little-endian tiff suport

lib/index.js

@@ -5,7 +5,7 @@ var libpath = process.env.TEST_COV ? '../lib-cov/' : '../lib/';
 var detector = require(libpath + 'detector');
 
 var handlers = {};
-var types = ['png', 'gif', 'bmp', 'psd', 'jpg'];
+var types = ['png', 'gif', 'bmp', 'psd', 'jpg', 'tiff'];
 
 // load all available handlers
 types.forEach(function (type) {

lib/types/tiff.js

@@ -0,0 +1,69 @@
+// based on http://www.compix.com/fileformattif.htm
+// TODO: support big-endian as well
+
+var fs = require('fs');
+
+module.exports = function (buffer, filepath) {
+
+  if (!filepath) {
+    throw new Error('Tiff can\'t support buffers, pass file instead');
+  }
+
+  var signature = buffer.toString('ascii', 0, 2);
+
+  var read;
+  // if ('II' === signature) {
+  //   read = [
+  //     buffer.readUInt16LE,
+  //     buffer.readUInt32LE
+  //   ];
+  // } else { //if ('MM' === signature) {
+  //   read = [
+  //     buffer.readUInt16BE,
+  //     buffer.readUInt32BE
+  //   ];
+  // }
+
+  // TODO: check if other versions exist
+  var version = buffer.readUInt16LE(2);
+  if (version !== 42) {
+    throw new TypeError('only version 42 Tiff images allowed');
+  }
+
+  var ifdOffset = buffer.readUInt32LE(4);
+
+  // read only till the end of the file
+  var bufferSize = 1024;
+  var fileSize = fs.statSync(filepath).size;
+  if (ifdOffset + bufferSize > fileSize) {
+    bufferSize = fileSize - ifdOffset - 10;
+  }
+
+  // populate the buffer
+  var endBuffer = new Buffer(bufferSize);
+  var descriptor = fs.openSync(filepath, 'r');
+  fs.readSync(descriptor, endBuffer, 0, bufferSize, ifdOffset);
+
+  var ifdLength = endBuffer.readUInt16LE(0);
+  var ifdBuffer = endBuffer.slice(2);
+
+  var tag, width, height;
+  while (ifdBuffer.length) {
+    tag = ifdBuffer.readUInt16LE(0);
+    if (tag === 256) {
+      width = ifdBuffer.readUInt32LE(8);
+    } else if (tag === 257) {
+      height = ifdBuffer.readUInt32LE(8);
+    }
+    if (tag === 0 || (width && height)) {
+      break;
+    } else {
+      ifdBuffer = ifdBuffer.slice(12);
+    }
+  }
+
+  return {
+    'width': width,
+    'height': height
+  };
+};

specs/all.spec.js

@@ -37,7 +37,7 @@ describe('Valid images', function () {
 
     describe(file, function() {
 
-      var bufferDimensions, asyncDimensions;
+      var type, bufferDimensions, asyncDimensions;
       var bufferSize = 8192;
 
       beforeEach(function (done) {
@@ -46,7 +46,12 @@ describe('Valid images', function () {
         var filepath = path.resolve(file);
         var descriptor = fs.openSync(filepath, 'r');
         fs.readSync(descriptor, buffer, 0, bufferSize, 0);
-        bufferDimensions = imageSize(buffer);
+        type = detector(buffer);
+
+        // tiff cannot support buffers, unless the buffer contains the entire file
+        if (type !== 'tiff') {
+          bufferDimensions = imageSize(buffer);
+        }
 
         imageSize(file, function (err, _dim) {
           asyncDimensions = _dim;
@@ -58,8 +63,11 @@ describe('Valid images', function () {
         var expected = sizes[file] || sizes.default;
         expect(asyncDimensions.width).to.be(expected.width);
         expect(asyncDimensions.height).to.be(expected.height);
-        expect(bufferDimensions.width).to.be(expected.width);
-        expect(bufferDimensions.height).to.be(expected.height);
+
+        if (type !== 'tiff') {
+          expect(bufferDimensions.width).to.be(expected.width);
+          expect(bufferDimensions.height).to.be(expected.height);
+        }
       });
     });
   });