import { observeElfStringTableEntry } from "../../domain/elfStringTable.js";
import {
  BinaryFormatFailure,
  BinaryStringReadLimitFailure,
} from "./BinaryContainer.js";

export const readElfString = (bytes: Buffer, offset: number): string => {
  return readElfStringBytes(bytes, offset).toString("latin1");
};

/** Read exact string-table bytes; ELF does not prescribe a character encoding. */
export const readElfStringBytes = (bytes: Buffer, offset: number): Buffer => {
  const observed = observeElfStringTableEntry(bytes, offset, 65536);
  if (observed.state === "outside")
    throw new BinaryFormatFailure(
      "malformed",
      "ELF string offset is outside its string table",
    );
  if (observed.state === "truncated") {
    if (offset + observed.examinedBytes < bytes.length)
      throw new BinaryStringReadLimitFailure(observed.examinedBytes);
    throw new BinaryFormatFailure(
      "malformed",
      "ELF string is unterminated inside its string table",
    );
  }
  return observed.bytes;
};