public class Utils {
public static int crc16(byte[] data, int offset, int length) {
if (data == null || offset < 0 || offset > data.length - 1 || offset + length > data.length) {
return 0;
}
int crc = 0xFFFF;
for (int i = 0; i < length; ++i) {
crc ^= data[offset + i] << 8;
for (int j = 0; j < 8; ++j) {
crc = (crc & 0x8000) > 0 ? (crc << 1) ^ 0x1021 : crc << 1;
}
}
return crc & 0xFFFF;
}
}
1 Like
What is to be achieved, what is the purpose of this code?
2 Likes
Topic closed in Kodular's community. Please ask only in one community
3 Likes
Crc16 ccitt false
1 Like
it's easier to use code writen in javascript.
Can you find other code in javascript?
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For Bitwise operarions, I can't suggest any Blocks.
But you may go to Niotron IDE and paste your java code there, compile the extension and import it in your project. Just a suggestion.
1.Save this code as crc16.html.
<script>
const crctab16 = new Uint16Array([
0x0000, 0xCC01, 0xD801, 0x1400, 0xF001, 0x3C00, 0x2800, 0xE401, 0xA001, 0x6C00, 0x7800, 0xB401, 0x5000, 0x9C01, 0x8801, 0x4400
]);
var crc16 = function (data) {
var res = 0xffff;
for (let b of data) {
res = crctab16[(b ^ res) & 15] ^ (res >> 4);
res = crctab16[((b >> 4) ^ res) & 15] ^ (res >> 4);
}
window.AppInventor.setWebViewString ((res) & 0xffff);
};
</script>
- upload it to assets
- make blocks like this:
1 Like
If you still want just blocks, see
I think this code is different because the result I expected was different, I have a code of the same crc16 in javascript can you teach me how to do the same as you did in this one?
function crc16(data, offset, length) {
if (data == null || offset < 0 || offset > data.length - 1 || offset + length > data.length) {
return 0;
}
crc = 0xFFFF;
for (i = 0; i < length; ++i) {
crc ^= data[offset + i] << 8;
for (j = 0; j < 8; ++j) {
crc = (crc & 0x8000) > 0 ? (crc << 1) ^ 0x1021 : crc << 1;
}
}
return crc & 0xFFFF;
}
function crc16(data, offset, length) {
if (data == null || offset < 0 || offset > data.length - 1 || offset + length > data.length) {
return 0;
}
crc = 0xFFFF;
for (i = 0; i < length; ++i) {
crc ^= data[offset + i] << 8;
for (j = 0; j < 8; ++j) {
crc = (crc & 0x8000) > 0 ? (crc << 1) ^ 0x1021 : crc << 1;
}
}
return crc & 0xFFFF;
}
Show us an example of input and output, for example
crc(123,0,2) return --> 15802
https://gist.github.com/tijnkooijmans/10981093
@SimpleFunction(description = "crc16")
public int crc16(String date, int offset, int length) {
byte[] data = date.getBytes();
if (data == null || offset < 0 || offset > data.length - 1 || offset + length > data.length) {
return 0;
}
int crc = 0xFFFF;
for (int i = 0; i < length; ++i) {
crc ^= data[offset + i] << 8;
for (int j = 0; j < 8; ++j) {
crc = (crc & 0x8000) > 0 ? (crc << 1) ^ 0x1021 : crc << 1;
}
}
return crc & 0xFFFF;
}
I don't understand how the code works what I know is that I have to calculate the crc 16 cciitt false from a text I have, I don't understand how to provide the input data like your example there
What result did you expect?
What information did you enter?
just the text of the text box, what I want to calculate the crc (using his example I used the same blocks and put the text and nothing else)
I want to calculate the crc of this text (00020126360014BR.GOV.BCB.PIX0114+55649995929035204000053039865802BR5917Leide dayane lima6007Acreuna62070503***6304) and I know the result is (2418) in hexadecimal
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thank you very much, that's exactly what I wanted, thank you very much♥️
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DO YOUR homework.... if not, You're going to fail.... must do BY YOURSELF, try first, then ask for help
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