From fd53b3e112b0a174177d31ddd7fd93323268d91d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Carl=20=C3=85stholm?= Date: Tue, 10 Sep 2024 21:50:48 +0200 Subject: [PATCH] stdlib: Rewrite SDL_wcstol impl SDL_wcstol should now fully adhere to the libc spec. --- include/SDL3/SDL_stdinc.h | 17 +++---- src/stdlib/SDL_string.c | 102 +++++++++++++++++++++++--------------- 2 files changed, 69 insertions(+), 50 deletions(-) diff --git a/include/SDL3/SDL_stdinc.h b/include/SDL3/SDL_stdinc.h index 4b7aae2ff9..093b3d066f 100644 --- a/include/SDL3/SDL_stdinc.h +++ b/include/SDL3/SDL_stdinc.h @@ -1499,21 +1499,18 @@ extern SDL_DECLSPEC int SDLCALL SDL_wcsncasecmp(const wchar_t *str1, const wchar /** * Parse a `long` from a wide string. * - * This function makes fewer guarantees than the C runtime `wcstol`: + * If `str` starts with whitespace, then those whitespace characters are skipped before attempting to parse the number. * - * - Only the bases 10 and 16 are guaranteed to be supported. The behavior for - * other bases is unspecified. - * - It is unspecified what this function returns when the parsed integer does - * not fit inside a `long`. + * If the parsed number does not fit inside a `long`, the result is clamped to the minimum and maximum representable `long` values. * * \param str The null-terminated wide string to read. Must not be NULL. * \param endp If not NULL, the address of the first invalid wide character * (i.e. the next character after the parsed number) will be * written to this pointer. - * \param base The base of the integer to read. The values 0, 10 and 16 are - * supported. If 0, the base will be inferred from the integer's - * prefix. - * \returns The parsed `long`. + * \param base The base of the integer to read. Supported values are 0 and 2 to 36 inclusive. + * If 0, the base will be inferred from the number's + * prefix (0x for hexadecimal, 0 for octal, decimal otherwise). + * \returns The parsed `long`, or 0 if no number could be parsed. * * \threadsafety It is safe to call this function from any thread. * @@ -1826,7 +1823,7 @@ extern SDL_DECLSPEC long long SDLCALL SDL_strtoll(const char *str, char **endp, * - Only the bases 10 and 16 are guaranteed to be supported. The behavior for * other bases is unspecified. * - It is unspecified what this function returns when the parsed integer does - * not fit inside a `long long`. + * not fit inside an `unsigned long long`. * * \param str The null-terminated string to read. Must not be NULL. * \param endp If not NULL, the address of the first invalid character (i.e. diff --git a/src/stdlib/SDL_string.c b/src/stdlib/SDL_string.c index 907f9537c0..4006b35003 100644 --- a/src/stdlib/SDL_string.c +++ b/src/stdlib/SDL_string.c @@ -371,46 +371,78 @@ static size_t SDL_ScanLong(const char *text, int count, int radix, long *valuep) #endif #if !defined(HAVE_WCSTOL) +// SDL_ScanLongW assumes that wchar_t can converted to int without truncating bits +SDL_COMPILE_TIME_ASSERT(wchar_t_int, sizeof(wchar_t) <= sizeof(int)); + static size_t SDL_ScanLongW(const wchar_t *text, int count, int radix, long *valuep) { - const wchar_t *textstart = text; - long value = 0; + const wchar_t *text_start = text; + const wchar_t *number_start = text_start; + unsigned long value = 0; bool negative = false; - if (*text == '-') { - negative = true; - ++text; - } - if (radix == 16 && SDL_wcsncmp(text, L"0x", 2) == 0) { - text += 2; - } - for (;;) { - int v; - if (*text >= '0' && *text <= '9') { - v = *text - '0'; - } else if (radix == 16 && SDL_isupperhex(*text)) { - v = 10 + (*text - 'A'); - } else if (radix == 16 && SDL_islowerhex(*text)) { - v = 10 + (*text - 'a'); - } else { - break; + if (radix == 0 || (radix >= 2 && radix <= 36)) { + while (SDL_isspace(*text)) { + ++text; } - value *= radix; - value += v; - ++text; - - if (count > 0 && (text - textstart) == count) { - break; + if (*text == '-' || *text == '+') { + negative = *text == '-'; + ++text; } + if ((radix == 0 || radix == 16) && *text == '0') { + ++text; + if (*text == 'x' || *text == 'X') { + radix = 16; + ++text; + } else if (radix == 0) { + radix = 8; + } + } else if (radix == 0) { + radix = 10; + } + number_start = text; + do { + unsigned long digit; + if (*text >= '0' && *text <= '9') { + digit = *text - '0'; + } else if (radix > 10) { + if (*text >= 'A' && *text < 'A' + (radix - 10)) { + digit = 10 + (*text - 'A'); + } else if (*text >= 'a' && *text < 'a' + (radix - 10)) { + digit = 10 + (*text - 'a'); + } else { + break; + } + } else { + break; + } + { // saturate to ULONG_MAX + unsigned long next_value = value * radix + digit; + if (next_value < value) { + next_value = ~0UL; + } + value = next_value; + } + ++text; + } while (count == 0 || (text - text_start) != count); } - if (valuep && text > textstart) { - if (negative && value) { - *valuep = -value; + if (text == number_start) { // no number was parsed, so no character were consumed + text = text_start; + } + if (valuep) { + if (negative) { + *valuep = 0UL - value; + if (*valuep > 0) { + *valuep = ((~0UL) >> 1) + 1UL; // LONG_MIN + } } else { *valuep = value; + if (*valuep < 0) { + *valuep = (~0UL) >> 1; // LONG_MAX + } } } - return text - textstart; + return text - text_start; } #endif @@ -824,18 +856,8 @@ long SDL_wcstol(const wchar_t *string, wchar_t **endp, int base) #ifdef HAVE_WCSTOL return wcstol(string, endp, base); #else - size_t len; long value = 0; - - if (!base) { - if ((SDL_wcslen(string) > 2) && (SDL_wcsncmp(string, L"0x", 2) == 0)) { - base = 16; - } else { - base = 10; - } - } - - len = SDL_ScanLongW(string, 0, base, &value); + size_t len = SDL_ScanLongW(string, 0, base, &value); if (endp) { *endp = (wchar_t *)string + len; }