/* AILang Str runtime primitives.
 *
 * Provides ABI-stable string operations against the existing
 * constant-Str layout (NUL-terminated byte buffer, passed as
 * `ptr` in LLVM IR). Lives separately from runtime/rc.c so that
 * a future heap-Str ABI milestone can swap the implementations
 * without touching the RC runtime.
 *
 * Linked unconditionally by `ail build` (Gc, Bump, Rc) so that
 * any program that monomorphises `eq__Str` (auto-loaded from
 * the prelude) finds the symbol. Programs that never call
 * `eq` on Str leave @ail_str_eq as a dead-stripped no-op at
 * link time under clang -O2.
 */

#include <stdbool.h>
#include <string.h>

/* Byte-equality on NUL-terminated strings. Mirrors strcmp(...) == 0
 * but exposed under a stable AILang-namespaced ABI so the codegen
 * caller does not assume libc's strcmp shape. Heap-Str ABI milestone
 * will replace the body with length-prefixed comparison without
 * changing the signature. */
bool ail_str_eq(const char *a, const char *b) {
    return strcmp(a, b) == 0;
}

/* Three-way comparison of NUL-terminated strings. Normalises libc
 * strcmp's signed-int output to exactly -1 / 0 / +1 so the codegen
 * caller can branch on `icmp slt i32 result, 0` and
 * `icmp eq i32 result, 0` against constants directly without
 * worrying about strcmp implementations that return values outside
 * {-1, 0, +1}. Heap-Str ABI milestone will replace the body with
 * length-prefixed comparison without changing the signature. */
int ail_str_compare(const char *a, const char *b) {
    int r = strcmp(a, b);
    if (r < 0) return -1;
    if (r > 0) return 1;
    return 0;
}