temp.push(this[i]);
}
- for (var i=targetstart; i<targetstart+temp.length; i++) {
- target[i] = temp[i-targetstart];
+ for (var i=target_start; i<target_start+temp.length; i++) {
+ target[i] = temp[i-target_start];
}
};
return String.fromCharCode(0xFFFD); // UTF 8 invalid char
}
}
+
+// read/write bit-twiddling
+
+Buffer.prototype.readUInt8 = function(offset, noAssert) {
+ var buffer = this;
+
+ if (!noAssert) {
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset < buffer.length,
+ 'Trying to read beyond buffer length');
+ }
+
+ if (offset >= buffer.length) return;
+
+ return buffer.parent[buffer.offset + offset];
+};
+
+function readUInt16(buffer, offset, isBigEndian, noAssert) {
+ var val = 0;
+
+
+ if (!noAssert) {
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset + 1 < buffer.length,
+ 'Trying to read beyond buffer length');
+ }
+
+ if (offset >= buffer.length) return 0;
+
+ if (isBigEndian) {
+ val = buffer.parent[buffer.offset + offset] << 8;
+ if (offset + 1 < buffer.length) {
+ val |= buffer.parent[buffer.offset + offset + 1];
+ }
+ } else {
+ val = buffer.parent[buffer.offset + offset];
+ if (offset + 1 < buffer.length) {
+ val |= buffer.parent[buffer.offset + offset + 1] << 8;
+ }
+ }
+
+ return val;
+}
+
+Buffer.prototype.readUInt16LE = function(offset, noAssert) {
+ return readUInt16(this, offset, false, noAssert);
+};
+
+Buffer.prototype.readUInt16BE = function(offset, noAssert) {
+ return readUInt16(this, offset, true, noAssert);
+};
+
+function readUInt32(buffer, offset, isBigEndian, noAssert) {
+ var val = 0;
+
+ if (!noAssert) {
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset + 3 < buffer.length,
+ 'Trying to read beyond buffer length');
+ }
+
+ if (offset >= buffer.length) return 0;
+
+ if (isBigEndian) {
+ if (offset + 1 < buffer.length)
+ val = buffer.parent[buffer.offset + offset + 1] << 16;
+ if (offset + 2 < buffer.length)
+ val |= buffer.parent[buffer.offset + offset + 2] << 8;
+ if (offset + 3 < buffer.length)
+ val |= buffer.parent[buffer.offset + offset + 3];
+ val = val + (buffer.parent[buffer.offset + offset] << 24 >>> 0);
+ } else {
+ if (offset + 2 < buffer.length)
+ val = buffer.parent[buffer.offset + offset + 2] << 16;
+ if (offset + 1 < buffer.length)
+ val |= buffer.parent[buffer.offset + offset + 1] << 8;
+ val |= buffer.parent[buffer.offset + offset];
+ if (offset + 3 < buffer.length)
+ val = val + (buffer.parent[buffer.offset + offset + 3] << 24 >>> 0);
+ }
+
+ return val;
+}
+
+Buffer.prototype.readUInt32LE = function(offset, noAssert) {
+ return readUInt32(this, offset, false, noAssert);
+};
+
+Buffer.prototype.readUInt32BE = function(offset, noAssert) {
+ return readUInt32(this, offset, true, noAssert);
+};
+
+
+/*
+ * Signed integer types, yay team! A reminder on how two's complement actually
+ * works. The first bit is the signed bit, i.e. tells us whether or not the
+ * number should be positive or negative. If the two's complement value is
+ * positive, then we're done, as it's equivalent to the unsigned representation.
+ *
+ * Now if the number is positive, you're pretty much done, you can just leverage
+ * the unsigned translations and return those. Unfortunately, negative numbers
+ * aren't quite that straightforward.
+ *
+ * At first glance, one might be inclined to use the traditional formula to
+ * translate binary numbers between the positive and negative values in two's
+ * complement. (Though it doesn't quite work for the most negative value)
+ * Mainly:
+ * - invert all the bits
+ * - add one to the result
+ *
+ * Of course, this doesn't quite work in Javascript. Take for example the value
+ * of -128. This could be represented in 16 bits (big-endian) as 0xff80. But of
+ * course, Javascript will do the following:
+ *
+ * > ~0xff80
+ * -65409
+ *
+ * Whoh there, Javascript, that's not quite right. But wait, according to
+ * Javascript that's perfectly correct. When Javascript ends up seeing the
+ * constant 0xff80, it has no notion that it is actually a signed number. It
+ * assumes that we've input the unsigned value 0xff80. Thus, when it does the
+ * binary negation, it casts it into a signed value, (positive 0xff80). Then
+ * when you perform binary negation on that, it turns it into a negative number.
+ *
+ * Instead, we're going to have to use the following general formula, that works
+ * in a rather Javascript friendly way. I'm glad we don't support this kind of
+ * weird numbering scheme in the kernel.
+ *
+ * (BIT-MAX - (unsigned)val + 1) * -1
+ *
+ * The astute observer, may think that this doesn't make sense for 8-bit numbers
+ * (really it isn't necessary for them). However, when you get 16-bit numbers,
+ * you do. Let's go back to our prior example and see how this will look:
+ *
+ * (0xffff - 0xff80 + 1) * -1
+ * (0x007f + 1) * -1
+ * (0x0080) * -1
+ */
+Buffer.prototype.readInt8 = function(offset, noAssert) {
+ var buffer = this;
+ var neg;
+
+ if (!noAssert) {
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset < buffer.length,
+ 'Trying to read beyond buffer length');
+ }
+
+ if (offset >= buffer.length) return;
+
+ neg = buffer.parent[buffer.offset + offset] & 0x80;
+ if (!neg) {
+ return (buffer.parent[buffer.offset + offset]);
+ }
+
+ return ((0xff - buffer.parent[buffer.offset + offset] + 1) * -1);
+};
+
+function readInt16(buffer, offset, isBigEndian, noAssert) {
+ var neg, val;
+
+ if (!noAssert) {
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset + 1 < buffer.length,
+ 'Trying to read beyond buffer length');
+ }
+
+ val = readUInt16(buffer, offset, isBigEndian, noAssert);
+ neg = val & 0x8000;
+ if (!neg) {
+ return val;
+ }
+
+ return (0xffff - val + 1) * -1;
+}
+
+Buffer.prototype.readInt16LE = function(offset, noAssert) {
+ return readInt16(this, offset, false, noAssert);
+};
+
+Buffer.prototype.readInt16BE = function(offset, noAssert) {
+ return readInt16(this, offset, true, noAssert);
+};
+
+function readInt32(buffer, offset, isBigEndian, noAssert) {
+ var neg, val;
+
+ if (!noAssert) {
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset + 3 < buffer.length,
+ 'Trying to read beyond buffer length');
+ }
+
+ val = readUInt32(buffer, offset, isBigEndian, noAssert);
+ neg = val & 0x80000000;
+ if (!neg) {
+ return (val);
+ }
+
+ return (0xffffffff - val + 1) * -1;
+}
+
+Buffer.prototype.readInt32LE = function(offset, noAssert) {
+ return readInt32(this, offset, false, noAssert);
+};
+
+Buffer.prototype.readInt32BE = function(offset, noAssert) {
+ return readInt32(this, offset, true, noAssert);
+};
+
+function readFloat(buffer, offset, isBigEndian, noAssert) {
+ if (!noAssert) {
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset + 3 < buffer.length,
+ 'Trying to read beyond buffer length');
+ }
+
+ return require('./buffer_ieee754').readIEEE754(buffer, offset, isBigEndian,
+ 23, 4);
+}
+
+Buffer.prototype.readFloatLE = function(offset, noAssert) {
+ return readFloat(this, offset, false, noAssert);
+};
+
+Buffer.prototype.readFloatBE = function(offset, noAssert) {
+ return readFloat(this, offset, true, noAssert);
+};
+
+function readDouble(buffer, offset, isBigEndian, noAssert) {
+ if (!noAssert) {
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset + 7 < buffer.length,
+ 'Trying to read beyond buffer length');
+ }
+
+ return require('./buffer_ieee754').readIEEE754(buffer, offset, isBigEndian,
+ 52, 8);
+}
+
+Buffer.prototype.readDoubleLE = function(offset, noAssert) {
+ return readDouble(this, offset, false, noAssert);
+};
+
+Buffer.prototype.readDoubleBE = function(offset, noAssert) {
+ return readDouble(this, offset, true, noAssert);
+};
+
+
+/*
+ * We have to make sure that the value is a valid integer. This means that it is
+ * non-negative. It has no fractional component and that it does not exceed the
+ * maximum allowed value.
+ *
+ * value The number to check for validity
+ *
+ * max The maximum value
+ */
+function verifuint(value, max) {
+ assert.ok(typeof (value) == 'number',
+ 'cannot write a non-number as a number');
+
+ assert.ok(value >= 0,
+ 'specified a negative value for writing an unsigned value');
+
+ assert.ok(value <= max, 'value is larger than maximum value for type');
+
+ assert.ok(Math.floor(value) === value, 'value has a fractional component');
+}
+
+Buffer.prototype.writeUInt8 = function(value, offset, noAssert) {
+ var buffer = this;
+
+ if (!noAssert) {
+ assert.ok(value !== undefined && value !== null,
+ 'missing value');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset < buffer.length,
+ 'trying to write beyond buffer length');
+
+ verifuint(value, 0xff);
+ }
+
+ if (offset < buffer.length) {
+ buffer.parent[buffer.offset + offset] = value;
+ }
+};
+
+function writeUInt16(buffer, value, offset, isBigEndian, noAssert) {
+ if (!noAssert) {
+ assert.ok(value !== undefined && value !== null,
+ 'missing value');
+
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset + 1 < buffer.length,
+ 'trying to write beyond buffer length');
+
+ verifuint(value, 0xffff);
+ }
+
+ for (var i = 0; i < Math.min(buffer.length - offset, 2); i++) {
+ buffer.parent[buffer.offset + offset + i] =
+ (value & (0xff << (8 * (isBigEndian ? 1 - i : i)))) >>>
+ (isBigEndian ? 1 - i : i) * 8;
+ }
+
+}
+
+Buffer.prototype.writeUInt16LE = function(value, offset, noAssert) {
+ writeUInt16(this, value, offset, false, noAssert);
+};
+
+Buffer.prototype.writeUInt16BE = function(value, offset, noAssert) {
+ writeUInt16(this, value, offset, true, noAssert);
+};
+
+function writeUInt32(buffer, value, offset, isBigEndian, noAssert) {
+ if (!noAssert) {
+ assert.ok(value !== undefined && value !== null,
+ 'missing value');
+
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset + 3 < buffer.length,
+ 'trying to write beyond buffer length');
+
+ verifuint(value, 0xffffffff);
+ }
+
+ for (var i = 0; i < Math.min(buffer.length - offset, 4); i++) {
+ buffer.parent[buffer.offset + offset + i] =
+ (value >>> (isBigEndian ? 3 - i : i) * 8) & 0xff;
+ }
+}
+
+Buffer.prototype.writeUInt32LE = function(value, offset, noAssert) {
+ writeUInt32(this, value, offset, false, noAssert);
+};
+
+Buffer.prototype.writeUInt32BE = function(value, offset, noAssert) {
+ writeUInt32(this, value, offset, true, noAssert);
+};
+
+
+/*
+ * We now move onto our friends in the signed number category. Unlike unsigned
+ * numbers, we're going to have to worry a bit more about how we put values into
+ * arrays. Since we are only worrying about signed 32-bit values, we're in
+ * slightly better shape. Unfortunately, we really can't do our favorite binary
+ * & in this system. It really seems to do the wrong thing. For example:
+ *
+ * > -32 & 0xff
+ * 224
+ *
+ * What's happening above is really: 0xe0 & 0xff = 0xe0. However, the results of
+ * this aren't treated as a signed number. Ultimately a bad thing.
+ *
+ * What we're going to want to do is basically create the unsigned equivalent of
+ * our representation and pass that off to the wuint* functions. To do that
+ * we're going to do the following:
+ *
+ * - if the value is positive
+ * we can pass it directly off to the equivalent wuint
+ * - if the value is negative
+ * we do the following computation:
+ * mb + val + 1, where
+ * mb is the maximum unsigned value in that byte size
+ * val is the Javascript negative integer
+ *
+ *
+ * As a concrete value, take -128. In signed 16 bits this would be 0xff80. If
+ * you do out the computations:
+ *
+ * 0xffff - 128 + 1
+ * 0xffff - 127
+ * 0xff80
+ *
+ * You can then encode this value as the signed version. This is really rather
+ * hacky, but it should work and get the job done which is our goal here.
+ */
+
+/*
+ * A series of checks to make sure we actually have a signed 32-bit number
+ */
+function verifsint(value, max, min) {
+ assert.ok(typeof (value) == 'number',
+ 'cannot write a non-number as a number');
+
+ assert.ok(value <= max, 'value larger than maximum allowed value');
+
+ assert.ok(value >= min, 'value smaller than minimum allowed value');
+
+ assert.ok(Math.floor(value) === value, 'value has a fractional component');
+}
+
+function verifIEEE754(value, max, min) {
+ assert.ok(typeof (value) == 'number',
+ 'cannot write a non-number as a number');
+
+ assert.ok(value <= max, 'value larger than maximum allowed value');
+
+ assert.ok(value >= min, 'value smaller than minimum allowed value');
+}
+
+Buffer.prototype.writeInt8 = function(value, offset, noAssert) {
+ var buffer = this;
+
+ if (!noAssert) {
+ assert.ok(value !== undefined && value !== null,
+ 'missing value');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset < buffer.length,
+ 'Trying to write beyond buffer length');
+
+ verifsint(value, 0x7f, -0x80);
+ }
+
+ if (value >= 0) {
+ buffer.writeUInt8(value, offset, noAssert);
+ } else {
+ buffer.writeUInt8(0xff + value + 1, offset, noAssert);
+ }
+};
+
+function writeInt16(buffer, value, offset, isBigEndian, noAssert) {
+ if (!noAssert) {
+ assert.ok(value !== undefined && value !== null,
+ 'missing value');
+
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset + 1 < buffer.length,
+ 'Trying to write beyond buffer length');
+
+ verifsint(value, 0x7fff, -0x8000);
+ }
+
+ if (value >= 0) {
+ writeUInt16(buffer, value, offset, isBigEndian, noAssert);
+ } else {
+ writeUInt16(buffer, 0xffff + value + 1, offset, isBigEndian, noAssert);
+ }
+}
+
+Buffer.prototype.writeInt16LE = function(value, offset, noAssert) {
+ writeInt16(this, value, offset, false, noAssert);
+};
+
+Buffer.prototype.writeInt16BE = function(value, offset, noAssert) {
+ writeInt16(this, value, offset, true, noAssert);
+};
+
+function writeInt32(buffer, value, offset, isBigEndian, noAssert) {
+ if (!noAssert) {
+ assert.ok(value !== undefined && value !== null,
+ 'missing value');
+
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset + 3 < buffer.length,
+ 'Trying to write beyond buffer length');
+
+ verifsint(value, 0x7fffffff, -0x80000000);
+ }
+
+ if (value >= 0) {
+ writeUInt32(buffer, value, offset, isBigEndian, noAssert);
+ } else {
+ writeUInt32(buffer, 0xffffffff + value + 1, offset, isBigEndian, noAssert);
+ }
+}
+
+Buffer.prototype.writeInt32LE = function(value, offset, noAssert) {
+ writeInt32(this, value, offset, false, noAssert);
+};
+
+Buffer.prototype.writeInt32BE = function(value, offset, noAssert) {
+ writeInt32(this, value, offset, true, noAssert);
+};
+
+function writeFloat(buffer, value, offset, isBigEndian, noAssert) {
+ if (!noAssert) {
+ assert.ok(value !== undefined && value !== null,
+ 'missing value');
+
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset + 3 < buffer.length,
+ 'Trying to write beyond buffer length');
+
+ verifIEEE754(value, 3.4028234663852886e+38, -3.4028234663852886e+38);
+ }
+
+ require('./buffer_ieee754').writeIEEE754(buffer, value, offset, isBigEndian,
+ 23, 4);
+}
+
+Buffer.prototype.writeFloatLE = function(value, offset, noAssert) {
+ writeFloat(this, value, offset, false, noAssert);
+};
+
+Buffer.prototype.writeFloatBE = function(value, offset, noAssert) {
+ writeFloat(this, value, offset, true, noAssert);
+};
+
+function writeDouble(buffer, value, offset, isBigEndian, noAssert) {
+ if (!noAssert) {
+ assert.ok(value !== undefined && value !== null,
+ 'missing value');
+
+ assert.ok(typeof (isBigEndian) === 'boolean',
+ 'missing or invalid endian');
+
+ assert.ok(offset !== undefined && offset !== null,
+ 'missing offset');
+
+ assert.ok(offset + 7 < buffer.length,
+ 'Trying to write beyond buffer length');
+
+ verifIEEE754(value, 1.7976931348623157E+308, -1.7976931348623157E+308);
+ }
+
+ require('./buffer_ieee754').writeIEEE754(buffer, value, offset, isBigEndian,
+ 52, 8);
+}
+
+Buffer.prototype.writeDoubleLE = function(value, offset, noAssert) {
+ writeDouble(this, value, offset, false, noAssert);
+};
+
+Buffer.prototype.writeDoubleBE = function(value, offset, noAssert) {
+ writeDouble(this, value, offset, true, noAssert);
+};
+++ /dev/null
-// slice(start, end)
-Buffer.prototype.slice = function(start, end) {
- if (end === undefined) end = this.length;
- if (end > this.length) throw new Error('oob');
- if (start > end) throw new Error('oob');
-
- return new Buffer(this.parent, end - start, +start + this.offset);
-};
-
-
-// Legacy methods for backwards compatibility.
-
-Buffer.prototype.utf8Slice = function(start, end) {
- return this.toString('utf8', start, end);
-};
-
-Buffer.prototype.binarySlice = function(start, end) {
- return this.toString('binary', start, end);
-};
-
-Buffer.prototype.asciiSlice = function(start, end) {
- return this.toString('ascii', start, end);
-};
-
-Buffer.prototype.utf8Write = function(string, offset) {
- return this.write(string, offset, 'utf8');
-};
-
-Buffer.prototype.binaryWrite = function(string, offset) {
- return this.write(string, offset, 'binary');
-};
-
-Buffer.prototype.asciiWrite = function(string, offset) {
- return this.write(string, offset, 'ascii');
-};
-
-Buffer.prototype.readUInt8 = function(offset, noAssert) {
- var buffer = this;
-
- if (!noAssert) {
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset < buffer.length,
- 'Trying to read beyond buffer length');
- }
-
- if (offset >= buffer.length) return;
-
- return buffer.parent[buffer.offset + offset];
-};
-
-function readUInt16(buffer, offset, isBigEndian, noAssert) {
- var val = 0;
-
-
- if (!noAssert) {
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset + 1 < buffer.length,
- 'Trying to read beyond buffer length');
- }
-
- if (offset >= buffer.length) return 0;
-
- if (isBigEndian) {
- val = buffer.parent[buffer.offset + offset] << 8;
- if (offset + 1 < buffer.length) {
- val |= buffer.parent[buffer.offset + offset + 1];
- }
- } else {
- val = buffer.parent[buffer.offset + offset];
- if (offset + 1 < buffer.length) {
- val |= buffer.parent[buffer.offset + offset + 1] << 8;
- }
- }
-
- return val;
-}
-
-Buffer.prototype.readUInt16LE = function(offset, noAssert) {
- return readUInt16(this, offset, false, noAssert);
-};
-
-Buffer.prototype.readUInt16BE = function(offset, noAssert) {
- return readUInt16(this, offset, true, noAssert);
-};
-
-function readUInt32(buffer, offset, isBigEndian, noAssert) {
- var val = 0;
-
- if (!noAssert) {
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset + 3 < buffer.length,
- 'Trying to read beyond buffer length');
- }
-
- if (offset >= buffer.length) return 0;
-
- if (isBigEndian) {
- if (offset + 1 < buffer.length)
- val = buffer.parent[buffer.offset + offset + 1] << 16;
- if (offset + 2 < buffer.length)
- val |= buffer.parent[buffer.offset + offset + 2] << 8;
- if (offset + 3 < buffer.length)
- val |= buffer.parent[buffer.offset + offset + 3];
- val = val + (buffer.parent[buffer.offset + offset] << 24 >>> 0);
- } else {
- if (offset + 2 < buffer.length)
- val = buffer.parent[buffer.offset + offset + 2] << 16;
- if (offset + 1 < buffer.length)
- val |= buffer.parent[buffer.offset + offset + 1] << 8;
- val |= buffer.parent[buffer.offset + offset];
- if (offset + 3 < buffer.length)
- val = val + (buffer.parent[buffer.offset + offset + 3] << 24 >>> 0);
- }
-
- return val;
-}
-
-Buffer.prototype.readUInt32LE = function(offset, noAssert) {
- return readUInt32(this, offset, false, noAssert);
-};
-
-Buffer.prototype.readUInt32BE = function(offset, noAssert) {
- return readUInt32(this, offset, true, noAssert);
-};
-
-
-/*
- * Signed integer types, yay team! A reminder on how two's complement actually
- * works. The first bit is the signed bit, i.e. tells us whether or not the
- * number should be positive or negative. If the two's complement value is
- * positive, then we're done, as it's equivalent to the unsigned representation.
- *
- * Now if the number is positive, you're pretty much done, you can just leverage
- * the unsigned translations and return those. Unfortunately, negative numbers
- * aren't quite that straightforward.
- *
- * At first glance, one might be inclined to use the traditional formula to
- * translate binary numbers between the positive and negative values in two's
- * complement. (Though it doesn't quite work for the most negative value)
- * Mainly:
- * - invert all the bits
- * - add one to the result
- *
- * Of course, this doesn't quite work in Javascript. Take for example the value
- * of -128. This could be represented in 16 bits (big-endian) as 0xff80. But of
- * course, Javascript will do the following:
- *
- * > ~0xff80
- * -65409
- *
- * Whoh there, Javascript, that's not quite right. But wait, according to
- * Javascript that's perfectly correct. When Javascript ends up seeing the
- * constant 0xff80, it has no notion that it is actually a signed number. It
- * assumes that we've input the unsigned value 0xff80. Thus, when it does the
- * binary negation, it casts it into a signed value, (positive 0xff80). Then
- * when you perform binary negation on that, it turns it into a negative number.
- *
- * Instead, we're going to have to use the following general formula, that works
- * in a rather Javascript friendly way. I'm glad we don't support this kind of
- * weird numbering scheme in the kernel.
- *
- * (BIT-MAX - (unsigned)val + 1) * -1
- *
- * The astute observer, may think that this doesn't make sense for 8-bit numbers
- * (really it isn't necessary for them). However, when you get 16-bit numbers,
- * you do. Let's go back to our prior example and see how this will look:
- *
- * (0xffff - 0xff80 + 1) * -1
- * (0x007f + 1) * -1
- * (0x0080) * -1
- */
-Buffer.prototype.readInt8 = function(offset, noAssert) {
- var buffer = this;
- var neg;
-
- if (!noAssert) {
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset < buffer.length,
- 'Trying to read beyond buffer length');
- }
-
- if (offset >= buffer.length) return;
-
- neg = buffer.parent[buffer.offset + offset] & 0x80;
- if (!neg) {
- return (buffer.parent[buffer.offset + offset]);
- }
-
- return ((0xff - buffer.parent[buffer.offset + offset] + 1) * -1);
-};
-
-function readInt16(buffer, offset, isBigEndian, noAssert) {
- var neg, val;
-
- if (!noAssert) {
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset + 1 < buffer.length,
- 'Trying to read beyond buffer length');
- }
-
- val = readUInt16(buffer, offset, isBigEndian, noAssert);
- neg = val & 0x8000;
- if (!neg) {
- return val;
- }
-
- return (0xffff - val + 1) * -1;
-}
-
-Buffer.prototype.readInt16LE = function(offset, noAssert) {
- return readInt16(this, offset, false, noAssert);
-};
-
-Buffer.prototype.readInt16BE = function(offset, noAssert) {
- return readInt16(this, offset, true, noAssert);
-};
-
-function readInt32(buffer, offset, isBigEndian, noAssert) {
- var neg, val;
-
- if (!noAssert) {
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset + 3 < buffer.length,
- 'Trying to read beyond buffer length');
- }
-
- val = readUInt32(buffer, offset, isBigEndian, noAssert);
- neg = val & 0x80000000;
- if (!neg) {
- return (val);
- }
-
- return (0xffffffff - val + 1) * -1;
-}
-
-Buffer.prototype.readInt32LE = function(offset, noAssert) {
- return readInt32(this, offset, false, noAssert);
-};
-
-Buffer.prototype.readInt32BE = function(offset, noAssert) {
- return readInt32(this, offset, true, noAssert);
-};
-
-function readFloat(buffer, offset, isBigEndian, noAssert) {
- if (!noAssert) {
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset + 3 < buffer.length,
- 'Trying to read beyond buffer length');
- }
-
- return require('./buffer_ieee754').readIEEE754(buffer, offset, isBigEndian,
- 23, 4);
-}
-
-Buffer.prototype.readFloatLE = function(offset, noAssert) {
- return readFloat(this, offset, false, noAssert);
-};
-
-Buffer.prototype.readFloatBE = function(offset, noAssert) {
- return readFloat(this, offset, true, noAssert);
-};
-
-function readDouble(buffer, offset, isBigEndian, noAssert) {
- if (!noAssert) {
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset + 7 < buffer.length,
- 'Trying to read beyond buffer length');
- }
-
- return require('./buffer_ieee754').readIEEE754(buffer, offset, isBigEndian,
- 52, 8);
-}
-
-Buffer.prototype.readDoubleLE = function(offset, noAssert) {
- return readDouble(this, offset, false, noAssert);
-};
-
-Buffer.prototype.readDoubleBE = function(offset, noAssert) {
- return readDouble(this, offset, true, noAssert);
-};
-
-
-/*
- * We have to make sure that the value is a valid integer. This means that it is
- * non-negative. It has no fractional component and that it does not exceed the
- * maximum allowed value.
- *
- * value The number to check for validity
- *
- * max The maximum value
- */
-function verifuint(value, max) {
- assert.ok(typeof (value) == 'number',
- 'cannot write a non-number as a number');
-
- assert.ok(value >= 0,
- 'specified a negative value for writing an unsigned value');
-
- assert.ok(value <= max, 'value is larger than maximum value for type');
-
- assert.ok(Math.floor(value) === value, 'value has a fractional component');
-}
-
-Buffer.prototype.writeUInt8 = function(value, offset, noAssert) {
- var buffer = this;
-
- if (!noAssert) {
- assert.ok(value !== undefined && value !== null,
- 'missing value');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset < buffer.length,
- 'trying to write beyond buffer length');
-
- verifuint(value, 0xff);
- }
-
- if (offset < buffer.length) {
- buffer.parent[buffer.offset + offset] = value;
- }
-};
-
-function writeUInt16(buffer, value, offset, isBigEndian, noAssert) {
- if (!noAssert) {
- assert.ok(value !== undefined && value !== null,
- 'missing value');
-
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset + 1 < buffer.length,
- 'trying to write beyond buffer length');
-
- verifuint(value, 0xffff);
- }
-
- for (var i = 0; i < Math.min(buffer.length - offset, 2); i++) {
- buffer.parent[buffer.offset + offset + i] =
- (value & (0xff << (8 * (isBigEndian ? 1 - i : i)))) >>>
- (isBigEndian ? 1 - i : i) * 8;
- }
-
-}
-
-Buffer.prototype.writeUInt16LE = function(value, offset, noAssert) {
- writeUInt16(this, value, offset, false, noAssert);
-};
-
-Buffer.prototype.writeUInt16BE = function(value, offset, noAssert) {
- writeUInt16(this, value, offset, true, noAssert);
-};
-
-function writeUInt32(buffer, value, offset, isBigEndian, noAssert) {
- if (!noAssert) {
- assert.ok(value !== undefined && value !== null,
- 'missing value');
-
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset + 3 < buffer.length,
- 'trying to write beyond buffer length');
-
- verifuint(value, 0xffffffff);
- }
-
- for (var i = 0; i < Math.min(buffer.length - offset, 4); i++) {
- buffer.parent[buffer.offset + offset + i] =
- (value >>> (isBigEndian ? 3 - i : i) * 8) & 0xff;
- }
-}
-
-Buffer.prototype.writeUInt32LE = function(value, offset, noAssert) {
- writeUInt32(this, value, offset, false, noAssert);
-};
-
-Buffer.prototype.writeUInt32BE = function(value, offset, noAssert) {
- writeUInt32(this, value, offset, true, noAssert);
-};
-
-
-/*
- * We now move onto our friends in the signed number category. Unlike unsigned
- * numbers, we're going to have to worry a bit more about how we put values into
- * arrays. Since we are only worrying about signed 32-bit values, we're in
- * slightly better shape. Unfortunately, we really can't do our favorite binary
- * & in this system. It really seems to do the wrong thing. For example:
- *
- * > -32 & 0xff
- * 224
- *
- * What's happening above is really: 0xe0 & 0xff = 0xe0. However, the results of
- * this aren't treated as a signed number. Ultimately a bad thing.
- *
- * What we're going to want to do is basically create the unsigned equivalent of
- * our representation and pass that off to the wuint* functions. To do that
- * we're going to do the following:
- *
- * - if the value is positive
- * we can pass it directly off to the equivalent wuint
- * - if the value is negative
- * we do the following computation:
- * mb + val + 1, where
- * mb is the maximum unsigned value in that byte size
- * val is the Javascript negative integer
- *
- *
- * As a concrete value, take -128. In signed 16 bits this would be 0xff80. If
- * you do out the computations:
- *
- * 0xffff - 128 + 1
- * 0xffff - 127
- * 0xff80
- *
- * You can then encode this value as the signed version. This is really rather
- * hacky, but it should work and get the job done which is our goal here.
- */
-
-/*
- * A series of checks to make sure we actually have a signed 32-bit number
- */
-function verifsint(value, max, min) {
- assert.ok(typeof (value) == 'number',
- 'cannot write a non-number as a number');
-
- assert.ok(value <= max, 'value larger than maximum allowed value');
-
- assert.ok(value >= min, 'value smaller than minimum allowed value');
-
- assert.ok(Math.floor(value) === value, 'value has a fractional component');
-}
-
-function verifIEEE754(value, max, min) {
- assert.ok(typeof (value) == 'number',
- 'cannot write a non-number as a number');
-
- assert.ok(value <= max, 'value larger than maximum allowed value');
-
- assert.ok(value >= min, 'value smaller than minimum allowed value');
-}
-
-Buffer.prototype.writeInt8 = function(value, offset, noAssert) {
- var buffer = this;
-
- if (!noAssert) {
- assert.ok(value !== undefined && value !== null,
- 'missing value');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset < buffer.length,
- 'Trying to write beyond buffer length');
-
- verifsint(value, 0x7f, -0x80);
- }
-
- if (value >= 0) {
- buffer.writeUInt8(value, offset, noAssert);
- } else {
- buffer.writeUInt8(0xff + value + 1, offset, noAssert);
- }
-};
-
-function writeInt16(buffer, value, offset, isBigEndian, noAssert) {
- if (!noAssert) {
- assert.ok(value !== undefined && value !== null,
- 'missing value');
-
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset + 1 < buffer.length,
- 'Trying to write beyond buffer length');
-
- verifsint(value, 0x7fff, -0x8000);
- }
-
- if (value >= 0) {
- writeUInt16(buffer, value, offset, isBigEndian, noAssert);
- } else {
- writeUInt16(buffer, 0xffff + value + 1, offset, isBigEndian, noAssert);
- }
-}
-
-Buffer.prototype.writeInt16LE = function(value, offset, noAssert) {
- writeInt16(this, value, offset, false, noAssert);
-};
-
-Buffer.prototype.writeInt16BE = function(value, offset, noAssert) {
- writeInt16(this, value, offset, true, noAssert);
-};
-
-function writeInt32(buffer, value, offset, isBigEndian, noAssert) {
- if (!noAssert) {
- assert.ok(value !== undefined && value !== null,
- 'missing value');
-
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset + 3 < buffer.length,
- 'Trying to write beyond buffer length');
-
- verifsint(value, 0x7fffffff, -0x80000000);
- }
-
- if (value >= 0) {
- writeUInt32(buffer, value, offset, isBigEndian, noAssert);
- } else {
- writeUInt32(buffer, 0xffffffff + value + 1, offset, isBigEndian, noAssert);
- }
-}
-
-Buffer.prototype.writeInt32LE = function(value, offset, noAssert) {
- writeInt32(this, value, offset, false, noAssert);
-};
-
-Buffer.prototype.writeInt32BE = function(value, offset, noAssert) {
- writeInt32(this, value, offset, true, noAssert);
-};
-
-function writeFloat(buffer, value, offset, isBigEndian, noAssert) {
- if (!noAssert) {
- assert.ok(value !== undefined && value !== null,
- 'missing value');
-
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset + 3 < buffer.length,
- 'Trying to write beyond buffer length');
-
- verifIEEE754(value, 3.4028234663852886e+38, -3.4028234663852886e+38);
- }
-
- require('./buffer_ieee754').writeIEEE754(buffer, value, offset, isBigEndian,
- 23, 4);
-}
-
-Buffer.prototype.writeFloatLE = function(value, offset, noAssert) {
- writeFloat(this, value, offset, false, noAssert);
-};
-
-Buffer.prototype.writeFloatBE = function(value, offset, noAssert) {
- writeFloat(this, value, offset, true, noAssert);
-};
-
-function writeDouble(buffer, value, offset, isBigEndian, noAssert) {
- if (!noAssert) {
- assert.ok(value !== undefined && value !== null,
- 'missing value');
-
- assert.ok(typeof (isBigEndian) === 'boolean',
- 'missing or invalid endian');
-
- assert.ok(offset !== undefined && offset !== null,
- 'missing offset');
-
- assert.ok(offset + 7 < buffer.length,
- 'Trying to write beyond buffer length');
-
- verifIEEE754(value, 1.7976931348623157E+308, -1.7976931348623157E+308);
- }
-
- require('./buffer_ieee754').writeIEEE754(buffer, value, offset, isBigEndian,
- 52, 8);
-}
-
-Buffer.prototype.writeDoubleLE = function(value, offset, noAssert) {
- writeDouble(this, value, offset, false, noAssert);
-};
-
-Buffer.prototype.writeDoubleBE = function(value, offset, noAssert) {
- writeDouble(this, value, offset, true, noAssert);
-};
-
-SlowBuffer.prototype.readUInt8 = Buffer.prototype.readUInt8;
-SlowBuffer.prototype.readUInt16LE = Buffer.prototype.readUInt16LE;
-SlowBuffer.prototype.readUInt16BE = Buffer.prototype.readUInt16BE;
-SlowBuffer.prototype.readUInt32LE = Buffer.prototype.readUInt32LE;
-SlowBuffer.prototype.readUInt32BE = Buffer.prototype.readUInt32BE;
-SlowBuffer.prototype.readInt8 = Buffer.prototype.readInt8;
-SlowBuffer.prototype.readInt16LE = Buffer.prototype.readInt16LE;
-SlowBuffer.prototype.readInt16BE = Buffer.prototype.readInt16BE;
-SlowBuffer.prototype.readInt32LE = Buffer.prototype.readInt32LE;
-SlowBuffer.prototype.readInt32BE = Buffer.prototype.readInt32BE;
-SlowBuffer.prototype.readFloatLE = Buffer.prototype.readFloatLE;
-SlowBuffer.prototype.readFloatBE = Buffer.prototype.readFloatBE;
-SlowBuffer.prototype.readDoubleLE = Buffer.prototype.readDoubleLE;
-SlowBuffer.prototype.readDoubleBE = Buffer.prototype.readDoubleBE;
-SlowBuffer.prototype.writeUInt8 = Buffer.prototype.writeUInt8;
-SlowBuffer.prototype.writeUInt16LE = Buffer.prototype.writeUInt16LE;
-SlowBuffer.prototype.writeUInt16BE = Buffer.prototype.writeUInt16BE;
-SlowBuffer.prototype.writeUInt32LE = Buffer.prototype.writeUInt32LE;
-SlowBuffer.prototype.writeUInt32BE = Buffer.prototype.writeUInt32BE;
-SlowBuffer.prototype.writeInt8 = Buffer.prototype.writeInt8;
-SlowBuffer.prototype.writeInt16LE = Buffer.prototype.writeInt16LE;
-SlowBuffer.prototype.writeInt16BE = Buffer.prototype.writeInt16BE;
-SlowBuffer.prototype.writeInt32LE = Buffer.prototype.writeInt32LE;
-SlowBuffer.prototype.writeInt32BE = Buffer.prototype.writeInt32BE;
-SlowBuffer.prototype.writeFloatLE = Buffer.prototype.writeFloatLE;
-SlowBuffer.prototype.writeFloatBE = Buffer.prototype.writeFloatBE;
-SlowBuffer.prototype.writeDoubleLE = Buffer.prototype.writeDoubleLE;
-SlowBuffer.prototype.writeDoubleBE = Buffer.prototype.writeDoubleBE;
projects / buffer.git / commitdiff