This class contains miscellaneous utility methods. More...

#include <Util.h>

Static Public Member Functions
static bool	skipSpace (istream &in, bool=false)
	Skip over space characters in input stream.
static bool	skipBlank (istream &in)
	Advance to the first non-blank character, skipping over comments.
static bool	readWord (istream &, string &, bool=false)
	Read next word from input stream.
static bool	readInt (istream &, int &, bool=false)
	Read an integer from the input stream.
static bool	verify (istream &, char c, bool=false)
	Verify the next non-space input character.
static bool	prefix (string &, string &)
	Test if one string is a prefix of another.
static int	strnlen (char *, int)
	Replacement for the missing strnlen function.
static void	genPerm (int, int *)
	Create random permutation on integers 1..n and return in p.
static uint32_t	getTime ()
	Return time expressed as a free-running microsecond clock.
static void	warning (const string &)
static void	fatal (const string &)
static double	randfrac ()
	Generate a random fraction.
static int	randint (int, int)
	Generate a random integer in a range.
static double	randexp (double)
static int	randgeo (double)
	Return a random number from a geometric distribution.
static int	randTruncGeo (double, int)
	Return a random number from a truncated geometric distribution with mean 1/p and maximum value k.
static double	randpar (double, double)
	Return a random number from a Pareto distribution with mean mu and shape s.
Static Public Attributes
static const int32_t	BIGINT32 = 0x7ffffff

Detailed Description

This class contains miscellaneous utility methods.

Definition at line 20 of file Util.h.

Member Function Documentation

uint32_t grafalgo::Util::getTime ( ) [static]

Return time expressed as a free-running microsecond clock.

Uses the gettimeofday system call, but converts result to simple microsecond clock for greater convenience.

Definition at line 138 of file Util.cpp.

bool grafalgo::Util::prefix	(	string &	s1,
		string &	s2
	)		`[static]`

Test if one string is a prefix of another.

Parameters:

s1	is a reference to a string
s2	is a reference to another string

Returns:: true if s1 is a non-empty prefix of s2, else false.

Definition at line 110 of file Util.cpp.

double grafalgo::Util::randfrac ( ) [inline, static]

Generate a random fraction.

Returns:: a double in [0,1]

Definition at line 63 of file Util.h.

int grafalgo::Util::randgeo ( double p ) [inline, static]

Return a random number from a geometric distribution.

Parameters:

p	is success probability (so 1/p is mean)

Returns:: a random value from the distribution

Definition at line 82 of file Util.h.

int grafalgo::Util::randint	(	int	lo,
		int	hi
	)		`[inline, static]`

Generate a random integer in a range.

Parameters:

lo	is the low end of the range
hi	is the high end of the range

Returns:: a random integer in [lo,hi]; the distribution is not very uniform for ranges larger than 10^7

Definition at line 71 of file Util.h.

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bool grafalgo::Util::readInt	(	istream &	in,
		int &	i,
		bool	sameline = `false`
	)		`[static]`

Read an integer from the input stream.

Parameters:

in	is an open input stream
i	is an int in which result is returned
sameline	is an optional argument; if it is true, do not scan past the end of the line; default is false

Returns:: true on success, else false

Definition at line 75 of file Util.cpp.

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bool grafalgo::Util::readWord	(	istream &	in,
		string &	s,
		bool	sameline = `false`
	)		`[static]`

Read next word from input stream.

A word is a non-blank string starting with an alpha and including alphas, digits, forward slashes and underscores.

Parameters:

in	is an open input stream
s	is a string in which result is returned
sameline	is an optional argument; if it is true, do not scan past the end of the line; default is false

Returns:: true on success, else false

Definition at line 55 of file Util.cpp.

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bool grafalgo::Util::skipBlank ( istream & in ) [static]

Advance to the first non-blank character, skipping over comments.

Leave the non-blank character in the input stream. A comment is anything that starts with the sharp sign '#' and continues to the end of the line. Return false on error or eof.

Definition at line 34 of file Util.cpp.

bool grafalgo::Util::skipSpace	(	istream &	in,
		bool	sameline = `false`
	)		`[static]`

Skip over space characters in input stream.

Parameters:

in	is an open input stream
sameline	is an optional argument; if it is true, do not skip past the end of the line; the default is false

Returns:: true if we find a non-space character before eof or error, else false

Definition at line 20 of file Util.cpp.

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bool grafalgo::Util::verify	(	istream &	in,
		char	c,
		bool	strict = `false`
	)		`[static]`

Verify the next non-space input character.

Parameters:

in	is an open input stream
c	is the expected next non-blank character
strict	is an optional flag; if true, then we don't skip over space characters; default is false

Returns:: true if c is present in the input, else false; if c is found, it is read and discarded, otherwise the character checked is left in the input stream

Definition at line 96 of file Util.cpp.

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The documentation for this class was generated from the following files:

/Users/jst/src/grafalgo/cpp/include/Util.h
/Users/jst/src/grafalgo/cpp/misc/Util.cpp

Static Public Member Functions

Static Public Attributes

Detailed Description

Member Function Documentation