external/bsd/kyua-testers/dist/text.c

   1 // Copyright 2012 Google Inc.
   2 // All rights reserved.
   3 //
   4 // Redistribution and use in source and binary forms, with or without
   5 // modification, are permitted provided that the following conditions are
   6 // met:
   7 //
   8 // * Redistributions of source code must retain the above copyright
   9 //   notice, this list of conditions and the following disclaimer.
  10 // * Redistributions in binary form must reproduce the above copyright
  11 //   notice, this list of conditions and the following disclaimer in the
  12 //   documentation and/or other materials provided with the distribution.
  13 // * Neither the name of Google Inc. nor the names of its contributors
  14 //   may be used to endorse or promote products derived from this software
  15 //   without specific prior written permission.
  16 //
  17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28
  29 #include "text.h"
  30
  31 #include <assert.h>
  32 #include <errno.h>
  33 #include <stdarg.h>
  34 #include <stdlib.h>
  35 #include <stdio.h>
  36
  37 #include "error.h"
  38
  39
  40 /// Calculates the length of a formatting string with its replacements.
  41 ///
  42 /// \param format The formatting string.
  43 /// \param ap List of arguments to apply to the formatting string.
  44 ///
  45 /// \return -1 if there is an error; or the final length otherwise.
  46 static int
  47 calculate_length(const char* format, va_list ap)
  48 {
  49     va_list ap2;
  50
  51     char buffer[1];
  52     va_copy(ap2, ap);
  53     const int needed = vsnprintf(buffer, sizeof(buffer), format, ap);
  54     va_end(ap2);
  55     return needed;
  56 }
  57
  58
  59 /// Generates a string from a format string and its replacements.
  60 ///
  61 /// \param [out] output Pointer to the dynamically-allocated string with the
  62 ///     result of the operation.  The caller must release this with free().
  63 /// \param format The formatting string.
  64 /// \param ... Arguments to apply to the formatting string.
  65 ///
  66 /// \return OK if the string could be formatted; an error otherwise.
  67 kyua_error_t
  68 kyua_text_printf(char** output, const char* format, ...)
  69 {
  70     kyua_error_t error;
  71     va_list ap;
  72
  73     va_start(ap, format);
  74     error = kyua_text_vprintf(output, format, ap);
  75     va_end(ap);
  76
  77     return error;
  78 }
  79
  80
  81 /// Generates a string from a format string and its replacements.
  82 ///
  83 /// \param [out] output Pointer to the dynamically-allocated string with the
  84 ///     result of the operation.  The caller must release this with free().
  85 /// \param format The formatting string.
  86 /// \param ap List of to apply to the formatting string.
  87 ///
  88 /// \return OK if the string could be formatted; an error otherwise.
  89 kyua_error_t
  90 kyua_text_vprintf(char** output, const char* format, va_list ap)
  91 {
  92     va_list ap2;
  93
  94     va_copy(ap2, ap);
  95     const int length = calculate_length(format, ap2);
  96     va_end(ap2);
  97     if (length < 0)
  98         return kyua_libc_error_new(errno, "Could not calculate length of "
  99                                    "string with format '%s'", format);
 100
 101     char* buffer = (char*)malloc(length + 1);
 102     if (buffer == NULL)
 103         return kyua_oom_error_new();
 104
 105     va_copy(ap2, ap);
 106     const int printed_length = vsnprintf(buffer, length + 1, format, ap2);
 107     va_end(ap2);
 108     assert(printed_length == length);
 109     if (printed_length < 0) {
 110         free(buffer);
 111         return kyua_libc_error_new(errno, "Could generate string with format "
 112                                    "'%s'", format);
 113     }
 114
 115     *output = buffer;
 116     return kyua_error_ok();
 117 }