Source: ../../libxorp/utils.hh
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// -*- c-basic-offset: 4; tab-width: 8; indent-tabs-mode: t -*-
// Copyright (c) 2001-2008 XORP, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software")
// to deal in the Software without restriction, subject to the conditions
// listed in the XORP LICENSE file. These conditions include: you must
// preserve this copyright notice, and you cannot mention the copyright
// holders in advertising related to the Software without their permission.
// The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
// notice is a summary of the XORP LICENSE file; the license in that file is
// legally binding.
// $XORP: xorp/libxorp/utils.hh,v 1.22 2008/07/23 05:10:57 pavlin Exp $
#ifndef __LIBXORP_UTILS_HH__
#define __LIBXORP_UTILS_HH__
#include <list>
#include <vector>
#include "utility.h"
//
// Set of utilities
//
#define PATH_CURDIR "."
#define PATH_PARENT ".."
#define NT_PATH_DELIMITER_CHAR '\\'
#define NT_PATH_DELIMITER_STRING "\\"
#define NT_PATH_ENV_DELIMITER_CHAR ';'
#define NT_PATH_ENV_DELIMITER_STRING ";"
#define NT_PATH_DRIVE_DELIMITER_CH ':'
#define NT_EXECUTABLE_SUFFIX ".exe"
// NT specific
#define NT_PATH_UNC_PREFIX "\\\\"
#define NT_PATH_DRIVE_SUFFIX ":"
#define UNIX_PATH_DELIMITER_CHAR '/'
#define UNIX_PATH_DELIMITER_STRING "/"
#define UNIX_PATH_ENV_DELIMITER_CHAR ':'
#define UNIX_PATH_ENV_DELIMITER_STRING ":"
#define UNIX_EXECUTABLE_SUFFIX ""
#ifdef HOST_OS_WINDOWS
#define PATH_DELIMITER_CHAR NT_PATH_DELIMITER_CHAR
#define PATH_DELIMITER_STRING NT_PATH_DELIMITER_STRING
#define PATH_ENV_DELIMITER_CHAR NT_PATH_ENV_DELIMITER_CHAR
#define PATH_ENV_DELIMITER_STRING NT_PATH_ENV_DELIMITER_STRING
#define EXECUTABLE_SUFFIX NT_EXECUTABLE_SUFFIX
#else // ! HOST_OS_WINDOWS
#define PATH_DELIMITER_CHAR UNIX_PATH_DELIMITER_CHAR
#define PATH_DELIMITER_STRING UNIX_PATH_DELIMITER_STRING
#define PATH_ENV_DELIMITER_CHAR UNIX_PATH_ENV_DELIMITER_CHAR
#define PATH_ENV_DELIMITER_STRING UNIX_PATH_ENV_DELIMITER_STRING
#define EXECUTABLE_SUFFIX UNIX_EXECUTABLE_SUFFIX
#endif // ! HOST_OS_WINDOWS
/**
* Convert a UNIX style path to the platform's native path format.
*
* @param path the UNIX style path to be converted.
* @return the converted path.
*/
inline string
unix_path_to_native(const string& unixpath)
{
#ifdef HOST_OS_WINDOWS
string nativepath = unixpath;
string::size_type n = 0;
while (string::npos != (n = nativepath.find(UNIX_PATH_DELIMITER_CHAR, n))) {
nativepath[n] = NT_PATH_DELIMITER_CHAR;
}
return (nativepath);
#else // ! HOST_OS_WINDOWS
return string(unixpath);
#endif // ! HOST_OS_WINDOWS
}
/**
* Determine if a provided native path string is an absolute path, or
* possibly relative to a user's home directory under UNIX.
*
* @param path a path in native format to inspect.
* @param homeok allow paths relative to a home directory to be regarded
* as absolute paths by this function.
* @return true if the path if satisfies the criteria for an absolute path.
*/
inline bool
is_absolute_path(const string& path, bool homeok = false)
{
if (path.empty())
return false;
#ifdef HOST_OS_WINDOWS
if ((path.find(NT_PATH_UNC_PREFIX) == 0) ||
((path.size() >= 2) && isalpha(path[0]) && path[1] == ':'))
return true;
return false;
UNUSED(homeok);
#else // ! HOST_OS_WINDOWS
if (path[0] == '/')
return true;
if (homeok && path[0] == '~')
return true;
return false;
#endif // ! HOST_OS_WINDOWS
}
/**
* Tokenize a string by breaking into separate strings when separator
* character is encountered.
*
* @param s string to be tokenized.
* @param sep separator to break string it.
* @return list of tokens.
*/
list<string> split(const string& s, char sep);
/**
* Remove the heading and trailing empty spaces from string value.
*
* @param s string that may have heading and trailing empty spaces.
* @return copy of the string with heading and trailing empty spaces removed.
*/
string strip_empty_spaces(const string& s);
/**
* Test if a string contains an empty space (i.e., <SPACE> or <TAB>).
*
* @param s the string to test.
* @return true if the string contains an empty space, otherwise false.
*/
bool has_empty_space(const string& s);
/**
* Return basename of a path.
*
* @param argv0 the argv[0] supplied to main().
*/
const char* xorp_basename(const char* argv0);
/**
* Template to delete a list of pointers, and the objects pointed to.
*
* @param delete_list the list of pointers to objects to delete.
*/
template<class T> void
delete_pointers_list(list<T *>& delete_list)
{
list<T *> tmp_list;
// Swap the elements, so the original container never contains
// entries that point to deleted elements.
swap(tmp_list, delete_list);
for (typename list<T *>::iterator iter = tmp_list.begin();
iter != tmp_list.end();
++iter) {
T *elem = (*iter);
delete elem;
}
tmp_list.clear();
}
/**
* Template to delete an array of pointers, and the objects pointed to.
*
* @param delete_vector the vector of pointers to objects to delete.
*/
template<class T> void
delete_pointers_vector(vector<T *>& delete_vector)
{
vector<T *> tmp_vector;
// Swap the elements, so the original container never contains
// entries that point to deleted elements.
swap(tmp_vector, delete_vector);
for (typename vector<T *>::iterator iter = tmp_vector.begin();
iter != tmp_vector.end();
++iter) {
T *elem = (*iter);
delete elem;
}
tmp_vector.clear();
}
/**
* Create a temporary file with unique name.
*
* This function takes the given file name template, and adds a suffix
* to it to create an unique file name in a chosen temporary directory.
* The temporary directory is selected from the following list by choosing
* the first directory that allows us the create the temporary file
* (in the given order):
* (a) The value of one of the following environment variables if defined
* (in the given order):
* - "TMPDIR"
* - "TEMP" (Windows only)
* - "TMP" (Windows only)
* (b) Argument @ref tmp_dir if it is not an empty string.
* (c) The system-specific path of the directory designated for
* temporary files:
* - GetTempPath() (Windows only)
* (d) The "P_tmpdir" directory if this macro is defined (typically in
* the <stdio.h> include file).
* (e) The first directory from the following list we can write to:
* - "C:\TEMP" (Windows only)
* - "/tmp" (UNIX only)
* - "/usr/tmp" (UNIX only)
* - "/var/tmp" (UNIX only)
*
* For example, if the file name template is "foo", and if the chosen
* temporary directory is "/tmp", then the temporary file name would be
* like "/tmp/foo.XXXXXX" where "XXXXXX" is alpha-numerical suffix
* chosen automatically to compose the unique file name. The created file
* has mode 0600 (i.e., readable and writable only by the owner).
*
* @param tmp_dir the preferred directory to store the file.
* @param filename_template the file name template.
* @param final_filename a return-by-reference argument that on success
* returns the final name of the temporary file (including the directory name).
* @param errmsg the error message (if error).
* @return a file descriptor pointer for the temporary file (opened for
* reading and writing) on success, otherwise NULL.
*/
FILE* xorp_make_temporary_file(const string& tmp_dir,
const string& filename_template,
string& final_filename,
string& errmsg);
#ifdef HOST_OS_WINDOWS
/**
* Helper function to quote command line arguments for MSVCRT-linked programs.
*
* Given an argv array represented by an STL list of strings, and a
* writable command line string, walk through the arguments and perform
* quoting/escaping according to the rules for invoking programs linked
* against the Microsoft Visual C Runtime Library.
*
* This function is necessary because the Win32 CreateProcess() API
* function accepts a single command line string, as opposed to a
* UNIX-style argv[] array; arguments must therefore be delimited by
* white space, so white space in arguments themselves must be quoted.
*
* Note that such extensive quoting shouldn't be performed for the
* pathname to the executable -- generally it is desirable to only
* wrap the path name with quotes, and then pass that string to this
* helper function.
*
* @param args list of argument strings to be escaped.
* @param cmdline string to which the escaped command line should be appended.
*/
void win_quote_args(const list<string>& args, string& cmdline);
#endif // HOST_OS_WINDOWS
/**
* Count the number of bits that are set in a 32-bit wide integer.
*
* Code taken from the following URL (the "Population Count (Ones Count)"
* algorithm):
* http://aggregate.org/MAGIC/
*
* Note: this solution appears to be faster even compared to the
* "Parallel Count" and "MIT HACKMEM Count" from:
* http://www-db.stanford.edu/~manku/bitcount/bitcount.html
*
* @param x the value to test.
* @return the number of bits that are set in @ref x.
*/
inline uint32_t
xorp_bit_count_uint32(uint32_t x)
{
//
// 32-bit recursive reduction using SWAR...
// but first step is mapping 2-bit values
// into sum of 2 1-bit values in sneaky way.
//
x -= ((x >> 1) & 0x55555555);
x = (((x >> 2) & 0x33333333) + (x & 0x33333333));
x = (((x >> 4) + x) & 0x0f0f0f0f);
x += (x >> 8);
x += (x >> 16);
x &= 0x0000003f;
return (x);
}
/**
* Count the number of leading zeroes in a 32-bit wide integer.
*
* Code taken from the following URL (the "Leading Zero Count" algorithm):
* http://aggregate.org/MAGIC/
*
* @param x the value to test.
* @return the number of leading zeroes in @ref x.
*/
inline uint32_t
xorp_leading_zero_count_uint32(uint32_t x)
{
x |= (x >> 1);
x |= (x >> 2);
x |= (x >> 4);
x |= (x >> 8);
x |= (x >> 16);
return (32 - xorp_bit_count_uint32(x));
}
/**
* A template class for aligning buffer data with a particular data type.
*
* The technically correct solution is to allocate (using malloc())
* new buffer and copy the original data to it. By definition, the
* malloc()-ed data is aligned, and therefore it can be casted to the
* desired type.
*
* The more efficient solution (but probably technically incorrect),
* is to assume that the first byte of "vector<uint8_t>" buffer is aligned
* similar to malloc()-ed data, and therefore it can be casted to the
* desired type without creating a copy of it.
*
* The desired behavior can be chosen by setting the
* AlignData::_data_is_copied constant to true or false.
* Note that the constant is predefined for all AlignData instances.
* If necessary, the constant can become a variable that can have
* different value for each AlignData instance.
*/
template <typename A>
class AlignData {
public:
/**
* Constructor.
*
* @param buffer the buffer with the data.
*/
AlignData(const vector<uint8_t>& buffer) {
if (_data_is_copied) {
_data = malloc(sizeof(uint8_t) * buffer.size());
memcpy(_data, &buffer[0], sizeof(uint8_t) * buffer.size());
_const_data = _data;
} else {
_data = NULL;
_const_data = &buffer[0];
}
_payload = reinterpret_cast<const A*>(_const_data);
}
/**
* Destructor.
*/
~AlignData() {
if (_data != NULL)
free(_data);
}
/**
* Get the aligned payload from the beginning of the buffer.
*
* @return the aligned payload from the beginning of the buffer.
*/
const A* payload() const { return (_payload); }
/**
* Get the aligned payload by given offset from the beginning of the
* buffer.
*
* Note that the given offset itself is suppose to point to aligned
* location.
*
* @param offset the offset from the beginning of the buffer.
* @return the aligned payload by given offset from the beginning of
* the buffer.
*/
const A* payload_by_offset(size_t offset) const {
const void* offset_data;
offset_data = reinterpret_cast<const uint8_t*>(_const_data) + offset;
return (reinterpret_cast<const A*>(offset_data));
}
private:
static const bool _data_is_copied = false;
void* _data;
const void* _const_data;
const A* _payload;
};
#endif // __LIBXORP_UTILS_HH__
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