Optimize string processing by caching strlen() results in loops

[Copilot]

37 loops across the codebase were calling strlen() in their condition on every iteration, resulting in O(n²) complexity for string traversal.

Changes

• cprintf.c (6 instances): Color parsing and formatted output
• k2v.c (29 instances): Key-value parsing, validation, and string manipulation
• mount.c (1 instance): Directory path creation
• ruri.c (1 instance): Argument parsing

Example

// Before: strlen() called n times = O(n²)
for (size_t i = 0; i < strlen(buf); i++) {
    process(buf[i]);
}

// After: strlen() called once = O(n)
size_t len = strlen(buf);
for (size_t i = 0; i < len; i++) {
    process(buf[i]);
}

For a 1000-character string, this reduces ~500K character comparisons to ~1K.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• esm.ubuntu.com
  • Triggering command: /usr/lib/apt/methods/https (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Identify and suggest improvements to slow or inefficient code

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