diff options
| -rw-r--r-- | src/game/bg_lib.c | 344 | ||||
| -rw-r--r-- | src/game/bg_lib.h | 2 |
2 files changed, 346 insertions, 0 deletions
diff --git a/src/game/bg_lib.c b/src/game/bg_lib.c index 877ca68a..5f242934 100644 --- a/src/game/bg_lib.c +++ b/src/game/bg_lib.c @@ -1389,6 +1389,248 @@ double atof( const char *string ) return value * sign; } +/* +============== +strtod + +Without an errno variable, this is a fair bit less useful than it is in libc +but it's still a fair bit more capable than atof or _atof +Handles inf[inity], nan (ignoring case), hexadecimals, and decimals +Handles decimal exponents like 10e10 and hex exponents like 0x7f8p20 +10e10 == 10000000000 (power of ten) +0x7f8p20 == 0x7f800000 (decimal power of two) +The variable pointed to by endptr will hold the location of the first character +in the nptr string that was not used in the conversion +============== +*/ +double strtod( const char *nptr, const char **endptr ) +{ + double res; + qboolean neg = qfalse; + + // skip whitespace + while( isspace( *nptr ) ) + nptr++; + + // special string parsing + if( Q_stricmpn( nptr, "nan", 3 ) == 0 ) + { + floatint_t nan; + + if( endptr ) + *endptr = &nptr[3]; + + // nan can be followed by a bracketed number (in hex, octal, + // or decimal) which is then put in the mantissa + // this can be used to generate signalling or quiet NaNs, for + // example (though I doubt it'll ever be used) + // note that nan(0) is infinity! + if( nptr[3] == '(' ) + { + const char *end; + int mantissa = strtol( &nptr[4], &end, 0 ); + + if( *end == ')' ) + { + nan.ui = 0x7f800000 | ( mantissa & 0x7fffff ); + + if( endptr ) + *endptr = &end[1]; + return nan.f; + } + } + + nan.ui = 0x7fffffff; + return nan.f; + } + + if( Q_stricmpn( nptr, "inf", 3 ) == 0 ) + { + floatint_t inf; + inf.ui = 0x7f800000; + + if( endptr == NULL ) + return inf.f; + + if( Q_stricmpn( &nptr[3], "inity", 5 ) == 0 ) + *endptr = &nptr[8]; + else + *endptr = &nptr[3]; + + return inf.f; + } + + // normal numeric parsing + // sign + if( *nptr == '-' ) + { + nptr++; + neg = qtrue; + } + else if( *nptr == '+' ) + nptr++; + + // hex + if( Q_stricmpn( nptr, "0x", 2 ) == 0 ) + { + // track if we use any digits + const char *s = &nptr[1], *end = s; + nptr += 2; + + for( res = 0;; ) + { + if( isdigit( *nptr ) ) + res = 16 * res + ( *nptr++ - '0' ); + else if( *nptr >= 'A' && *nptr <= 'F' ) + res = 16 * res + 10 + *nptr++ - 'A'; + else if( *nptr >= 'a' && *nptr <= 'f' ) + res = 16 * res + 10 + *nptr++ - 'a'; + else + break; + } + + // if nptr moved, save it + if( end + 1 < nptr ) + end = nptr; + + if( *nptr == '.' ) + { + float place; + nptr++; + + // 1.0 / 16.0 == 0.0625 + // I don't expect the float accuracy to hold out for + // very long but since we need to know the length of + // the string anyway we keep on going regardless + for( place = 0.0625;; place /= 16.0 ) + { + if( isdigit( *nptr ) ) + res += place * ( *nptr++ - '0' ); + else if( *nptr >= 'A' && *nptr <= 'F' ) + res += place * ( 10 + *nptr++ - 'A' ); + else if( *nptr >= 'a' && *nptr <= 'f' ) + res += place * ( 10 + *nptr++ - 'a' ); + else + break; + } + + if( end < nptr ) + end = nptr; + } + + // parse an optional exponent, representing multiplication + // by a power of two + // exponents are only valid if we encountered at least one + // digit already (and have therefore set end to something) + if( end != s && tolower( *nptr ) == 'p' ) + { + int exp; + float res2; + // apparently (confusingly) the exponent should be + // decimal + exp = strtol( &nptr[1], &end, 10 ); + if( &nptr[1] == end ) + { + // no exponent + if( endptr ) + *endptr = nptr; + return res; + } + if( exp > 0 ) + { + while( exp-- > 0 ) + { + res2 = res * 2; + // check for infinity + if( res2 <= res ) + break; + res = res2; + } + } + else + { + while( exp++ < 0 ) + { + res2 = res / 2; + // check for underflow + if( res2 >= res ) + break; + res = res2; + } + } + } + if( endptr ) + *endptr = end; + return res; + } + // decimal + else + { + // track if we find any digits + const char *end = nptr, *p = nptr; + // this is most of the work + for( res = 0; isdigit( *nptr ); + res = 10 * res + *nptr++ - '0' ); + // if nptr moved, we read something + if( end < nptr ) + end = nptr; + if( *nptr == '.' ) + { + // fractional part + float place; + nptr++; + for( place = 0.1; isdigit( *nptr ); place /= 10.0 ) + res += ( *nptr++ - '0' ) * place; + // if nptr moved, we read something + if( end + 1 < nptr ) + end = nptr; + } + // exponent + // meaningless without having already read digits, so check + // we've set end to something + if( p != end && tolower( *nptr ) == 'e' ) + { + int exp; + float res10; + exp = strtol( &nptr[1], &end, 10 ); + if( &nptr[1] == end ) + { + // no exponent + if( endptr ) + *endptr = nptr; + return res; + } + if( exp > 0 ) + { + while( exp-- > 0 ) + { + res10 = res * 10; + // check for infinity to save us time + if( res10 <= res ) + break; + res = res10; + } + } + else if( exp < 0 ) + { + while( exp++ < 0 ) + { + res10 = res / 10; + // check for underflow + // (test for 0 would probably be just + // as good) + if( res10 >= res ) + break; + res = res10; + } + } + } + if( endptr ) + *endptr = end; + return res; + } +} + double _atof( const char **stringPtr ) { const char *string; @@ -1468,6 +1710,108 @@ double _atof( const char **stringPtr ) return value * sign; } +/* +============== +strtol + +Handles any base from 2 to 36. If base is 0 then it guesses +decimal, hex, or octal based on the format of the number (leading 0 or 0x) +Will not overflow - returns LONG_MIN or LONG_MAX as appropriate +*endptr is set to the location of the first character not used +============== +*/ +long strtol( const char *nptr, const char **endptr, int base ) +{ + long res; + qboolean pos = qtrue; + + if( endptr ) + *endptr = nptr; + + // bases other than 0, 2, 8, 16 are very rarely used, but they're + // not much extra effort to support + if( base < 0 || base == 1 || base > 36 ) + return 0; + + // skip leading whitespace + while( isspace( *nptr ) ) + nptr++; + + // sign + if( *nptr == '-' ) + { + nptr++; + pos = qfalse; + } + else if( *nptr == '+' ) + nptr++; + + // look for base-identifying sequences e.g. 0x for hex, 0 for octal + if( nptr[0] == '0' ) + { + nptr++; + + // 0 is always a valid digit + if( endptr ) + *endptr = nptr; + + if( *nptr == 'x' || *nptr == 'X' ) + { + if( base != 0 && base != 16 ) + { + // can't be hex, reject x (accept 0) + if( endptr ) + *endptr = nptr; + return 0; + } + + nptr++; + base = 16; + } + else if( base == 0 ) + base = 8; + } + else if( base == 0 ) + base = 10; + + for( res = 0;; ) + { + int val; + + if( isdigit( *nptr ) ) + val = *nptr - '0'; + else if( islower( *nptr ) ) + val = 10 + *nptr - 'a'; + else if( isupper( *nptr ) ) + val = 10 + *nptr - 'A'; + else + break; + + if( val >= base ) + break; + + // we go negative because LONG_MIN is further from 0 than + // LONG_MAX + if( res < ( LONG_MIN + val ) / base ) + res = LONG_MIN; // overflow + else + res = res * base - val; + + nptr++; + + if( endptr ) + *endptr = nptr; + } + if( pos ) + { + // can't represent LONG_MIN positive + if( res == LONG_MIN ) + res = LONG_MAX; + else + res = -res; + } + return res; +} int atoi( const char *string ) { diff --git a/src/game/bg_lib.h b/src/game/bg_lib.h index 69cf77ef..50c44558 100644 --- a/src/game/bg_lib.h +++ b/src/game/bg_lib.h @@ -104,8 +104,10 @@ int toupper( int c ); double atof( const char *string ); double _atof( const char **stringPtr ); +double strtod( const char *nptr, const char **endptr ); int atoi( const char *string ); int _atoi( const char **stringPtr ); +long strtol( const char *nptr, const char **endptr, int base ); int sscanf( const char *buffer, const char *fmt, ... ); |