Keydata objects are used to load and hold "configuration" data for a given application.
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#include <misc.h>
Inheritance diagram for Keydata:
Collaboration diagram for Keydata:
Data Structures
Public Member Functions
void
load (const char *keypath)
Load additional key values into the currrent object from the specfied config source (a config file/section pair).
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void
loadPrefix (const char *prefix, const char *keypath)
Load additional key values into the currrent object from the specfied config source (a config file/section pair).
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void
loadFile (const char *filepath, const char *
keys=NULL, const char *pre=NULL)
Load additional keys into the current object using a real filename that is directly passed rather than a computed key path.
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Load default keywords into the current object.
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Create an empty key data object.
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Create a new key data object and use "Load" method to load an initial config file section into it.
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Alternate constructor can take a define list and an optional pathfile to parse.
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Destroy the keydata object and all allocated memory.
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Unlink the keydata object from the cache file stream.
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Get a count of the number of data "values" that is associated with a specific keyword.
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Get the first data value for a given keyword.
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const char *
getLast (const char *sym)
Get the last (most recently set) value for a given keyword.
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bool
isKey (const char *sym)
Find if a given key exists.
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const char *
getString (const char *sym, const char *def=NULL)
Get a string value, with an optional default if missing.
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long
getLong (const char *sym, long def=0)
Get a long value, with an optional default if missing.
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double
getDouble (const char *key, double def=0.)
unsigned
getIndex (char **data, unsigned max)
Get an index array of ALL keywords that are stored by the current keydata object.
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Get the count of keyword indexes that are actually available so one can allocate a table to receive getIndex.
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void
setValue (const char *sym, const char *data)
Set (replace) the value of a given keyword.
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const char *const *
getList (const char *sym)
Return a list of all values set for the given keyword returned in order.
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Clear all values associated with a given keyword.
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A convient notation for accessing the keydata as an associative array of keyword/value pairs through the [] operator.
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Static Public Member Functions
static member to end keydata i/o allocations.
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Protected Member Functions
virtual void *
first (size_t size)
Allocate first workspace from paged memory.
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Allocate a string from the memory pager pool and copy the string into it's new memory area.
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virtual void *
alloc (size_t size)
Allocate memory from either the currently active page, or allocate a new page for the object.
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char *
alloc (const char *str)
Allocate a string from the memory pager pool and copy the string inti it's new memory area.
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purge the current memory pool.
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Clean for memory cleanup before exiting.
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Return the total number of pages that have been allocated for this memory pool.
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Private Member Functions
Compute a hash key signature id for a symbol name.
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Private Attributes
Static Private Attributes
Friends
Shutdown the file stream cache.
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Detailed Description
Keydata objects are used to load and hold "configuration" data for a given application.
This class is used to load and then hold "<code>keyword = value</code>" pairs parsed from a text based "config" file that has been divided into "<code>[sections]</code>". The syntax is:
[section_name]
key1=value1
key2=value2
Essentially, the "path" is a "keypath" into a theoretical namespace of key pairs, hence one does not use "real" filepaths that may be OS dependent. The "<code>/</code>" path refers to "<code>/etc</code>" prefixed (on UNIX) directories and this is processed within the constructor. It could refer to the /config prefix on QNX, or even, gasp, a "<code>C:\WINDOWS</code>". Hence, a keypath of "<code>/bayonne.d/vmhost/smtp</code>" actually resolves to a "<code>/etc/bayonne.d/vmhost.conf</code>" and loads key value pairs from the [smtp] section of that .conf file.
Similarly, something like "<code>~bayonne/smtp</code>" path refers to a "<code>~/.bayonnerc</code>" and loads key pairs from the [smtp] section. This coercion occurs before the name is passed to the open call.
I actually use derived keydata based classes as global initialized objects, and they hence automatically load and parse config file entries even before "main" has started.
Keydata can hold multiple values for the same key pair. This can occur either from storing a "list" of data items in a config file, or when overlaying multiple config sources (such as /etc/....conf and ~/.confrc segments) into a single object. The keys are stored as cumulative (read-only/replacable) config values under a hash index system for quick retrieval.
Keydata can also load a table of "initialization" values for keyword pairs that were not found in the external file.
One typically derives an application specific keydata class to load a specific portion of a known config file and initialize it's values. One can then declare a global instance of these objects and have configuration data initialized automatically as the executable is loaded.
Hence, if I have a "[paths]" section in a "<code>/etc/server.conf?</code>" file, I might define something like:
class KeyPaths : public Keydata
{
public:
KeyPaths() : Keydata("/server/paths")
{
static Keydata::Define *defvalues = {
{"datafiles", "/var/server"},
{NULL, NULL}};
// override with [paths] from "~/.serverrc" if avail.
load("~server/paths");
load(defvalues);
}
};
KeyPaths keypaths;
- Author
- David Sugar dyfet.nosp@m.@ost.nosp@m.el.co.nosp@m.m load text configuration files into keyword pairs.
Definition at line 352 of file misc.h.
Constructor & Destructor Documentation
Create an empty key data object.
Keydata::Keydata
(
const char *
keypath )
Create a new key data object and use "Load" method to load an initial config file section into it.
- Parameters
-
keypath (filepath/section) specifies the home path.
Keydata::Keydata
(
Define *
pairs,
const char *
keypath = NULL
)
Alternate constructor can take a define list and an optional pathfile to parse.
- Parameters
-
pairs of keyword values from a define list
keypath of optional file and section to load from
virtual Keydata::~Keydata
(
)
virtual
Destroy the keydata object and all allocated memory.
This may also clear the "cache" file stream if no other keydata objects currently reference it.
Member Function Documentation
virtual void* MemPager::alloc
(
size_t
size )
protectedvirtualinherited
Allocate memory from either the currently active page, or allocate a new page for the object.
- Parameters
-
size size of memory to allocate.
- Returns
- pointer to allocated memory.
Reimplemented in SharedMemPager.
char* MemPager::alloc
(
const char *
str )
protectedinherited
Allocate a string from the memory pager pool and copy the string inti it's new memory area.
This checks only the last active page for available space before allocating a new page.
- Parameters
-
str string to allocate and copy into paged memory pool.
- Returns
- copy of string from allocated memory.
void MemPager::clean
(
void
)
protectedinherited
Clean for memory cleanup before exiting.
void Keydata::clrValue
(
const char *
sym )
Clear all values associated with a given keyword.
This does not de-allocate the keyword from memory, however.
- Returns
- keyword name to clear.
static void Keydata::end
(
void
)
static
static member to end keydata i/o allocations.
virtual void* MemPager::first
(
size_t
size )
protectedvirtualinherited
Allocate first workspace from paged memory.
This method scans all currently allocated blocks for available space before adding new pages and hence is both slower and more efficient.
- Parameters
-
size size of memory to allocate.
- Returns
- pointer to allocated memory.
Reimplemented in SharedMemPager.
char* MemPager::first
(
char *
str )
protectedinherited
Allocate a string from the memory pager pool and copy the string into it's new memory area.
This method allocates memory by first searching for an available page, and then allocating a new page if no space is found.
- Parameters
-
str string to allocate and copy into paged memory pool.
- Returns
- copy of string from allocated memory.
bool Keydata::getBool
(
const char *
key )
Get a bool value.
- Parameters
-
sym keyword name.
- Returns
- true or false.
int Keydata::getCount
(
const char *
sym )
Get a count of the number of data "values" that is associated with a specific keyword.
Each value is from an accumulation of "<code>load()</code>" requests.
- Parameters
-
sym keyword symbol name.
- Returns
- count of values associated with keyword.
unsigned Keydata::getCount
(
void
)
Get the count of keyword indexes that are actually available so one can allocate a table to receive getIndex.
- Returns
- number of keywords found.
double Keydata::getDouble
(
const char *
key,
double
def = 0.
)
Get a floating value.
- Parameters
-
sym keyword name.
default if not set.
- Returns
- value of key.
const char* Keydata::getFirst
(
const char *
sym )
Get the first data value for a given keyword.
This will typically be the /etc set global default.
- Parameters
-
sym keyword symbol name.
- Returns
- first set value for this symbol.
unsigned Keydata::getIndex
(
const char *
sym )
private
Compute a hash key signature id for a symbol name.
- Returns
- key signature index path.
- Parameters
-
sym symbol name.
unsigned Keydata::getIndex
(
char **
data,
unsigned
max
)
Get an index array of ALL keywords that are stored by the current keydata object.
- Returns
- number of keywords found.
- Parameters
-
data pointer of array to hold keyword strings.
max number of entries the array can hold.
const char* Keydata::getLast
(
const char *
sym )
Get the last (most recently set) value for a given keyword.
This is typically the value actually used.
- Parameters
-
sym keyword symbol name.
- Returns
- last set value for this symbol.
const char* const* Keydata::getList
(
const char *
sym )
Return a list of all values set for the given keyword returned in order.
- Returns
- list pointer of array holding all keyword values.
- Parameters
-
sym keyword name to fetch.
long Keydata::getLong
(
const char *
sym,
long
def = 0
)
Get a long value, with an optional default if missing.
- Parameters
-
sym keyword name.
default if not present.
- Returns
- long value of key.
int MemPager::getPages
(
void
)
inlineinherited
Return the total number of pages that have been allocated for this memory pool.
- Returns
- number of pages allocated.
Definition at line 181 of file misc.h.
const char* Keydata::getString
(
const char *
sym,
const char *
def = NULL
)
Get a string value, with an optional default if missing.
- Parameters
-
sym keyword name.
default if not present.
- Returns
- string value of key.
Keysym* Keydata::getSymbol
(
const char *
sym,
bool
create
)
protected
bool Keydata::isKey
(
const char *
sym )
Find if a given key exists.
- Parameters
-
sym keyword to find.
- Returns
- true if exists.
void Keydata::load
(
const char *
keypath )
Load additional key values into the currrent object from the specfied config source (a config file/section pair).
These values will overlay the current keywords when matches are found. This can be used typically in a derived config object class constructor to first load a /etc section, and then load a matching user specific entry from ~/. to override default system values with user specific keyword values.
- Parameters
-
keypath (filepath/section)
void Keydata::load
(
Define *
pairs )
Load default keywords into the current object.
This only loads keyword entries which have not already been defined to reduce memory usage. This form of Load is also commonly used in the constructor of a derived Keydata class.
- Parameters
-
pairs list of NULL terminated default keyword/value pairs.
void Keydata::loadFile
(
const char *
filepath,
const char *
keys = NULL,
const char *
pre = NULL
)
Load additional keys into the current object using a real filename that is directly passed rather than a computed key path.
This also uses a [keys] section as passed to the object.
- Parameters
-
filepath to load from
keys section to parse from, or NULL to parse from head
pre optional key prefix
void Keydata::loadPrefix
(
const char *
prefix,
const char *
keypath
)
Load additional key values into the currrent object from the specfied config source (a config file/section pair).
These values will overlay the current keywords when matches are found. This can be used typically in a derived config object class constructor to first load a /etc section, and then load a matching user specific entry from ~/. to override default system values with user specific keyword values. This varient puts a prefix in front of the key name.
- Parameters
-
prefix
keypath (filepath/section)
const char* Keydata::operator[]
(
const char *
keyword )
inline
A convient notation for accessing the keydata as an associative array of keyword/value pairs through the [] operator.
Definition at line 611 of file misc.h.
void MemPager::purge
(
void
)
protectedinherited
purge the current memory pool.
void Keydata::setValue
(
const char *
sym,
const char *
data
)
Set (replace) the value of a given keyword.
This new value will become the value returned from getLast(), while the prior value will still be stored and found from getList() .
- Parameters
-
sym keyword name to set.
data string to store for the keyword.
void Keydata::unlink
(
void
)
Unlink the keydata object from the cache file stream.
This should be used if you plan to keepa Keydata object after it is loaded once all keydata objects have been loaded, otherwise the cfgFile stream will remain open. You can also use endKeydata().
Friends And Related Function Documentation
void endKeydata
(
void
)
friend
Shutdown the file stream cache.
This should be used before detaching a deamon, exec(), fork(), etc.
Definition at line 623 of file misc.h.
Field Documentation
std::ifstream* Keydata::cfgFile
staticprivate
int Keydata::count
staticprivate
char Keydata::lastpath[256+1]
staticprivate
int Keydata::link
private
int Keydata::sequence
staticprivate
The documentation for this class was generated from the following file: