X-Git-Url: http://svarog.pmf.uns.ac.rs/gitweb/?p=mjc2wsl.git;a=blobdiff_plain;f=src%2Fmjc2wsl.java;h=bc6f4656427485f057a9bfe8e4b4676113b3d616;hp=16b0e3766a5c721e008097b7f223841b105fae4b;hb=dd51d4504d3c15dd2c58bf9ece80cd182b02d5d5;hpb=29066990720e2feaa5ed90608a9a6a7ea983f7a7 diff --git a/src/mjc2wsl.java b/src/mjc2wsl.java index 16b0e37..bc6f465 100644 --- a/src/mjc2wsl.java +++ b/src/mjc2wsl.java @@ -1,3 +1,21 @@ +/* + Copyright (C) 2014 Doni Pracner + + This file is part of mjc2wsl. + + mjc2wsl is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + mjc2wsl is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with mjc2wsl. If not, see . +*/ import java.io.*; import java.util.*; @@ -10,28 +28,10 @@ import java.util.*; * @author Doni Pracner, http://perun.dmi.rs/pracner http://quemaster.com */ public class mjc2wsl{ - public static String versionN = "0.1.4"; + public static String versionN = "0.1.5"; + + private TransMessages messages = new TransMessages(); - public static final int M_ERR = 2, M_WAR = 1, M_DEB = 0; - - private int printLevel = M_ERR; - - private int[] messageCounters = new int[M_ERR+1]; - - private void message(String mes, int level){ - if (level>=printLevel) - System.out.println(mes); - messageCounters[level]++; - } - - private void printMessageCounters(){ - printMessageCounters(System.out); - } - - private void printMessageCounters(PrintStream out){ - out.println("total errors:"+messageCounters[M_ERR]+" warnings:"+messageCounters[M_WAR]); - } - private boolean genPauseAfterEachAddress=false, genPrintForEachAddress = false, genPrintEStackOnChange = false; @@ -108,61 +108,38 @@ public class mjc2wsl{ bprint = 56, trap = 57; - public String getStandardStart(){ - return getStandardStart(10); - } - - public String getStandardStart(int numWords){ - StringBuilder ret = new StringBuilder( - "C:\" This file automatically converted from microjava bytecode\";\n" - +"C:\" with mjc2wsl v "+versionN+"\";\n"); - - ret.append("VAR < tempa := 0, tempb := 0, tempres :=0,\n\t"); - ret.append("mjvm_locals := ARRAY(1,0), "); - ret.append("\n\tmjvm_statics := ARRAY("+numWords+",0), "); - ret.append("\n mjvm_estack := < >, mjvm_mstack := < >, "); - ret.append("\n mjvm_fp := 0, mjvm_sp := 0,"); - ret.append("\n t_e_m_p := 0 > :"); - - return ret.toString(); - } - - public String getStandardEnd(){ - return "SKIP\nENDVAR"; - } - private boolean originalInComments = false; private HashMap opMap = null; private String opCodeFile = "mj-bytecodes.properties"; - private HashMap getOpMap() { - if (opMap==null) { - opMap = new HashMap (60, 0.98f); - try{ - BufferedReader in = new BufferedReader( - new InputStreamReader(getClass().getResourceAsStream(opCodeFile))); - String str = in.readLine(); - while (str != null) { - String[] ss = str.split("="); - opMap.put(Integer.parseInt(ss[0]),ss[1]); - str = in.readLine(); - } - in.close(); - }catch (Exception ex) { - ex.printStackTrace(); - } - } - return opMap; + private HashMap getOpMap() { + if (opMap == null) { + opMap = new HashMap(60, 0.98f); + try { + BufferedReader in = new BufferedReader(new InputStreamReader( + getClass().getResourceAsStream(opCodeFile))); + String str = in.readLine(); + while (str != null) { + String[] ss = str.split("="); + opMap.put(Integer.parseInt(ss[0]), ss[1]); + str = in.readLine(); + } + in.close(); + } catch (Exception ex) { + ex.printStackTrace(); + } + } + return opMap; } public String getOpString(int op) { - return getOpMap().get(op); + return getOpMap().get(op); } - + public String describeOpCode(int op) { - return op + " (" + getOpString(op) + ")"; + return op + " (" + getOpString(op) + ")"; } private InputStream mainIn; @@ -206,13 +183,75 @@ public class mjc2wsl{ return (get2() << 16) + (get2() << 16 >>> 16); } - private String loc(int i){ - //arrays start at 1 in WSL, so we need an offset - return "mjvm_locals[" + (i+1)+"]"; + public String createStandardStart(){ + return createStandardStart(10); } + + public String createStandardStart(int numWords){ + StringBuilder ret = new StringBuilder( + "C:\" This file automatically converted from microjava bytecode\";\n" + +"C:\" with mjc2wsl v "+versionN+"\";\n"); + + ret.append("BEGIN "); + ret.append("VAR < tempa := 0, tempb := 0, tempres :=0,\n\t"); + ret.append("mjvm_locals := ARRAY(1,0), "); + ret.append("\n\tmjvm_statics := ARRAY("+numWords+",0), "); + ret.append("\n\tmjvm_arrays := < >, "); + ret.append("\n\tmjvm_objects := < >, "); + ret.append("\n mjvm_estack := < >, mjvm_mstack := < > > : "); - private String genStatic(int i){ - return "mjvm_statics[" + (i+1)+"]"; + return ret.toString(); + } + + public String createStandardEnd(){ + StringBuilder ret = new StringBuilder("SKIP\nENDVAR"); + ret.append("\nWHERE\n"); + + ret.append("\nPROC Print_MJ(val, format VAR)==\n"); + ret.append(createComment("print spacing", C_SPEC)); + + ret.append("\n\tIF format>1 THEN\n\t\tFOR i:=2 TO "); + ret.append("format STEP 1 DO PRINFLUSH(\" \") OD\n"); + ret.append("\tFI;\n\tPRINFLUSH(val)\nEND\n"); + + ret.append("\nEND\n"); + + return ret.toString(); + } + + private String createStartVar(String... vars){ + StringBuilder ret = new StringBuilder("VAR < "); + ret.append(vars[0] + " := 0"); + for (int i=1; i : "); + + return ret.toString(); + } + + private String createEndVar(){ + return "ENDVAR;"; + } + + private String createLocal(int i) { + // arrays start at 1 in WSL, so we need an offset + return "mjvm_locals[" + (i + 1) + "]"; + } + + private String createStatic(int i) { + return "mjvm_statics[" + (i + 1) + "]"; + } + + private String createArray(int i) { + return "mjvm_arrays[" + i + "]"; + } + + private String createArray(String i) { + return "mjvm_arrays[" + i + "]"; + } + + private String createObject(String i) { + return "mjvm_objects[" + i + "]"; } /** @@ -235,67 +274,71 @@ public class mjc2wsl{ //Expression stack - private String cmdToEStack(int i) { + private String createToEStack(int i) { String res = "mjvm_estack := <" + i + " > ++ mjvm_estack;"; - if (genPrintEStackOnChange) res +="PRINT(\"eStack\",mjvm_estack);"; + if (genPrintEStackOnChange) + res += "PRINT(\"eStack\",mjvm_estack);"; return res; } - private String cmdToEStack(String i) { + private String createToEStack(String i) { String res = "mjvm_estack := <" + i + " > ++ mjvm_estack;"; - if (genPrintEStackOnChange) res +="PRINT(\"eStack\",mjvm_estack);"; + if (genPrintEStackOnChange) + res += "PRINT(\"eStack\",mjvm_estack);"; return res; } - private String cmdFromEStack(String st) { - String res = st + " := HEAD(mjvm_estack); mjvm_estack := TAIL(mjvm_estack);"; - if (genPrintEStackOnChange) res +="PRINT(\"eStack\",mjvm_estack);"; + private String createFromEStack(String st) { + String res = st + + " := HEAD(mjvm_estack); mjvm_estack := TAIL(mjvm_estack);"; + if (genPrintEStackOnChange) + res += "PRINT(\"eStack\",mjvm_estack);"; return res; } - - private String cmdPopEStack() { + + private String createPopEStack() { String res = "mjvm_estack := TAIL(mjvm_estack);"; - if (genPrintEStackOnChange) res +="PRINT(\"eStack\",mjvm_estack);"; + if (genPrintEStackOnChange) + res += "PRINT(\"eStack\",mjvm_estack);"; return res; } - - - private String getTopTwo(){ - return cmdFromEStack("tempa") + "\n" + cmdFromEStack("tempb"); + + private String createTopTwoEStack() { + return createFromEStack("tempa") + "\n" + createFromEStack("tempb"); } - private String getTop() { - return cmdFromEStack("tempa"); + private String createTopEStack() { + return createFromEStack("tempa"); } //Method stack - - private String cmdToMStack(int i) { + + private String createToMStack(int i) { return "mjvm_mstack := <" + i + " > ++ mjvm_mstack;"; } - private String cmdToMStack(String i) { + private String createToMStack(String i) { return "mjvm_mstack := <" + i + " > ++ mjvm_mstack;"; } - private String cmdFromMStack(String st) { + private String createFromMStack(String st) { return st + " := HEAD(mjvm_mstack); mjvm_mstack := TAIL(mjvm_mstack);"; } - + private String getRelationFor(int opcode) throws Exception { - switch (opcode) { - case jeq: return "="; - case jne: return "<>"; - case jlt: return "<"; - case jle: return "<="; - case jgt: return ">"; - case jge: return ">="; - } - throw new Exception("Wrong opcode for a relation"); + switch (opcode) { + case jeq: return "="; + case jne: return "<>"; + case jlt: return "<"; + case jle: return "<="; + case jgt: return ">"; + case jge: return ">="; + } + throw new Exception("Wrong opcode for a relation"); } - + private boolean isJumpCode(int opcode) { - return (opcode>=jmp) && (opcode<=jge); + return (opcode >= jmp) && (opcode <= jge); } public void convertStream(InputStream ins) throws Exception{ @@ -309,61 +352,69 @@ public class mjc2wsl{ int numberOfWords = get4(); int mainAdr = get4(); - prl(getStandardStart(numberOfWords)); - prl("SKIP;\n ACTIONS A_S_start:\n A_S_start == CALL a"+(14+mainAdr)+" END"); + prl(createStandardStart(numberOfWords)); + prl("SKIP;\n ACTIONS a" + (14 + mainAdr) + " :"); int op = get(); while (op >= 0) { if (originalInComments) prl(createComment(describeOpCode(op), C_OC)); - prl("a" + counter + " == "); + prl(" a" + counter + " == "); if (genPrintForEachAddress) { - prl("PRINT(\"a"+counter+"\");"); - if (genPauseAfterEachAddress) - prl("debug_disposable_string := @Read_Line(Standard_Input_Port);"); + prl("PRINT(\"a" + counter + "\");"); + if (genPauseAfterEachAddress) + prl("debug_disposable_string := @Read_Line(Standard_Input_Port);"); } switch (op) { case load: { - prl(cmdToEStack(loc(get()))); + prl(createToEStack(createLocal(get()))); break; } case load_0: case load_1: case load_2: case load_3: { - prl(cmdToEStack(loc(op - load_0))); + prl(createToEStack(createLocal(op - load_0))); break; } case store: { - prl(cmdFromEStack(loc(get()))); + prl(createFromEStack(createLocal(get()))); break; } case store_0: case store_1: case store_2: case store_3: { - prl(cmdFromEStack(loc(op - store_0))); + prl(createFromEStack(createLocal(op - store_0))); break; } - - case getstatic:{ - prl(cmdToEStack(genStatic(get2()))); + + case getstatic: { + prl(createToEStack(createStatic(get2()))); break; - } + } case putstatic: { - prl(cmdFromEStack(genStatic(get2()))); + prl(createFromEStack(createStatic(get2()))); break; } - //TODO getfield, putfield - case getfield: - case putfield:{ - prl(createComment("fields are not processed properly", C_ERR)); - message("fields are not processed properly", M_ERR); - get2(); - break; + + case getfield: { + int f = get2(); + prl(createTopEStack()); + prl(createToEStack(createObject("tempa") + "[" + (f + 1) + "]")); + break; } - + case putfield: { + int f = get2(); + // we need to use a temparray as a pointer, WSL + // otherwise tries to access it as a list of lists and fails + prl(createTopTwoEStack()); + prl("VAR < tempArray := " + createObject("tempb") + " > :"); + prl("tempArray[" + (f + 1) + "]:=tempa ENDVAR;"); + break; + } + case const_: { - prl(cmdToEStack(get4())); + prl(createToEStack(get4())); break; } @@ -373,73 +424,136 @@ public class mjc2wsl{ case const_3: case const_4: case const_5: { - prl(cmdToEStack(op - const_0)); + prl(createToEStack(op - const_0)); break; } case add: { - prl(getTopTwo()); + prl(createTopTwoEStack()); prl("tempres := tempb + tempa;"); - prl(cmdToEStack("tempres")); + prl(createToEStack("tempres")); break; } case sub: { - prl(getTopTwo()); + prl(createTopTwoEStack()); prl("tempres := tempb - tempa;"); - prl(cmdToEStack("tempres")); + prl(createToEStack("tempres")); break; } case mul: { - prl(getTopTwo()); + prl(createTopTwoEStack()); prl("tempres := tempb * tempa;"); - prl(cmdToEStack("tempres")); + prl(createToEStack("tempres")); break; } case div: { - prl(getTopTwo()); + prl(createStartVar("tempa", "tempb", "tempres")); + prl(createTopTwoEStack()); prl("IF tempa = 0 THEN ERROR(\"division by zero\") FI;"); prl("tempres := tempb DIV tempa;"); - prl(cmdToEStack("tempres")); + prl(createToEStack("tempres")); + prl(createEndVar()); break; } case rem: { - prl(getTopTwo()); + prl(createStartVar("tempa", "tempb", "tempres")); + prl(createTopTwoEStack()); prl("IF tempa = 0 THEN ERROR(\"division by zero\") FI;"); prl("tempres := tempb MOD tempa;"); - prl(cmdToEStack("tempres")); + prl(createToEStack("tempres")); + prl(createEndVar()); break; } - case neg :{ - prl(getTop()); - prl(cmdToEStack("-tempa")); + case neg: { + prl(createTopEStack()); + prl(createToEStack("-tempa")); break; - } - //TODO shl, shr - - case inc : { + } + + case shl: { + prl(createTopTwoEStack()); + prl("VAR :"); + prl("\tFOR i:=1 TO tempa STEP 1 DO tempres := tempres * 2 OD;"); + prl(createToEStack("tempres")); + prl("ENDVAR;"); + break; + } + case shr: { + prl(createTopTwoEStack()); + prl("VAR :"); + prl("\tFOR i:=1 TO tempa STEP 1 DO tempres := tempres DIV 2 OD;"); + prl(createToEStack("tempres")); + prl("ENDVAR;"); + break; + } + + case inc: { int b1 = get(), b2 = get(); - prl(loc(b1)+" := " +loc(b1)+" + "+b2); - break; - } - //TODO new_ newarray - case new_ : - get();//needs a short, but a byte will be taken bellow as well - case newarray :{ - prl(createComment("memory allocation not processed properly", C_ERR)); - message("memory allocation not processed properly", M_ERR); - get(); - break; - } - //TODO aload, asstore, baload, bastore - //TODO arraylength - //TODO dup, dup2 - - case pop : { - prl(cmdPopEStack()); - break; - } - + prl(createLocal(b1) + " := " + createLocal(b1) + " + " + b2 + ";"); + break; + } + + case new_: { + int size = get2(); + // TODO maybe objects and arrays should be in the same list? + prl("mjvm_objects := mjvm_objects ++ < ARRAY(" + size + + ",0) >;"); + prl(createToEStack("LENGTH(mjvm_objects)")); + break; + } + case newarray: { + get();// 0 - bytes, 1 - words; ignore for now + // TODO take into consideration 0/1 + prl(createTopEStack()); + prl("mjvm_arrays := mjvm_arrays ++ < ARRAY(tempa,0) >;"); + prl(createToEStack("LENGTH(mjvm_arrays)")); + break; + } + + case aload: + case baload: { + prl(createTopTwoEStack()); + prl(createToEStack(createArray("tempb") + "[tempa+1]")); + break; + } + case astore: + case bastore: { + prl(createFromEStack("tempres")); + prl(createTopTwoEStack()); + // we need to use a temparray as a pointer, WSL + // otherwise tries to access it as a list of lists and fails + prl("VAR < tempArray := " + createArray("tempb") + " > :"); + prl("tempArray[tempa+1]:=tempres ENDVAR;"); + break; + } + case arraylength: { + prl(createTopEStack()); + prl("tempb := LENGTH("+ createArray("tempa") + ");"); + prl(createToEStack("tempb")); + break; + } + + case dup: { + prl(createTopEStack()); + prl(createToEStack("tempa")); + prl(createToEStack("tempa")); + break; + } + case dup2: { + prl(createTopTwoEStack()); + prl(createToEStack("tempb")); + prl(createToEStack("tempa")); + prl(createToEStack("tempb")); + prl(createToEStack("tempa")); + break; + } + + case pop: { + prl(createPopEStack()); + break; + } + case jmp: { prl("CALL a" + (counter + get2()) + ";"); break; @@ -451,10 +565,9 @@ public class mjc2wsl{ case jle: case jgt: case jge: { - prl(getTopTwo()); - prl("IF tempb "+ getRelationFor(op) - +" tempa THEN CALL a" + (counter + get2()) - +" ELSE CALL a" + (counter+1) + prl(createTopTwoEStack()); + prl("IF tempb " + getRelationFor(op) + " tempa THEN CALL a" + + (counter + get2()) + " ELSE CALL a" + (counter + 1) + " FI;"); break; } @@ -465,62 +578,60 @@ public class mjc2wsl{ } case return_: { - prl("IF EMPTY?(mjvm_mstack) THEN CALL Z FI"); - //else we let things return - prl("END b"+counter+" =="); + // we let the actions return + // there is nothing to clean up + prl("SKIP\n END\n b" + counter + " =="); break; } case enter: { int parameters = get(); - + int locals = get(); - prl(cmdToMStack("mjvm_locals")); - prl("mjvm_locals := ARRAY("+locals+",0);"); - for (int i = parameters-1; i >= 0; i--) - prl(cmdFromEStack(loc(i))); + prl(createToMStack("mjvm_locals")); + prl("mjvm_locals := ARRAY(" + locals + ",0);"); + for (int i = parameters - 1; i >= 0; i--) + prl(createFromEStack(createLocal(i))); break; } case exit: { - prl(cmdFromMStack("mjvm_locals")); + prl(createFromMStack("mjvm_locals")); break; } // read, print - case read:{ - //TODO make it a char for read - message("char is read like a number", M_WAR); - prl(createComment("char is read like a number",C_SPEC)); - } case bread: { + // TODO make it a char for read + messages.message("char is read like a number", TransMessages.M_WAR); + prl(createComment("char is read like a number", C_SPEC)); + } + case read: { prl("tempa := @String_To_Num(@Read_Line(Standard_Input_Port));"); - prl(cmdToEStack("tempa")); + prl(createToEStack("tempa")); break; } // the prints - case print:{ + case bprint: { // TODO need to make it a char on print - message("chars will be printed as number codes", M_WAR); - prl(createComment("char will be printed as a number code",C_SPEC)); + messages.message("chars will be printed as number codes", TransMessages.M_WAR); + prl(createComment("char will be printed as a number code", + C_SPEC)); } - case bprint: { + case print: { // TODO printing numbers needs different lengths of spacing - prl(getTopTwo()); - pr(createComment("print spacing",C_SPEC)); - prl("IF tempa>1 THEN FOR i:=2 TO tempa STEP 1 DO PRINFLUSH(\" \") OD FI;"); - prl("PRINFLUSH(tempb);"); + prl(createTopTwoEStack()); + prl("Print_MJ(tempb,tempa);"); break; } case trap: { - prl("ERROR(\"Runtime error: trap("+get()+")\");"); + prl("ERROR(\"Runtime error: trap(" + get() + ")\");"); break; } - - + default: prl(createComment("unknown op error: " + op, C_ERR)); - message("unknown op error: "+ op, M_ERR); + messages.message("unknown op error: " + op, TransMessages.M_ERR); break; } @@ -528,15 +639,14 @@ public class mjc2wsl{ op = get(); if (op >= 0) if (wasJump) - prl("SKIP END"); + prl("SKIP\n END"); else - prl("CALL a" + counter + " END"); + prl("CALL a" + counter + "\n END"); } - prl("CALL Z;\nSKIP END\nENDACTIONS;\n"); - prl(getStandardEnd()); - + prl("SKIP\n END\nENDACTIONS;\n"); + prl(createStandardEnd()); } - + public void convertFile(File f) { try { convertStream(new FileInputStream(f)); @@ -546,14 +656,55 @@ public class mjc2wsl{ } public void printHelp() { + printVersion(); + printUsage(); + printHelpOutput(); + printHelpHelp(); + } + + public void printLongHelp() { + printVersion(); + printUsage(); + System.out.println(); + printHelpOutput(); + System.out.println(); + printHelpGenerating(); + System.out.println(); + printHelpHelp(); + } + + public void printHelpOutput() { + System.out.println("Output options:"); + System.out.println(" --screen print output to screen"); + System.out.println(" -o --oc[+-] include original code in comments"); + System.out.println(" -v verbose, print warning messages"); + System.out.println(" -q quiet; don't print even the error messages"); + System.out.println(" -d print detailed debug messages"); + } + + public void printHelpGenerating() { + System.out.println("Options for generating extra code for tracking code execution"); + System.out.println(" --genEStackPrint generate print for all EStack changes"); + System.out.println(" --genAddrPrint generate prints after every address of the original code "); + System.out.println(" --genAddrPause generate a pause after every address of the original code "); + System.out.println(" --genAddr short for --genAddrPrint and --genAddrPause"); + System.out.println(" --genAll short for applying all code generation"); + } + + public void printHelpHelp() { + System.out.println("Help and info options"); + System.out.println(" -h basic help"); + System.out.println(" --help print more detailed help"); + System.out.println(" --version or -version print version and exit"); + } + + public void printUsage(){ + System.out.println("usage:\n\t mjc2wsl {options} filename [outfile]"); + } + + public void printVersion() { System.out.println("MicroJava bytecode to WSL converter. v " + versionN + ", by Doni Pracner"); - System.out.println("usage:\n\t mjc2wsl {options} filename [outfile]"); - System.out.println("options:\n\t--screen print output to screen"); - System.out.println("\t-o --oc[+-] include original code in comments"); - System.out.println("\t-v verbose, print warning messages"); - System.out.println("\t-q don't print even the error messages"); - System.out.println("\t-d print detailed debug messages"); } public String makeDefaultOutName(String inname){ @@ -572,6 +723,13 @@ public class mjc2wsl{ if (args[i].compareTo("-h") == 0) { printHelp(); return; + } else if (args[i].compareTo("--help") == 0) { + printLongHelp(); + return; + } else if (args[i].compareTo("--version") == 0 + || args[i].compareTo("-version") == 0) { + printVersion(); + return; } else if (args[i].compareTo("-o") == 0 || args[i].startsWith("--oc")) { if (args[i].length() == 2) @@ -583,11 +741,11 @@ public class mjc2wsl{ } else if (args[i].compareTo("--screen") == 0) { out = new PrintWriter(System.out); } else if (args[i].compareTo("-d") == 0) { - printLevel = M_DEB;//print debug info + messages.setPrintLevel(TransMessages.M_DEB);// print debug info } else if (args[i].compareTo("-v") == 0) { - printLevel = M_WAR;//print warnings + messages.setPrintLevel(TransMessages.M_WAR);// print warnings } else if (args[i].compareTo("-q") == 0) { - printLevel = M_ERR+1;//no printing + messages.setPrintLevel(TransMessages.M_QUIET);// no printing } else if (args[i].compareToIgnoreCase("--genEStackPrint") == 0) { genPrintEStackOnChange = true; } else if (args[i].compareToIgnoreCase("--genAddrPause") == 0) { @@ -601,7 +759,8 @@ public class mjc2wsl{ genPrintEStackOnChange = true; genPrintForEachAddress = true; genPauseAfterEachAddress = true; - }i++; + } + i++; } if (i >= args.length) { @@ -633,7 +792,7 @@ public class mjc2wsl{ long mili = Calendar.getInstance().getTimeInMillis() - now.getTimeInMillis(); System.out.println("conversion time:" + mili + " ms"); - printMessageCounters(); + messages.printMessageCounters(); out.close(); } else System.out.println("file does not exist");