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author | 2023-04-03 11:16:17 +0200 | |
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committer | 2023-04-03 11:16:17 +0200 | |
commit | 57dc742c76d7876a2457594715a7b5bc2c9a92bd (patch) | |
tree | 76be1ec744face5bf4f617d4c9fca084707e4268 /vendor/github.com/cilium/ebpf/btf/strings.go | |
parent | [bugfix/frontend] Preload css styles (#1638) (diff) | |
download | gotosocial-57dc742c76d7876a2457594715a7b5bc2c9a92bd.tar.xz |
[chore]: Bump github.com/KimMachineGun/automemlimit from 0.2.4 to 0.2.5 (#1666)
Bumps [github.com/KimMachineGun/automemlimit](https://github.com/KimMachineGun/automemlimit) from 0.2.4 to 0.2.5.
- [Release notes](https://github.com/KimMachineGun/automemlimit/releases)
- [Commits](https://github.com/KimMachineGun/automemlimit/compare/v0.2.4...v0.2.5)
---
updated-dependencies:
- dependency-name: github.com/KimMachineGun/automemlimit
dependency-type: direct:production
update-type: version-update:semver-patch
...
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Diffstat (limited to 'vendor/github.com/cilium/ebpf/btf/strings.go')
-rw-r--r-- | vendor/github.com/cilium/ebpf/btf/strings.go | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/vendor/github.com/cilium/ebpf/btf/strings.go b/vendor/github.com/cilium/ebpf/btf/strings.go new file mode 100644 index 000000000..67626e0dd --- /dev/null +++ b/vendor/github.com/cilium/ebpf/btf/strings.go @@ -0,0 +1,128 @@ +package btf + +import ( + "bufio" + "bytes" + "errors" + "fmt" + "io" +) + +type stringTable struct { + base *stringTable + offsets []uint32 + strings []string +} + +// sizedReader is implemented by bytes.Reader, io.SectionReader, strings.Reader, etc. +type sizedReader interface { + io.Reader + Size() int64 +} + +func readStringTable(r sizedReader, base *stringTable) (*stringTable, error) { + // When parsing split BTF's string table, the first entry offset is derived + // from the last entry offset of the base BTF. + firstStringOffset := uint32(0) + if base != nil { + idx := len(base.offsets) - 1 + firstStringOffset = base.offsets[idx] + uint32(len(base.strings[idx])) + 1 + } + + // Derived from vmlinux BTF. + const averageStringLength = 16 + + n := int(r.Size() / averageStringLength) + offsets := make([]uint32, 0, n) + strings := make([]string, 0, n) + + offset := firstStringOffset + scanner := bufio.NewScanner(r) + scanner.Split(splitNull) + for scanner.Scan() { + str := scanner.Text() + offsets = append(offsets, offset) + strings = append(strings, str) + offset += uint32(len(str)) + 1 + } + if err := scanner.Err(); err != nil { + return nil, err + } + + if len(strings) == 0 { + return nil, errors.New("string table is empty") + } + + if firstStringOffset == 0 && strings[0] != "" { + return nil, errors.New("first item in string table is non-empty") + } + + return &stringTable{base, offsets, strings}, nil +} + +func splitNull(data []byte, atEOF bool) (advance int, token []byte, err error) { + i := bytes.IndexByte(data, 0) + if i == -1 { + if atEOF && len(data) > 0 { + return 0, nil, errors.New("string table isn't null terminated") + } + return 0, nil, nil + } + + return i + 1, data[:i], nil +} + +func (st *stringTable) Lookup(offset uint32) (string, error) { + if st.base != nil && offset <= st.base.offsets[len(st.base.offsets)-1] { + return st.base.lookup(offset) + } + return st.lookup(offset) +} + +func (st *stringTable) lookup(offset uint32) (string, error) { + i := search(st.offsets, offset) + if i == len(st.offsets) || st.offsets[i] != offset { + return "", fmt.Errorf("offset %d isn't start of a string", offset) + } + + return st.strings[i], nil +} + +func (st *stringTable) Length() int { + last := len(st.offsets) - 1 + return int(st.offsets[last]) + len(st.strings[last]) + 1 +} + +func (st *stringTable) Marshal(w io.Writer) error { + for _, str := range st.strings { + _, err := io.WriteString(w, str) + if err != nil { + return err + } + _, err = w.Write([]byte{0}) + if err != nil { + return err + } + } + return nil +} + +// search is a copy of sort.Search specialised for uint32. +// +// Licensed under https://go.dev/LICENSE +func search(ints []uint32, needle uint32) int { + // Define f(-1) == false and f(n) == true. + // Invariant: f(i-1) == false, f(j) == true. + i, j := 0, len(ints) + for i < j { + h := int(uint(i+j) >> 1) // avoid overflow when computing h + // i ≤ h < j + if !(ints[h] >= needle) { + i = h + 1 // preserves f(i-1) == false + } else { + j = h // preserves f(j) == true + } + } + // i == j, f(i-1) == false, and f(j) (= f(i)) == true => answer is i. + return i +} |