Read snarkjs proof file into Rust code

[ppoliani]

@ananas-block is there a simple example of how we can compare the proof.json created via snarkjs into the values required by this library.

More specifically, the circom tool set allows you to run snarkjs groth16 prove which creates a json for the proof. That file has the following fields

• pi_a: array with 3 bigInts (the third one is the number 1)
• pi_b: nested array of bigInts
• pi_c: array with 3 bigInts (the third one is the number 1)

Have tried multiple combinations but I can make the verifier verify successfully.

Let me share an example of such json file:

{
 "pi_a": [
  "7009850523380053417559359838274166345753459194827739539298258909727627620654",
  "8548305476914007287325069713428341320454044376283723944078898404773884726316",
  "1"
 ],
 "pi_b": [
  [
   "15892179406650945016703084011668441157894244396481426517502514759790693299090",
   "12656884454551498574200568284978773565242679009778067861652394211967848934857"
  ],
  [
   "7337817382302232780034223753908236778025711865739231129080101998424953224332",
   "9448638272149622936404627582112169394940750029902189763015703572300433784990"
  ],
  [
   "1",
   "0"
  ]
 ],
 "pi_c": [
  "2625468363450068209652280038415340055639418870448524270859981997692020323166",
  "1760889068094629347884977005056513991804173440921197754307899447129721200844",
  "1"
 ],
 "protocol": "groth16",
 "curve": "bn128"
}

Not sure how to convert those three values to value required by the Groth16Verifier

proof_a: &'a [u8; 64],
proof_b: &'a [u8; 128],
proof_c: &'a [u8; 64],

I've tried to follow the tests here

groth16-solana/src/groth16.rs

Line 350 in 8892dae

let proof_a: G1 = G1::deserialize_with_mode(

but to no avail. I literally used the exact same code.

The PROOF value here

groth16-solana/src/groth16.rs

Line 320 in 8892dae

pub const PROOF: [u8; 256] = [

is a byte array. So I believe if I can turn the above json into such a byte array then the verification should pass. But the question is how to do that in Rust?