binio.cc

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/*
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * binio.cpp - Binary stream I/O classes
 * Copyright (C) 2002, 2003 Simon Peter <dn.tlp@gmx.net>
 */

#include <cstring>
#include <stdexcept>

#include "binio.h"

#if BINIO_WITH_MATH

#include <cmath>

#ifdef __QNXNTO__
#define pow std::powf
#endif  // __QNXNTO__

// If 'math.h' doesn't define HUGE_VAL, we try to use HUGE instead.
#ifndef HUGE_VAL
#define HUGE_VAL HUGE
#endif

#endif

/***** Defines *****/

#if BINIO_ENABLE_STRING
// String buffer size for std::string readString() method
#define STRINGBUFSIZE 256
#endif

/***** binio *****/

const binio::Flags binio::system_flags = binio::detect_system_flags();

binio::Flags binio::detect_system_flags() {
  Flags f = 0;

  // Endian test
  union {
    int word;
    Byte byte;
  } endian_test;

  endian_test.word = 1;
  if (endian_test.byte != 1) f |= BigEndian;

  // IEEE-754 floating-point test
  float fl = 6.5f;
  Byte *dat = (Byte *)&fl;

  if (sizeof(float) == 4 && sizeof(double) == 8) {
    if (f & BigEndian) {
      if (dat[0] == 0x40 && dat[1] == 0xD0 && !dat[2] && !dat[3])
        f |= FloatIEEE;
    } else {
      if (dat[3] == 0x40 && dat[2] == 0xD0 && !dat[1] && !dat[0])
        f |= FloatIEEE;
    }
  }

  return f;
}

binio::binio() : my_flags(system_flags), err(NoError) {}

binio::~binio() {}

void binio::setFlag(Flag f, bool set) {
  if (set)
    my_flags |= f;
  else
    my_flags &= !f;
}

bool binio::getFlag(Flag f) { return (my_flags & f ? true : false); }

binio::Error binio::error() {
  Error e = err;

  err = NoError;
  return e;
}

bool binio::eof() { return (err & Eof ? true : false); }

/***** binistream *****/

binistream::binistream() {}

binistream::~binistream() {}

binistream::Int binistream::readInt(unsigned int size) {
  unsigned int i;
  Int val = 0, in;

  // Check if 'size' doesn't exceed our system's biggest type.
  if (size > sizeof(Int)) {
    err |= Unsupported;
    throw runtime_error(
        "The size of the integer to be read exceeds our system's biggest type");
    return 0;
  }

  for (i = 0; i < size; i++) {
    in = getByte();
    if (getFlag(BigEndian))
      val <<= 8;
    else
      in <<= i * 8;
    val |= in;
  }

  return val;
}

binistream::Float binistream::readFloat(FType ft) {
  if (getFlag(FloatIEEE)) {
    // Read IEEE-754 floating-point value

    unsigned int i = 0;
    unsigned int size = 0;
    Byte in[8];
    bool swap;

    // Determine appropriate size for given type.
    switch (ft) {
      case Single:
        size = 4;
        break;  // 32 bits
      case Double:
        size = 8;
        break;  // 64 bits
    }

    // Determine byte ordering, depending on what we do next
    if (system_flags & FloatIEEE)
      swap = getFlag(BigEndian) ^ (system_flags & BigEndian);
    else
      swap = !getFlag(BigEndian);

    if (!swap && ((size == sizeof(float)) || (size == sizeof(double)))) {
      if (size == 4) {
        float f;
        getRaw((char *)&f, size);
        return (Float)f;
      } else {
        double d;
        getRaw((char *)&d, size);
        return (Float)d;
      }
    } else {
      // Read the float byte by byte, converting endianess
      for (i = 0; i < size; i++)
        if (swap)
          in[size - i - 1] = getByte();
        else
          in[i] = getByte();

      if (system_flags & FloatIEEE) {
        // Compatible system, let the hardware do the conversion
        switch (ft) {
          case Single:
            return *(float *)in;
          case Double:
            return *(double *)in;
        }
      } else {  // Incompatible system, convert manually
        switch (ft) {
          case Single:
            return ieee_single2float(in);
          case Double:
            return ieee_double2float(in);
        }
      }
    }
  }

  // User tried to read a (yet) unsupported floating-point type. Bail out.
  err |= Unsupported;
  return 0.0;
}

binistream::Float binistream::ieee_single2float(Byte *data) {
  signed int sign = data[0] >> 7 ? -1 : 1;
  unsigned int exp = ((data[0] << 1) & 0xff) | ((data[1] >> 7) & 1),
               fracthi7 = data[1] & 0x7f;
  Float fract = fracthi7 * 65536.0 + data[2] * 256.0 + data[3];

  // Signed and unsigned zero
  if (!exp && !fracthi7 && !data[2] && !data[3]) return sign * 0.0;

  // Signed and unsigned infinity (maybe unsupported on non-IEEE systems)
  if (exp == 255) {
    if (!fracthi7 && !data[2] && !data[3]) {
#ifdef HUGE_VAL
      if (sign == -1)
        return -HUGE_VAL;
      else
        return HUGE_VAL;
#else
      err |= Unsupported;
      if (sign == -1)
        return -1.0;
      else
        return 1.0;
#endif
    } else {  // Not a number (maybe unsupported on non-IEEE systems)
#ifdef NAN
      return NAN;
#else
      err |= Unsupported;
      return 0.0;
#endif
    }
  }

  if (!exp)  // Unnormalized float values
    return sign * pow(2, -126.) * fract * pow(2, -23.);
  else  // Normalized float values
    return sign * pow(2, exp - 127.) * (fract * pow(2, -23.) + 1);

  err |= Fatal;
  return 0.0;
}

binistream::Float binistream::ieee_double2float(Byte *data) {
  signed int sign = data[0] >> 7 ? -1 : 1;
  unsigned int exp = ((unsigned int)(data[0] & 0x7f) << 4) | (data[1] >> 4),
               fracthi4 = data[1] & 0xf;
  Float fract = fracthi4 * pow(2, 48.) + data[2] * pow(2, 40.) +
                data[3] * pow(2, 32.) + data[4] * pow(2, 24.) +
                data[5] * pow(2, 16.) + data[6] * pow(2, 8.) + data[7];

  // Signed and unsigned zero
  if (!exp && !fracthi4 && !data[2] && !data[3] && !data[4] && !data[5] &&
      !data[6] && !data[7])
    return sign * 0.0;

  // Signed and unsigned infinity  (maybe unsupported on non-IEEE systems)
  if (exp == 2047) {
    if (!fracthi4 && !data[2] && !data[3] && !data[4] && !data[5] && !data[6] &&
        !data[7]) {
#ifdef HUGE_VAL
      if (sign == -1)
        return -HUGE_VAL;
      else
        return HUGE_VAL;
#else
      err |= Unsupported;
      if (sign == -1)
        return -1.0;
      else
        return 1.0;
#endif
    } else {  // Not a number (maybe unsupported on non-IEEE systems)
#ifdef NAN
      return NAN;
#else
      err |= Unsupported;
      return 0.0;
#endif
    }
  }

  if (!exp)  // Unnormalized float values
    return sign * pow(2, -1022.) * fract * pow(2, -52.);
  else  // Normalized float values
    return sign * pow(2, exp - 1023.) * (fract * pow(2, -52.) + 1);

  err |= Fatal;
  return 0.0;
}

#if !BINIO_WITH_MATH
binio::Float binio::pow(Float base, signed int exp)
/* Our own, stripped-down version of pow() for not having to depend on 'math.h'.
 * This one handles float values for the base and an integer exponent, both
 * positive and negative.
 */
{
  int i;
  Float val = base;

  if (!exp) return 1.0;

  for (i = 1; i < (exp < 0 ? -exp : exp); i++) val *= base;

  if (exp < 0) val = 1.0 / val;

  return val;
}
#endif

unsigned long binistream::readString(char *str, unsigned long maxlen) {
  unsigned long i;

  for (i = 0; i < maxlen; i++) {
    str[i] = (char)getByte();
    if (err) {
      str[i] = '\0';
      return i;
    }
  }

  return maxlen;
}

unsigned long binistream::readString(char *str,
                                     unsigned long maxlen,
                                     const char delim) {
  unsigned long i;

  for (i = 0; i < maxlen; i++) {
    str[i] = (char)getByte();
    if (str[i] == delim || err) {
      str[i] = '\0';
      return i;
    }
  }

  str[maxlen] = '\0';
  return maxlen;
}

#if BINIO_ENABLE_STRING
std::string binistream::readString(const char delim) {
  char buf[STRINGBUFSIZE + 1];
  std::string tempstr;
  unsigned long read;

  do {
    read = readString(buf, STRINGBUFSIZE, delim);
    tempstr.append(buf, read);
  } while (read == STRINGBUFSIZE);

  return tempstr;
}
#endif

binistream::Int binistream::peekInt(unsigned int size) {
  Int val = readInt(size);
  if (!err) seek(-(long)size, Add);
  return val;
}

binistream::Float binistream::peekFloat(FType ft) {
  Float val = readFloat(ft);

  if (!err) switch (ft) {
      case Single:
        seek(-4, Add);
        break;
      case Double:
        seek(-8, Add);
        break;
    }

  return val;
}

bool binistream::ateof() {
  Error olderr = err;  // Save current error state
  bool eof_then;

  peekInt(1);
  eof_then = eof();  // Get error state of next byte
  err = olderr;      // Restore original error state
  return eof_then;
}

void binistream::ignore(unsigned long amount) {
  unsigned long i;

  for (i = 0; i < amount; i++) getByte();
}

/***** binostream *****/

binostream::binostream() {}

binostream::~binostream() {}

void binostream::writeInt(Int val, unsigned int size) {
  unsigned int i;

  // Check if 'size' doesn't exceed our system's biggest type.
  if (size > sizeof(Int)) {
    err |= Unsupported;
    throw runtime_error(
        "The size of the integer to be stored exceeds our system's biggest type");
    return;
  }

  for (i = 0; i < size; i++) {
    if (getFlag(BigEndian))
      putByte((unsigned char)(val >> ((size - i - 1) * 8)) & 0xff);
    else {
      putByte((unsigned char)val & 0xff);
      val >>= 8;
    }
  }
}

void binostream::writeFloat(Float f, FType ft) {
  if (getFlag(FloatIEEE)) {  // Write IEEE-754 floating-point value

    unsigned int i = 0;
    unsigned int size = 0;
    Byte *out = NULL;
    bool swap;

    if (system_flags & FloatIEEE) {
      // compatible system, let the hardware do the conversion
      float outf = (float)f;
      double outd = (double)f;

      // Hardware could be big or little endian, convert appropriately
      swap = getFlag(BigEndian) ^ (system_flags & BigEndian);

      switch (ft) {
        case Single:
          size = 4;
          break;  // 32 bits
        case Double:
          size = 8;
          break;  // 64 bits
      }

      if (!swap && ((size == sizeof(float)) || (size == sizeof(double)))) {
        if (size == 4) {
          putRaw((char *)&outf, size);
          return;
        } else {
          putRaw((char *)&outd, size);
          return;
        }
      } else {
        // Determine appropriate size for given type and convert by hardware
        switch (ft) {
          case Single:
            out = (Byte *)&outf;
            break;  // 32 bits
          case Double:
            out = (Byte *)&outd;
            break;  // 64 bits
        }
      }
    } else {
#if BINIO_WITH_MATH
      // incompatible system, do the conversion manually
      Byte buf[8];

      // Our own value is always big endian, just check whether we have to
      // convert for a different stream format.
      swap = !getFlag(BigEndian);

      // Convert system's float to requested IEEE-754 float
      switch (ft) {
        case Single:
          size = 4;
          float2ieee_single(f, buf);
          break;
        case Double:
          size = 8;
          float2ieee_double(f, buf);
          break;
      }

      out = buf;  // Make the value ready for writing
#else
      // No necessary support routines to do the conversion, bail out!
      err |= Unsupported;
      return;
#endif
    }

    // Write the float byte by byte, converting endianess
    if (swap) out += size - 1;
    for (i = 0; i < size; i++) {
      putByte(*out);
      if (swap)
        out--;
      else
        out++;
    }

    return;  // We're done.
  }

  // User tried to write an unsupported floating-point type. Bail out.
  err |= Unsupported;
}

#ifdef BINIO_WITH_MATH

/*
 * Single and double floating-point to IEEE-754 equivalent conversion functions
 * courtesy of Ken Turkowski.
 *
 * Copyright (C) 1989-1991 Ken Turkowski. <turk@computer.org>
 *
 * All rights reserved.
 *
 * Warranty Information
 *  Even though I have reviewed this software, I make no warranty
 *  or representation, either express or implied, with respect to this
 *  software, its quality, accuracy, merchantability, or fitness for a
 *  particular purpose.  As a result, this software is provided "as is,"
 *  and you, its user, are assuming the entire risk as to its quality
 *  and accuracy.
 *
 * This code may be used and freely distributed as long as it includes
 * this copyright notice and the above warranty information.
 */

/****************************************************************
 * The following two routines make up for deficiencies in many
 * compilers to convert properly between unsigned integers and
 * floating-point.  Some compilers which have this bug are the
 * THINK_C compiler for the Macintosh and the C compiler for the
 * Silicon Graphics MIPS-based Iris.
 ****************************************************************/

#ifdef applec /* The Apple C compiler works */
#define FloatToUnsigned(f) ((unsigned long)(f))
#else
#define FloatToUnsigned(f) \
  ((unsigned long)(((long)((f)-2147483648.0)) + 2147483647L + 1))
#endif

#define SEXP_MAX 255
#define SEXP_OFFSET 127
#define SEXP_SIZE 8
#define SEXP_POSITION (32 - SEXP_SIZE - 1)

void binostream::float2ieee_single(Float num, Byte *bytes) {
  long sign;
  long bits;

  if (num < 0) { /* Can't distinguish a negative zero */
    sign = 0x80000000;
    num *= -1;
  } else {
    sign = 0;
  }

  if (num == 0) {
    bits = 0;
  } else {
    Float fMant;
    int expon;

    fMant = frexp(num, &expon);

    if ((expon > (SEXP_MAX - SEXP_OFFSET + 1)) || !(fMant < 1)) {
      /* NaN's and infinities fail second test */
      bits = sign | 0x7F800000; /* +/- infinity */
    }

    else {
      long mantissa;

      if (expon < -(SEXP_OFFSET - 2)) { /* Smaller than normalized */
        int shift = (SEXP_POSITION + 1) + (SEXP_OFFSET - 2) + expon;
        if (shift < 0) { /* Way too small: flush to zero */
          bits = sign;
        } else { /* Nonzero denormalized number */
          mantissa = (long)(fMant * (double)(1L << shift));
          bits = sign | mantissa;
        }
      }

      else { /* Normalized number */
        mantissa = (long)floor(fMant * (1L << (SEXP_POSITION + 1)));
        mantissa -= (1L << SEXP_POSITION); /* Hide MSB */
        bits = sign | ((long)((expon + SEXP_OFFSET - 1)) << SEXP_POSITION) |
               mantissa;
      }
    }
  }

  bytes[0] = (unsigned char)(bits >> 24); /* Copy to byte string */
  bytes[1] = (unsigned char)(bits >> 16);
  bytes[2] = (unsigned char)(bits >> 8);
  bytes[3] = (unsigned char)bits;
}

#define DEXP_MAX 2047
#define DEXP_OFFSET 1023
#define DEXP_SIZE 11
#define DEXP_POSITION (32 - DEXP_SIZE - 1)

void binostream::float2ieee_double(Float num, Byte *bytes) {
  long sign;
  long first, second;

  if (num < 0) { /* Can't distinguish a negative zero */
    sign = 0x80000000;
    num *= -1;
  } else {
    sign = 0;
  }

  if (num == 0) {
    first = 0;
    second = 0;
  } else {
    Float fMant, fsMant;
    int expon;

    fMant = frexp(num, &expon);

    if ((expon > (DEXP_MAX - DEXP_OFFSET + 1)) || !(fMant < 1)) {
      /* NaN's and infinities fail second test */
      first = sign | 0x7FF00000; /* +/- infinity */
      second = 0;
    }

    else {
      long mantissa;

      if (expon < -(DEXP_OFFSET - 2)) { /* Smaller than normalized */
        int shift = (DEXP_POSITION + 1) + (DEXP_OFFSET - 2) + expon;
        if (shift < 0) { /* Too small for something in the MS word */
          first = sign;
          shift += 32;
          if (shift < 0) { /* Way too small: flush to zero */
            second = 0;
          } else { /* Pretty small demorn */
            second = FloatToUnsigned(floor(ldexp(fMant, shift)));
          }
        } else { /* Nonzero denormalized number */
          fsMant = ldexp(fMant, shift);
          mantissa = (long)floor(fsMant);
          first = sign | mantissa;
          second = FloatToUnsigned(floor(ldexp(fsMant - (double)mantissa, 32)));
        }
      }

      else { /* Normalized number */
        fsMant = ldexp(fMant, DEXP_POSITION + 1);
        mantissa = (long)floor(fsMant);
        mantissa -= (1L << DEXP_POSITION); /* Hide MSB */
        fsMant -= (1L << DEXP_POSITION);
        first = sign | ((long)((expon + DEXP_OFFSET - 1)) << DEXP_POSITION) |
                mantissa;
        second = FloatToUnsigned(floor(ldexp(fsMant - (double)mantissa, 32)));
      }
    }
  }

  bytes[0] = (unsigned char)(first >> 24);
  bytes[1] = (unsigned char)(first >> 16);
  bytes[2] = (unsigned char)(first >> 8);
  bytes[3] = (unsigned char)first;
  bytes[4] = (unsigned char)(second >> 24);
  bytes[5] = (unsigned char)(second >> 16);
  bytes[6] = (unsigned char)(second >> 8);
  bytes[7] = (unsigned char)second;
}

#endif  // BINIO_WITH_MATH

unsigned long binostream::writeString(const char *str, unsigned long amount) {
  unsigned int i;

  if (!amount) amount = strlen(str);

  for (i = 0; i < amount; i++) {
    putByte(str[i]);
    if (err) return i;
  }

  return amount;
}

#if BINIO_ENABLE_STRING
unsigned long binostream::writeString(const std::string &str) {
  return writeString(str.c_str());
}
#endif