JP2002043950A - Encoding method and apparatus, and decoding method and apparatus - Google Patents

Abstract

(57) [Problem] To detect and use repetition of certain data in encoding / decoding, it is possible to perform encoding / decoding using repetition of data of at least two different sizes. And the compression ratio is improved. A part which can be replaced by copying processed data is detected, a data length of the part is acquired, and subsequently, replacement can be performed by repeating data of any one of a plurality of sizes. When the part is acquired, Copythen Repeat Byte, Copy then Repeat according to the size of the data
One of the commands Word, Copy then Repeat DoubleWord is generated. In addition, when a portion where data repetition cannot be applied is detected following a portion that can be replaced by copying processed data, a Copythen Raw command is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to encoding and decoding of image data. In particular, one pixel is represented by multi-values such as gray scale or color image data.
The present invention relates to an encoding and decoding technique suitable for encoding a data structure having dimensions or more dimensions for compression and decoding the code.

[0002]

2. Description of the Related Art Conventionally, as a method for compressing image data, there is a method using a run-length code. When the same data is repeated, the run-length code encodes the data and the repetition length. Run-length codes can be encoded at very high speed by software.However, even when there is a correlation in both the horizontal and vertical directions, such as image data, only the horizontal correlation contributes to compression, and the vertical The correlation does not contribute to compression. For this reason, it is difficult to obtain a high compression rate by applying to image data.

As another method, there is a method using a delta row code. The delta row code encodes the length of the continuous data when the same data as the immediately preceding line continues. The Delta Row code can be encoded at a considerably high speed by software, but even when there is a correlation in both the horizontal and vertical directions, such as image data, only the vertical correlation contributes to compression.
Even if there is a horizontal correlation, it does not contribute to compression. For this reason, it is difficult to obtain a high compression rate by applying to image data.

As another method, there is a method using a Huffman code. Huffman code examines the distribution of data,
It encodes data with a high appearance frequency into a short code. When the Huffman code has a correlation in both the horizontal and vertical directions as in image data, the correlation in either direction does not contribute to compression. For this reason, it is difficult to obtain a high compression rate by applying to image data.

[0005] In addition, various codes such as LZ77 code, LZ78 code and JBIG code have been devised.
In each case, it is necessary to examine data other than the data immediately to the left and the data immediately above where the horizontal / vertical correlation is most remarkable. For this reason, there are disadvantages in that the amount of calculation in the encoding is large, a considerable amount of time is required for encoding when encoding by software, and the scale of the decoder increases when decoding by hardware.

As another method, a run-length code and a delta-row code are used in combination to reduce the amount of calculation by examining only the data immediately to the left and the data immediately above where the horizontal / vertical correlation is most remarkable. In addition to reducing the time required for encoding by software, at least two of the three types of operations used when utilizing both horizontal and vertical correlations, namely, data repetition, copying, and raw data, are performed simultaneously. There is a method of increasing the compression rate by encoding. However, according to this method, the repetition data represented by the run-length code is limited to one type, for example, one byte. Since a fill pattern or a dither pattern for color reduction is often composed of 8 × 8 pixels, the same byte is often repeated when the image data is binary, and
Run length codes with repeated bytes work effectively. However, when the image data is multi-valued, the same byte is not continuous, and for example, the same byte is often repeated every other byte, and there is a disadvantage that the run-length code does not work effectively.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above-described problem. It is an object of the present invention to enable encoding and decoding by using repetition of the above data, and to further increase the compression ratio. This makes it possible to increase the compression ratio even for image data in which one pixel is represented by multi-values such as gray scale or color image data. Another object of the present invention is to provide three types of operations generally used in encoding using both horizontal and vertical correlations, such as repetition of certain data, copying of processed data, and copying of raw data. An object of the present invention is to enable at least two of them to be coded at the same time and to increase the compression ratio. Another object of the present invention is to obtain a high compression ratio by encoding a data structure of two or more dimensions such as image data using correlation in both horizontal and vertical directions. In particular, the aim is to reduce the amount of calculation by performing compression using the data immediately above and the data immediately above where horizontal and vertical correlations are most noticeable, and to reduce the time required for encoding with software. I do.

[0008]

According to one aspect of the present invention, there is provided a first method for detecting a portion which can be replaced by copying of processed data and obtaining a data length of the portion. Acquisition means, a second acquisition means for detecting a part that can be replaced by repetition of data of any one of a plurality of sizes, and acquiring the contents of the data and the data length of the part; A third acquisition unit for detecting a portion not acquired by the second or the second acquisition unit and acquiring the data content and data length of the portion, and a data length and data content of each portion detected by the first or the third acquisition unit Generating means for generating encoded data based on the encoding device.

According to another aspect of the present invention for achieving the above object, an analyzing means for analyzing a command consisting of a code string having a predetermined data length, and a storage for storing decoded data. Means for outputting decoded data based on an analysis result of the analysis means, wherein the output means obtains and outputs a corresponding part of the decoded data from the storage means, and outputs the first data. An output unit, a second output unit that obtains data having a specified size from a plurality of sizes from a subsequent code string, and repeats and outputs the data by a specified repetition number, and a specified data length And a third output means for obtaining and outputting the following data from a subsequent code string.

[0010]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram illustrating a hardware configuration of a printing system according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a host computer, which comprises a CPU 2, a memory 3, a hard disk 4, a floppy (registered trademark) drive 5, and a host parallel port 6. The host computer 1 and the printer 7 are connected via a host parallel port 6.

The CPU 2 executes various control programs and application programs stored in the memory 3. The memory 3 stores a program read from the hard disk 4 or the floppy drive 5 and data required by the program.

The hard disk 4 stores programs such as an operating system 10, an application program (application) 11, a printer driver program 12, and a communication driver program 15, which will be described later with reference to FIG.

The floppy drive 5 can mount a floppy disk such as an installation disk 8, and reads a program stored in the mounted floppy disk. The host parallel port 6 can send data to the printer 7. The printer 7 receives print data from the host parallel port 6 and performs printing. Reference numeral 8 denotes an installation disk. In this embodiment, a printer driver program 1 shown in FIG.
2 and an installation program for installing it.

A normal installation operation is performed when an operator sets the installation disk 8 in the floppy drive 5 (or a CD-ROM drive not shown) and starts an installation program. When the installation program is started, the printer driver program 12 is read from the installation disk 8, and
The data is written to the hard disk 4. The installation program uses a function provided by the operating system 10 to set the printer driver program 12 so that the application 11 can use the printer driver program 12.

FIG. 2 is a block diagram showing a control configuration of a printing system to which the printing apparatus according to the present embodiment can be applied.

In FIG. 2, reference numeral 10 denotes an operating system (OS), which manages hardware resources such as a CPU 2, a memory 3, a hard disk 4, a floppy drive 5, a host parallel port 6, an application program 11, and a printer driver program 1.
2. Manage software such as the communication program 15. Reference numeral 11 denotes an application program which creates print data in accordance with an instruction from an operator and issues a print command to a printer driver program 12 via the operating system 10.

A printer driver program 12 creates bitmap data for the printer 7 to perform printing based on a print command issued from the application program 11, and encodes the bitmap data according to an encoding procedure described later. Then, encoded bitmap data is output together with data necessary for print control such as a paper size, a line length and the number of lines of the bitmap data. A communication program 15 controls the host parallel port 6 to transmit data to the printer 7.

Reference numeral 6 denotes a host parallel port, which is an IEEE
8-bit data signals Data1 to Data8 specified in the E standard "IEEE Std 1284-1994" and control the printer 7 4.
Bit control signals nStorobe, nAutoFd, nSelectIn, nIni
t, a 5-bit status signal nAck, B indicating the status of the printer 7
It is connected to the printer parallel port 16 in the printer 7 by usy, PError, Select, and nFault.

Next, a control configuration of the printer 7 will be described. The printer parallel port 16 is connected to the host parallel port 6 by the above-mentioned signal. Reference numeral 17 denotes a control circuit, which is composed of, for example, a one-chip CPU, and includes a printer parallel port 16, a FIFO memory 19,
0, shift register 21, and printer engine 22
Control.

Reference numeral 19 denotes a FIFO (first in first out) memory, which is a printer parallel port 16.
Stores the received data, and outputs the stored data to the decoding circuit 20 in a first-in first-out order. The decoding circuit 20
The code string data stored in the FIFO memory 19 is decoded and output to the shift register 21. Reference numeral 21 denotes a shift register, which converts the parallel data output from the decoding circuit 20 into serial data and outputs the serial data to the printer engine 22. A printer engine 22 uses a laser beam printer engine in this embodiment. The printer engine 22 receives an engine command and transmits an engine status using a serial signal with the control circuit 17, and starts a one-page printing process when a PRINT command is received from the control circuit 17, and the paper is set to a predetermined value. Is reached, the printing on the paper is performed according to the serial data output from the shift register 21.

Hereinafter, the printing operation will be described. When the operator operates the application program 11 on the host computer 1 side to generate print data and instructs printing, print instructions are passed from the application program 11 to the printer driver program 12 via the operating system 10. The printer driver program 12 creates bitmap data based on a print command issued from the application program 11. The printer driver program 12 generates encoded data from the created bitmap data based on an encoding procedure described later, and generates data necessary for print control such as a paper size, a line length and the number of lines of the bitmap data. Output with The communication program 15
The data and encoded data necessary for print control created by the printer driver program 12 are transmitted via the host parallel port 6.

The control circuit 17 is a printer parallel port 1
6 and receives it. If the received command is a command for instructing the start of printing, the control circuit 17
Transmits a PRINT command to the printer engine 22. Upon receiving the PRINT command, the printer engine 22 starts printing.

The decoding circuit 20 decodes the encoded data stored in the FIFO memory 19 and outputs the decoded data to the shift register 21 based on a decoding procedure described later. The shift register 21 has a counter for counting the length of the main scan. Each time the start of the main scan is notified from the printer engine 22, the counter is set to a predetermined value and then the counter is larger than "0". And the decoding circuit 2 at a predetermined timing.
The parallel data output by 0 is converted into serial data, output to the printer engine 22, and decremented by a counter. When the paper reaches a predetermined position, the printer engine 22 notifies that data output is required every time the main scanning is started, and performs printing based on the serial data output from the shift register 21.

Next, coded data generated by the printer driver 12 of the present embodiment will be described with reference to FIGS.

FIG. 3 shows the printer driver 1 shown in FIG.
FIG. 2 is a view for explaining an example of a command code table used for generating encoded data. Symbols described in the present embodiment are byte repeat indicating the repetition of the same data byte, word repeat indicating the repetition of the same data word, double word repeat indicating the repetition of the same data double word, and the data of the immediately preceding line. At least one of three types of operations, copy to copy and raw data for directly specifying the contents of a data string, is specified. Here, a word represents 2 bytes, and a double word represents 4 bytes.

As shown in FIG. 3, when the bit of the command code is "11000000", it is an EOL command, indicating that the line immediately before the end of the line is copied.

When the bit of the command code is "111000
"00" is an EOP command, indicating the end of the page. This command only indicates the end of decoding, and does not represent image data.

If the upper 2 bits of the command code are "01", it is a Copy then Repeat Byte command, and the data of the immediately preceding line is replaced with the lower 3 bits (S0 to S2).
After copying the number of bytes (S bytes) specified by, repeat the 1-byte repetition data immediately after the command code by adding 2 to L specified by the middle three bits (L0 to L2). Show.

If the upper three bits of the command code are "100", it is a Copy then Repeat Word command, and the data of the immediately preceding line is copied after the S byte specified by the lower three bits, and then immediately after the command code. This indicates that 2-byte repetition data is to be repeated the number of times obtained by adding 2 to L specified by the middle two bits (L0, L1).

If the upper 3 bits of the command code are "101", it is a Copy then Repeat Double Word command, and after copying the data of the immediately preceding line by the S byte specified by the lower 3 bits, immediately after the command code This means that the 4-byte repetition data is repeated by adding 2 to L specified by the middle two bits (L0, L1).

If the upper 2 bits of the command code are "00", it is a Copy then Raw command, and the data of the immediately preceding line is copied immediately after the command code after copying the S byte specified by the lower 3 bits. Subsequently, it indicates that data of the number of bytes obtained by adding 1 to R (R0 to R2) specified by the middle three bits is used as it is.

If the upper 3 bits of the command code are "110" and any of the remaining bits is 1, Cop
This is a yLong command, which indicates that data of the immediately preceding line is to be copied eight times as many bytes as S specified by the lower 5 bits (S0 to S4).

When the upper 3 bits of the command code are "111" and any of the remaining bits are 1, the Ext
End command, the second following the Extend command code
And the command code is combined into one command, and the count corresponding to the numerical value E specified by the lower 5 bits (E0 to E4) is added to the count indicated by the second command code.

FIG. 4 is a diagram showing an example of a second command code following the Extend command shown in FIG.

As shown in FIG. 4, when the upper two bits of the second command code are “01”, the Copythen Repeat By
This is a te Long command, and after copying the data of the immediately preceding line by S bytes specified by the lower 3 bits (S0 to S1), repeats the 1-byte repeated data immediately after the second command code by the middle 3 bits ( Extend to L specified by L0-L2)
8 times the numerical value E specified by the command is added, and 2 is added.

If the upper 2 bits of the second command code are "10", it is a Copy then Repeat Word Long command, and the data of the immediately preceding line is copied after the S byte specified by the lower 3 bits. The 2-byte repeated data immediately after the command code of No. 2 is the middle 3 bits (L0 ~
It indicates that eight times the numerical value E specified by the Extend command is added to L specified by L2), and 2 is subtracted therefrom.

When the upper two bits of the second command code are "11", Copy then Repeat Double Word Lo
ng command, after copying the data of the immediately preceding line by S bytes specified by the lower 3 bits, the 4 bytes of repeated data immediately after the second command code to L specified by the middle 3 bits, Numeric value E specified by Extend command
Is repeated 8 times, and 2 is subtracted.

When the upper two bits of the second command code are “00”, it is a Copy then RawLong command, and after copying the data of the immediately preceding line by the S byte specified by the lower three bits, Extend to R specified by the middle 3 bits (R0 to R2) immediately following the command code
It indicates that data of the number of bytes obtained by adding eight times the numerical value E specified by the command and further adding 1 is used as it is.

Next, with reference to FIG. 5, an example of reference numerals shown in FIGS. 3 and 4 will be described. FIG. 5 is a diagram illustrating an example of a command operation according to the present embodiment.

As shown in FIG. 5, "0x01, 0x01, 0x48, 0xFF, 0x
`` E1, 0x81, 0x55, 0x00, 0xC0 '' indicates a part of the code string,
It represents one line. The line length is 2
0 bytes, and the previous line is “(1),
(2), (3), ... (20) ".

If the code shown in the figure is given, the first command "0x01" is a bit string "00000001".
This is a Copythen Raw command, the number of copies S is 1, and the raw data size (R + 1) is 1. Therefore, after the 1-byte data "(1)" is copied from the immediately preceding line, the 1-byte data "0x01" following the command code becomes the data as it is (see reference numeral 51).

The next command "0x48" is a bit string "010010".
00 ”, it is a Copy thenRepeatByte command, the number of copies S is 0, and the number of repeats (L + 2) is 3. Therefore, the one-byte repeated data “0xFF” following the command code is repeated three times (see reference numeral 52).

The next command "0xE1" is a bit string "111000
01 ”, it is an Extend command, and E is 1. The second command code “0x81” corresponds to the bit string “100000
01 ", it is a Copythen Repeat Word Long command, the copy number S is 0, and L is 0, so the repeat number" L + 8 * E-2 "is 6. Therefore, 1
After the byte data "(6)" is copied from the immediately preceding line, the 2-byte repeated data "0x55, 0x00" following the second command code is repeated six times (see reference numeral 53).

The next command "0xC0" is a bit string "110000".
00 ”, it is an EOL command, and two bytes“ (19), (20) ”up to the end of the line are copied from the immediately preceding line (see reference numeral 54).

Next, the effect of simultaneously encoding a plurality of operations will be described. When encoding is performed using copy / repetition / raw data operation, unless a plurality of operations are simultaneously encoded, each of the copy / repetition / raw data must be a one-byte command. If the copying and repetition, the copying and the raw data, or the repetition and the raw data are encoded at the same time, the two operations can be converted into one-byte commands, and the compression ratio is improved.

On the other hand, by encoding a plurality of operations at the same time, the length that can be expressed by a 1-byte command is reduced. For example, in the case of a 1-byte command for each of copy, repetition, and raw data, assuming that 2 bits are used for distinguishing operations, 6 bits can be used to represent the length, and up to about 63 Length can be expressed. On the other hand, if a plurality of operations are encoded simultaneously, only three bits can be used to represent the length in the above example, and only a length up to about seven can be used.

In a bitmap printed by a printer,
It is similar to the previous line, but generally slightly different. For this reason, the combination of short-length copying and short-length repetition, or short-length copying and short-length raw data is often very large. This tendency is particularly remarkable when printing text, that is, character fonts. For this reason, it is often the case that the compression rate is improved by simultaneously encoding a plurality of operations while limiting the length. Therefore, when the present invention is applied to data for a printer, the compression rate is improved by encoding a plurality of operations at the same time as in the present embodiment.

Next, the effect of the EOL command will be described. Since the EOL command is used to copy until the end of the line, it can be replaced with a copy command of a certain length. Generally, a bitmap printed by a printer has a certain amount of blank space on the right side. For example, if the length of the right margin is 2.54 cm, the printer is a laser beam printer of 600 dpi, and one pixel is 4 bits,
It becomes a blank of 0 bits, which is equivalent to 300 bytes. To represent a copy of length 300, lengths 256 and 4
A Copy Long command of length 0 and a Copy command of length 4 not defined in FIG.
It becomes bytes. Since the EOL command does not include a length, it can be represented by 1 byte regardless of the number of bytes that act, improving the code compression rate and eliminating the need for Copy commands of lengths 1 to 7. .

Next, the encoding process performed by the printer driver 12 will be described. FIG. 6A and FIG. 6B are flowcharts illustrating the encoding process of the printer driver according to the present embodiment. In FIG. 6A, first, in step S11, the number of bytes in which the row to be processed and the data in the immediately preceding row continuously match is obtained, and this is set as a variable copy.
To be stored. In step S12, it is determined whether or not the previous line matches the end of the line. If they match up to the end of the line, the process proceeds to step S13, outputs an EOL command, and proceeds to step S31. On the other hand, if the end of the line has not been reached, the process proceeds to step S14, and it is determined whether or not the content of the variable copy is 8 or more. Here, if copy ≧ 8, a CopyLong command is generated and viewed in step S15.
Proceed to 16. Depending on the size of the copy, Copy Lon
Multiple g commands will be generated. Also, in step S14, if copy ≦ 7, step S15
Skip to step S16.

In step S16, the number of repetitions of the same byte is checked and stored in a variable len. This process is called Copythen
Since Repeat Byte Long can be specified only up to 257 repetitions, it is performed until len is 257 or less and processing reaches the end of the line. If the result of the processing in step S16 is that len contains a numerical value other than 0, the process proceeds from step S17 to step S18, where co
According to the numerical value in py and the numerical value in len (S0 ~ S3
And then generates L0-L2 or E0-E4 based on the value of len) Copythen Repeat Byte or Copy then Repeat
Generate Byte Long.

If len is 0 in step S17, the number of repetitions of the same word (the number of repetitions of the same two consecutive bytes) is checked in step S20 and stored in the variable len. This process is called Copythen Repeat
Since Word Long can be specified only up to 253 repetitions, it is performed until len is less than 253 and the processing reaches the end of the line. As a result of the processing in step S20, if len contains a numerical value other than 0, the process proceeds from step S21 to step S22, and according to the numerical value in copy and the numerical value in len (S0 to S3 are generated by the value of copy, and Generate L0-L2 or E0-E4 based on the value), Copythen Repeat Word or Copy then Repeat W
Generates ord Long.

If len is 0 in step S21, the number of repetitions of the same double word (the number of repetitions of the same four consecutive bytes) is checked in step S24 and stored in the variable len. This process is called Copythe
Since n Repeat Double Word Long can be specified only up to 253 repetitions, it is performed until len is 253 or less and processing reaches the end of the line. If the result of the processing in step S24 is that len contains a numerical value other than 0, the processing proceeds from step S25 to step S2.
6 and follow the values in copy and len (copy
Generate S0-S3 with the value of len and generate L0-L2 or E0-E4 based on the value of len), Copythen Repeat Double Word
Or, generate Copy then Repeat Double Word Long.

Further, if len is 0 in step 25, it means that no byte match with the previous line, no repetition in byte units, no repetition in word units, and no repetition in double word units can be found. In this case, step S
At 28, count the number of bytes during which no byte match with previous row, repeat by byte, repeat by word, repeat by doubleword is found and store this in len (in this process len is Be sure to be 1 or more). Then, in step S29, Copythen Raw is generated according to the numerical value in copy and the numerical value in len (S0 to S3 are generated by the value of copy, and R0 to R2 or E0 to E4 are generated based on the value of len). I do.

As described above, steps S18 and S2
If a command is generated in any of 2, S26, and S29, the process proceeds to step S30, determines whether the process has reached the end of the line, and if not, returns the process to step S11. The above process is repeated for the row. On the other hand, when it is determined in step S30 that the end of the line has been reached, the process proceeds to step S31, and it is determined whether there is a line to be processed next, that is, the end of the page. This is the end of the page (if it is determined that there is no line to be processed next in the print page, the process proceeds to step S32 to generate an EOP command and end this processing. On the other hand, there is still a line to be processed If it is determined, the process proceeds to step S33, and the process returns to step S11 with the next line as a processing target.Then, referring to the program list shown in FIGS. Details will be described.

FIG. 7 is a diagram showing an example of a program list for realizing the encoding procedure of the printer driver 12 described with reference to FIGS. 6A and 6B. The program in FIG.
Consists of functions written in a language.

In FIG. 7, line 1 defines the function name, arguments, and return type. The function name of this function is encode, and the start address sr of the bitmap data is
c, start address ds of buffer for storing encoded data
t, the byte number width and the line number height of one line are received, the bitmap data is encoded, the encoded data is stored in the buffer, and the number of bytes stored in the buffer is returned as a return value.

During the encoding process, the start address src and the start address dst are updated to indicate the start address of the unprocessed line of the bitmap data and the start address of the unprocessed buffer, respectively.

Lines 3, 4, 5, and 6 are temporary variables x, y, len, copy, copy2, data, dsttop, dataw, p
Define w, datad, pdw. x stores the offset of the bitmap data from the head of the line being processed. y stores the number of the line being processed. len stores the length of the raw data being processed or the length of repetition.
copy and copy2 store the number of repetitions being processed. dat
a stores repeated data. Also, dsttop is a function enc
The start address dst of the buffer that stores the encoded data when ode is called is stored. dataw is an area for temporarily storing word data, and pw is an area for temporarily storing a pointer to the word data. Also, da
tad is an area for temporarily storing double word data, and pd is an area for temporarily storing a pointer pointing to double word data.

When the function encode is called, the value of the buffer start address dst is stored in dsttop in line 4.

Next, in the first for loop from row 7 to row 74, y is initialized to 0, and the loop is repeated until y becomes equal to height. At the end of each loop, 1 is added to y, and width, that is, the length of one line is added to src (S31, S33).

In the first for loop, lines 8 to 73
The second for loop up to is executed. In the second for loop, x is initialized to 0, and the loop is repeated until x becomes equal to width (S30).

[Processes Corresponding to Steps S11 to S15] In the second for loop, the copy
Set. Next, it is determined whether or not y is 0 in row 10, and y is determined.
If it is 0, it goes to row 24 because it is the top line. If y is not 0, a while loop from line 11 to line 13 is first executed to compare with the data of the immediately preceding line. whi
In the le loop, x is less than width and src [x], the xth byte of the current line (current byte)
While src [x-width], the xth byte of the previous line (the byte immediately above the current byte), is equal to 1 in x and copy in row 12. At the point of exit from the while loop, copy stores the length at which the immediately preceding line and the data continuously match, that is, the copy count, and x is updated according to the length. Next, at line 14, x and widt
Determine whether h is equal. If x and width are equal, data matches the previous line continuously until the end of the line, and EO
Since it can be encoded into an L command, 0xC0, that is, the EOL command is stored in the output buffer in row 15, and dst
Is updated, and the break in line 16 terminates the second for loop.

If x and width are not equal, the while loop from line 18 to line 22 is executed. In the while loop, while copy is greater than 7, the processing from line 19 to line 21 is repeated. First, in line 19, copy2, which is not larger, is stored in copy2. Here, min is a macro that returns an argument that is not large among the two arguments. next,
In line 20, the CopyLong command is stored in the output buffer,
Update dst. Next, a copy count corresponding to the Copy Long command output in line 20 is subtracted from copy in line 21. The CopyLong command is output in this way,
At the time of exiting the while loop, copy is 7 or less.

[Processes Corresponding to Steps S16 to S18] Next, in line 24, the byte next to the current byte is left in the current line, and src [x], that is, the current byte and src [x + 1] ] That is, it is determined whether the next byte matches. If the next byte of the current byte is not left on the current line, or if the current byte and the next byte do not match, there is no repetition of the byte, so go to line 34. If the byte next to the current byte is left on the current line and src [x], the current byte, and src [x + 1], the next byte, match, the line number is first determined in line 25. Then, src [x], that is, repeated data is stored in data. Next, a for loop from line 26 to line 28 is executed. In the for loop, 2 is added to x in order to skip two matched data as initialization processing, and le
Store 2 in n, x is smaller than width and len is 257
Execute loop while smaller. At the end of each loop,
Add 1 to x and len. In the loop, at line 27, src
If [x], that is, the current data is not equal to data, that is, the repeated data, break terminates the for loop. In this way, at the time of exiting the loop, the number of repeated data consecutive to len is stored, and x
Has been updated according to the value of len.

If len is greater than 7 in line 29, E
Store the xtend command in the output buffer and update dst,
In line 30, the Copythen Repeat command is stored in the output buffer and dst is updated. In line 31, data, that is, the repeated data is stored in the output buffer and dst is updated.
Return to the second for loop with continue of 2.

[Processes Corresponding to Steps S20 to S22]
At line 24, if the byte next to the current byte is not left on the current line, or if the current byte and the next byte do not match, at line 34 the pointer pw to the word data is set to & src [ x], that is, the address of the current byte.

Next, at line 35, the next three bytes of the current byte are left on the current line, and pw [0], the current word, matches pw [1], the next word. Is determined. If the next three bytes of the current byte are not left on the current line, or if the current word and the next word do not match, then there is no word repetition, so go to line 51. The next three bytes of the current byte are left on the current line and pw [0]
That is, if the current word and pw [1], that is, the next word match, the number of repetitions is calculated.
In step 6, pw [0], that is, repeated data is stored in dataw. Next, a for loop from line 37 to line 39 is executed. In the for loop, 4 is added to x in order to skip two matched data as initialization processing, and len
Is stored in x, and x + 1 is smaller than width and len is 25
Run the loop for less than three. At the end of each loop, 2 is added to x and 1 is added to len. During the loop, at line 38, pw [len], that is, the current data is dat
aw, if not equal to the repetition data, brea
This for loop is ended by k. In this way, at the time of exiting the loop, the number of repeated data consecutive to len is stored, and x is updated according to the value of len.

If len is not greater than 5 in line 40, a Copy then RepeatWord command is stored in the output buffer in line 41 to update dst. If len is greater than 5 in line 40, the Extend command is stored in the output buffer in line 43 to update dst, and in line 44 Copythen Repe
Stores the at Word Long command in the output buffer and updates dst.

[Processes Corresponding to Steps S24 to S26] Next, in the row 46, the pointer pw to the word data is set to ds
t, that is, the current output address is stored. Then row 4
At 7, dataw, that is, repeated data, is stored in * pw, that is, the word area indicated by the current output address. Next, dst is updated in line 48, and the second f
or loop back.

At line 35, if the next three bytes of the current byte are not left on the current line, or if the current word and the next word do not match, at line 51 the double-word data is Store & src [x], that is, the address of the current byte, in the pointer pd.

Next, at line 52, the next seven bytes of the current byte are left on the current line, and pd [0], the current doubleword, and pd [1], the next doubleword, Determine whether they match. If the next 7 bytes of the current byte are not left on the current line, or if the current doubleword and the next doubleword do not match, there is no doubleword repetition, so go to line 68. If the next 7 bytes of the current byte are left on the current line and pd [0], the current doubleword, and pd [1], the next doubleword, match, find the number of repetitions, First at line 53, da
pd [0], that is, repeated data is stored in tad. Next, a for loop from line 54 to line 56 is executed. In the for loop, 8 is added to x and 2 is stored in len in order to skip two matched data as initialization processing, and the loop is executed while x + 3 is smaller than width and len is smaller than 253. At the end of each loop, x is 4
Is added to len. During the loop, at line 55, if pd [len], ie, the current data is not equal to datad, ie, the repeated data, break causes this f
or end loop. In this way, at the time of exiting the loop, the number of repeated data consecutive to len is stored, and x is updated according to the value of len.

If len is not larger than 5 in the line 57, a Copy then RepeatDoubleWord command is stored in the output buffer in a line 58 to update dst. In line 57, len is 5
If it is larger, the Extend command is stored in the output buffer at line 60 and dst is updated.
n Stores the Repeat Double Word Long command in the output buffer and updates dst.

Next, at line 63, dst, that is, the current output address is stored in the pointer pd to the double word data. Next, in line 64, datad, that is, repeated data is stored in * pd, that is, the double word area indicated by the current output address. Next, dst is updated in line 65, and line 66 is updated.
Returns to the second for loop with continue.

[Processes Corresponding to Steps S28 to S29] In the row 52, if the next 7 bytes of the current byte are not left in the current line, or the current double word and the next double word match. Line 68 if not
By calling the function count_raw described below,
The length to be stored as raw data is stored in len. Next, if len is greater than 7 in line 69, the Extend command is stored in the output buffer and dst is updated.
The opythen Raw command is stored in the output buffer to update dst, the raw data is copied to the output buffer by the library function memcpy in line 71, and x is set according to the length of the raw data copied in line 71 in line 72. And dst and update the second f
or loop back.

When all the current lines have been processed in this way and x becomes equal to the width, the second for loop is terminated, and the process returns to the first for loop. At the end of each loop, y
, And the width, that is, the length of one line, is added to src, so that the processing of the next line is started. When the processing of all the lines is completed in this way and y becomes equal to the height, the first for loop is ended, and 0
xE0, that is, the EOP command is stored in the output buffer, and dst is updated. Next, in line 76, the number of bytes stored in the buffer is obtained by subtracting dsttop, ie, the start address of the buffer, from dst, ie, the end address of the buffer, and the function is terminated using that as the return value.

Next, the processing procedure of the function count_raw will be described in detail with reference to the program list shown in FIG.

FIG. 8 is a diagram showing an example of a program list for realizing the function count_raw shown in FIG. FIG.
Shows an example described using C language as a programming language.

In FIG. 8, line 1 defines a function name, an argument, and a return value type. The function name of this function is count_ra
w, the head address src of the current line of the bitmap data from the caller, the offset x from the head of the line at the current position, the line number y, the number of bytes of one line widt
h, receives the upper limit of the raw data length limit, and returns the length to be stored as raw data as a return value.

During the process, the offset x from the head of the line at the current position is updated to indicate the current position.
The argument is passed by value according to the C language convention, so the updated value is not reflected in the calling argument.

Lines 3, 4 and 5 are temporary variables len, p
Define w and pd. len stores the length to be stored as raw data. pw is an area for temporarily storing a pointer to word data. Further, pd is an area for temporarily storing a pointer indicating double word data.

When the function count_raw is called, len is initialized to 0 in a for loop from line 7 to line 22, and x is
Repeat the loop as long as it is less than width and len is less than limit. At the end of each loop, 1 is added to x and len.

In the loop, first, in line 8, len is 0, that is, the first data of the raw data and the data next to the current data are left in the current line, and the current data and the next data Are equal to each other, the number of repeated bytes at the beginning of the data is 2 or more, and the data should be encoded as repeated bytes. Therefore, the for loop is terminated by a break.

Next, at line 9, if the next data following the current data is left in the current line, and the current data, the next data, and the next data are all equal, Since the number of repeated bytes is 3 or more and should be encoded as repeated data of bytes, br
The for loop is terminated by eak.

Next, at line 10, & sr is added to the pointer pw to the word data and the pointer pd to the double word data.
c [x], that is, the address of the current byte is stored.

Next, in row 11, three bytes of data are left in the current line after the current byte, and pw
If [0], that is, the current word is equal to pw [1], that is, the word next to the current word, the number of word repetitions is 2 or more and should be encoded as word repetition data. To end.
Next, at row 12, seven bytes of data are left on the current line following the current byte, and pd [0], the current doubleword, is the next to pd [1], the current doubleword. If it is equal to the double word, the number of repetitions of the double word is 2 or more, and it should be encoded as double word repetition data. Therefore, the for loop is terminated by a break.

Next, in line 13, if y is not 0, that is, if it is not the first line and the data immediately above is equal to the current data, lines 14 to 19 are executed. First, in line 14, if len is 7 or less, the length of the raw data exceeds 7 by encoding as a copy and the Extend command is required, so that the code is extended by 1 byte. Break because you can avoid becoming
Ends the for loop.

Next, in line 15, if the next data is left on the current line and the next data and the data immediately above it are equal, the number of copies is 2 or more, so that the data should be encoded as a copy. So the break ends the for loop. Next, in line 16, if the next data is left on the current line and the next data is equal to the next data, the number of copies is 1 and the number of repeated bytes is 2 or more. Since the encoding should be performed as a copy + byte repetition, the for loop is terminated by a break.

Next, in line 17, & sr is added to the pointer pw to the word data and the pointer pd to the double word data.
c [x + 1], that is, the address next to the current byte is stored.

Next, at line 18, four bytes of data are left in the current line after the current byte, and pw
If [0], the next word of the current byte, is equal to pw [1], the next word, then the copy number is 1 and the word repeat count is 2 or more, so it should be encoded as a copy + word repeat So, for break
End the loop.

Next, at line 19, 8 bytes of data are left on the current line after the current byte, and pd
[0], that is, the next doubleword of the current byte is pd
[1] That is, if it is equal to the next double word,
Since the number of copies is 1 and the number of repetitions of the double word is 2 or more, it should be encoded as the repetition of copy + double word.

If the condition for terminating the for loop is not satisfied, the process returns to the for loop, and 1 is added to x and len.
Continue the loop. In this way, the loop continues until it encounters data that should not be encoded in the raw data, processes all of the data in one line, or reaches the upper limit of the raw data length limit. When the loop ends, the length to be encoded as raw data is stored in len, and the function ends with the value of len as the return value in line 22.

As described above, encoding by the printer driver program 12 of the present embodiment is realized.

Next, the details of the decoding circuit 20 shown in FIG. 2 will be described with reference to FIG.

FIG. 9 is a block diagram showing details of the decoding circuit 20 shown in FIG. In FIG. 9, when all of the copy counter 32, the repeat counter 33, and the raw data counter 35 are 0, the command decode circuit 31 converts the coded data constituted by the codes shown in FIGS. It receives and decodes the encoded data, and outputs and sets the number of copies, the number of repetitions, and the number of raw data to a copy counter 32, a repeat counter 33, and a raw data counter 35, respectively. The command decode circuit 31 outputs the decoded command as a byte,
If the data includes a word or double word repetition operation, the repetition data is received from the FIFO 19,
The size of the data to be repeated (eg, the number of bytes (for example, if the command is Copythen Word Repeat
Then 2 bytes))).

When the EOL command is decoded, the command decode circuit 31 outputs an EOL signal to the subtraction circuit 36 instead of outputting the number of copies to the copy counter 32. When the command decode circuit 31 decodes the Extend command, after internally storing the count value included in the Extend command, the command decode circuit 31 receives the next command from the FIFO 19, performs decoding, and executes the internally stored count value. And a count value corresponding to the second command code is calculated and output as the number of copies, the number of repetitions, or the number of raw data.

The copy counter 32 holds the number of copies output from the command decode circuit 31 or the subtraction circuit 36. The repeat counter 33 includes the command decode circuit 3
1 holds the number of repetitions output. The repeat data register 34 outputs the
Holds data to be repeated. The data size register 43 holds the size of the data to be repeated output from the command decode circuit 31. Raw data counter 35
Holds the number of raw data output from the command decode circuit 31. The subtraction circuit 36 is a command decoding circuit 31
Outputs the EOL signal, calculates the difference between the line length register 37 and the address counter 38, and outputs the difference to the copy counter 32. The line length register 37 is
The number of bytes of one line previously output by the control circuit 17 is held.

The address counter 38 holds the current address of the line buffer 39, and
0, repeat output circuit 41, or raw data output circuit 4
Each time 2 accesses the line buffer, the count is incremented. When the number of bytes reaches the number of bytes of one line held by the line length register 37, the count returns to 0. The line buffer 39 holds at least one line of decoded data, and inputs or outputs decoded data according to the current address held by the address counter 38.

The copy output circuit 40 includes a copy counter 3
If the value held by 2 is not 0, the address counter 3
8, the data of the line immediately before held by the line buffer 39 is output as decoded data, and 1 is subtracted from the copy counter 32 every time one byte is output.

When the value held by the copy counter 32 is 0 and the value held by the repeat counter 33 is not 0, the repeat output circuit 41
3 outputs, as decoded data, the repeated data held in the repeat data register 34 having the size specified by the size of the data to be held held in the buffer 3, and outputs the decoded data to the position of the line buffer 39 indicated by the address counter 38. Each time the data is stored and one byte is output, 1 is subtracted from the repeat counter 33.

The raw data output circuit 42 stores the data in the FIFO 19 when the value held by the copy counter 32 and the value held by the repeat counter 33 are both 0 and the value held by the raw data counter 34 is not 0. The raw data is output as decoded data, the output decoded data is stored at the position of the line buffer 39 indicated by the address counter 38, and 1 is subtracted from the raw data counter 34 every time one byte is output.

The operation of the decoding circuit described above will be described below. The command decode circuit 31
When the g command is decoded, the number of copies is set in the copy counter 32, and 0 is set in the repeat counter 33 and the raw data counter 35, respectively. Copy counter 3
When the number of copies is set to 2, the copy output circuit 40 reads the data at the position indicated by the address counter 38 of the line buffer 39 and outputs it as decoded data. One is added to the address counter 38 and one is subtracted from the copy counter 32. This is repeated until the copy counter 32 becomes 0, and when it becomes 0, the command decode circuit decodes the next command.

When command decode circuit 31 decodes the EOL command, 0 is set in repeat counter 33 and raw data counter 35, respectively. Also,
The EOL signal is output, and the subtraction circuit 36 calculates the difference between the line length register 37 and the address counter 38 and sets the difference in the copy counter 32. When the number of copies is set in the copy counter 32, processing is performed in the same manner as in the case of the CopyLong command.

The command decode circuit 31 sets Copy then
Repeat Byte command or Copythen Repeat Byte Long
When the command is decoded, the copy counter 32 indicates the number of copies, the repeat counter 33 indicates the number of repetitions, the repeat data register 34 indicates 1-byte repeat data, the data size register 43 indicates 1, and the raw data counter 35 indicates. Is set to 0. When the number of copies is set in the copy counter 32, the same processing as that of the CopyLong command is performed, and then the copy counter 32 is set.
Becomes 0. Next, since the number of repetitions is set in the repeat counter 33, the repeat output circuit 41 outputs the 1-byte repetition data stored in the repeat data register 34 as decoded data, and outputs the address counter 38 of the line buffer 39. Write to the position indicated by. One is added to the address counter 38 and one is subtracted from the repeat counter 33. This is repeated until the repeat counter 33 becomes 0, and when it becomes 0, the command decode circuit decodes the next command.

The command decode circuit 31 sets Copy then
When the Repeat Word command or the Copythen Word Byte Long command is decoded, the copy counter 32 indicates the number of copies, the repeat counter 33 indicates the number of repeats, the repeat data register 34 indicates the 2-byte repeat data, and the data size register 43 indicates the number of copies. 2 is set in the raw data counter 35, and 0 is set in the raw data counter 35. When the number of copies is set in the copy counter 32, the same processing as that of the CopyLong command is performed, and then the copy counter 32 is set.
Becomes 0. Next, since the number of repetitions is set in the repeat counter 33, the repeat output circuit 41 outputs the 2-byte repetition data stored in the repeat data register 34 as decoded data, and the address counter 38 of the line buffer 39. 1 at the position indicated by
Write twice byte by byte. The address counter 38 has 1
Is added twice, and 1 is subtracted from the repeat counter 33. This is repeated until the repeat counter 33 becomes 0, and when it becomes 0, the command decode circuit decodes the next command.

The command decode circuit 31 determines that Copy then
Repeat Double Word command or Copythen Repeat Do
When the uble Word Long command is decoded, the copy counter 32 indicates the number of copies, the repeat counter 33 indicates the number of repetitions, the repeat data register 34 indicates 4 bytes of repeated data, and the data size register 43 indicates 4 bytes.
However, 0 is set in the raw data counter 35, respectively. When the number of copies is set in the copy counter 32, first,
Processing is performed in the same manner as in the case of the CopyLong command, and the copy counter 32 eventually becomes zero. Next, since the number of repetitions is set in the repeat counter 33, the repeat output circuit 41 outputs the 4-byte repetition data stored in the repeat data register 34 as decoded data, and the address counter 38 of the line buffer 39. Is written four times, one byte at a time, indicated by. 1 is added to the address counter 38 four times, and 1 is subtracted from the repeat counter 33. Repeat counter 33 is 0
This is repeated until the value becomes 0. When the value becomes 0, the command decode circuit decodes the next command.

The command decode circuit 31 sets Copy then
When the Raw command or the Copythen Raw Long command is decoded, the copy number is set in the copy counter 32, 0 is set in the repeat counter 33, and the raw data number is set in the raw data counter 35. When the number of copies is set in the copy counter 32, the process is performed in the same manner as in the case of the CopyLong command, and the copy counter 32 eventually becomes zero. Next, since the number of raw data is set in the raw data counter 35, the raw data output circuit 42 reads the raw data of 1 byte from the FIFO 19 and outputs it as decoded data, while the address counter 38 of the line buffer 39 indicates. Write to position. One is added to the address counter 38 and one is subtracted from the raw data counter 35. This is repeated until the raw data counter 35 becomes 0. When the raw data counter 35 becomes 0, the command decode circuit decodes the next command.

When the command decode circuit 31 decodes the EOP command, 0 is stored in the copy counter 32,
0 is set in the repeat counter 33 and the raw data counter 35
Is set to 0, and decoding is performed by the control circuit 1 next.
7 until started.

As described above, according to the present embodiment, the data immediately to the left and immediately above are referred to at the time of encoding. Therefore, data having a correlation in both the horizontal and vertical directions, such as image data, is encoded at a high compression rate. In addition, since data other than the data immediately to the left and right above is not referred to, the amount of calculation in encoding is small, and even when encoding is performed by software, high-speed encoding can be performed. Further, according to the present embodiment, since a plurality of operations (copy and repeat, copy and raw data) are simultaneously encoded or decoded, image data can be encoded at a high compression rate. According to the present embodiment,
Since encoding can be performed on repeated data of a plurality of sizes (byte, word, double word), image data of multivalued data can be encoded at a high compression rate.

In the above embodiment, the decoding circuit 20
Is configured by hardware, but may be decrypted by software instead. Various procedures for realizing the processing by the decoding circuit 20 shown in FIG. 9 by software can be considered, and an example of the procedure is shown in FIG.

FIG. 10 is a flowchart for explaining the procedure of the decoding process according to the present embodiment. In FIG. 10, first, in step S101, the next command is fetched, the command is fetched, and the command is decoded. As a result of this decoding, if an EOP code indicating the end of the page is detected, the process ends from step S102.

In step S103, each counter and register are initialized, and in step S104, it is determined whether or not an EOL code is detected as a result of decoding. If an EOL code is detected, the process proceeds to step S105, where the number of remaining bytes of the line is set in a copy counter,
Proceed to step S108.

On the other hand, if it is not an EOL code, the process proceeds from step S104 to step S106, where a copy counter, a repeat counter, and a raw data counter are respectively set according to the result of decoding.
To set the repeat data register and data size register. For example, in the case of a Copythen Repeat Byte command, a value obtained by analyzing the command is set in a copy counter and a repeat counter, and the raw data counter is set to 0. Further, one byte of data following the command is set in the repeat data register,
Set 1 to the data size register.

In step S108, it is determined whether or not the content of the copy counter is 0.
If not, the flow advances to step S109 to extract the number of bytes of the copy counter from the data of the immediately preceding line and output the decoded data.

In step S110, it is determined whether the content of the repeat counter is 0. If the content of the repeat counter is not 0, the flow advances to step S111 to repeatedly output the content of the repeat data register (obtain the data size from the data size register and obtain the data to be repeated) by the number indicated by the repeat counter.

In step S112, it is determined whether the content of the raw data counter is 0. If not, the process proceeds to step S113. In step S113, data for the number of bytes indicated by the raw data counter following the command is obtained and output as decoded data.

Thereafter, the process returns to step S101,
The above processing is repeated until the processing of the page is completed.

By realizing the above processing by a computer, the decoding processing of the present embodiment can be realized by software.

In the above embodiment, the encoding is performed by dividing the processing at the end of the line. Instead, the processing is not divided by the end of the line, and the rightmost data of one line is replaced by the leftmost data of the next line. The processing may be performed assuming that the processing is continued.

In the above-described embodiment, three types of repetitions of 1 byte, 2 bytes, and 4 bytes are processed. Instead, 8 bytes, 16 bytes, 3 bytes, 6 bytes, etc. May be repeated.

Further, in the above-described embodiment, for example, in the case of a long repetition of 1 byte, the data is encoded into a Copy then Repeat Byte Long command. the
n RepeatWord, Copy then Repeat Double Word, Copy t
It may be encoded as a hen Repeat Word Long command or the like.

The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but can be applied to a single device (for example, a copier, a facsimile). Device). Further, an object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and a computer (or CPU or MPU) of the system or apparatus to execute the storage medium Needless to say, this can also be achieved by reading and executing the program code stored in the program.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

Examples of a storage medium for supplying the program code include a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, and CD.
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0128]

As described above, according to the present invention,
In detecting and utilizing repetition of certain data in encoding / decoding, encoding / decoding can be performed using repetition of data of at least two different sizes, thereby increasing the compression rate. Becomes possible. This makes it possible to increase the compression ratio even for image data in which one pixel is represented by multi-values such as gray scale or color image data. Further, according to the present invention, three kinds of operations generally used in encoding using correlation in both horizontal and vertical directions, such as repetition of certain data, copying of processed data, and At least two of them can be encoded simultaneously, and the compression ratio can be further increased. Further, according to the present invention, a high compression rate can be obtained by encoding a data structure of two or more dimensions such as image data using correlation in both horizontal and vertical directions. In particular, the amount of calculation can be reduced by performing compression using data immediately to the left and data immediately above where the horizontal / vertical correlation is most remarkable, and the time required for encoding by software can be shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a hardware configuration of a printing system according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a control configuration of a printing system to which the printing apparatus according to the present embodiment can be applied.

FIG. 3 is a diagram illustrating an example of a command code table used by the printer driver 12 illustrated in FIG. 2 to generate encoded data.

FIG. 4 is a diagram showing an example of a second command code following the Extend command shown in FIG. 3;

FIG. 5 is a diagram illustrating an example of a command operation according to the embodiment;

FIG. 6A is a flowchart illustrating an encoding process of a printer driver according to the present embodiment.

FIG. 6B is a flowchart illustrating an encoding process of the printer driver according to the present embodiment.

FIG. 7 is a diagram showing an example of a program list for realizing the encoding procedure of the printer driver 12 described in FIGS. 6A and 6B.

FIG. 8 is a diagram showing an example of a program list for realizing the function count_raw shown in FIG. 7;

FIG. 9 is a block diagram illustrating details of a decoding circuit 20 illustrated in FIG. 2;

FIG. 10 is a flowchart illustrating a procedure of a decoding process according to the embodiment;

Claims (19)

[Claims] A first obtaining means for detecting a portion which can be replaced by copying the processed data and obtaining a data length of the portion; and replacing the data by repeating data of any one of a plurality of sizes. A second obtaining means for detecting a possible portion and obtaining the content of the data and the data length of the portion; detecting a portion which is not obtained by the first and second obtaining means; Encoding means for acquiring encoded data based on the data length and data content of each part detected by the first to third acquiring means. apparatus. 2. The apparatus according to claim 1, wherein the generation unit generates encoded data representing a data length obtained by the first obtaining unit to the third obtaining unit by a single command. Encoding device. 3. The encoding apparatus according to claim 2, wherein the single command is composed of one byte. 4. The data to be encoded has a two-dimensional array structure, and the first obtaining means determines a portion which can be replaced by copying data at the same column position of the immediately preceding row data. The encoding device according to claim 1, wherein the encoding is detected. 5. The encoding apparatus according to claim 1, wherein the second acquisition unit includes a one-byte length, a two-byte length, and a four-byte length as the plurality of types of sizes. 6. The data to be encoded has a two-dimensional array structure, and the generation unit, when the part detected by the first acquisition unit reaches the end of the row, the part Is replaced with a predetermined command code. 7. The encoding apparatus according to claim 1, wherein the data length acquired by the second acquisition unit is indicated by the number of repetitions of the data of the selected size. 8. An analyzing means for analyzing a command consisting of a code string having a predetermined data length, a storing means for storing decoded data, and an output for outputting decoded data based on an analysis result of the analyzing means. Means, wherein the output means obtains and outputs a corresponding portion of the decoded data from the storage means, and outputs data having a designated size from a plurality of sizes. A second output unit that obtains from the subsequent code sequence and repeats and outputs the specified number of repetitions, and a third output unit that obtains and outputs data of a specified data length from the subsequent code sequence A decoding device characterized by the above-mentioned. 9. The decoding method according to claim 8, wherein the command indicates execution of the combination of the first and second output units or the combination of the first and third output units. apparatus. 10. A first acquisition step of detecting a portion that can be replaced by copying processed data and acquiring the data length of the portion, and replacing the data by repeating data of any one of a plurality of sizes. A second obtaining step of detecting a possible portion and obtaining the content of the data and the data length of the portion; detecting a portion not obtained by the first and second obtaining steps; And a generating step of generating encoded data based on the data length and data content of each part detected in the first to third obtaining steps. Method. 11. The method according to claim 10, wherein the generating step generates encoded data representing a data length obtained in the first to third obtaining steps by a single command. Encoding method. 12. The encoding method according to claim 11, wherein the single command is composed of one byte. 13. The data to be encoded has a two-dimensional array structure, and in the first obtaining step, a portion that can be replaced by copying data at the same column position of the immediately preceding row data is replaced. The encoding method according to claim 10, wherein the encoding is detected. 14. The encoding method according to claim 10, wherein the second acquisition step includes a one-byte length, a two-byte length, and a four-byte length as the plurality of types of sizes. 15. The data to be encoded has a two-dimensional array structure. In the generation step, when the part detected in the first acquisition step reaches the end of the row, the part is Is replaced with a predetermined command code. 16. The encoding method according to claim 10, wherein the data length obtained in the second obtaining step is indicated by the number of repetitions of the data of the selected size. 17. An analyzing step of analyzing a command consisting of a code string having a predetermined data length, a storing step of storing decoded data in a memory, and outputting decoded data based on an analysis result of the analyzing step. A first output step of obtaining and outputting a corresponding portion of the decrypted data from the memory, and a data having a size specified from a plurality of sizes. And a third output step of obtaining and outputting data of a specified data length from the subsequent code string by repeating the same for a specified number of repetitions. A decoding method comprising: 18. The decoding according to claim 17, wherein the command indicates that the first and second output steps are executed in combination or the first and third output steps are executed in combination. Method. 19. A storage medium storing a control program for realizing a method according to claim 10 by a computer.