* Add strtod and strtol to bg_lib.c

1 files changed, 344 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 )
 {