nothing will be printed */
  96.     if (size > 0)
  97.         str[0] = 0;
  98.    
  99.     /* vsnprintf_write ensures that str will be terminated by zero. */
  100.     return printf_core(fmt, &ps, ap);
  101. }
  102.  
  103.  /** @}
  104.  */
  105.  
  106.