基于C语言的词法分析器源码(编译原理作业).zip

#pragma once #include"headers.h" extern long sourceFileSize; extern char* sourceFileBuffer; long bufferAccessPointer = 0; char strToken[MAX_STD]; int strTokenPointer = 0; char getChar(char direciton) { if (direciton == 'f') { if (bufferAccessPointer < sourceFileSize) { char ch = sourceFileBuffer[bufferAccessPointer]; bufferAccessPointer++; return ch; } } else if (direciton == 'a') { if (bufferAccessPointer > 0) { bufferAccessPointer--; char ch = sourceFileBuffer[bufferAccessPointer]; return ch; } } } void retrack() { if (bufferAccessPointer > 0) bufferAccessPointer--; } void strTokenClear() { strTokenPointer = 0; int flag = 0; for (int i = 0; i < MAX_STD; ++i) { flag = 0; if (strToken[i] != '\0') { strToken[i] = '\0'; flag = 1; } if (flag == 0) break; } } //get valid token forward or afterward void getValidToken(char* ch, char direction) { if (direction == 'f') { while ((isBlank(*ch) || isNULL(*ch) || isBreak(*ch) || isTab(*ch)) && bufferAccessPointer < sourceFileSize) { *ch = getChar('f'); } } else if (direction == 'a') { while ((isBlank(*ch) || isNULL(*ch) || isBreak(*ch) || isTab(*ch)) && bufferAccessPointer > 0) { *ch = getChar('a'); } } } void Concat(char ch) { if (ch != '\0') { strToken[strTokenPointer] = ch; strTokenPointer++; } } int analyzer() { char ch = getChar('f'); getValidToken(&ch, 'f'); strTokenClear(); //isNULL(ch) ? printf("[Debug] get char is NULL\n") : printf("[Debug] get char is %c\n", ch); //Keywords or identifier judge if (isLetter(ch)) { while (isLetter(ch) || isDigit(ch) || ch == '_') { Concat(ch); ch = getChar('f'); } retrack(); int IN_code = isKeyword(strToken); if (IN_code != -1) return IN_code + 1; else return _identifier_encode; } //Keywords or identifier judge else if (ch == '_') { while (isLetter(ch) || isDigit(ch) || ch == '_') { Concat(ch); ch = getChar('f'); } retrack(); int IN_code = isKeyword(strToken); if (IN_code != -1) return IN_code + 1; else return _identifier_encode; } //Number judge else if (isDigit(ch)) { if (ch == '0') { Concat(ch); ch = getChar('f'); if (ch == 'x' || ch == 'X') { Concat(ch); ch = getChar('f'); while (isDigit(ch)||(ch>='a'&&ch<='f')||(ch>='A'&&ch<='F')) { Concat(ch); ch = getChar('f'); } retrack(); return _number_encode; } } _Bool getDotFlag = false; _Bool getFloatFlag = false; while (isDigit(ch) || (ch == '.' && !getDotFlag&&!getFloatFlag)||((ch=='e'||ch=='E')&&!getFloatFlag)) { if (ch == '.') getDotFlag = true; else if (ch == 'e' || ch == 'E') getFloatFlag = true; Concat(ch); ch = getChar('f'); } retrack(); return _number_encode; } //Number or dot judge else if (ch == '.') { Concat(ch); ch = getChar('f'); if (isDigit(ch)) { while (isDigit(ch)) { Concat(ch); ch = getChar('f'); } retrack(); return _number_encode; } else retrack(); return _dot; } //Delimiter judge switch (ch) { case '(': { Concat(ch); return _parenthesis_left; } case ')': { Concat(ch); return _parenthesis_right; } case '[': { Concat(ch); return _bracket_left; } case ']': { Concat(ch); return _bracket_right; } case '{': { Concat(ch); return _brace_left; } case '}': { Concat(ch); return _brace_right; } case '\\': { Concat(ch); return _back_slash; } case ';': { Concat(ch); return _semicolon; } case '\'': { Concat(ch); return _single_quotes; } case '\"': { Concat(ch); return _double_quotes; } case ',': { Concat(ch); return _comma; } case '#': { Concat(ch); return _sharp; } default: break; } if (ch == '<') { Concat(ch); ch = getChar('f'); if (ch == '<') { Concat(ch); ch = getChar('f'); if (ch == '=') { Concat(ch); return _left_shift_equal; } else { retrack(); return _left_shift; } } else if (ch == '=') { Concat(ch); return _less_equal; } else { retrack(); return _less; } } else if (ch == '>') { Concat(ch); ch = getChar('f'); if (ch == '>') { Concat(ch); ch = getChar('f'); if (ch == '=') { Concat(ch); return _right_shift_equal; } else { retrack(); return _right_shift; } } else if (ch == '=') { Concat(ch); return _great_equal; } else { retrack(); return _great; } } else if (ch == '+') { Concat(ch); ch = getChar('f'); if (ch == '+') { Concat(ch); return _increment; } else if (ch == '=') { Concat(ch); return _plus_equal; } else { retrack(); return _plus; } } else if (ch == '-') { Concat(ch); ch = getChar('f'); if (ch == '-') { Concat(ch); return _decrement; } else if (ch == '=') { Concat(ch); return _sub_equal; } else if (isDigit(ch)) { Concat(ch); _Bool getDotFlag=false; ch = getChar('f'); while ((ch=='.'&&!getDotFlag)||isDigit(ch)) { if (ch == '.') getDotFlag = true; Concat(ch); ch = getChar('f'); } retrack(); return _number_encode; } else { retrack(); return _sub; } } else if (ch == '*') { Concat(ch); ch = getChar('f'); if (ch == '=') { Concat(ch); return _mul_equal; } else { retrack(); return _mul_deref; } } else if (ch == '/') { Concat(ch); ch = getChar('f'); if (ch == '=') { Concat(ch); return _div_equal; } else { retrack(); return _div; } } else if (ch == '%') { Concat(ch); ch = getChar('f'); if (ch == '=') { Concat(ch); return _mod_equal; } else { retrack(); return _mod; } } else if (ch == '=') { Concat(ch); ch = getChar('f'); if (ch == '=') { Concat(ch); return _equal; } else { retrack(); return _assignment; } } else if (ch == '?') { Concat(ch); return _question_mark; } else if (ch == ':') { Concat(ch); return _colon; } else if (ch == '&') { Concat(ch); ch = getChar('f'); if (ch == '&') { Concat(ch); return _and; } else if (ch == '=') { Concat(ch); return _bit_and_equal; } else { retrack(); return _bit_and_addr; } } else if (ch == '|') { Concat(ch); ch = getChar('f'); if (ch == '|') { Concat(ch); return _or; } else if (ch == '=') { Concat(ch); return _bit_or_equal; } else { retrack(); return _bit_or; } } else if (ch == '^') { Concat(ch); ch = getChar('f'); if (ch == '=') { Concat(ch); return _bit_xor_equal; } else { retrack(); return _bit_xor; } } else if (ch == '!') { Concat(ch); ch = getChar('f'); if (ch == '=') { Concat(ch); return _not_equal; } else { retrack(); return _not; } } else if (ch == '~') { Concat(ch); return _bit_not; } return -1; }