CN1119865C - method of letter compression - Google Patents

Abstract

The invention relates to a letter compression method, which is used for storing a letter, wherein the letter is contained in a symbol set, and the method is characterized by comprising the following steps: setting a five-bit code, wherein the first bit is a head code, namely a specific bit, the second bit to the fifth bit are tail codes, namely storage units, the symbol set is set in the tail codes, and the four tail codes can form sixteen codes; step two, the head code is represented by '0' and '1', and the tail code corresponding to the head code '0', namely the symbol set, is 'A to M'; the tail code corresponding to the head code "1" is "N to Z"; step three, respectively coding the tail codes of the symbol sets from A to M into hexadecimal '0 to 9 and from A to C', and similarly, the tail codes of the symbol sets from N to Z are also '0 to 9 and from A to C'; therefore, twenty-six English letters can be equivalently coded into five bits, the storage space is effectively reduced, and more telephone identification codes can be stored in a smaller storage space.

Description

method of letter compression

The invention relates to a method for letter compression, in particular to a method for letter compression applied to a telephone set storing a caller identification code (CallerID).

Due to market demands, a telephone set with a telephone identification code has been gradually popularized. The phone identification code usually includes information such as the name (or code) of the caller, the time and date of the call, and when the call is dialed in, the user can know who the caller is in advance, so as to decide whether to answer the call or not. Such an approach can make the user answer the phone more at ease, and of course, it has a positive effect on preventing illegal things from happening.

Since a person's name is usually within 16 letters, and because the ASCII code system uses 8-bit codes to code codes representing 256 different symbols, the English capital letters are from hexadecimal 21H to 3AH, so The storage space for depositing the name part of the telephone identification code is designed to be 16 bytes (Bytes), but such a practice obviously needs to be improved.

Please refer to FIG. 1 , in a telephone set with a telephone identification code, the data structure of the telephone identification code in the prior art is usually divided into three parts. The first part 11 is 2 bytes and is used to store the time. For example, at 10:30, the data stored in the first part is "1030". The second part 12 is also 2 bytes for storing the date, such as "1120" on November 20th. The size of the third part 13 is 16 bytes, which is used to store the name code of the caller, such as "AB...N", then there is a third part 13 which is 21, 22, ..., 2E in hexadecimal ; wherein the first part and the second part are expressed in BCD code (binary-decimal system), and the third part 13 is expressed in ASCII code.

In fact, the name code of the third part 13 can be composed of uppercase English letters, and there are 26 English letters, so five digits can be used to complete the encoding, and eight digits are not needed. However, the addressing of the memory is usually in units of bytes. If in order to save storage space, the five-bit coded data "one after another" will be stored in eight bits (equal to one byte) in units of five bits in order to save storage space. In the memory of the address unit, it becomes much more complicated in reading and writing data and processing.

The purpose of the present invention is to provide a method for letter compression, which can effectively reduce the storage space of twenty-six English letters in a manner equivalent to five-digit encoding, so that a smaller storage space can store more phone identification codes .

The purpose of the present invention is achieved like this:

A letter compression method for storing a letter contained in a symbol set, which is characterized in that it includes the following steps:

Step 1, a five-bit code is set, the first is a header code that is a specific position, the second to the fifth is a tail code that is a storage unit, the collection of symbols is set in the tail code, and the four tail codes can be Form sixteen codes;

Step 2, the header code is represented by "0" and "1", and the tail code corresponding to the header code "0" is the set of symbols "A, B, C, D, E, F, G, H, I, J, K, L, M"; the tail code corresponding to the head code "1" is "N, O, P, Q, R, S, T, U, V, W, X, Y, Z";

Step 3, code the end codes of the symbol sets "A, B, C, D, E, F, G, H, I, J, K, L, M" into hexadecimal "0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C", the same symbol set "N, O, P, Q, R, S, T, U, V, W, X, Y, The tail code of Z is also "0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C".

In the above-mentioned letter compression method, wherein, the word order of the letter is represented by the symbol set {A} being 0, {B} being 1, ..., to {Z} being 25; the letter The quotient of the word order divided by 13 determines the value of the header code, and the remainder determines the value of the storage unit.

In the above letter compression method, wherein, the size of the storage unit for storing a letter is four bits.

In the above-mentioned letter compression method, wherein, the four-bit tail code storage unit forms 16 bits to form a 10-byte storage space, and the 10-byte storage space can accommodate up to 16 letter.

The present invention divides the English symbol set into half, if the stored English alphabet is the letter of the first half, then set a specific bit as "0", otherwise "1"; secondly, after dividing half according to the stored English alphabet The order of words in the two subsets determines the value of a storage unit (4 bits). Therefore, only 5 bits are needed to store a letter, so the space for storing the phone identification code can be greatly reduced.

The purpose, features and advantages of the present invention can be further understood through the following description of an embodiment of the method for letter compression of the present invention in conjunction with the accompanying drawings. Among them, the attached figure is:

Fig. 1 is a prior art telephone identification code data structure.

Fig. 2 is and the phone identification code data structure in the letter compression method that the present invention proposes.

See Figure 2. As mentioned earlier, the English letters in the name of the phone identification code 30 can be coded with five bits in fact, but if they are coded purely according to the order of the letters, it will be more complicated when processing, so in This proposes a coding method that can be coded by five bits and is not complicated to process, such as the Header/Tailer comparison table listed. Assign the first half of the English letter "A, B, C, D, E, F, G, H, I, J, K, L, M" to the head code "0", while the second half of the English letter "N , O, P, Q, R, S, T, U, V, W, X, Y, Z" is "1". Secondly, the tail codes of A to M are respectively coded as "0" to "C" in hexadecimal, and the tail codes of "N" to "Z" are also "0" to "C" in the same way.

The time and date of the first part and the second part do not need to be further processed because they are BCD codes (binary-decimal system), so there is no change. The difference is that 16 specific bits of the header part 31 are planned to store the header code (Header) of 16 letters respectively; at the same time, with 16 storage units, each storage unit has 4 Bits, which can represent up to ten Six kinds of codes represent the thirteen English letters (A～M or N～Z) that are divided into half.

That is, when the central processing unit (CPU) is writing a certain English letter of the phone identification code name into the memory, it must be judged whether the English letter belongs to the first thirteen letters or the last thirteen letters. If it is the first thirteen letters, write "0" into a specific bit, and then write the word sequence (0 to 12) of the letter into a storage unit; otherwise, if it belongs to the last thirteen letters, write "1" is written into the specific bit, and then the word sequence (0 to 12) of the letter exceeding "M" is written into the storage unit. The storage unit is four bits, plus the specific bit, a total of five bits. The letters are stored in five bits, so the storage space can be greatly reduced.

When writing data, you can first subtract the ASCII code of "A" from the ASCII code of the input letter (21 in hexadecimal, 33 in decimal) to get the word order of the letter, for example, when inputting "A" , the ASCII code of "A" itself is subtracted, and the word order is 0, and for example, the ASCII code of "Z" (decimal is 58), minus the ASCII code of "A" (decimal is 33), you can get Word order 25. Then divide the word order by 13, the resulting quotient is the header (Header), and the remainder is the tailer (Tailer). For example, the word order of "A" is 0, divided by 13, the header code is 0 , the tail code is also 0, and the word order of "Z" is 25, which can be divided by 13 to get the head code 1 and the tail code 12 (hexadecimal is C). Of course, if it is not implemented by division, it can also be done by subtraction, and the principle is the same.

When reading data, the data of the header part 31 and the tail part 32 can be read out one by one. When reading a head code and a tail code, multiply the head code by 13, add the tail code, and add the ASCII code of "A" to restore the ASCII code of the original letter.

In FIG. 2, for clarity, an example with the name "JOHNSONYKK" is given. From the header code/tail code comparison table, the header code is "01011111100" and the tail code is "9170510BAA" (expressed in hexadecimal). Since this embodiment takes the storage of sixteen letters as an example, the head code/tail code will be filled with hexadecimal "0" and "F" respectively for the part that is less than sixteen letters, so the data actually stored in the memory is, The header code part is 31 "6F00", and the tail code part is 32 "9170510BAAFFFFFF". Why is the tail code not filled with "0" like the head code? Because if the tail code is also "0", when the central processing unit reads back the data, it will be misjudged as the English letter "A". In order to prevent misjudgment, the tail code is supplemented with hexadecimal "F" instead of " 0".

In fact, the present invention can also be applied to store 8 letters, 24 letters, 32 letters, etc. If 8 letters are stored, only 5 bytes are needed, and 24 letters are stored, only 15 words are needed. Section, 32 letters are 20 bytes.... It can be seen that compared with ordinary storage, each byte stores a letter, which can be compressed to five-eighths of the storage space.

In application, the present invention uses commonly used letters {'A', 'B',...'Z'} as a set of symbols, half of which is used for encoding, and of course, it can be changed to other symbols as required, or Add some commonly used symbols (in this embodiment, in fact, six symbols can be programmed).

The above-mentioned mathematical operations can be realized by using the logical operation unit (ALU) of the central processing unit, and the technology of the central processing unit is a prior art, so the present invention does not describe it much. From the above illustrations and descriptions, we can see that the storage space of the phone identification code (CallerID) to store the letters of the name can be reduced to five-eighths by utilizing the special design of the code and data structure. In other words, the same storage space More phone IDs can be recorded.

Claims (4)

1. the method for a letter compression, in order to store a letter, this letter system is included in the assemble of symbol, it is characterized in that may further comprise the steps:

Step 1 is provided with First Five-Year Plan position coding, and first is that the head sign indicating number is a certain bits, and second to the 5th is that the tail sign indicating number is a memory cell, and described assemble of symbol just is arranged in the tail sign indicating number, and four tail sign indicating numbers can be formed 16 kinds of sign indicating numbers;

Step 2, head sign indicating number represent that with " 0 " and " 1 " head sign indicating number " a 0 " pairing tail sign indicating number is that assemble of symbol is " A, B, C, D, E, F, G, H, I, J, K, L, M "; Head sign indicating number " 1 " pairing tail sign indicating number is " N, O, P, Q, R, S, T, U, V, W, X, Y, Z ";

Step 3 is compiled the tail sign indicating number of assemble of symbol " A, B, C, D, E, F, G, H; I, J, K, L, M " respectively and to be sexadesimal system " 0,1,2,3,4; 5,6,7,8,9, A, B, C ", and in like manner the tail sign indicating number of assemble of symbol " N; O, P, Q, R, S, T, U, V; W, X, Y, Z " also is " 0,1,2,3,4; 5,6,7,8,9, A, B, C ".

2. the method for letter compression as claimed in claim 1 is characterized in that: the word preface of described letter by assemble of symbol A} is 0, and B} is 1 ...., to { Z} 25 represents; The word preface that this is alphabetical is the value of decision head sign indicating number divided by 13 merchant, and its remainder determines the value of this memory cell.

3. the method for letter compression as claimed in claim 1 is characterized in that: described size in order to the memory cell of storing a letter is to be four positions.

4. the method for letter compression as claimed in claim 1 is characterized in that: the tail code memory unit of described four positions forms 16 positions, form the memory space of one 10 byte-sized, and the memory space of this 10 byte-sized holds 16 letters at most.