JPH04189164A - Character font management method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a management system for character font data used in printers and the like.

[Prior Art] Conventionally, a font management table for managing font data is provided in a font cache, as seen in, for example, Japanese Unexamined Patent Publication No. 1-115647, but this font management table has a fixed length for each font. , which had the largest management area.

Problems to be Solved by the Invention] However, if the font management table is secured with a fixed length and maximum size in this way, the number of characters used in the same font, such as a large point size font used for a heading sentence, will increase. If the number of fonts is small, there is a problem in that the memory used as the font management table is wasted.

In addition, there is a recent tendency to treat copyright symbols, registered trademark symbols, alphabets with diactive marks, etc. as character fonts, which increases the size of the font management table, so conventional methods do not use them as font management tables. There was a problem that the amount of memory used increased considerably.

SUMMARY OF THE INVENTION Accordingly, the present invention aims to provide a character font management method that can improve the usage efficiency of memory used as a font management table, and thus minimize the amount of memory required.

Further, the present invention aims to provide a character font management system that allows smooth processing of searching, registering, and deleting font data.

[Means and effects for solving the problem] The invention corresponding to claim (1) includes at least a dot data memory that stores font data in dot format, and a font management table that manages the font data stored in this memory. It has a font cache, and when a character output request occurs, it refers to the cache control table to check whether the corresponding font is registered in the dot data memory, and if it is registered, refers to the font management table. The corresponding font data is called from the dot data memory and outputted, and if it is not registered, the dot format font data of that character is newly registered in the dot data memory, and the information for managing that font data is stored in the font management table. Register at
The font management table is expanded every time font data is registered in the dot data memory.

The invention corresponding to claim (2) is a dot data memory that stores at least dot-format font data, a font management table that manages the font data stored in this memory, and a character code that specifies the address of this font management table. It is equipped with a font cache with a hash table and a character usage frequency prediction data table, and when a character output request occurs, it refers to the cache control table and checks whether or not the corresponding font is registered in the dot data memory. If the character is registered, the corresponding font data is retrieved from the dot data memory by referring to the character code hash table and the font management table and output, and if it is not registered, the dot format font data of the character is output. At the same time as new font data is registered in the dot data memory, information for managing the font data is registered in the font management table.The font management table is expanded every time font data is registered in the dot data memory, and the character code hash table is The size is determined based on character usage frequency prediction data of the usage frequency prediction data table.

The invention corresponding to claim (3) is, in the character font management method described in claim (1) or (2), first marking the data as invalid, and then marking the time or time period when no characters are output. The purpose of this method is to erase font data by freeing memory based on the stored contents.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a cache control table for managing dot-format font data stored in a font cache 2, in which roux codes are secured in units of, for example, 12 points of Mincho fonts. This cache control table 1 stores a cache control Nα (number), a same font link pointer, a font data block start address, and a free area designation pointer.

3 is a cache control number for storing the cache control number in the cache control table 1 of the specified font when searching, registering, and extinguishing font data.
, is the memory.

4 is a character code control table; 5 is a character code table provided in the font cache 2;
These are designed to manage fonts when using a character code system such as ANK characters that is expressed as one hide.

The character code control table 4 has a size of 256 characters because a 1-byte code system is used, and stores pointers to the character code hash table 5.

The character code hash table 5 includes a font management list 6a that constitutes a font management table provided in the font cache 2.

Pointers to 6b and 6c are stored. The size of the character code hash table 5 is determined by applying a predetermined calculation formula to the predicted data values of the character usage frequency prediction data table 7. In this embodiment, for simplicity, the value of the character usage frequency prediction data is defined as the size of the character code hash table 5.

The font management lists 6a, 6b, and 6c each store a dot data pointer, a same font link, a same code link, and a cache number.

Further, to determine which record in the character code hash table 5 is to be referred to, a predetermined hash function is used for the predicted data value of the character usage frequency prediction data table 7 and the cache control number of the cache control Nα memory 3. Determined by applying.

In this embodiment, the remainder obtained by dividing the cache control Nα by the character use frequency prediction data is used as the record position of the character food hash table 5.

The character usage frequency prediction data is defined by determining the size of the character code hash table 5 based on the appearance frequency of each character predicted in advance.

8 is a first character code management table; 9 is a second character code management table provided in the font cache 2; Manage. The first character code management table 8 is a table referenced from the first byte of the character code, and a pointer to the second character code management table 9 is stored. The second character code management table 9 is a table that is referenced from the second hide of the character code, and is a table that is referenced from the second hide of the character code.
Pointers to a, 6b, and 6c are stored. The first character code management table 8 and the second character code management table 9 can have a size of 94 when JIS codes are used.

10a and 10b are dot data memories provided in the font cache 2 and storing font data in dot format; this memory Oa.

10b is managed by the cache control table 1, and is the font management list 6a, 6b.

The address of the font data is specified by the dot data pointer 6c.

Character code hash table 5 and font management list 6a in the font cache 2.

6b, 6cs The second character code management table 9 and the dot data memories 10a and 10b are all dynamically allocated. ``In such a configuration, cache operations are mainly divided into search, registration, and deletion processing.

(a) Search process In this process, it is first checked whether the font requested for output is registered in the cache control table 1 or not. If the cache is registered, the cache control N
o. Store in memory 3. Also, if it is not registered, the search ends.

Next, search for font data by character code,
Here, processing differs depending on whether the character code is a 1-byte system or a 2-byte system.

In the case of a 1-byte character code system, the character code control table 4 is checked from the character code to obtain a pointer to the character code hash table 5. Next, the record position in the character code hash table 5 is determined from the character food, character usage frequency prediction data, and cache control number, and the font management list 6a is obtained.

Find pointers to 6b and 6c. Here, if the pointer is not registered in the character code control table 4 or the character code table 5, the search ends.

Next, follow the same code links in font management lists 6a, 6b, and 6c to create font management list 6 a +
cache ho in 6b, 6c, and gear 2. A search is made for a font having the same values as the cache control number of the memory 3, and if found, that font is output, and if not found, the search ends. Here, when tracing the same code link in the font management lists 6a, 6b, and 6c, if the dot data pointer has a NULL value, it is determined that the font management list is invalid and is ignored, and the search continues.

In the case of a 2-byte character code system, the first character code management table 8 starts from the first byte of the character code requested to be output.
is checked to obtain a pointer to the second character code management table 9. Next, check the second character code management table 9 from the second byte of the character code. Font management list 6g, 6b,
Find a pointer to 6c. Here, if no pointer is registered in the first character code management table 8 or the second character code management table 9, the search ends.

The subsequent processing is the same as in the case of the 1-byte character code system, while following the same code links in the font management lists 6a, 6b, and 6c. The cache controller will search for fonts with the same value.

(b) Registration Process First, it is checked whether the font requested for registration is registered in the cache control table 1 or not. If registered, the cache magnet is stored in the cache control Nα memory 3.

If it is not registered, cache control table 1
A new record is created and its table contents are stored in the cache control Nα memory 3. Next, as an area for storing dot fonts in the font cache 2, dot data memory lQa, 10bs font management lists 6a, 6b, 6c and character code hash table 5 are used.
Alternatively, secure the second character code management table 9. If an area is already allocated, that area will be used; if there is no area, a new area will be allocated. and cache control table 1 and character code control table 4 or first
Using the character code management table 8, link the same fonts and the same codes in the font management lists 6a, 6b, and 6c [connect and cache No., and cache control No.
o. Store the value in memory 3 and store the dot font in the dot data memory.

(c) Erasing processing Erasing processing consists of marking and garbage collection.

For marking, dot data memory 10a.

10b's memory is released. Next, obtain the same font link pointer from the cache control table 1 of the font to be deleted, and trace the same font link from the font management lists 6a, 6b, and 6c pointed to by that pointer to obtain the dot data pointer of all linked font management lists. Set NULL to . Furthermore, the corresponding record in the cache control table 1 is changed to an unused state.

That is, from the state shown in FIG. 2(a) to FIG. 2(b)
Change the state to the one shown below.

Garbage collection is performed during the time when no characters are being output.
In other words, this is done using idle time.

In this garbage collection, first, in the case of a 1-byte character code system, it is checked which pointers are registered from the beginning of the character code control table 4. If there is a registered pointer, the same code link is followed for all the font management lists registered in the character code hash table 5 that the pointer points to, and the dot data pointers of all the linked font management lists are If the contents are examined and a NULL value is found, it is separated from the same code link and the memory is released. Also, after checking all the contents of the character code hash table,
When there is no registration pointer in the character code hash table, the character code hash table itself also releases its memory.

That is, if the state is as shown in FIG. 3(a) before the memory is released, the state is as shown in FIG. 3(b).

Note that for the 2-byte character code system, all unnecessary memory can be freed by performing the same operation on the second character code management table 9.

In this way, the memory for managing dot data only needs to be reserved for the cached fonts, which improves memory usage efficiency and reduces the consumption of the cache memory 2.

In addition, the processing of searching, registering, and deleting font data increases compared to the conventional method, but we use a hash method in which characters that appear frequently for retrieval are allocated to a large hash table, and also for deleting. Since marking and garbage collection using idle time are used, smooth processing is possible without slowing down the processing speed.

In addition, since the amount of cache memory consumed can be reduced, the number of characters that can be cached can be increased, which means that more characters can be output quickly, resulting in faster character output overall. .

[Effects of the Invention] As detailed above, according to the present invention, it is possible to provide a character font management method that can improve the usage efficiency of memory used as a font management table and can therefore minimize the amount of memory required. It is.

Further, according to the present invention, it is possible to provide a character font management system that allows processing of searching, registering, and deleting font data to be performed quickly and smoothly.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention. Fig. 1 is a block diagram showing the main part configuration, Fig. 2 is a diagram showing marking processing during erasing processing, and Fig. 3 is a diagram showing garbage collection processing during erasing processing. FIG. 1... Cashier control table, 2... Font cache, 5... Character code hash table, 6a
. 6b, 6c... Font management list (font management table), 7... Character usage frequency prediction data table,
10a, 10b-=dot data memory. Applicant's agent Patent attorney Takehiko Suzue

Claims (3)

[Claims] (1) A font cache is provided, which includes at least a dot data memory that stores font data in dot format, and a font management table that manages the font data stored in this memory, and when a character output request occurs, the cache control table is checking whether the corresponding font is registered in the dot data memory by referring to it, and if it is registered, referring to the font management table and calling and outputting the corresponding font data from the dot data memory; If it is not registered, the dot-format font data of that character is newly registered in the dot data memory, and the information for managing that font data is linked to the font management table for each same font and character code using a pointer. Register and
A character font management method characterized in that the font management table is expanded each time font data is registered in the dot data memory. (2) A font cache that includes at least a dot data memory that stores font data in dot format, a font management table that manages the font data stored in this memory, and a character code hash table that specifies the address of this font management table. and a character usage frequency prediction data table, and when a character output request occurs, it refers to the cache control table to check whether or not the corresponding font is registered in the dot data memory. For example, the character code hash table and the font management table are referred to, and the corresponding font data is called and outputted from the dot data memory, and if it is not registered, the dot-format font data of that character is newly stored in the dot data memory. At the same time, information for managing the font data is registered in the font management table by linking each same font and character code with a pointer, and the font management table is updated every time font data is registered in the dot data memory. The character font management method is expanded, and the size of the character code hash table is determined based on character usage frequency prediction data of the character usage frequency prediction data table. (3) In the character font management method according to claim (1) or (2), data is first marked as invalid, and then data is stored in memory based on the content marked during a time or time period when no characters are output. A character font management method characterized by erasing font data by releasing it.