[PERF] Implement Gas-Efficient Byte Array Concatenator in Yul

[mijinummi]

Labels: medium-difficulty, yul, memory, gasguard
Difficulty: Medium
Module: contracts/utils/

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🧠 Concept

Build an assembly helper function bytesConcat(bytes calldata a, bytes calldata b) that constructs concatenated byte arrays directly in contiguous free memory.

⚠️ Problem

Solidity's native bytes.concat() allocates temporary intermediate memory buffers and executes repetitive loop boundaries for each byte segment.

📁 Implementation Scope

• contracts/utils/YulBytesUtils.sol
• test/utils/YulBytesUtils.test.ts

🛠️ Requirements

1. Read free memory pointer at 0x40.
2. Copy memory chunks using 32-byte word loops (calldatacopy / mcopy where available).
3. Update free memory pointer precisely without allocating unused padding space.

🎯 Acceptance Criteria

• Reduces gas usage when joining dynamic payload segments.
• Outputs accurately concatenated byte arrays in unit tests.

[Kaizer4show]

@Kaizer4show has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi maintainer, I would like to work on this issue please

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[tecmalik]

@tecmalik has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

please assign this to me i would love to work on the issue

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[suleimanjem-hash]

@suleimanjem-hash has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello Maintained

Can I work on this

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[drips-wave]

Congratulations, @suleimanjem-hash! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

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[Caneryy]

@Caneryy has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi there, can I work on this issue?

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