lib/strings+test: port lpad/rpad from Hare

This commit is contained in:
2026-05-19 16:01:25 +09:00
parent 3176d83d37
commit e5c1d6baa4
5 changed files with 364 additions and 0 deletions

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@@ -724,3 +724,66 @@ export fn rsplitn(in: str, delim: str, n: i32) []str = {
export fn split(in: str, delim: str) []str = {
return splitn(in, delim, types.I32_MAX);
};
// lpad — left-pad `s` with `p` rune until the result reaches `maxlen`
// bytes. Length comparison is BYTES, mirroring Hare's `len(s) >= maxlen`
// at ref/hare/strings/pad.ha:9. A multibyte `p` whose encoded width
// doesn't divide `maxlen - s.len` evenly leaves a trailing pad byte
// pair sliced mid-codepoint at byte `maxlen-1`, exactly as Hare's
// `res[..maxlen]` does (ref/hare/strings/pad.ha:20). When
// `(maxlen - s.len) * pad.len >= maxlen` (multibyte pad overflows the
// budget), `s` is entirely sliced off — same as Hare. Caller releases
// with `os.free(r.ptr, r.len: u64)`. Hare's `nomem` return is dropped:
// `os.alloc` aborts on OOM. Buf size == r.len keeps the free-contract
// shape of [[dup]] / [[concat]] / [[join]]; Hare's `alloc([], maxlen)!`
// over-allocs via append then slices, but Hare's slice-free recovers
// the true capacity from the heap allocator (rt/ensure.ha:24), which
// ww's munmap-based `os.free` cannot do.
export fn lpad(s: str, p: rune, maxlen: i32) str = {
if (s.len >= maxlen) { return dup(s); };
let scratch: [4]u8;
let pad: []u8 = runebytes(scratch[0:4], p);
let buf: *u8 = os.alloc(maxlen: u64): *u8;
let padwrite: i32 = (maxlen - s.len) * pad.len;
if (padwrite > maxlen) { padwrite = maxlen; };
let off: i32 = 0;
for (off < padwrite) {
buf[off] = pad.ptr[off % pad.len];
off += 1;
};
let k: i32 = 0;
let srem: i32 = maxlen - off;
if (srem > s.len) { srem = s.len; };
for (k < srem) {
buf[off + k] = s[k];
k += 1;
};
let r: str;
r.ptr = buf;
r.len = maxlen;
return r;
};
// rpad — right-pad `s` with `p` rune until the result reaches `maxlen`
// bytes. Symmetric with [[lpad]]. ref/hare/strings/pad.ha:39.
export fn rpad(s: str, p: rune, maxlen: i32) str = {
if (s.len >= maxlen) { return dup(s); };
let scratch: [4]u8;
let pad: []u8 = runebytes(scratch[0:4], p);
let buf: *u8 = os.alloc(maxlen: u64): *u8;
let k: i32 = 0;
for (k < s.len) {
buf[k] = s[k];
k += 1;
};
let padwrite: i32 = maxlen - s.len;
let i: i32 = 0;
for (i < padwrite) {
buf[s.len + i] = pad.ptr[i % pad.len];
i += 1;
};
let r: str;
r.ptr = buf;
r.len = maxlen;
return r;
};

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@@ -1204,6 +1204,116 @@ fn expect_str(toks: []str, i: i32, want: str) void = {
os.free(t3.ptr: *void, (t3.cap: u64) * 16u64);
};
// ---- lpad / rpad -----------------------------------------------------
// ref/hare/strings/pad.ha:23 (@test fn lpad), :54 (@test fn rpad). Hare's
// row triple (s<maxlen, s==maxlen, s=="" empty) is mirrored; ww extras
// pin s>maxlen (early return path), multibyte s with byte-length
// counting, and multibyte pad rune (encoded width >1 byte). The
// multibyte-pad rows pin Hare's `[..maxlen]` slice contract — a
// multibyte trailing pad may be truncated mid-codepoint, exactly as
// Hare does.
@test fn lpad_cases() void = {
// Hare row 1: shorter s, ASCII pad.
signalled = 1770;
let r1: str = strings.lpad("2", '0', 5);
if (!streq(r1, "00002")) { fail(); };
if (r1.len != 5) { fail(); };
os.free(r1.ptr: *void, r1.len: u64);
// Hare row 2: s.len == maxlen — early dup path.
signalled = 1771;
let r2: str = strings.lpad("12345", '0', 5);
if (!streq(r2, "12345")) { fail(); };
if (r2.len != 5) { fail(); };
os.free(r2.ptr: *void, r2.len: u64);
// Hare row 3: empty s, full-width pad.
signalled = 1772;
let r3: str = strings.lpad("", '0', 5);
if (!streq(r3, "00000")) { fail(); };
if (r3.len != 5) { fail(); };
os.free(r3.ptr: *void, r3.len: u64);
// ww row 1: s.len > maxlen — early dup path returns input copy.
signalled = 1773;
let r4: str = strings.lpad("abcdef", '_', 3);
if (!streq(r4, "abcdef")) { fail(); };
if (r4.len != 6) { fail(); };
os.free(r4.ptr: *void, r4.len: u64);
// ww row 2: multibyte s — byte-length contract (Hare `len(s)`).
// "café" is 5 bytes; maxlen 7 → 2 pad bytes prepended.
signalled = 1774;
let r5: str = strings.lpad("café", '_', 7);
if (!streq(r5, "__café")) { fail(); };
if (r5.len != 7) { fail(); };
os.free(r5.ptr: *void, r5.len: u64);
// ww row 3: multibyte pad rune. 'α' U+03B1 is 2 bytes (0xCE 0xB1).
// s="x" (1 byte), maxlen=5 → npads = 5 - 1 = 4, pad_bytes=2,
// total writes = 4*2 + 1 = 9 bytes; result `[..5]` = "αα" (4 bytes)
// + 0xCE (truncated leading byte of next α) — exactly Hare's slice.
signalled = 1775;
let r6: str = strings.lpad("x", 0x03B1u32: rune, 5);
if (r6.len != 5) { fail(); };
if (r6.ptr[0] != 0xCEu8) { fail(); }; // α byte 0
if (r6.ptr[1] != 0xB1u8) { fail(); }; // α byte 1
if (r6.ptr[2] != 0xCEu8) { fail(); }; // α byte 0
if (r6.ptr[3] != 0xB1u8) { fail(); }; // α byte 1
if (r6.ptr[4] != 0xCEu8) { fail(); }; // truncated α byte 0
os.free(r6.ptr: *void, r6.len: u64);
};
@test fn rpad_cases() void = {
// Hare row 1: shorter s, ASCII pad.
signalled = 1780;
let r1: str = strings.rpad("2", '0', 5);
if (!streq(r1, "20000")) { fail(); };
if (r1.len != 5) { fail(); };
os.free(r1.ptr: *void, r1.len: u64);
// Hare row 2: s.len == maxlen — early dup path.
signalled = 1781;
let r2: str = strings.rpad("12345", '0', 5);
if (!streq(r2, "12345")) { fail(); };
if (r2.len != 5) { fail(); };
os.free(r2.ptr: *void, r2.len: u64);
// Hare row 3: empty s.
signalled = 1782;
let r3: str = strings.rpad("", '0', 5);
if (!streq(r3, "00000")) { fail(); };
if (r3.len != 5) { fail(); };
os.free(r3.ptr: *void, r3.len: u64);
// ww row 1: s.len > maxlen — early dup path.
signalled = 1783;
let r4: str = strings.rpad("abcdef", '_', 3);
if (!streq(r4, "abcdef")) { fail(); };
if (r4.len != 6) { fail(); };
os.free(r4.ptr: *void, r4.len: u64);
// ww row 2: multibyte s — byte-length contract.
signalled = 1784;
let r5: str = strings.rpad("café", '_', 7);
if (!streq(r5, "café__")) { fail(); };
if (r5.len != 7) { fail(); };
os.free(r5.ptr: *void, r5.len: u64);
// ww row 3: multibyte pad rune (2-byte 'α'). s="x" (1 byte),
// maxlen=5 → "xαα" appended is 1 + 4 = 5 bytes (no truncation).
signalled = 1785;
let r6: str = strings.rpad("x", 0x03B1u32: rune, 5);
if (r6.len != 5) { fail(); };
if (r6.ptr[0] != 'x') { fail(); };
if (r6.ptr[1] != 0xCEu8) { fail(); }; // α byte 0
if (r6.ptr[2] != 0xB1u8) { fail(); }; // α byte 1
if (r6.ptr[3] != 0xCEu8) { fail(); }; // α byte 0
if (r6.ptr[4] != 0xB1u8) { fail(); }; // α byte 1
os.free(r6.ptr: *void, r6.len: u64);
};
export fn main() i32 = {
signalled = 1; dup_cases();
signalled = 2; concat_cases();
@@ -1242,5 +1352,7 @@ export fn main() i32 = {
signalled = 35; splitn_cases();
signalled = 36; rsplitn_cases();
signalled = 37; split_cases();
signalled = 38; lpad_cases();
signalled = 39; rpad_cases();
return 0;
};

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@@ -2522,6 +2522,69 @@ export fn split(in: str, delim: str) []str = {
return splitn(in, delim, types.I32_MAX);
};
// lpad — left-pad `s` with `p` rune until the result reaches `maxlen`
// bytes. Length comparison is BYTES, mirroring Hare's `len(s) >= maxlen`
// at ref/hare/strings/pad.ha:9. A multibyte `p` whose encoded width
// doesn't divide `maxlen - s.len` evenly leaves a trailing pad byte
// pair sliced mid-codepoint at byte `maxlen-1`, exactly as Hare's
// `res[..maxlen]` does (ref/hare/strings/pad.ha:20). When
// `(maxlen - s.len) * pad.len >= maxlen` (multibyte pad overflows the
// budget), `s` is entirely sliced off — same as Hare. Caller releases
// with `os.free(r.ptr, r.len: u64)`. Hare's `nomem` return is dropped:
// `os.alloc` aborts on OOM. Buf size == r.len keeps the free-contract
// shape of [[dup]] / [[concat]] / [[join]]; Hare's `alloc([], maxlen)!`
// over-allocs via append then slices, but Hare's slice-free recovers
// the true capacity from the heap allocator (rt/ensure.ha:24), which
// ww's munmap-based `os.free` cannot do.
export fn lpad(s: str, p: rune, maxlen: i32) str = {
if (s.len >= maxlen) { return dup(s); };
let scratch: [4]u8;
let pad: []u8 = runebytes(scratch[0:4], p);
let buf: *u8 = os.alloc(maxlen: u64): *u8;
let padwrite: i32 = (maxlen - s.len) * pad.len;
if (padwrite > maxlen) { padwrite = maxlen; };
let off: i32 = 0;
for (off < padwrite) {
buf[off] = pad.ptr[off % pad.len];
off += 1;
};
let k: i32 = 0;
let srem: i32 = maxlen - off;
if (srem > s.len) { srem = s.len; };
for (k < srem) {
buf[off + k] = s[k];
k += 1;
};
let r: str;
r.ptr = buf;
r.len = maxlen;
return r;
};
// rpad — right-pad `s` with `p` rune until the result reaches `maxlen`
// bytes. Symmetric with [[lpad]]. ref/hare/strings/pad.ha:39.
export fn rpad(s: str, p: rune, maxlen: i32) str = {
if (s.len >= maxlen) { return dup(s); };
let scratch: [4]u8;
let pad: []u8 = runebytes(scratch[0:4], p);
let buf: *u8 = os.alloc(maxlen: u64): *u8;
let k: i32 = 0;
for (k < s.len) {
buf[k] = s[k];
k += 1;
};
let padwrite: i32 = maxlen - s.len;
let i: i32 = 0;
for (i < padwrite) {
buf[s.len + i] = pad.ptr[i % pad.len];
i += 1;
};
let r: str;
r.ptr = buf;
r.len = maxlen;
return r;
};
// strconv — number↔string conversions.
//
// Mirrors Hare's strconv:: surface. The *tos functions return a

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@@ -2522,6 +2522,69 @@ export fn split(in: str, delim: str) []str = {
return splitn(in, delim, types.I32_MAX);
};
// lpad — left-pad `s` with `p` rune until the result reaches `maxlen`
// bytes. Length comparison is BYTES, mirroring Hare's `len(s) >= maxlen`
// at ref/hare/strings/pad.ha:9. A multibyte `p` whose encoded width
// doesn't divide `maxlen - s.len` evenly leaves a trailing pad byte
// pair sliced mid-codepoint at byte `maxlen-1`, exactly as Hare's
// `res[..maxlen]` does (ref/hare/strings/pad.ha:20). When
// `(maxlen - s.len) * pad.len >= maxlen` (multibyte pad overflows the
// budget), `s` is entirely sliced off — same as Hare. Caller releases
// with `os.free(r.ptr, r.len: u64)`. Hare's `nomem` return is dropped:
// `os.alloc` aborts on OOM. Buf size == r.len keeps the free-contract
// shape of [[dup]] / [[concat]] / [[join]]; Hare's `alloc([], maxlen)!`
// over-allocs via append then slices, but Hare's slice-free recovers
// the true capacity from the heap allocator (rt/ensure.ha:24), which
// ww's munmap-based `os.free` cannot do.
export fn lpad(s: str, p: rune, maxlen: i32) str = {
if (s.len >= maxlen) { return dup(s); };
let scratch: [4]u8;
let pad: []u8 = runebytes(scratch[0:4], p);
let buf: *u8 = os.alloc(maxlen: u64): *u8;
let padwrite: i32 = (maxlen - s.len) * pad.len;
if (padwrite > maxlen) { padwrite = maxlen; };
let off: i32 = 0;
for (off < padwrite) {
buf[off] = pad.ptr[off % pad.len];
off += 1;
};
let k: i32 = 0;
let srem: i32 = maxlen - off;
if (srem > s.len) { srem = s.len; };
for (k < srem) {
buf[off + k] = s[k];
k += 1;
};
let r: str;
r.ptr = buf;
r.len = maxlen;
return r;
};
// rpad — right-pad `s` with `p` rune until the result reaches `maxlen`
// bytes. Symmetric with [[lpad]]. ref/hare/strings/pad.ha:39.
export fn rpad(s: str, p: rune, maxlen: i32) str = {
if (s.len >= maxlen) { return dup(s); };
let scratch: [4]u8;
let pad: []u8 = runebytes(scratch[0:4], p);
let buf: *u8 = os.alloc(maxlen: u64): *u8;
let k: i32 = 0;
for (k < s.len) {
buf[k] = s[k];
k += 1;
};
let padwrite: i32 = maxlen - s.len;
let i: i32 = 0;
for (i < padwrite) {
buf[s.len + i] = pad.ptr[i % pad.len];
i += 1;
};
let r: str;
r.ptr = buf;
r.len = maxlen;
return r;
};
// strconv — number↔string conversions.
//
// Mirrors Hare's strconv:: surface. The *tos functions return a

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@@ -2413,6 +2413,69 @@ export fn split(in: str, delim: str) []str = {
return splitn(in, delim, types.I32_MAX);
};
// lpad — left-pad `s` with `p` rune until the result reaches `maxlen`
// bytes. Length comparison is BYTES, mirroring Hare's `len(s) >= maxlen`
// at ref/hare/strings/pad.ha:9. A multibyte `p` whose encoded width
// doesn't divide `maxlen - s.len` evenly leaves a trailing pad byte
// pair sliced mid-codepoint at byte `maxlen-1`, exactly as Hare's
// `res[..maxlen]` does (ref/hare/strings/pad.ha:20). When
// `(maxlen - s.len) * pad.len >= maxlen` (multibyte pad overflows the
// budget), `s` is entirely sliced off — same as Hare. Caller releases
// with `os.free(r.ptr, r.len: u64)`. Hare's `nomem` return is dropped:
// `os.alloc` aborts on OOM. Buf size == r.len keeps the free-contract
// shape of [[dup]] / [[concat]] / [[join]]; Hare's `alloc([], maxlen)!`
// over-allocs via append then slices, but Hare's slice-free recovers
// the true capacity from the heap allocator (rt/ensure.ha:24), which
// ww's munmap-based `os.free` cannot do.
export fn lpad(s: str, p: rune, maxlen: i32) str = {
if (s.len >= maxlen) { return dup(s); };
let scratch: [4]u8;
let pad: []u8 = runebytes(scratch[0:4], p);
let buf: *u8 = os.alloc(maxlen: u64): *u8;
let padwrite: i32 = (maxlen - s.len) * pad.len;
if (padwrite > maxlen) { padwrite = maxlen; };
let off: i32 = 0;
for (off < padwrite) {
buf[off] = pad.ptr[off % pad.len];
off += 1;
};
let k: i32 = 0;
let srem: i32 = maxlen - off;
if (srem > s.len) { srem = s.len; };
for (k < srem) {
buf[off + k] = s[k];
k += 1;
};
let r: str;
r.ptr = buf;
r.len = maxlen;
return r;
};
// rpad — right-pad `s` with `p` rune until the result reaches `maxlen`
// bytes. Symmetric with [[lpad]]. ref/hare/strings/pad.ha:39.
export fn rpad(s: str, p: rune, maxlen: i32) str = {
if (s.len >= maxlen) { return dup(s); };
let scratch: [4]u8;
let pad: []u8 = runebytes(scratch[0:4], p);
let buf: *u8 = os.alloc(maxlen: u64): *u8;
let k: i32 = 0;
for (k < s.len) {
buf[k] = s[k];
k += 1;
};
let padwrite: i32 = maxlen - s.len;
let i: i32 = 0;
for (i < padwrite) {
buf[s.len + i] = pad.ptr[i % pad.len];
i += 1;
};
let r: str;
r.ptr = buf;
r.len = maxlen;
return r;
};
// strconv — number↔string conversions.
//
// Mirrors Hare's strconv:: surface. The *tos functions return a