| 1 | #include <stdbool.h> |
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| 2 | #include <stdlib.h> |
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| 3 | #include <string.h> |
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| 4 | #include <wchar.h> |
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| 5 | |
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| 6 | /* Do not include the above headers in the example. |
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| 7 | */ |
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| 8 | wchar_t * |
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| 9 | mbstouwcs (const char *s) |
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| 10 | { |
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| 11 | /* Include the null terminator in the conversion. */ |
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| 12 | size_t len = strlen (s) + 1; |
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| 13 | wchar_t *result = reallocarray (NULL, nmemb: len, size: sizeof (wchar_t)); |
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| 14 | if (result == NULL) |
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| 15 | return NULL; |
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| 16 | |
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| 17 | wchar_t *wcp = result; |
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| 18 | mbstate_t state; |
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| 19 | memset (&state, '\0', sizeof (state)); |
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| 20 | |
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| 21 | while (true) |
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| 22 | { |
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| 23 | wchar_t wc; |
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| 24 | size_t nbytes = mbrtowc (&wc, s, len, &state); |
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| 25 | if (nbytes == 0) |
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| 26 | { |
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| 27 | /* Terminate the result string. */ |
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| 28 | *wcp = L'\0'; |
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| 29 | break; |
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| 30 | } |
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| 31 | else if (nbytes == (size_t) -2) |
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| 32 | { |
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| 33 | /* Truncated input string. */ |
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| 34 | errno = EILSEQ; |
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| 35 | free (ptr: result); |
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| 36 | return NULL; |
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| 37 | } |
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| 38 | else if (nbytes == (size_t) -1) |
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| 39 | { |
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| 40 | /* Some other error (including EILSEQ). */ |
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| 41 | free (ptr: result); |
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| 42 | return NULL; |
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| 43 | } |
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| 44 | else |
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| 45 | { |
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| 46 | /* A character was converted. */ |
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| 47 | *wcp++ = towupper (wc); |
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| 48 | len -= nbytes; |
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| 49 | s += nbytes; |
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| 50 | } |
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| 51 | } |
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| 52 | return result; |
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| 53 | } |
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| 54 | |
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