Question

我在D中编写了一个小实用程序，用于将find -print0的输出转换为printf％b格式。这样的实用程序已经存在（来自http://www.dwheeler.com/essays/filenames-in-shell.html的nul2pfb），但链接已经死了，我找不到程序，所以我决定自己在D中实现它。我使用以下zsh命令进行测试：

diff <(find) <(for i in "$(find -print0 | dd | char2code)"; do printf '%b\n' "$i"; done)

预期输出为空，但我发现包含连字符的某些文件名处理错误。

我的源代码是：

import std.stdio;
import std.conv;
import std.ascii;
import std.c.stdlib;

void main()
  {
    foreach (ubyte[] mybuff; chunks(stdin, 4096)) {
    encodeline (mybuff);
  }
}

@safe void encodeline (ubyte[] mybuff) {
  // char[] outstring;
  foreach (ubyte i; mybuff) {
    char b = to!char(i);
    switch (i) {
      case 'a': .. case 'z':
      case 'A': .. case 'Z':
      case '0': .. case '9':
      case '/':
      case '.':
      case '_':
      case ':': writeChar(b); break;
      default: writeOctal(b); break;
      case 0: writeChar ('\n'); break;
      case '\\': writeString(`\\`); break;
      case '\t': writeString(`\t`); break;
      case '\n': writeString(`\n`); break;
      case '\r': writeString(`\r`); break;
      case '\f': writeString(`\f`); break;
      case '\v': writeString(`\v`); break;
      case '\a': writeString(`\a`); break;
      case '\b': writeString(`\b`); break;
    }
  }
  // writeString (outstring);
}

@trusted void writeString (string a)
{
  write (a);
}

@trusted void writeOctal (int a)
{
  try
  {
    writef ("\\%.#o", a); // leading 0 needed for for zsh printf '%b'
  }
  catch (std.format.FormatException b)
  {
    write ("Format exception in function writeOctal");
    throw b;
  }
}

@trusted void writeChar (char a)
{
  try
  {
    write (a);
  }
  catch (std.format.FormatException b)
  {
    write ("Format exception in function writeChar");
    throw b;
  }
}

@trusted void writeNewline ()
{
  writeln;
}

这是diff输出的一部分：

Correct filenames:
./.ibam/profile-004-battery
./.ibam/profile-034-charge
./.ibam/profile-054-charge
./.ibam/profile-045-battery
(a bunch of lines skipped)
---
Wrong filenames:
./.ibam/profileh04-battery
./.ibam/profileh34-charge
./.ibam/profileh54-charge
./.ibam/profileh45-battery

似乎-0正被h替换。

更新：在writef的转换说明符中替换。＃with .4修复了问题，但我仍然看到通过/ proc搜索输出的差异。但是，当我这样做时（以root身份）也是如此

diff <(find / print) <(find / print) > (myhomedirectory)/log.txt

所以我选择忽略它。

Answer 1

事实证明，问题是每当八进制转义序列后面跟着一个0到7之间的数字，并且原始转义序列不是4个八进制数字长，这个数字就成了八进制转义序列的一部分，导致printf％b产生不正确的输出。这是通过在D程序中替换转换说明符中的＃by .4来解决的。

这是更正的源代码，删除了一些不需要的功能：

import std.stdio;
import std.conv;
import std.ascii;
import std.c.stdlib;

void main()
  {
    foreach (ubyte[] mybuff; chunks(stdin, 4096)) {
    encodeline (mybuff);
  }
}

@safe void encodeline (ubyte[] mybuff) {
  // char[] outstring;
  foreach (ubyte i; mybuff) {
    char b = to!char(i);
    switch (i) {
      case 'a': .. case 'z':
      case 'A': .. case 'Z':
      case '0': .. case '9':
      case '/':
      case '.':
      case '_':
      case ':': writeChar(b); break;
      default: writeOctal(b); break;
      case 0: writeChar ('\n'); break;
      case '\\': writeString(`\\`); break;
      case '\t': writeString(`\t`); break;
      case '\n': writeString(`\n`); break;
      case '\r': writeString(`\r`); break;
      case '\f': writeString(`\f`); break;
      case '\v': writeString(`\v`); break;
      case '\a': writeString(`\a`); break;
      case '\b': writeString(`\b`); break;
    }
  }
}

@trusted void writeString (string a)
{
  write (a);
}

@trusted void writeOctal (int a)
{
  writef ("\\%.4o", a); // leading 0 needed for for zsh printf '%b'
}

@trusted void writeChar (char a)
{
  write (a);
}

小D程序输出错误

1 个答案: