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Use read_unaligned when reading u64 #257

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Use read_unaligned when reading u64 #257

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14 changes: 7 additions & 7 deletions src/app/content/courses/pinocchio-for-dummies/middleware-entrypoint/en.mdx
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Original file line number Diff line number Diff line change
Expand Up @@ -124,9 +124,9 @@ Always verify that account offsets and lengths match expectations. Use [sbpf.xyz

```rust
if *input == 4
&& (*input.add(ACCOUNT1_DATA_LEN).cast::<u64>() == 165)
&& (*input.add(ACCOUNT2_DATA_LEN).cast::<u64>() == 82)
&& (*input.add(IX12_ACCOUNT3_DATA_LEN).cast::<u64>() == 165)
&& (input.add(ACCOUNT1_DATA_LEN).cast::<u64>().read_unaligned() == 165)
&& (input.add(ACCOUNT2_DATA_LEN).cast::<u64>().read_unaligned() == 82)
&& (input.add(IX12_ACCOUNT3_DATA_LEN).cast::<u64>().read_unaligned() == 165)
{
//...
}
Expand All @@ -145,16 +145,16 @@ fn align(input: u64) -> u64 {

// The `authority` account can have variable data length.
let account_4_data_len_aligned =
align(*input.add(IX12_ACCOUNT4_DATA_LEN).cast::<u64>()) as usize;
align(input.add(IX12_ACCOUNT4_DATA_LEN).cast::<u64>().read_unaligned()) as usize;
let offset = IX12_EXPECTED_INSTRUCTION_DATA_LEN_OFFSET + account_4_data_len_aligned;
```

Once validation passes, extract instruction data, transmute accounts, and process normally:

```rust
// Check that we have enough instruction data.
if input.add(offset).cast::<usize>().read() >= INSTRUCTION_DATA_SIZE {
let discriminator = input.add(offset + size_of::<u64>()).cast::<u8>().read();
if unsafe { input.add(offset).cast::<usize>().read_unaligned() } >= INSTRUCTION_DATA_SIZE {
let discriminator = unsafe { input.add(offset + size_of::<u64>()).cast::<u8>().read() };

// Check for instruction discriminator.
if likely(discriminator == 12) {
Expand All @@ -179,4 +179,4 @@ if input.add(offset).cast::<usize>().read() >= INSTRUCTION_DATA_SIZE {
};
}
}
```
```