cwrap.js

cwrap = function cwrap(ident, returnType, argTypes) {
    argTypes = argTypes || [];
    var cfunc = getCFunc(ident);
    // When the function takes numbers and returns a number, we can just return
    // the original function
    var numericArgs = argTypes.every(function(type){ return type === 'number'});
    var numericRet = (returnType !== 'string');
    if ( numericRet && numericArgs) {
      return cfunc;
    }
    // Creation of the arguments list (["$1","$2",...,"$nargs"])
    var argNames = argTypes.map(function(x,i){return '$'+i});
    var funcstr = "(function(" + argNames.join(',') + ") {";
    var nargs = argTypes.length;
    if (!numericArgs) {
      // Generate the code needed to convert the arguments from javascript
      // values to pointers
      ensureJSsource();
      funcstr += 'var stack = ' + JSsource['stackSave'].body + ';';
      for (var i = 0; i < nargs; i++) {
        var arg = argNames[i], type = argTypes[i];
        if (type === 'number') continue;
        var convertCode = JSsource[type + 'ToC']; // [code, return]
        funcstr += 'var ' + convertCode.arguments + ' = ' + arg + ';';
        funcstr += convertCode.body + ';';
        funcstr += arg + '=(' + convertCode.returnValue + ');';
      }
    }

    // When the code is compressed, the name of cfunc is not literally 'cfunc' anymore
    var cfuncname = parseJSFunc(function(){return cfunc}).returnValue;
    // Call the function
    funcstr += 'var ret = ' + cfuncname + '(' + argNames.join(',') + ');';
    if (!numericRet) { // Return type can only by 'string' or 'number'
      // Convert the result to a string
      var strgfy = parseJSFunc(function(){return Pointer_stringify}).returnValue;
      funcstr += 'ret = ' + strgfy + '(ret);';
    }
    funcstr += "if (typeof EmterpreterAsync === 'object') { assert(!EmterpreterAsync.state, 'cannot start async op with normal JS calling cwrap') }";
    if (!numericArgs) {
      // If we had a stack, restore it
      ensureJSsource();
      funcstr += JSsource['stackRestore'].body.replace('()', '(stack)') + ';';
    }
    funcstr += 'return ret})';
    return eval(funcstr);
  };