mytest.py

import sys
from antlr4 import *
from gen.CLexer import CLexer
from gen.CParser import CParser
from gen.CVisitor import CVisitor
import itertools

result = open('result.java', 'w')       # opening output file to write
contextList = []
dataList = ["d", "c", "f", "s"]         # popular data types in c like %d, %c, %f, %s
ignoreList = ["unsigned"]


class MyCVisitor(CVisitor):
    def __init__(self):
        pass

    def visitTranslationUnit(self, ctx):            # store root of the traversal tree...
        contextList.append(ctx)
        pass


class CoverCases:
    def printWithoutNewLine(self, var):              # print the word without newline
        print(var, file=result, end=" ")

    def printWithNewLine(self, var):                # print the word with newline
        print(var, file=result, end="\n")

    def spaceGeneration(self, tab):                  # for proper indentations...
        for x in range(tab):
            print("\t", file=result, end="")

    def removeLastChar(self):                       # remove space before [++] [,] [;] [--]
        size = result.tell()
        with open("result.java", "r") as f:
            file_str = str(f.read())
            f.close()
        last_chr = file_str[size-1]
        if last_chr == " ":                         # if last character is whitespace the remove
            result.truncate(size - 1)

    def checkIgnore(self, var):
        if var in ignoreList:                       # write nothing if found this...
            return 1
        return 0


class Header:                                       # to handle header files
    def include_library(self, var):
        # to be implemented later...
        return


def main(argv):

    inputFile = FileStream(argv[1])
    lexer = CLexer(inputFile)
    stream = CommonTokenStream(lexer)
    parser = CParser(stream)
    tree = parser.compilationUnit()

    v = MyCVisitor()
    v.visit(tree)

    print("package demo;\n\npublic class DemoTranslation {\n", file=result, end="")  # default format of java program

    tab = 0                                 # for handling indentation...
    beginFlag = 1                           # to check for line beginning...
    argFlag = 0                             # for command line input...
    ignore = 0                              # java translation for command line input...
    funFlag = 0                             # for return type of functions...
    printFlag = 0                           # to handle print statements...
    forFlag = 0                             # to handle for loop...
    c = 0                                   # index of variable list...
    declarationFlag = 0                     # to handle newline in declaration of arrays etc...
    stringLiteral = ""                      # message part in print statements...
    variableList = []                       # variables part in print statements...
    solve = CoverCases()                    # instance of class to access class functions...
    header = Header()                       # instance of class to handle header files...

    mainFlag = 0
    skipFlag = 0
    defFlag = 0
    tempString = ""

    while len(contextList) > 0:             # runs till we found node in the traversal tree...

        t = 0
        firstChild = contextList[0]
        contextList.pop(0)

        # print(str(firstChild.getText()) + "-- " + str(type(firstChild)))

        if str(type(firstChild)) == "<class 'gen.CParser.CParser.FunctionDefinitionContext'>":  # handle functions
            funFlag = 1
        if str(type(firstChild)) == "<class 'gen.CParser.CParser.DeclarationContext'>":     # to handle array list
            declarationFlag += 1
        if firstChild.getText() in ["for"]:                                                 # to handle for loop
            forFlag += 2

        if str(type(firstChild)) == "<class 'gen.CParser.CParser.ExternalDeclarationContext'>":     # for function declaration
            if defFlag != 0:
                solve.spaceGeneration(tab + 1)
                print(tempString, file=result, end="\n")
                tempString = ""
            defFlag += 1
            declarationFlag = 0
            skipFlag = 0
        if str(type(firstChild)) == "<class 'gen.CParser.CParser.FunctionDefinitionContext'>":      # check if function
            defFlag = 0
            skipFlag = 0

        if str(type(firstChild)) == "<class 'gen.CParser.CParser.IncludeContext'>":     # check if header file
            header.include_library(firstChild)
            continue

        if firstChild.getChildCount() > 0:
            if str(type(firstChild)) == "<class 'gen.CParser.CParser.ParameterTypeListContext'>" and defFlag != 0:
                tempString = ""
                skipFlag += 1
                defFlag = 0
                continue
            if skipFlag != 0:           # skip function declaration
                tempString = ""
                continue
            for x in range(0, firstChild.getChildCount()):      # add child of node for next traversal
                contextList.insert(t, firstChild.children[x])
                t = t + 1
        elif firstChild.getChildCount() == 0:                       # enters when leaf is found...
            word = firstChild.getText()
            if skipFlag != 0:                                       # skip function declaration
                tempString = ""
                continue
            if defFlag != 0:
                tempString += word + " "
                continue
            if beginFlag == 1:                                      # to add indentation
                solve.spaceGeneration(tab)
                if (word != "}") and beginFlag == 1:
                    print("\t", file=result, end="")
            if solve.checkIgnore(word):
                continue
            elif word in [";"]:                                     # new line begins after this...
                solve.removeLastChar()
                if forFlag == 0:
                    solve.printWithNewLine(word)
                    beginFlag = 1
                else:
                    forFlag -= 1
                    solve.printWithoutNewLine(word)
                declarationFlag = 0
            elif word in ["{"]:                                     # new line begins after this...
                if declarationFlag == 0:
                    solve.printWithNewLine(word)
                    tab += 1
                    beginFlag = 1
                else:
                    solve.printWithoutNewLine(word)
            elif word in ["printf"]:                                # translate print statement...
                print("System.out.print", file=result, end="")
                printFlag = 1
                beginFlag = 0
            elif word in ["int", "void"] and funFlag == 1:          # handle return type of functions...
                print("public static " + word, file=result, end=" ")
                beginFlag = 0
                funFlag = 0
            elif word in ["main"]:
                solve.printWithoutNewLine(word)
                mainFlag += 1

                argFlag = 1
            elif word in ["}"]:                                     # new line begins after this...
                if declarationFlag == 0:
                    solve.printWithNewLine(word)
                    tab -= 1
                    beginFlag = 1
                else:
                    print(word, file=result, end=" ")
            elif word in ["("] and argFlag == 1:
                solve.printWithoutNewLine(word)
                ignore = 1
            elif word in ["("]:
                solve.printWithoutNewLine(word)
                c = -1
                if printFlag == 1:
                    printFlag = 2
            elif word in [")"] and argFlag == 1:
                print("String[] args )", file=result, end=" ")
                ignore = 0
                argFlag = 0
            elif word in ["++", "--"]:
                solve.removeLastChar()
                solve.printWithoutNewLine(word)
            elif word in [","] and printFlag == 0:
                solve.removeLastChar()
                solve.printWithoutNewLine(word)
            else:                                       # translation of print arguments and messages(differently)...
                if printFlag == 2:                      # store message of print statement...
                    stringLiteral = word
                    printFlag = 3
                elif printFlag == 3:                    # variable part of print statement...
                    temp1 = 0
                    if word in [")"]:
                        for var in stringLiteral:       # look for data type in message part...
                            if temp1 == 1:
                                if var in dataList:     # if data type is found
                                    print("\");\n", file=result, end="")
                                    solve.spaceGeneration(tab+1) # for proper indentations...
                                    print("System.out.print(", file=result, end=" ")
                                    if variableList[0] in ["argc"]:     # command line input translation...
                                        print("args.length+1 ) ;\n", file=result, end="")
                                    else:
                                        print(variableList[0] + " );\n", file=result, end="")
                                    solve.spaceGeneration(tab+1) # for proper indentations...
                                    print("System.out.print( \"", file=result, end="")
                                    variableList.pop(0)
                                else:
                                    print("%"+var, file=result, end="")  # if % is not used as data type(like %d)...
                                temp1 = 0
                            elif var == "%":
                                temp1 = 1
                            else:
                                print(var, file=result, end="")
                        variableList = [""]                                           # reset variable list...
                        c = -1
                        printFlag = 0
                        print(")", file=result, end="")
                    if word not in [",", ")"]:
                        variableList.insert(c, variableList[c]+word)  # handle expression in print...
                    else:
                        variableList.append("")
                        c += 1
                else:                                                               # print rest of the program
                    if ignore == 0:
                        solve.printWithoutNewLine(word)
                        beginFlag = 0

    print("}", file=result, end="")


if __name__ == '__main__':
    main(sys.argv)