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Simplify TrustyHashLite by using byte-sized chunks 

Original used 4-byte chunks (Uint32). This change simplifies the
iteration and padding logic, at the expense of speed.

The full TrustyHash still uses 4-byte chunks for best speed.
This commit is contained in:
Steffen Prince 2016-06-17 00:10:20 -05:00
parent 11fa86cadc
commit 1dc37a0e77
2 changed files with 13 additions and 13 deletions
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20
README.md
View File

@ -111,9 +111,9 @@ crypto.subtle.digest("SHA-256", this.result)
.then(function(buffer) {
var hexCodes = []
var view = new DataView(buffer)
for (var i = 0; i < view.byteLength; i += 4) {
var stringValue = view.getUint32(i).toString(16)
var paddedValue = ('00000000' + stringValue).slice(-8)
for (var i = 0; i < view.byteLength; i += 1) {
var stringValue = view.getUint8(i).toString(16)
var paddedValue = ('0' + stringValue).slice(-2)
hexCodes.push(paddedValue)}
alert(hexCodes.join(""))})}}
document.body.appendChild(fileinput)
@ -192,24 +192,24 @@ var view = new DataView(buffer)
We create a view so we can read the buffer in chunks.
```
for (var i = 0; i < view.byteLength; i += 4) {
for (var i = 0; i < view.byteLength; i += 1) {
```
With each chunk...
With each byte-size chunk...
```
var stringValue = view.getUint32(i).toString(16)
var stringValue = view.getUint8(i).toString(16)
```
...convert each chunk to a number and get a string, which is just something we
can print.
can print. The string will be one or two hex digits.
```
var paddedValue = ('00000000' + stringValue).slice(-8)
var paddedValue = ('0' + stringValue).slice(-2)
```
To correctly print the string as a hex code, we need to add zeroes to the front
in case the number is less than 8 digits.
To correctly print the string as a hex code, we need to add a zero to the front
in case the number is less than two hex digits, keeping the last two digits.
```
hexCodes.push(paddedValue)}

6
TrustyHashLite.html
View File

@ -11,9 +11,9 @@ crypto.subtle.digest("SHA-256", this.result)
.then(function(buffer) {
var hexCodes = []
var view = new DataView(buffer)
for (var i = 0; i < view.byteLength; i += 4) {
var stringValue = view.getUint32(i).toString(16)
var paddedValue = ('00000000' + stringValue).slice(-8)
for (var i = 0; i < view.byteLength; i += 1) {
var stringValue = view.getUint8(i).toString(16)
var paddedValue = ('0' + stringValue).slice(-2)
hexCodes.push(paddedValue)}
alert(hexCodes.join(""))})}}
</script>