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  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 <string.h>
  38. #include <memstr.h>
  39.  
  40. typedef struct {
  41.     size_t size;    /* Total size of the buffer (in bytes) */
  42.     size_t len;     /* Number of already used bytes */
  43.     char *dst;      /* Destination */
  44. } vsnprintf_data_t;
  45.  
  46. /** Write UTF-8 string to given buffer.
  47.  *
  48.  * Write at most data->size plain characters including trailing zero.
  49.  * According to C99, snprintf() has to return number of characters that
  50.  * would have been written if enough space had been available. Hence
  51.  * the return value is not the number of actually printed characters
  52.  * but size of the input string.
  53.  *
  54.  * @param str  Source UTF-8 string to print.
  55.  * @param size Number of plain characters in str.
  56.  * @param data Structure describing destination string, counter
  57.  *             of used space and total string size.
  58.  *
  59.  * @return Number of UTF-8 characters to print (not characters actually
  60.  *         printed).
  61.  *
  62.  */
  63. static int vsnprintf_write_utf8(const char *str, size_t size, vsnprintf_data_t *data)
  64. {
  65.     size_t left = data->size - data->len;
  66.    
  67.     if (left == 0)
  68.         return ((int) size);
  69.    
  70.     if (left == 1) {
  71.         /* We have only one free byte left in buffer
  72.          * -> store trailing zero
  73.          */
  74.         data->dst[data->size - 1] = 0;
  75.         data->len = data->size;
  76.         return ((int) size);
  77.     }
  78.    
  79.     if (left <= size) {
  80.         /* We have not enought space for whole string
  81.          * with the trailing zero => print only a part
  82.          * of string
  83.          */
  84.         index_t index = 0;
  85.        
  86.         while (index < size) {
  87.             wchar_t uc = utf8_decode(str, &index, size - 1);
  88.            
  89.             if (!utf8_encode(uc, data->dst, &data->len, data->size - 2))
  90.                 break;
  91.            
  92.             data->len++;
  93.             index++;
  94.         }
  95.        
  96.         /* Put trailing zero at end, but not count it
  97.          * into data->len so it could be rewritten next time
  98.          */
  99.         data->dst[data->len] = 0;
  100.        
  101.         return ((int) size);
  102.     }
  103.    
  104.     /* Buffer is big enought to print the whole string */
  105.     memcpy((void *)(data->dst + data->len), (void *) str, size);
  106.     data->len += size;
  107.    
  108.     /* Put trailing zero at end, but not count it
  109.      * into data->len so it could be rewritten next time
  110.      */
  111.     data->dst[data->len] = 0;
  112.    
  113.     return ((int) size);
  114. }
  115.  
  116. /** Write UTF-32 string to given buffer.
  117.  *
  118.  * Write at most data->size plain characters including trailing zero.
  119.  * According to C99, snprintf() has to return number of characters that
  120.  * would have been written if enough space had been available. Hence
  121.  * the return value is not the number of actually printed characters
  122.  * but size of the input string.
  123.  *
  124.  * @param str  Source UTF-32 string to print.
  125.  * @param size Number of bytes in str.
  126.  * @param data Structure describing destination string, counter
  127.  *             of used space and total string size.
  128.  *
  129.  * @return Number of UTF-8 characters to print (not characters actually
  130.  *         printed).
  131.  *
  132.  */
  133. static int vsnprintf_write_utf32(const wchar_t *str, size_t size, vsnprintf_data_t *data)
  134. {
  135.     index_t index = 0;
  136.    
  137.     while (index < (size / sizeof(wchar_t))) {
  138.         size_t left = data->size - data->len;
  139.        
  140.         if (left == 0)
  141.             return ((int) size);
  142.        
  143.         if (left == 1) {
  144.             /* We have only one free byte left in buffer
  145.              * -> store trailing zero
  146.              */
  147.             data->dst[data->size - 1] = 0;
  148.             data->len = data->size;
  149.             return ((int) size);
  150.         }
  151.        
  152.         if (!utf8_encode(str[index], data->dst, &data->len, data->size - 2))
  153.             break;
  154.        
  155.         data->len++;
  156.         index++;
  157.     }
  158.    
  159.     /* Put trailing zero at end, but not count it
  160.      * into data->len so it could be rewritten next time
  161.      */
  162.     data->dst[data->len] = 0;
  163.    
  164.     return ((int) size);
  165. }
  166.  
  167. int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)
  168. {
  169.     vsnprintf_data_t data = {
  170.         size,
  171.         0,
  172.         str
  173.     };
  174.     printf_spec_t ps = {
  175.         (int(*) (const char *, size_t, void *)) vsnprintf_write_utf8,
  176.         (int(*) (const wchar_t *, size_t, void *)) vsnprintf_write_utf32,
  177.         &data
  178.     };
  179.    
  180.     /* Print 0 at end of string - fix the case that nothing will be printed */
  181.     if (size > 0)
  182.         str[0] = 0;
  183.    
  184.     /* vsnprintf_write ensures that str will be terminated by zero. */
  185.     return printf_core(fmt, &ps, ap);
  186. }
  187.  
  188. /** @}
  189.  */
  190.