v0.1.0

gagle · Apr 25, 2012 · 4e45a02 · 4e45a02
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Showing 12 changed files with 358 additions and 9 deletions.
diff --git a/README.md b/README.md
@@ -7,7 +7,11 @@ Node BufferedReader
 
 [Availability](#availability) | [Compatibility](#compatibility) | [Documentation](#documentation)
 
-Version: 0.0.6
+Version: 0.1.0
+
+When you need to read a file you typically read a chunk of bytes called "buffer" to avoid multiple calls to the underliying I/O layer, so instead of reading directly from the disk, you read from the previous filled buffer. Doing that you win performance.
+
+This library allows you to read files using internal buffers, so you don't have to worry about them. In addition, you can read a text file line by line.
 
 <a name="availability"></a>
 #### Availability [↑](#start) ####

diff --git a/build/buffered-reader.js b/build/buffered-reader.js
diff --git a/build/package.json b/build/package.json
@@ -1,8 +1,9 @@
 {
 	"name": "buffered-reader",
-	"version": "0.0.6",
+	"version": "0.1.0",
 	"description": "Fully configurable buffered reader.",
-	"keywords": ["buffer", "reader", "line", "read line", "read file", "read text file", "file"],
+	"keywords": ["buffer", "reader", "line", "read line", "file", "read file", "read text file",
+		"read binary file", "binary"],
 	"author": {
 		"name": "Gabriel Llamas"
 	},

diff --git a/examples/chunkBytes.js b/examples/chunkBytes.js
@@ -0,0 +1,29 @@
+var BufferedReader = require ("../build/buffered-reader");
+
+console.log ("File size: 16");
+
+new BufferedReader ("file").readBytes (10, function (error, bytes, bytesRead){
+	if (error) console.log (error);
+
+	console.log (bytes);
+	console.log ("Bytes read: " + bytesRead);
+
+	this.readBytes (8, function (error, bytes, bytesRead){
+		if (error) console.log (error);
+
+		console.log (bytes);
+		console.log ("Bytes read: " + bytesRead);
+
+		this.readBytes (4, function (error, bytes, bytesRead){
+			if (error) console.log (error);
+
+			//No more bytes, reached the end of the file
+			console.log (bytes);
+			console.log ("Bytes read: " + bytesRead);
+
+			this.close (function (error){
+				if (error) console.log (error);
+			});
+		});
+	});
+});
diff --git a/examples/file b/examples/file
diff --git a/src/buffered-reader.js b/src/buffered-reader.js
@@ -4,17 +4,20 @@
  *
  * @author Gabriel Llamas
  * @created 10/04/2012
- * @modified 21/04/2012
- * @version 0.0.6
+ * @modified 25/04/2012
+ * @version 0.1.0
  */
 "use strict";
 
 var EVENTS = require ("events");
 var FS = require ("fs");
-var PATH = require ("path");
 
 var BUFFER_SIZE = 16384;
 
+var INVALID_BUFFER_SIZE = new Error ("The buffer size must be greater than 0.");
+var INVALID_BYTES_RANGE_ERROR = new Error ("The number of bytes must be greater than 0.");
+var NO_FILE_ERROR = new Error ("The source is not a file.");
+
 var BufferedReader = function (fileName, bufferSize, encoding){
 	EVENTS.EventEmitter.call (this);
 
@@ -27,12 +30,22 @@ var BufferedReader = function (fileName, bufferSize, encoding){
 		bufferSize = BUFFER_SIZE;
 	}
 
+	if (bufferSize < 1) throw INVALID_BUFFER_SIZE;
+
 	this._settings = {
 		encoding: encoding,
 		bufferSize: bufferSize
 	};
 
 	this._fileName = fileName;
+	this._fd = null;
+	this._buffer = null;
+	this._fileOffset = 0;
+	this._bufferOffset = 0;
+	this._eof = false;
+	this._noMoreBuffers = false;
+	this._fileSize = null;
+	this._dataOffset = 0;
 };
 
 BufferedReader.prototype = Object.create (EVENTS.EventEmitter.prototype);
@@ -104,4 +117,147 @@ BufferedReader.prototype.read = function (){
 	});
 };
 
+BufferedReader.prototype._open = function (cb){
+	if (this._fd) return cb (null, this._fd);
+
+	var me = this;
+	FS.stat (this._fileName, function (error, stats){
+		if (error) return cb (error, null);
+		if (stats.isFile ()){
+			FS.open (me._fileName, "r", function (error, fd){
+				if (error) return cb (error, null);
+
+				me._fileSize = stats.size;
+				me._fd = fd;
+				me._buffer = new Buffer (me._settings.bufferSize);
+				me._read (function (error){
+					if (error){
+						return cb (error, null);
+					}else{
+						cb (null, me._fd);
+					}
+				});
+			});
+		}else{
+			cb (NO_FILE_ERROR, null);
+		}
+	});
+};
+
+BufferedReader.prototype._read = function (cb){
+	var me = this;
+	var size = this._settings.bufferSize;
+	FS.read (this._fd, this._buffer, 0, size, this._fileOffset, function (error, bytesRead){
+		if (error) return cb (error);
+
+		me._bufferValidSize = bytesRead;
+		me._fileOffset += bytesRead;
+		if (me._fileOffset === me._fileSize){
+			me._noMoreBuffers = true;
+		}
+		if (bytesRead < size){
+			me._buffer = me._buffer.slice (0, bytesRead);
+		}
+		cb ();
+	});
+};
+
+BufferedReader.prototype.close = function (cb){
+	if (cb) cb = cb.bind (this);
+	if (!this._fd){
+		if (cb) cb (null);
+		return;
+	}
+
+	var me = this;
+	FS.close (this._fd, function (error){
+		me._fd = null;
+		me._buffer = null;
+		if (cb) cb.call (me, error);
+	});
+};
+
+BufferedReader.prototype.readBytes = function (bytes, cb){
+	cb = cb.bind (this);
+	if (bytes < 1) return cb (INVALID_BYTES_RANGE_ERROR, null, -1);
+	if (this._eof) return cb (null, null, 0);
+
+	var fill = function (){
+		var endData = bytes - me._dataOffset;
+		var endBuffer = me._buffer.length - me._bufferOffset;
+		var end = endData > endBuffer ? endBuffer : endData;
+
+		me._buffer.copy (data, me._dataOffset, me._bufferOffset, me._bufferOffset + end);
+		me._bufferOffset += end;
+		if (me._bufferOffset === me._buffer.length) me._bufferOffset = 0;
+		me._dataOffset += end;
+
+		if (me._dataOffset === bytes){
+			me._dataOffset = 0;
+			me._eof = me._noMoreBuffers;
+			cb (null, data, bytes);
+		}else{
+			if (me._noMoreBuffers){
+				me._eof = true;
+				end = me._dataOffset;
+				me._dataOffset = 0;
+				cb (null, data.slice (0, end), end);
+			}else{
+				me._read (function (error){
+					if (error) return cb (error, null, -1);
+
+					fill ();
+				});
+			}
+		}
+	};
+
+	var me = this;
+	var data = new Buffer (bytes);
+
+	this._open (function (error, fd){
+		if (error) return cb (error, null, -1);
+
+		var len = me._buffer.length;
+
+		if (bytes < len){
+			var end = me._bufferOffset + bytes;
+
+			if (end <= len){
+				me._buffer.copy (data, 0, me._bufferOffset, end);
+				me._bufferOffset = end;
+				cb (null, data, bytes);
+			}else{
+				var last = len - me._bufferOffset;
+				if (last !== 0){
+					me._buffer.copy (data, 0, me._bufferOffset, me._bufferOffset + last);
+				}
+				if (me._noMoreBuffers){
+					me._eof = true;
+					return cb (null, data.slice (0, last), last);
+				}
+
+				me._read (function (error){
+					if (error) return cb (error, null);
+
+					len = me._buffer.length;
+					var remaining = bytes - last;
+					if (len <= remaining){
+						me._eof = true;
+						me._buffer.copy (data, last, 0, len);
+						var lastChunk = last + len;
+						cb (null, data.slice (0, lastChunk), lastChunk);
+					}else{
+						me._bufferOffset = remaining;
+						me._buffer.copy (data, last, 0, me._bufferOffset);
+						cb (null, data, bytes);
+					}
+				});
+			}
+		}else{
+			fill ();
+		}
+	});
+};
+
 module.exports = BufferedReader;
diff --git a/src/package.json b/src/package.json
@@ -1,8 +1,9 @@
 {
 	"name": "buffered-reader",
-	"version": "0.0.6",
+	"version": "0.1.0",
 	"description": "Fully configurable buffered reader.",
-	"keywords": ["buffer", "reader", "line", "read line", "read file", "read text file", "file"],
+	"keywords": ["buffer", "reader", "line", "read line", "file", "read file", "read text file",
+		"read binary file", "binary"],
 	"author": {
 		"name": "Gabriel Llamas"
 	},

diff --git a/test/tests/file b/test/tests/file
diff --git a/test/tests/test1.js b/test/tests/test1.js
@@ -0,0 +1,59 @@
+var BufferedReader = require ("../../build/buffered-reader");
+
+new BufferedReader ("file", 5).readBytes (2, function (error, bytes, bytesRead){
+	if (error) console.log (error);
+	console.log (bytes);
+	console.log ("bytes read: " + bytesRead);
+
+	this.readBytes (2, function (error, bytes, bytesRead){
+		if (error) console.log (error);
+		console.log (bytes);
+		console.log ("bytes read: " + bytesRead);
+
+		this.readBytes (2, function (error, bytes, bytesRead){
+			if (error) console.log (error);
+			console.log (bytes);
+			console.log ("bytes read: " + bytesRead);
+
+			this.readBytes (2, function (error, bytes, bytesRead){
+				if (error) console.log (error);
+				console.log (bytes);
+				console.log ("bytes read: " + bytesRead);
+
+				this.readBytes (2, function (error, bytes, bytesRead){
+					if (error) console.log (error);
+					console.log (bytes);
+					console.log ("bytes read: " + bytesRead);
+
+					this.readBytes (2, function (error, bytes, bytesRead){
+						if (error) console.log (error);
+						console.log (bytes);
+						console.log ("bytes read: " + bytesRead);
+
+						this.readBytes (2, function (error, bytes, bytesRead){
+							if (error) console.log (error);
+							console.log (bytes);
+							console.log ("bytes read: " + bytesRead);
+
+							this.readBytes (2, function (error, bytes, bytesRead){
+								if (error) console.log (error);
+								console.log (bytes);
+								console.log ("bytes read: " + bytesRead);
+
+								this.readBytes (2, function (error, bytes, bytesRead){
+									if (error) console.log (error);
+									console.log (bytes);
+									console.log ("bytes read: " + bytesRead);
+
+									this.close (function (error){
+										if (error) console.log (error);
+									});
+								});
+							});
+						});
+					});
+				});
+			});
+		});
+	});
+});
diff --git a/test/tests/test2.js b/test/tests/test2.js
@@ -0,0 +1,41 @@
+var BufferedReader = require ("../../build/buffered-reader");
+
+new BufferedReader ("file", 5).readBytes (4, function (error, bytes, bytesRead){
+	if (error) console.log (error);
+	console.log (bytes);
+	console.log ("bytes read: " + bytesRead);
+
+	this.readBytes (3, function (error, bytes, bytesRead){
+		if (error) console.log (error);
+		console.log (bytes);
+		console.log ("bytes read: " + bytesRead);
+
+		this.readBytes (2, function (error, bytes, bytesRead){
+			if (error) console.log (error);
+			console.log (bytes);
+			console.log ("bytes read: " + bytesRead);
+
+			this.readBytes (1, function (error, bytes, bytesRead){
+				if (error) console.log (error);
+				console.log (bytes);
+				console.log ("bytes read: " + bytesRead);
+
+				this.readBytes (4, function (error, bytes, bytesRead){
+					if (error) console.log (error);
+					console.log (bytes);
+					console.log ("bytes read: " + bytesRead);
+
+					this.readBytes (3, function (error, bytes, bytesRead){
+						if (error) console.log (error);
+						console.log (bytes);
+						console.log ("bytes read: " + bytesRead);
+
+						this.close (function (error){
+							if (error) console.log (error);
+						});
+					});
+				});
+			});
+		});
+	});
+});