diff --git a/src/stdlib/SDL_string.c b/src/stdlib/SDL_string.c index 355fce16f8..07a58609b6 100644 --- a/src/stdlib/SDL_string.c +++ b/src/stdlib/SDL_string.c @@ -407,38 +407,27 @@ static size_t SDL_ScanUnsignedLongLongInternal(const char *text, int count, int } #endif -#if !defined(HAVE_VSSCANF) || !defined(HAVE_STRTOL) -static size_t SDL_ScanLong(const char *text, int count, int radix, long *valuep) -{ - const unsigned long long_max = (~0UL) >> 1; - unsigned long long value; - bool negative; - size_t len = SDL_ScanUnsignedLongLongInternal(text, count, radix, &value, &negative); - if (negative) { - const unsigned long abs_long_min = long_max + 1; - if (value == 0 || value > abs_long_min) { - value = 0ULL - abs_long_min; - } else { - value = 0ULL - value; - } - } else if (value > long_max) { - value = long_max; - } - *valuep = value; - return len; -} -#endif - -#if !defined(HAVE_WCSTOL) -// SDL_ScanLongW assumes that wchar_t can converted to int without truncating bits +#ifndef HAVE_WCSTOL +// SDL_ScanUnsignedLongLongInternalW assumes that wchar_t can be 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) +/** + * Parses an unsigned long long and returns the unsigned value and sign bit. + * + * Positive values are clamped to ULLONG_MAX. + * The result `value == 0 && negative` indicates negative overflow + * and might need to be handled differently depending on whether a + * signed or unsigned integer is being parsed. + */ +static size_t SDL_ScanUnsignedLongLongInternalW(const wchar_t *text, int count, int radix, unsigned long long *valuep, bool *negativep) { + const unsigned long long ullong_max = ~0ULL; + const wchar_t *text_start = text; const wchar_t *number_start = text_start; - unsigned long value = 0; + unsigned long long value = 0; bool negative = false; + bool overflow = false; if (radix == 0 || (radix >= 2 && radix <= 36)) { while (SDL_isspace(*text)) { @@ -461,7 +450,7 @@ static size_t SDL_ScanLongW(const wchar_t *text, int count, int radix, long *val } number_start = text; do { - unsigned long digit; + unsigned long long digit; if (*text >= '0' && *text <= '9') { digit = *text - '0'; } else if (radix > 10) { @@ -475,36 +464,82 @@ static size_t SDL_ScanLongW(const wchar_t *text, int count, int radix, long *val } else { break; } - { // saturate to ULONG_MAX - unsigned long next_value = value * radix + digit; - if (next_value < value) { - next_value = ~0UL; + if (value != 0 && radix > ullong_max / value) { + overflow = true; + } else { + value *= radix; + if (digit > ullong_max - value) { + overflow = true; + } else { + value += digit; } - value = next_value; } ++text; } while (count == 0 || (text - text_start) != count); } - if (text == number_start) { // no number was parsed, so no character were consumed + if (text == number_start) { + // no number was parsed, and thus no characters were consumed text = text_start; } - if (valuep) { + if (overflow) { if (negative) { - *valuep = 0UL - value; - if (*valuep > 0) { - *valuep = ((~0UL) >> 1) + 1UL; // LONG_MIN - } + value = 0; } else { - *valuep = value; - if (*valuep < 0) { - *valuep = (~0UL) >> 1; // LONG_MAX - } + value = ullong_max; } + } else if (value == 0) { + negative = false; } + *valuep = value; + *negativep = negative; return text - text_start; } #endif +#if !defined(HAVE_VSSCANF) || !defined(HAVE_STRTOL) +static size_t SDL_ScanLong(const char *text, int count, int radix, long *valuep) +{ + const unsigned long long_max = (~0UL) >> 1; + unsigned long long value; + bool negative; + size_t len = SDL_ScanUnsignedLongLongInternal(text, count, radix, &value, &negative); + if (negative) { + const unsigned long abs_long_min = long_max + 1; + if (value == 0 || value > abs_long_min) { + value = 0ULL - abs_long_min; + } else { + value = 0ULL - value; + } + } else if (value > long_max) { + value = long_max; + } + *valuep = value; + return len; +} +#endif + +#ifndef HAVE_WCSTOL +static size_t SDL_ScanLongW(const wchar_t *text, int count, int radix, long *valuep) +{ + const unsigned long long_max = (~0UL) >> 1; + unsigned long long value; + bool negative; + size_t len = SDL_ScanUnsignedLongLongInternalW(text, count, radix, &value, &negative); + if (negative) { + const unsigned long abs_long_min = long_max + 1; + if (value == 0 || value > abs_long_min) { + value = 0ULL - abs_long_min; + } else { + value = 0ULL - value; + } + } else if (value > long_max) { + value = long_max; + } + *valuep = value; + return len; +} +#endif + #if !defined(HAVE_VSSCANF) || !defined(HAVE_STRTOUL) || !defined(HAVE_STRTOD) static size_t SDL_ScanUnsignedLong(const char *text, int count, int radix, unsigned long *valuep) {