String Operations

native.memory provides a set of tools to handle strings in Native memory, covering C-style strings and length-prefixed strings.

C-style String (\0 terminated)

Read (read_cstr)

native.memory.read_cstr(addr, [max_len]) -> string | nil
native.memory.read_cstr_utf8(addr, [max_len]) -> string | nil

• Difference: read_cstr reads raw bytes, read_cstr_utf8 attempts UTF-8 decoding.
• max_len: Optional, maximum read length (overflow protection), default 512.
• Returns: Lua string, truncated at \0.

Write (write_cstr)

native.memory.write_cstr(addr, str) -> boolean
native.memory.write_cstr_utf8(addr, str) -> boolean

• Automatically appends \0 at the end of the string.

Example:

local buf = native.memory.alloc(64)
native.memory.write_cstr_utf8(buf, "Hello, LuaHook")
local txt = native.memory.read_cstr_utf8(buf)
log(txt) -- "Hello, LuaHook"
native.memory.free(buf)

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Length-Prefixed String (Len-Prefixed)

Handles custom string formats where the first byte is the length.

Read (read_lp_utf8)

native.memory.read_lp_utf8(addr, [max_len]) -> string | nil

• Format: [Length (1 byte)] [Body ...]
• Reads the first byte len, then reads the subsequent len bytes and converts to UTF-8.

Write (write_lp_utf8)

native.memory.write_lp_utf8(addr, str, [max_len]) -> boolean

• Writes the length byte, followed by the content.

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Auto Detection (read_auto_utf8)

native.memory.read_auto_utf8(addr, [max_len]) -> string | nil

Logic:

1. Check if the first byte is in the range [1..0x7F].
2. check if the memory content of that length matches UTF-8 printable character characteristics.
3. If it matches, parse as length-prefixed; otherwise, fallback to read_cstr mode.