Add reading/writing of floats and doubles from/to buffers

Code for readIEEE754/writeIEEE754 is from jspack: http://code.google.com/p/jspack/

1 files changed, 95 insertions, 0 deletions

diff --git a/lib/buffer.js b/lib/buffer.js
index 5df6f915f..b47dd715a 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -20,6 +20,7 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 var SlowBuffer = process.binding('buffer').SlowBuffer;
+var IEEE754 = require('buffer_ieee754');
 var assert = require('assert');
 
 
@@ -684,6 +685,43 @@ Buffer.prototype.readInt32 = function(offset, endian) {
 };
 
 
+Buffer.prototype.readFloat = function(offset, endian) {
+  var buffer = this;
+
+  assert.ok(endian !== undefined && endian !== null,
+    'missing endian');
+
+  assert.ok(endian == 'big' || endian == 'little',
+    'bad endian value');
+
+  assert.ok(offset !== undefined && offset !== null,
+    'missing offset');
+
+  assert.ok(offset + 3 < buffer.length,
+    'Trying to read beyond buffer length');
+
+  return IEEE754.readIEEE754(buffer, offset, endian, 23, 4);
+};
+
+Buffer.prototype.readDouble = function(offset, endian) {
+  var buffer = this;
+
+  assert.ok(endian !== undefined && endian !== null,
+    'missing endian');
+
+  assert.ok(endian == 'big' || endian == 'little',
+    'bad endian value');
+
+  assert.ok(offset !== undefined && offset !== null,
+    'missing offset');
+
+  assert.ok(offset + 7 < buffer.length,
+    'Trying to read beyond buffer length');
+
+  return IEEE754.readIEEE754(buffer, offset, endian, 52, 8);
+};
+
+
 /*
  * 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
@@ -843,6 +881,17 @@ function verifsint(value, max, min) {
   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, endian) {
   var buffer = this;
 
@@ -924,3 +973,49 @@ Buffer.prototype.writeInt32 = function(value, offset, endian) {
     buffer.writeUInt32(0xffffffff + value + 1, offset, endian);
   }
 };
+
+
+Buffer.prototype.writeFloat = function(value, offset, endian) {
+  var buffer = this;
+
+  assert.ok(value !== undefined && value !== null,
+    'missing value');
+
+  assert.ok(endian !== undefined && endian !== null,
+    'missing endian');
+
+  assert.ok(endian == 'big' || endian == 'little',
+    'bad endian value');
+
+  assert.ok(offset !== undefined && offset !== null,
+    'missing offset');
+
+  assert.ok(offset + 3 < buffer.length,
+    'Trying to read beyond buffer length');
+
+  verifIEEE754(value, 3.4028234663852886e+38, -3.4028234663852886e+38);
+  IEEE754.writeIEEE754(buffer, value, offset, endian, 23, 4);
+};
+
+
+Buffer.prototype.writeDouble = function(value, offset, endian) {
+  var buffer = this;
+
+  assert.ok(value !== undefined && value !== null,
+    'missing value');
+
+  assert.ok(endian !== undefined && endian !== null,
+    'missing endian');
+
+  assert.ok(endian == 'big' || endian == 'little',
+    'bad endian value');
+
+  assert.ok(offset !== undefined && offset !== null,
+    'missing offset');
+
+  assert.ok(offset + 7 < buffer.length,
+    'Trying to read beyond buffer length');
+
+  verifIEEE754(value, 1.7976931348623157E+308, -1.7976931348623157E+308);
+  IEEE754.writeIEEE754(buffer, value, offset, endian, 52, 8);
+};