AutoSizes Class Reference

Description:

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This class stores and manages tabulator positions and field sizes. The class supports a simple session handling, by storing each value once for the actual output session and a second time for a future session. The motivation for writing this class came from the requirements of logging library ALox . The goals here are:

• During a logging session, log output should be as much tabular as possible.
• On the same time, the log output should be as "narrow" as possible.

If used correctly, this class helps to achieve the following:

• A new log-output session increases tab stops and field widths during execution as needed.
• If values need to be increased, a certain amount of "extra padding" might be added to avoid too many small increments.
• Once all tab stops or fields have been logged with values of their maximum size, the log output will not vary in respect to tab stops and autosizes any more.
• If a subsequent session contains the very same log-output (aka the same requested tab positions and field width), all extra space is removed and the log output is 100% tabular beginning with the session start.
• If a subsequent session contains smaller values, then this session is formatted with the (still larger) width of the previous session. After that, the next session will use the smaller sizes.

This approach very well guarantees stable log output widths across sessions. Only if the execution path of a software changes (or logging verbosity setting is changed), adjustments are performed.

To preserve the information across sessions, this class provides methods to transform it's information from and to string representations which can be stored in configuration files.

As the use case of this class is not restricted to log output, this class is exposed as a general utility class of ALib Strings .

Definition at line 58 of file autosizes.hpp.

#include <autosizes.hpp>

Collaboration diagram for AutoSizes:

Inner Type Index:
struct	Entry

Public Type Index:
enum class	Types { Tabstop , Field }

Public Field Index:
size_t	ActualIndex

Public Method Index:
ALIB_API integer	Actual (Types type, integer requestedSize, integer growthPadding)
ALIB_API void	Consolidate ()
ALIB_API void	Export (AString &target)
ALIB_API void	Import (const String &source, lang::CurrentData session=lang::CurrentData::Clear)
integer	Next (Types type, integer requestedSize, integer growthPadding)
void	Reset ()
void	Start ()

Enumeration Details:

Types

enum class Types

strong

The entry type, tab stop or field width.

Enumerator
Tabstop	denotes a tab stop entry.
Field	denotes a field width entry.

Definition at line 66 of file autosizes.hpp.

Field Details:

ActualIndex

size_t ActualIndex

The actual index requested by Next. This field is reset to 0 with every invocation of Start. The field is public and may be read and manipulated, which is considered "expert use".

Definition at line 77 of file autosizes.hpp.

data

std::vector<Entry> data

protected

The current and measured sizes.

Definition at line 104 of file autosizes.hpp.

Method Details:

Actual()

integer Actual	(	Types	type,
		integer	requestedSize,
		integer	growthPadding )

---

Returns the actual auto value stored, respectively, if the given requested size is higher than what is stored, stores and returns the requested size.

In the latter case, the given extra growth is added to the requested size, but only if the value was set at least once before. In other words, the extra size is added only with the second growth and each subsequent one.

The requested size in addition replaces the current "session" value if it is higher than the currently stored value. To this value, the growth padding is not added.

Parameters

type	The type of entry.
requestedSize	The minimum size that is requested.
growthPadding	Added to the new size, if the requested size is greater than the stored size and if the stored size does not equal -1.

Returns

The (new) size of the auto field.

Definition at line 29 of file autosizes.cpp.

Consolidate()

void Consolidate

(

)

---

Consolidates the values. This method is usually not invoked directly. Instead, it is invoked with method Import.

The method loops through all values and copies the session values to the actual ones. The difference of both values is summed up during the loop and entries of type Types::Tabstop are adjusted by that difference. As a result, the new values represent the smallest output format that fits all rows, if the same output is performed as in the previous "session".

Definition at line 134 of file autosizes.cpp.

Export()

void Export

(

AString &

target

)

---

Exports the current session values by converting the stored values to a string representation and appending them to the given AString object.

The format of the entries written into the string is "(T|F,Actual,Measured) which should be self-explanatory.

Parameters

target

The AString to receive the our values

Definition at line 55 of file autosizes.cpp.

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Import()

void Import	(	const String &	source,
		lang::CurrentData	session = lang::CurrentData::Clear )

---

Imports values from the given String by parsing it. Usually, string data are used for importing values was previously generated with method Export.

If parameter session equals Clear (which is the default), then after the import, method Consolidate is invoked.

Note

Parsing is 100% error tolerant. If the given string does not contain what is expected (see method Export), then only a part or just nothing is imported. This is due to the purpose of this class, which is to allow nicer, tabbed output. If this is not possible due to import problems, the system should work normally still.
With debug builds, an ALIB_WARNING is written.

Parameters

source	The String that is parsed for the exported data.
session	Denotes if Consolidate is to be invoked after import. Defaults to Clear .

Definition at line 69 of file autosizes.cpp.

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Next()

integer Next ( Types type, integer requestedSize, integer growthPadding )

inline

---

Invokes Actual and then increases the internal position counter.

Parameters

type	The type of entry.
requestedSize	The minimum size that is requested.
growthPadding	Added to the new size if the requested size is greater than the stored size and if the stored size does not equal -1.

Returns

The (new) size of the auto field.

Definition at line 164 of file autosizes.hpp.

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Reset()

void Reset ( )

inline

---

Resets the all values, current ones and the once of the currently measured session.

Definition at line 113 of file autosizes.hpp.

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Start()

void Start ( )

inline

---

Initializes a new query sequence, which is a series of invocations of method Next.

Definition at line 131 of file autosizes.hpp.

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

• autosizes.hpp
• autosizes.cpp