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4f756d2a4d
The previous mb_to_wc and wc_to_mb had horrible and also buggy APIs. This commit introduces a fresh pair of functions to replace them, which generate output by writing to a BinarySink. So it's now up to the caller to decide whether it wants the output written to a fixed-size buffer with overflow checking (via buffer_sink), or dynamically allocated, or even written directly to some other output channel. Nothing uses the new functions yet. I plan to migrate things over in upcoming commits. What was wrong with the old APIs: they had that awkward undocumented Windows-specific 'flags' parameter that I described in the previous commit and took out of the dup_X_to_Y wrappers. But much worse, the semantics for buffer overflow were not just undocumented but actually inconsistent. dup_wc_to_mb() in utils assumed that the underlying wc_to_mb would fill the buffer nearly full and return the size of data it wrote. In fact, this was untrue in the case where wc_to_mb called WideCharToMultiByte: that returns straight-up failure, setting the Windows error code to ERROR_INSUFFICIENT_BUFFER. It _does_ partially fill the output buffer, but doesn't tell you how much it wrote! What's wrong with the new API: it's a bit awkward to write a sequence of wchar_t in native byte order to a byte-oriented BinarySink, so people using put_mb_to_wc directly have to do some annoying pointer casting. But I think that's less horrible than the previous APIs. Another change: in the new API for wc_to_mb, defchr can be "", but not NULL.
31 lines
936 B
C
31 lines
936 B
C
/*
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* dup_mb_to_wc: memory-allocating wrapper on mb_to_wc.
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*
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* Also dup_mb_to_wc_c: same but you already know the length of the
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* string, and you get told the length of the returned wide string.
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* (But it's still NUL-terminated, for convenience.)
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*/
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#include "putty.h"
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#include "misc.h"
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wchar_t *dup_mb_to_wc_c(int codepage, const char *string,
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size_t inlen, size_t *outlen_p)
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{
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strbuf *sb = strbuf_new();
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put_mb_to_wc(sb, codepage, string, inlen);
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if (outlen_p)
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*outlen_p = sb->len / sizeof(wchar_t);
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/* Append a trailing L'\0'. For this we only need to write one
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* byte _fewer_ than sizeof(wchar_t), because strbuf will append a
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* byte '\0' for us. */
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put_padding(sb, sizeof(wchar_t) - 1, 0);
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return (wchar_t *)strbuf_to_str(sb);
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}
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wchar_t *dup_mb_to_wc(int codepage, const char *string)
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{
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return dup_mb_to_wc_c(codepage, string, strlen(string), NULL);
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}
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