Show amount but the hex string in rawTx is not amount, but has been converted to another hex

[Sotatek-ToanTran]

Show amount but the hex string in rawTx is not amount, but has been converted to another hex

• Description
  We understand that "amount hex" feeds into singing tools and uses the showAmount() function to display the amount on the card.
  But in Solana, Solana's hex amount has been modified by some function, so when displayed it will no longer be correct.

Example:

# Sol transfer value encoding
  - input = 0.1
  - ouput = 00e1f50500000000

## Breakdown
  - programIdIndex = 02000000
  - low32 = 00e1f505 // store needed value
  - high32 = 00000000 // store needed value

## Value encode breakdown:
  - input : 0.1
  - execute : 
    => const v2e32 = 2^32
    => value = input * LAMPORTS_PER_SOL // 0.1 * 10^9
    => high32 = Math.floor(value / v2e32) // 100000000 / 2^32 = 0
    => low32 = value - (hi32 * v2e32); // 100000000 - (0 * 2^32) = 100000000

    // allocate data buffer
    => data = Buffer.alloc(8)

    // first 4 byte store programId, but let's not discuss it here
    // value start from offset 4 of data
    => data.writeUInt32LE(lo32, 4) // 0, 225, 245, 5,
    => data.writeInt32LE(hi32, 4+4) //  0, 0, 0, 0

    // data = [0, 225, 245, 5, 0, 0, 0, 0]

    => return data.toString('hex') // 00e1f50500000000
  - output : 00e1f50500000000

## Value decode breakdown:
  - input : 00e1f50500000000
  - execute :
    => const  v2e32 = 2^32
    => inputToBuffer = [ 0, 225, 245, 5, 0, 0, 0, 0]
    => low32 =  inputToBuffer.readUInt32LE(4) // 100000000
    => high32 =  inputToBuffer.readInt32LE(4 + 4) // 0
    => result = hi32 * v2e32 + lo32 // 0 * 2^32 + 100000000
  - output : 100000000 // 0.1 * 10^9

## Expect behavior:
  - input : 00e1f50500000000
  - execute : 
    => inputToBuffer = [0, 225, 245, 5, 0, 0, 0, 0]
    => low32Buffer = [0, 225, 245, 5]
    => high32Buffer = [0, 0, 0, 0]
    => amount = hiBufferRead * 2^32 + loBufferRead // 100000000
    => amountToHex = 05f5e100
  - output : 05f5e100 // showAmount( amountToHex , 9 )

• Expected Behavior
  Can we use some function inside signin tools to do this below transformation? We need to change the tag to display the correct amount?

## Expect behavior:
  - input : 00e1f50500000000
  - execute : 
    => inputToBuffer = [0, 225, 245, 5, 0, 0, 0, 0]
    => low32Buffer = [0, 225, 245, 5]
    => high32Buffer = [0, 0, 0, 0]
    => amount = hiBufferRead * 2^32 + loBufferRead // 100000000
    => amountToHex = 05f5e100
  - output : 05f5e100 // showAmount( amountToHex , 9 )

• Screenshots or appendix
  No screenshots.

[hank121314]

There is no any encoding method in these codes.
[0, 225, 245, 5, 0, 0, 0, 0] is only a BigInt bytes in little-endian.

const buffer = Buffer.from("00e1f50500000000", "hex");
const lamports = buffer.readBigUInt64LE(0);
console.log(lamports); // 100000000n

[Sotatek-ToanTran]

@hank121314
We understand that it is possible to convert this way. Our problem is how to implement it in singing tools? we need to calculate to get buffer.readBigUInt64LE(0) in signing tools. Since the data "amount in rawTx is not decoding, will the tag be displayed incorrectly if included?

[hank121314]

.baseConvert(data, Buffer.CACHE1, 8, ScriptAssembler.binaryCharset, ScriptAssembler.inLittleEndian). 
.showAmount(ScriptData.getDataBufferAll(Buffer.CACHE1), 9). 
.clearBuffer(Buffer.CACHE1)

The data should be 00e1f50500000000.

[Sotatek-ToanTran]

yes sir, you save our life, let me try it