kyle
2f9d3d97e6
Dixie is capped (max_inflight 2, queue_depth 8, queue_wait 20s) and never queued on llama-server. Streaming chat, thinking off, 45s fallback to clean. Digest and chunk-embedding caches are content-addressed SQLite (Honcho context is not cached). Recover uses the guarded Fetcher. guardian-star is refused in code.
65 lines
1.8 KiB
Go
65 lines
1.8 KiB
Go
// Copyright 2026 The Libc Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package libc // import "modernc.org/libc"
|
|
|
|
import (
|
|
"bytes"
|
|
"math"
|
|
"math/bits"
|
|
"unsafe"
|
|
)
|
|
|
|
// strlen dispatches between the two implementations below via the
|
|
// build-tagged strlenUseIndexByte constant; see strlen_simd.go and
|
|
// strlen_nosimd.go. Both implementations may read (within the page
|
|
// holding the string) past the terminating NUL, but never past a page
|
|
// boundary they have no byte in, so neither can fault.
|
|
// TestStrlenGuardPage verifies that.
|
|
|
|
// strlenIndexByte scans with bytes.IndexByte over chunks that stop at
|
|
// 4096-byte boundaries. IndexByte never reads past its slice, and
|
|
// 4096 divides every supported page size, so the scan touches only
|
|
// pages the string occupies.
|
|
func strlenIndexByte(s uintptr) Tsize_t {
|
|
p := s
|
|
for {
|
|
chunk := 4096 - p%4096
|
|
b := unsafe.Slice((*byte)(unsafe.Pointer(p)), chunk)
|
|
if i := bytes.IndexByte(b, 0); i >= 0 {
|
|
return Tsize_t(p + uintptr(i) - s)
|
|
}
|
|
p += chunk
|
|
}
|
|
}
|
|
|
|
const (
|
|
strlenWordSize = bits.UintSize / 8
|
|
strlenLowOnes = math.MaxUint / 0xff // every byte 0x01
|
|
strlenHighBits = strlenLowOnes << 7 // every byte 0x80
|
|
)
|
|
|
|
// strlenWords is the classic word-at-a-time scan: byte-wise to word
|
|
// alignment, then aligned native-word loads (which cannot cross a
|
|
// page boundary) with the usual zero-in-word bit test.
|
|
func strlenWords(s uintptr) Tsize_t {
|
|
p := s
|
|
for ; p%strlenWordSize != 0; p++ {
|
|
if *(*byte)(unsafe.Pointer(p)) == 0 {
|
|
return Tsize_t(p - s)
|
|
}
|
|
}
|
|
for {
|
|
x := *(*uint)(unsafe.Pointer(p))
|
|
if (x-strlenLowOnes)&^x&strlenHighBits != 0 {
|
|
break
|
|
}
|
|
p += strlenWordSize
|
|
}
|
|
for *(*byte)(unsafe.Pointer(p)) != 0 {
|
|
p++
|
|
}
|
|
return Tsize_t(p - s)
|
|
}
|