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1234 | cejka | 1 | /* |
2071 | jermar | 2 | * Copyright (c) 2006 Josef Cejka |
1234 | cejka | 3 | * All rights reserved. |
4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * - Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
1866 | jermar | 29 | /** @addtogroup libc |
1653 | cejka | 30 | * @{ |
31 | */ |
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32 | /** @file |
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33 | */ |
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34 | |||
1234 | cejka | 35 | #include <stdarg.h> |
36 | #include <stdio.h> |
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37 | #include <string.h> |
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38 | #include <io/printf_core.h> |
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39 | |||
40 | struct vsnprintf_data { |
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3351 | jermar | 41 | size_t size; /* total space for string */ |
42 | size_t len; /* count of currently used characters */ |
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43 | char *string; /* destination string */ |
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1234 | cejka | 44 | }; |
45 | |||
46 | /** Write string to given buffer. |
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3351 | jermar | 47 | * Write at most data->size characters including trailing zero. According to C99 |
48 | * has snprintf to return number of characters that would have been written if |
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49 | * enough space had been available. Hence the return value is not number of |
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50 | * really printed characters but size of input string. Number of really used |
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51 | * characters is stored in data->len. |
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52 | * |
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53 | * @param str Source string to print. |
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54 | * @param count Size of the source string. |
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55 | * @param data Structure with destination string, counter of used space |
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56 | * and total string size. |
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57 | * @return Number of characters to print (not characters really |
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58 | * printed!) |
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1234 | cejka | 59 | */ |
3351 | jermar | 60 | static int |
61 | vsnprintf_write(const char *str, size_t count, struct vsnprintf_data *data) |
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1234 | cejka | 62 | { |
1617 | cejka | 63 | size_t i; |
1234 | cejka | 64 | i = data->size - data->len; |
65 | |||
1617 | cejka | 66 | if (i == 0) { |
67 | return count; |
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1234 | cejka | 68 | } |
69 | |||
1617 | cejka | 70 | if (i == 1) { |
3351 | jermar | 71 | /* |
72 | * We have only one free byte left in buffer => write there |
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73 | * trailing zero. |
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74 | */ |
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1617 | cejka | 75 | data->string[data->size - 1] = 0; |
76 | data->len = data->size; |
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77 | return count; |
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78 | } |
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79 | |||
80 | if (i <= count) { |
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3351 | jermar | 81 | /* |
82 | * We have not enought space for whole string with the trailing |
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83 | * zero => print only a part of string. |
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84 | */ |
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85 | memcpy((void *)(data->string + data->len), (void *)str, i - 1); |
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86 | data->string[data->size - 1] = 0; |
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87 | data->len = data->size; |
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88 | return count; |
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1617 | cejka | 89 | } |
90 | |||
91 | /* Buffer is big enought to print whole string */ |
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92 | memcpy((void *)(data->string + data->len), (void *)str, count); |
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93 | data->len += count; |
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3351 | jermar | 94 | /* |
95 | * Put trailing zero at end, but not count it into data->len so it could |
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96 | * be rewritten next time. |
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97 | */ |
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1617 | cejka | 98 | data->string[data->len] = 0; |
99 | |||
1234 | cejka | 100 | return count; |
101 | } |
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102 | |||
1623 | cejka | 103 | /** Print formatted to the given buffer with limited size. |
3351 | jermar | 104 | * @param str Buffer. |
105 | * @param size Bffer size. |
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106 | * @param fmt Format string. |
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1623 | cejka | 107 | * \see For more details about format string see printf_core. |
108 | */ |
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1234 | cejka | 109 | int vsnprintf(char *str, size_t size, const char *fmt, va_list ap) |
110 | { |
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111 | struct vsnprintf_data data = {size, 0, str}; |
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3351 | jermar | 112 | struct printf_spec ps = { |
113 | (int(*)(void *, size_t, void *)) vsnprintf_write, |
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114 | &data |
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115 | }; |
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1234 | cejka | 116 | |
3351 | jermar | 117 | /* |
118 | * Print 0 at end of string - fix the case that nothing will be printed. |
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119 | */ |
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1234 | cejka | 120 | if (size > 0) |
121 | str[0] = 0; |
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122 | |||
123 | /* vsnprintf_write ensures that str will be terminated by zero. */ |
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124 | return printf_core(fmt, &ps, ap); |
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125 | } |
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126 | |||
1866 | jermar | 127 | /** @} |
1653 | cejka | 128 | */ |