词法分析器 - Justin的博客

自己写的Java词法分析器：
/*Author: Justin Han
* Time: 2019/11/19
*/

#include <stdio.h>
#include <string.h>

//定义字符类别号
#define ALPHABET 0
#define DEGIT 1
#define WHITESPACE 2
#define SEPCHAR 3
#define MATHCHAR 4
#define STRING 5

//定义字符类别内容
const char alphabet[52] = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 
                                          'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
const char degit[10] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
const char whitespace[3] = { ' ', '\n', '\t' };
const char sepchar[10] = { '{', '}', ';', ',', '.', '(', ')' ,'"', '[', ']'};
const char mathchar[9] = { '>', '<', '=', '+', '-', '|', '/', '*', '&'};

/*定义词类别号
* 整数 19
* 浮点数 20
* 字符串常量 21
* 特殊符号 sepchar数组下标+30
* 运算符号 mathchar数组下标+40
* 标识符 22
* 注释 23
*/
const char* tokens[19] = { "args", "class", "else", "for", "if", "int", "main", "new", "out", "package", "private", "public", "print", "println", "return", "static", "String", "System", "void" };
const char* mathWords[17] = { ">", "<", "=", "+", "-", "|", "/", "*", "&", ">=", "<=", "++", "--", "==" ,"||", "-=", "+="};
//字符转字符串函数
char* toString(char ch)
{
    char str[2];
    str[0] = ch;
    str[1] = 0;
    return str;
}

//生成单词符号
char* token(char* symbol, int charClass)
{
    char str[30] = "(";
    if (charClass == 0)
    {
        for (int i = 0; i < 19; i++)
        {
            if (strcmp(symbol, tokens[i]) == 0)
            {
                char buff[4];
                strcat(str, symbol);
                strcat(str, ", ");
                sprintf(buff, "%d", i);
                strcat(str, buff);
                strcat(str, ")\n");
                return str;
            }
        }
        strcat(str, symbol);
        strcat(str, ", 22");
        strcat(str, ")\n");
        return str;
    }
    else if (charClass == 11)
    {
        strcat(str, symbol);
        strcat(str, ", 19");
        strcat(str, ")\n");
        return str;
    }
    else if (charClass == 12)
    {
        strcat(str, symbol);
        strcat(str, ", 20");
        strcat(str, ")\n");
        return str;
    }
    else if (charClass == 3)
    {
        for (int i = 0; i < 10; i++)
        {
            if (strcmp(symbol, toString(sepchar[i])) == 0)
            {
                char buff[4];
                strcat(str, symbol);
                strcat(str, ", ");
                sprintf(buff, "%d", i+30);
                strcat(str, buff);
                strcat(str, ")\n");
                return str;
            }
        }
    }
    else if (charClass == 4)
    {
        for (int i = 0; i < 17; i++)
        {
            if (strcmp(symbol, mathWords[i]) == 0)
            {
                char buff[4];
                strcat(str, symbol);
                strcat(str, ", ");
                sprintf(buff, "%d", i + 40);
                strcat(str, buff);
                strcat(str, ")\n");
                return str;
            }
        }
    }
    else if (charClass == 5)
    {
        strcat(str, "\"");
        strcat(str, symbol);
        strcat(str, "\", 21");
        strcat(str, ")\n");
        return str;
    }
    else
    {
        strcat(str, symbol);
        strcat(str, ", 23");
        strcat(str, ")\n");
        return str;
    }
}

// 判断字符类别函数
int type(char ch)
{
    for (int i = 0; i < 52; i++)
    {
        if (ch == alphabet[i])
            return ALPHABET;
    }

    for (int i = 0; i < 10; i++)
    {
        if (ch==degit[i])
            return DEGIT;
    }

    for (int i = 0; i < 3; i++)
    {
        if (ch== whitespace[i])
            return WHITESPACE;
    }

    for (int i = 0; i < 10; i++)
    {
        if (ch== sepchar[i])
        {
            if (ch == '"') {
                return STRING;
            }
            else
                return SEPCHAR;
        }
    }

    for (int i = 0; i < 9; i++)
    {
        if (ch== mathchar[i])
            return MATHCHAR;
    }

}

char* tokenise(char* symbolList, char* symbol, char* fileName)
{
    FILE* fp;
    char ch;

    //如果没有找到文件，给出提升并退出
    if ((fp = fopen(fileName, "rt")) == NULL)
    {
        printf("没有找到文件，按任意键退出");
        getch();
        exit(1);
    }

    ch = fgetc(fp);
    while (ch != EOF)
    {
        switch (type(ch))
        {
    
            case WHITESPACE:
                ch = fgetc(fp);
                break;

            case ALPHABET:
                strcat(symbol, toString(ch));
                ch = fgetc(fp);
                while (type(ch) == 0 || type(ch) == 1)
                {
                    strcat(symbol, toString(ch));
                    ch = fgetc(fp);
                }
                strcat(symbolList, token(symbol, ALPHABET));
                symbol[0] = '\0';
                break;

            case DEGIT:
                strcat(symbol, toString(ch));
            
                ch = fgetc(fp);
                int isFloat = 11;
                while (type(ch)==1)
                {
                    strcat(symbol, toString(ch));
                    ch = fgetc(fp);
                }
                if (ch== '.')
                {
                    isFloat = 12;
                    strcat(symbol, toString(ch));
                    ch = fgetc(fp);
                    while (type(ch) == 1)
                    {
                        strcat(symbol, toString(ch));
                        ch = fgetc(fp);
                    }
                }
                strcat(symbolList, token(symbol, isFloat));
                symbol[0] = '\0';
                break;
        
            case MATHCHAR:
                strcat(symbol, toString(ch));
                ch = fgetc(fp);
                if (type(ch) == 4)
                {
                    strcat(symbol, toString(ch));
                    ch = fgetc(fp);
                }
                if (strcmp(symbol, "//") == 0)
                    strcat(symbolList, token(symbol, 23));
                else
                    strcat(symbolList, token(symbol, MATHCHAR));
                symbol[0] = '\0';
                break;

            case SEPCHAR:
                strcat(symbol, toString(ch));
                ch = fgetc(fp);
                strcat(symbolList, token(symbol, SEPCHAR));
                symbol[0] = '\0';
                break;
        
            case STRING:
                ch = fgetc(fp);
                while (ch != '"')
                {
                    strcat(symbol, toString(ch));
                    ch = fgetc(fp);
                }
                strcat(symbolList, token(symbol, STRING));
                ch = fgetc(fp);
                symbol[0] = '\0';
                break;

            default:
                printf("ERROR: Unknown Char: %c\n", ch);
                ch = fgetc(fp);
                break;
        }
    }
    fclose(fp);
    int i = strlen(symbolList);
    return symbolList;
}

void writeFile(char* string, char* fileName)
{
    FILE* fp;
    fp = fopen(fileName, "w");
    fputs(string, fp);
    fclose(fp);
    return;
}
int main()
{
    char* symbolList[6200];
    char result[6200];
    result[0] = '\0';
    symbolList[0] = '\0';
    //char* fileName = "F:\\编译技术实验\\实验1\\sample.txt";
    char fileName[40];
    char resultName[40];
    char* symbol[20];
    symbol[0] = '\0';

    printf("请输入源文件路径(不超过40个字符)：");
    scanf("%s", &fileName);
    strcat(result, tokenise(symbolList, symbol, fileName));

    printf("请输入结果文件路径(不超过40个字符)：");
    scanf("%s", &resultName);
    writeFile(result, resultName);

    printf("%s", result);
    return 0;
}