function.cc

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    x = domain[0][1];
  } else {
    x = in[0];
  }
  for (i = 0; i < n; ++i) {
    out[i] = c0[i] + pow(x, e) * (c1[i] - c0[i]);
    if (hasRange) {
      if (out[i] < range[i][0]) {
	out[i] = range[i][0];
      } else if (out[i] > range[i][1]) {
	out[i] = range[i][1];
      }
    }
  }
  return;
}

//------------------------------------------------------------------------
// StitchingFunction
//------------------------------------------------------------------------

StitchingFunction::StitchingFunction(Object *funcObj, Dict *dict) {
  Object obj1, obj2;
  int i;

  ok = gFalse;
  funcs = NULL;
  bounds = NULL;
  encode = NULL;
  scale = NULL;

  //----- initialize the generic stuff
  if (!init(dict)) {
    goto err1;
  }
  if (m != 1) {
    error(-1, "Stitching function with more than one input");
    goto err1;
  }

  //----- Functions
  if (!dict->lookup("Functions", &obj1)->isArray()) {
    error(-1, "Missing 'Functions' entry in stitching function");
    goto err1;
  }
  k = obj1.arrayGetLength();
  funcs = (Function **)gmallocn(k, sizeof(Function *));
  bounds = (double *)gmallocn(k + 1, sizeof(double));
  encode = (double *)gmallocn(2 * k, sizeof(double));
  scale = (double *)gmallocn(k, sizeof(double));
  for (i = 0; i < k; ++i) {
    funcs[i] = NULL;
  }
  for (i = 0; i < k; ++i) {
    if (!(funcs[i] = Function::parse(obj1.arrayGet(i, &obj2)))) {
      goto err2;
    }
    if (i > 0 && (funcs[i]->getInputSize() != 1 ||
		  funcs[i]->getOutputSize() != funcs[0]->getOutputSize())) {
      error(-1, "Incompatible subfunctions in stitching function");
      goto err2;
    }
    obj2.free();
  }
  obj1.free();

  //----- Bounds
  if (!dict->lookup("Bounds", &obj1)->isArray() ||
      obj1.arrayGetLength() != k - 1) {
    error(-1, "Missing or invalid 'Bounds' entry in stitching function");
    goto err1;
  }
  bounds[0] = domain[0][0];
  for (i = 1; i < k; ++i) {
    if (!obj1.arrayGet(i - 1, &obj2)->isNum()) {
      error(-1, "Invalid type in 'Bounds' array in stitching function");
      goto err2;
    }
    bounds[i] = obj2.getNum();
    obj2.free();
  }
  bounds[k] = domain[0][1];
  obj1.free();

  //----- Encode
  if (!dict->lookup("Encode", &obj1)->isArray() ||
      obj1.arrayGetLength() != 2 * k) {
    error(-1, "Missing or invalid 'Encode' entry in stitching function");
    goto err1;
  }
  for (i = 0; i < 2 * k; ++i) {
    if (!obj1.arrayGet(i, &obj2)->isNum()) {
      error(-1, "Invalid type in 'Encode' array in stitching function");
      goto err2;
    }
    encode[i] = obj2.getNum();
    obj2.free();
  }
  obj1.free();

  //----- pre-compute the scale factors
  for (i = 0; i < k; ++i) {
    if (bounds[i] == bounds[i+1]) {
      // avoid a divide-by-zero -- in this situation, function i will
      // never be used anyway
      scale[i] = 0;
    } else {
      scale[i] = (encode[2*i+1] - encode[2*i]) / (bounds[i+1] - bounds[i]);
    }
  }

  ok = gTrue;
  return;

 err2:
  obj2.free();
 err1:
  obj1.free();
}

StitchingFunction::StitchingFunction(StitchingFunction *func) {
  int i;

  k = func->k;
  funcs = (Function **)gmallocn(k, sizeof(Function *));
  for (i = 0; i < k; ++i) {
    funcs[i] = func->funcs[i]->copy();
  }
  bounds = (double *)gmallocn(k + 1, sizeof(double));
  memcpy(bounds, func->bounds, (k + 1) * sizeof(double));
  encode = (double *)gmallocn(2 * k, sizeof(double));
  memcpy(encode, func->encode, 2 * k * sizeof(double));
  scale = (double *)gmallocn(k, sizeof(double));
  memcpy(scale, func->scale, k * sizeof(double));
  ok = gTrue;
}

StitchingFunction::~StitchingFunction() {
  int i;

  if (funcs) {
    for (i = 0; i < k; ++i) {
      if (funcs[i]) {
	delete funcs[i];
      }
    }
  }
  gfree(funcs);
  gfree(bounds);
  gfree(encode);
  gfree(scale);
}

void StitchingFunction::transform(double *in, double *out) {
  double x;
  int i;

  if (in[0] < domain[0][0]) {
    x = domain[0][0];
  } else if (in[0] > domain[0][1]) {
    x = domain[0][1];
  } else {
    x = in[0];
  }
  for (i = 0; i < k - 1; ++i) {
    if (x < bounds[i+1]) {
      break;
    }
  }
  x = encode[2*i] + (x - bounds[i]) * scale[i];
  funcs[i]->transform(&x, out);
}

//------------------------------------------------------------------------
// PostScriptFunction
//------------------------------------------------------------------------

enum PSOp {
  psOpAbs,
  psOpAdd,
  psOpAnd,
  psOpAtan,
  psOpBitshift,
  psOpCeiling,
  psOpCopy,
  psOpCos,
  psOpCvi,
  psOpCvr,
  psOpDiv,
  psOpDup,
  psOpEq,
  psOpExch,
  psOpExp,
  psOpFalse,
  psOpFloor,
  psOpGe,
  psOpGt,
  psOpIdiv,
  psOpIndex,
  psOpLe,
  psOpLn,
  psOpLog,
  psOpLt,
  psOpMod,
  psOpMul,
  psOpNe,
  psOpNeg,
  psOpNot,
  psOpOr,
  psOpPop,
  psOpRoll,
  psOpRound,
  psOpSin,
  psOpSqrt,
  psOpSub,
  psOpTrue,
  psOpTruncate,
  psOpXor,
  psOpIf,
  psOpIfelse,
  psOpReturn
};

// Note: 'if' and 'ifelse' are parsed separately.
// The rest are listed here in alphabetical order.
// The index in this table is equivalent to the entry in PSOp.
char *psOpNames[] = {
  "abs",
  "add",
  "and",
  "atan",
  "bitshift",
  "ceiling",
  "copy",
  "cos",
  "cvi",
  "cvr",
  "div",
  "dup",
  "eq",
  "exch",
  "exp",
  "false",
  "floor",
  "ge",
  "gt",
  "idiv",
  "index",
  "le",
  "ln",
  "log",
  "lt",
  "mod",
  "mul",
  "ne",
  "neg",
  "not",
  "or",
  "pop",
  "roll",
  "round",
  "sin",
  "sqrt",
  "sub",
  "true",
  "truncate",
  "xor"
};

#define nPSOps (sizeof(psOpNames) / sizeof(char *))

enum PSObjectType {
  psBool,
  psInt,
  psReal,
  psOperator,
  psBlock
};

// In the code array, 'if'/'ifelse' operators take up three slots
// plus space for the code in the subclause(s).
//
//         +---------------------------------+
//         | psOperator: psOpIf / psOpIfelse |
//         +---------------------------------+
//         | psBlock: ptr=<A>                |
//         +---------------------------------+
//         | psBlock: ptr=<B>                |
//         +---------------------------------+
//         | if clause                       |
//         | ...                             |
//         | psOperator: psOpReturn          |
//         +---------------------------------+
//     <A> | else clause                     |
//         | ...                             |
//         | psOperator: psOpReturn          |
//         +---------------------------------+
//     <B> | ...                             |
//
// For 'if', pointer <A> is present in the code stream but unused.

struct PSObject {
  PSObjectType type;
  union {
    GBool booln;		// boolean (stack only)
    int intg;			// integer (stack and code)
    double real;		// real (stack and code)
    PSOp op;			// operator (code only)
    int blk;			// if/ifelse block pointer (code only)
  };
};

#define psStackSize 100

class PSStack {
public:

  PSStack() { sp = psStackSize; }
  void pushBool(GBool booln);
  void pushInt(int intg);
  void pushReal(double real);
  GBool popBool();
  int popInt();
  double popNum();
  GBool empty() { return sp == psStackSize; }
  GBool topIsInt() { return sp < psStackSize && stack[sp].type == psInt; }
  GBool topTwoAreInts()
    { return sp < psStackSize - 1 &&
	     stack[sp].type == psInt &&
             stack[sp+1].type == psInt; }
  GBool topIsReal() { return sp < psStackSize && stack[sp].type == psReal; }
  GBool topTwoAreNums()
    { return sp < psStackSize - 1 &&
	     (stack[sp].type == psInt || stack[sp].type == psReal) &&
	     (stack[sp+1].type == psInt || stack[sp+1].type == psReal); }
  void copy(int n);
  void roll(int n, int j);
  void index(int i);
  void pop();

private:

  GBool checkOverflow(int n = 1);
  GBool checkUnderflow();
  GBool checkType(PSObjectType t1, PSObjectType t2);

  PSObject stack[psStackSize];
  int sp;
};

GBool PSStack::checkOverflow(int n) {
  if (sp - n < 0) {
    error(-1, "Stack overflow in PostScript function");
    return gFalse;
  }
  return gTrue;
}

GBool PSStack::checkUnderflow() {
  if (sp == psStackSize) {
    error(-1, "Stack underflow in PostScript function");
    return gFalse;
  }
  return gTrue;
}

GBool PSStack::checkType(PSObjectType t1, PSObjectType t2) {
  if (stack[sp].type != t1 && stack[sp].type != t2) {
    error(-1, "Type mismatch in PostScript function");
    return gFalse;
  }
  return gTrue;
}

void PSStack::pushBool(GBool booln) {
  if (checkOverflow()) {
    stack[--sp].type = psBool;
    stack[sp].booln = booln;
  }
}

void PSStack::pushInt(int intg) {
  if (checkOverflow()) {
    stack[--sp].type = psInt;
    stack[sp].intg = intg;
  }
}

void PSStack::pushReal(double real) {
  if (checkOverflow()) {
    stack[--sp].type = psReal;
    stack[sp].real = real;
  }
}

GBool PSStack::popBool() {
  if (checkUnderflow() && checkType(psBool, psBool)) {
    return stack[sp++].booln;
  }
  return gFalse;
}

int PSStack::popInt() {
  if (checkUnderflow() && checkType(psInt, psInt)) {
    return stack[sp++].intg;
  }
  return 0;
}

double PSStack::popNum() {
  double ret;

  if (checkUnderflow() && checkType(psInt, psReal)) {
    ret = (stack[sp].type == psInt) ? (double)stack[sp].intg : stack[sp].real;
    ++sp;
    return ret;
  }
  return 0;
}

void PSStack::copy(int n) {
  int i;

  if (sp + n > psStackSize) {
    error(-1, "Stack underflow in PostScript function");
    return;
  }
  if (!checkOverflow(n)) {
    return;
  }
  for (i = sp + n - 1; i >= sp; --i) {
    stack[i - n] = stack[i];
  }
  sp -= n;
}

void PSStack::roll(int n, int j) {
  PSObject obj;
  int i, k;

  if (j >= 0) {
    j %= n;
  } else {
    j = -j % n;
    if (j != 0) {
      j = n - j;
    }
  }
  if (n <= 0 || j == 0) {
    return;
  }
  for (i = 0; i < j; ++i) {
    obj = stack[sp];
    for (k = sp; k < sp + n - 1; ++k) {
      stack[k] = stack[k+1];
    }
    stack[sp + n - 1] = obj;
  }
}

void PSStack::index(int i) {
  if (!checkOverflow()) {
    return;
  }
  --sp;
  stack[sp] = stack[sp + 1 + i];
}

void PSStack::pop() {
  if (!checkUnderflow()) {
    return;
  }
  ++sp;
}

PostScriptFunction::PostScriptFunction(Object *funcObj, Dict *dict) {
  Stream *str;
  int codePtr;
  GString *tok;

  code = NULL;
  codeSize = 0;
  ok = gFalse;

  //----- initialize the generic stuff
  if (!init(dict)) {
    goto err1;
  }
  if (!hasRange) {
    error(-1, "Type 4 function is missing range");
    goto err1;
  }

  //----- get the stream
  if (!funcObj->isStream()) {
    error(-1, "Type 4 function isn't a stream");
    goto err1;
  }
  str = funcObj->getStream();

  //----- parse the function
  codeString = new GString();
  str->reset();
  if (!(tok = getToken(str)) || tok->cmp("{")) {
    error(-1, "Expected '{' at start of PostScript function");
    if (tok) {
      delete tok;
    }
    goto err1;
  }
  delete tok;
  codePtr = 0;
  if (!parseCode(str, &codePtr)) {
    goto err2;
  }
  str->close();

  ok = gTrue;

 err2:
  str->close();
 err1:
  return;
}