JPH0659902A - Processing method for substituting character string - Google Patents

Abstract

PURPOSE:To provide a character string substituting method having faster speed and higher memory using efficiency as compared with a convensional method. CONSTITUTION:A substituting character string table for storing definition information for a character string to be substituted is prepared. Then a stack having a pointer to the character string to be substituted in the table and a pointer to the argument of the character string to be substituted in an input area as elements is parepared. The character string in the input area is retrieved and whether the character string is substituted or not is judged. When substitution is necessary, the table is referred to and the pointer to the character string to be substituted and the pointer to the argument of the character string to be substituted in the input area are stored in a stack. A character string specified by the pointer stored in the stack is copied to an output area to substitute the character string.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an efficient character string replacement processing method.

[0002]

2. Description of the Related Art As a method of inputting a character string and performing a character string replacement process, a processing method as shown in FIG. 6 is conventionally known.

This processing method is applied to "#define" in a preprocessor of a C compiler as shown in FIG.
By the definition of “f (x, y) x + y”, the character string “f
The process of replacing (100, 200) ”with the character string“ 100 + 200 ”will be described with reference to FIGS. 6 and 7.

First, a table (hereinafter referred to as a replacement character string table) for storing definition information of a character string to be replaced (in this example, "f (x, y) x + y") as data is generated ( S20). Next, the character string on the input area as shown in FIG. 7 is searched to determine whether it is a character string to be replaced (S21). If a character string to be replaced (in this case, "f" (n26), hereinafter referred to as a replaced character string) is found, this replaced character string and thereafter (in this case, "(10
0,200) == 300) {”(c27)) is copied to the save area and saved (S22). Of the saved character strings, the argument of the replaced character string “f” (in this case, “100”
Up to (c28) and "200" (c29), the character strings stored in the replacement character string table (in this case, "+" (c
30)) is copied to the output area (S23). Then, after the argument of the replaced character string (in this case, "== 300) {"
(C31)) is copied to the output area (S24). If there is no character string to be replaced in the input area, the character string in the input area is copied to the output area (S25).

[0005]

In the above-mentioned conventional method, when a character string to be replaced is found, it is necessary to save the character string after the character string to be replaced. It is necessary to prepare a new save area,
In addition, since the character string must be copied twice from the input area to the save area and from the save area to the output area, there is a disadvantage that the efficiency is low.

[0006]

SUMMARY OF THE INVENTION A character string replacement processing method of the present invention is a character replacement processing method in a C processor preprocessor for replacing a character string to be replaced in an input character string. A stack having a replacement character string table for storing column definition information is provided, and a stack having a pointer to the replacement character string in the table and a pointer to the argument of the replaced character string on the input area as an element is prepared, Whether the above character string is replaced or not is determined, and when the replacement is not necessary, the character string on the input area is output to an output area provided in advance, and when the replacement is necessary, the replacement character string table is referred to. A pointer to the replacement character string and a pointer to the argument of the replaced character string on the input area are stored in the stack, and the character string pointed to by the pointer in the stack is stored in the output area. Characterized by copying.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, details of the present invention will be described with reference to the drawings by using a character string replacing process in a preprocessor of a C compiler.

FIG. 1 is a flow chart of processing of an embodiment of the present invention. The operation of this embodiment will be described with reference to FIG.

Generation process of replacement character string table (S1)
Is a process for storing the definition of the character string to be replaced in the table as a token in advance. As shown in (T7) of FIG. 2, the replacement character string table is composed of a collection of replacement character string names (t9) and tokens (t10). Tokens include argument Dokun and string tokens.

For example, "#define f (x, y)
The definition "x + y" is stored in the replacement character string table (T8) in FIG. The replacement character string name is “f” and is stored as a character string in the field t9. (T11) is an argument token, and when there is an argument in the character string being defined,
Corresponds to that argument ("x" and "y" for this column), and indicates that when it finds the replaced string, it replaces this token with the argument string of that replaced string. There is.

(T12) is a character string token, which indicates that it is a character string other than the argument described in the definition character string.

Next, the control is transferred to the stack generation process (S2). In the stack generation process (S2), a table (which is called a stuff) having a pointer that points to the beginning of the character string as an element is generated. Next, the control is transferred to the replacement character string search process (S3). In the replacement character string search process (S3),
Search for a character string to be replaced in the input area. If there is a character string to be replaced, the control is moved to the process of storing the pointer of the character string in the input area on the stack (S4), and if the character string to be replaced does not exist,
The control is transferred to a process (S6) of copying the character string on the input area to the output area.

In the process of storing the pointer of the character string on the input area in the stack (S4), the previously generated replacement character string table is referred to, and the argument and character string of the replaced character string corresponding to the replacement character string name. From the token, the argument token is the start pointer of the string of the corresponding argument, and the string token is
Stores pointers to character strings other than the definition arguments. At this time, the first-in first-out method is used as a method of storing in the stack.

In the case of this column, as shown in FIG. 3, in the replacement character string table, the replacement character string name is "f" and the tokens are "argument token 1 (t11)" and "character string token (t12)". And "argument token 2 (t11)". The sequence of tokens is "argument token 1",
Since "character string token" and "argument token 2" follow, they are stored in this order in the stack. At this time, since the first-in, last-out method is adopted as the method of storing in the stack, first, the pointer of the character string corresponding to "argument token 2", in this case, the leading pointer of "200" is stored in the stack (p13). Next, the top pointer of “Δ + Δ” corresponding to the character string token is stored in the stack (p1
4). Furthermore, "10" corresponding to "argument token 1"
The leading pointer of "0" is stored in the stack (p15).

Next, the control is transferred to the copy processing (S5) of the character string pointed to by the pointer in the stack. In the copy processing of the character string pointed to by the pointer in the stack (S5), the stack is referenced, and the character string on the input area pointed to by the pointer stored in the stack and the character string other than the defined argument are copied to the output area. To do. In the case of this example, as shown in FIG. 4, first, the character string "100" pointed by the pointer (p15) lastly stacked on the stack is copied to the output area (c16). Further, the character string “Δ + Δ” pointed to by the pointer (p14) secondly stacked on the stack is copied (c17), and the character string “200” finally pointed by the pointer (p13) first stacked on the stack is copied. Is copied to the output area (c18).

When all the copying is completed, the control is transferred to the replacement character string retrieving process (S3).

In the replacement character string retrieval process (S3),
When the character string searched in the input area is a character string that does not need to be replaced, it is copied as it is to the output area (S6). In the case of this example, as shown in FIG. 5, since "if (" is a character string that does not need to be replaced, it is directly copied to the output area (c19).

[0018]

As described above, according to the present invention, a stack having a pointer to a character string is prepared, and the character string pointed to by the pointer in the stack is copied only once when necessary. It has the effect of processing at a higher speed than the method.

Further, by providing this stack, the save area is unnecessary, and the element of the stack uses only the number of the tokens when the replacement character string exists, so that the memory is efficiently used. effective.

[Brief description of drawings]

FIG. 1 is a flow chart of processing showing an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration example of a replacement character string table.

FIG. 3 is an operation explanatory diagram in the example of the present invention.

FIG. 4 is an operation explanatory diagram in the example of the present invention.

FIG. 5 is an operation explanatory diagram in the example of the present invention.

FIG. 6 is a flow chart of processing of a conventional technique.

FIG. 7 is an operation explanatory diagram of the example of the related art.

FIG. 8 is a flowchart of processing of a compiler.

[Explanation of symbols]

S1 Replacement character table generation processing S2 Stack generation processing S3 Replacement character string search processing S4 Stack storage processing S5 Stack reference and output area copy processing S6 Output area copy processing S20 Replacement character string table S21 Replacement character string search processing S22 Character string on input area is saved to save area S23 Replacement character string table is referenced and output area is copied S24 Character string on save area is output to output area Copy process S25 Copy process to output area

Claims (1)

[Claims] 1. A character string replacement processing method in a C processor preprocessor for replacing a character string to be replaced in an input character string, comprising a replacement character string table for storing definition information of a character string to be replaced, A stack having, as elements, a pointer to the replacement character string in the table and a pointer to the argument of the replaced character string on the input area is prepared, the presence or absence of replacement of the character string on the input area is determined, and the replacement is performed. If it is not necessary, the character string in the input area is output to the output area provided in advance, and when the replacement is necessary, the replacement character string table is referred to and the pointer to the replacement character string and the object in the input area are referenced. A character string replacement processing method, wherein a pointer to an argument of a replacement character string is stored in the stack, and the character string pointed to by the pointer in the stack is copied to the output area.