Hojun-Cho
1e2f55aed8
Replaces the -1 sentinel return on indexbyte/byteindex/rbyteindex/ index with Hare's optional-shaped tagged union. Callers `match` on the result and bind the index from the i32 variant. Two cgen fixes were needed first: 1. resolve_type for N_TTAGGED rounded value payload up to an 8-byte multiple. (i32 | void) was sized 12 — tag (8) + payload (4) — which made the reg-passing ABI compute size/8 = 1 word and drop the value word. 2. The call-arg push path special-cased struct and slice args but not tagged-return calls. A nested `f(g())` where g returns a tagged union pushed only AX (tag); the matching pop loaded a stale DX/SI for the value. Now pushes AX/DX[/CX] in order so the pop side drains tag → arg-reg[0], value(s) → arg-reg[1..]. strings.contains rewritten to match on the new tagged result. No other callers existed in lib/ — bufio/io still use their own shapes.
109 lines
2.7 KiB
Plaintext
109 lines
2.7 KiB
Plaintext
// strings — operations over the immutable str type ({ *u8, len }).
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// Mirrors Hare's strings::; `len` and `is-empty` aren't functions
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// (callers use `s.len` and `s.len == 0` directly).
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use os;
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// compare — bytewise three-way comparison: negative if a<b, 0 if equal,
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// positive if a>b. Matches Hare's strings::compare. ASCII-order, not
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// locale-aware. Callers that just need equality use `compare(a, b) == 0`.
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export fn compare(a: str, b: str) i32 = {
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let n: i32 = a.len;
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if (b.len < n) { n = b.len; };
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let i: i32 = 0;
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for (i < n) {
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if (a[i] != b[i]) { return (a[i]: i32) - (b[i]: i32); };
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i += 1;
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};
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return a.len - b.len;
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};
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export fn hasprefix(s: str, p: str) bool = {
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if (p.len > s.len) { return false; };
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let i: i32 = 0;
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for (i < p.len) {
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if (s[i] != p[i]) { return false; };
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i += 1;
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};
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return true;
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};
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export fn hassuffix(s: str, suf: str) bool = {
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if (suf.len > s.len) { return false; };
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let off: i32 = s.len - suf.len;
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let i: i32 = 0;
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for (i < suf.len) {
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if (s[off + i] != suf[i]) { return false; };
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i += 1;
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};
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return true;
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};
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// byteindex — first index of byte `c` in `s`. Hare-shaped optional:
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// (i32 | void). void variant indicates "not found".
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export fn byteindex(s: str, c: u8) (i32 | void) = {
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let i: i32 = 0;
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for (i < s.len) {
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if (s[i] == c) { return i; };
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i += 1;
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};
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return;
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};
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// rbyteindex — last index of byte `c` in `s`. Mirrors Hare's
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// strings::rbyteindex.
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export fn rbyteindex(s: str, c: u8) (i32 | void) = {
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let i: i32 = s.len - 1;
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for (i >= 0) {
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if (s[i] == c) { return i; };
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i -= 1;
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};
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return;
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};
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// index — first index of `sub` in `s`. Naive scan; fine for short
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// patterns and small strings, which dominate config and CLI parsing.
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// Empty `sub` matches at 0.
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export fn index(s: str, sub: str) (i32 | void) = {
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if (sub.len == 0) { return 0; };
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if (sub.len > s.len) { return; };
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let last: i32 = s.len - sub.len;
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let i: i32 = 0;
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for (i <= last) {
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let j: i32 = 0;
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let ok: bool = true;
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for (j < sub.len) {
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if (s[i + j] != sub[j]) { ok = false; j = sub.len; }
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else { j += 1; };
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};
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if (ok) { return i; };
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i += 1;
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};
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return;
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};
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export fn contains(s: str, sub: str) bool = {
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let r: (i32 | void) = index(s, sub);
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match (r) {
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case let i: i32 => return true;
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case void => return false;
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};
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return false;
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};
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// concat — joins two strings into a fresh str. Caller owns the
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// returned str's storage; release via `os.free(r.ptr, r.len)`. Mirrors
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// Hare's strings::concat shape.
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export fn concat(a: str, b: str) str = {
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let total: i32 = a.len + b.len;
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let buf: *u8 = os.alloc(total: u64): *u8;
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let i: i32 = 0;
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for (i < a.len) { buf[i] = a[i]; i += 1; };
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let j: i32 = 0;
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for (j < b.len) { buf[a.len + j] = b[j]; j += 1; };
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let r: str;
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r.ptr = buf;
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r.len = total;
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return r;
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};
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