| // Copyright 2012 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| //go:build aix || darwin || dragonfly || freebsd || hurd || (js && wasm) || linux || netbsd || openbsd || solaris || windows || plan9 |
| |
| package runtime |
| |
| func gogetenv(key string) string { |
| env := environ() |
| if env == nil { |
| throw("getenv before env init") |
| } |
| for _, s := range env { |
| if len(s) > len(key) && s[len(key)] == '=' && envKeyEqual(s[:len(key)], key) { |
| return s[len(key)+1:] |
| } |
| } |
| return "" |
| } |
| |
| // envKeyEqual reports whether a == b, with ASCII-only case insensitivity |
| // on Windows. The two strings must have the same length. |
| func envKeyEqual(a, b string) bool { |
| if GOOS == "windows" { // case insensitive |
| for i := 0; i < len(a); i++ { |
| ca, cb := a[i], b[i] |
| if ca == cb || lowerASCII(ca) == lowerASCII(cb) { |
| continue |
| } |
| return false |
| } |
| return true |
| } |
| return a == b |
| } |
| |
| func lowerASCII(c byte) byte { |
| if 'A' <= c && c <= 'Z' { |
| return c + ('a' - 'A') |
| } |
| return c |
| } |