main.c

/**
 * main.c
 * (C) 2013 Christian Gunderman
 * Modified by:
 * Author Email: gundermanc@gmail.com
 * Modifier Email:
 *
 * Description:
 * The Gunderscript executable application. This application can be used
 * as a complete standalone Gunderscript environment, however, it is a
 * bit rudimentary and is meant more as an example of how easy it is to
 * embed Gunderscript in C projects.
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <string.h>
#include <unistd.h>
#include "gunderscript.h"

#define GXSMAIN_BUILD_SCRIPT     "build-script"
#define GXSMAIN_RUN_SCRIPT       "run-script"
#define GXSMAIN_RUN_BYTECODE     "run-bytecode"

#define GXSMAIN_DEFAULT_MAIN     "main"
#define GXSMAIN_MAX_ASSOCIATED_SCRIPT_FN   255

static const size_t stackSize = 100000;  /* environment constants */
static const int callbacksSize = 55;

/**
 * Prints a brief help message
 */
static void print_help() {
  printf("Gunderscript Scripting Environment ");
  
#ifdef _WIN64
  printf("- Win64 Build\n");
#elif _WIN32
  printf("- Win32 Build\n");
#elif __linux__
#ifdef __LP64__
  printf("- Linux64 Build\n");
#else
  printf("- Linux32 Build\n");
#endif /* defined(__LP64__) */
#else
  printf("- Unknown Platform;\n");
#endif /* defined(__linux__) */
  printf("(C) 2013-2014 Christian Gunderman\n");
  printf("http://github.com/gundermanc/gunderscript\n");
#if defined( __DATE__) && defined(__TIME__)
  printf("Built on %s at %s\n\n", __DATE__, __TIME__);
#else
  printf("Build date unavaiable; Not compiled with GCC;\n\n");
#endif /* defined(__linux__) */
  printf("Usage: gunderscript [operation] ... \n");
  printf("  Operations:\n");
  printf("    build-script [script.gxs] [outputfile.gxb] \n");
  printf("         builds a script and outputs the bytecode to specified file.\n");
  printf("    run-script   [entrypoint] [script.gxs] \n");
  printf("         compiles and runs a script from the specfied \"entrypoint\" function.\n");
  printf("    run-bytecode [entrypoint] [bytecode.gxb] \n");
  printf("         runs a bytecode file generated with \"build-script\" \n\n\n");
  printf("Autoexecute:\n");
  printf("  Scripts will autoexecute if they are named the same as their copy of Gunderscript.\n");
  printf("  For example:\n");
  printf("\n  If your Gunderscript was called foobar (Linux) or foobar.exe (Windows), then\n");
  printf("  your program could be called foobar.gxs (uncompiled script), or\n");
  printf("  foobar.gxb (compiled bytecode).");
}

/**
 * Memory allocation failed
 */
static void print_alloc_error() {
  printf("Error allocating memory for Gunderscript object.");
}

/**
 * Print relevant Gunderscript error messages
 */
static void print_error(Gunderscript * ginst) {

  if(gunderscript_get_err(ginst) == GUNDERSCRIPTERR_BUILDERR) {

    /* compiler.c errors */
    printf("\n\nError encountered building script(s)\n");
    printf("Build Error Number: %i\n", gunderscript_build_err(ginst));
    printf("Detected around Line Number: %i\n", gunderscript_err_line(ginst));
    printf("Compiler Error: %s\n", gunderscript_err_message(ginst));
  } else if(gunderscript_get_err(ginst) == GUNDERSCRIPTERR_EXECERR) {

    /* vm.c and dependencies errors */
    printf("\n\nError encountered executing generated bytecode\n");
    printf("Virtual Machine Error Number: %i\n", gunderscript_function_err(ginst));
    printf("Virtual Machine Error: %s\n", gunderscript_err_message(ginst));
  } else {

    /* gunderscript.c errors */
    printf("\n\nError encountered setting up environment\n");
    printf("Setup Error: %s\n", gunderscript_err_message(ginst));
  }
}

/**
 * Moves the NULL character to remove a program extension, if there is one
 */
static void remove_suffix(char * str) {
  size_t len = strlen(str);
  int i = 0;

  if(len == 0) {
    return;
  }

  /* iterate string right to left */
  for(i = len-1; i > 0; i--) {
    if(str[i] == '.') {
      break;
    }
  }

  /* if no string extension, return */
  if(i == 0) {
    return;
  }

  str[i] = '\0';
}

/**
 * Execute the script named the same as this executable
 * TODO: this logic in this whole file is really messy, buuuttt, I'm lazy
 * and the library itself is beautiful so I am going to be lazy and just
 * leave this here..lolz
 */
static int execute_associated(Gunderscript * ginst, int argc, char * argv[]) {
  char fileName[GXSMAIN_MAX_ASSOCIATED_SCRIPT_FN];

  /* does [executable].gxs exist (the associated script) */
  strncpy(fileName, argv[0], GXSMAIN_MAX_ASSOCIATED_SCRIPT_FN);
  remove_suffix(fileName);
  strncat(fileName, ".gxs", GXSMAIN_MAX_ASSOCIATED_SCRIPT_FN - 4);
  if(access(fileName, F_OK) == 0) {

    /* initialize gunderscript object */
    if(!gunderscript_new_full(ginst, stackSize, callbacksSize)) {
      print_alloc_error();
      return 1;
    }

    /* compile the input script */
    if(!gunderscript_build_file(ginst, fileName)) {
      print_error(ginst);
      gunderscript_free(ginst);
      return 1;
    }

    /* execute the desired entry point */
    if(!gunderscript_function(ginst, GXSMAIN_DEFAULT_MAIN, strlen(GXSMAIN_DEFAULT_MAIN))) {
      print_error(ginst);
      gunderscript_free(ginst);
      return 1;
    }
    gunderscript_free(ginst);
    return 0;
  } else {

    /* the script file doesn't exist, check for a bytecode file instead */
    strncpy(fileName, argv[0], GXSMAIN_MAX_ASSOCIATED_SCRIPT_FN);
    remove_suffix(fileName);
    strncat(fileName, ".gxb", GXSMAIN_MAX_ASSOCIATED_SCRIPT_FN - 4);
    if(access(fileName, F_OK) == 0) {

      /* initialize gunderscript object */
      if(!gunderscript_new_vm(ginst, stackSize, callbacksSize)) {
	print_alloc_error();
	return 1;
      }

      /* import the compiled code from a BIN file */
      if(!gunderscript_import_bytecode(ginst, fileName)) {
	print_error(ginst);
	gunderscript_free(ginst);
	return 1;
      }
    
      /* execute the desired entry point */
      if(!gunderscript_function(ginst, GXSMAIN_DEFAULT_MAIN, strlen(GXSMAIN_DEFAULT_MAIN))) {
	print_error(ginst);
	gunderscript_free(ginst);
	return 1;
      }
      gunderscript_free(ginst);
      return 0;

    } else {
      print_help();
      return 1;
    }
  }
}

/**
 * Program entry point. For a summary of command-line arguments, see
 * print_help() or read the code, silly.
 */
int main(int argc, char * argv[]) {
  Gunderscript ginst;

  /* if no arguments, try to execute associated bytecode / script */
  if(argc == 1) {
    return execute_associated(&ginst, argc, argv);
  }

  /* check for proper number of arguments */
  if(argc != 4) {
    print_help();
    return 1;
  }

  /* build script */
  if(strcmp(argv[1], GXSMAIN_BUILD_SCRIPT) == 0) {

    /* initialize gunderscript object */
    if(!gunderscript_new_full(&ginst, stackSize, callbacksSize)) {
      print_alloc_error();
      return 1;
    }

    /* compile the input script */
    if(!gunderscript_build_file(&ginst, argv[2])) {
      print_error(&ginst);
      gunderscript_free(&ginst);
      return 1;
    }

    /* export the compiled code to a BIN file */
    if(!gunderscript_export_bytecode(&ginst, argv[3])) {
      print_error(&ginst);
      gunderscript_free(&ginst);
      return 1;
    }
    gunderscript_free(&ginst);
    return 0;

  } else if(strcmp(argv[1], GXSMAIN_RUN_SCRIPT) == 0) {

    /* initialize gunderscript object */
    if(!gunderscript_new_full(&ginst, stackSize, callbacksSize)) {
      print_alloc_error();
      return 1;
    }

    /* compile the input script */
    if(!gunderscript_build_file(&ginst, argv[3])) {
      print_error(&ginst);
      gunderscript_free(&ginst);
      return 1;
    }

    /* execute the desired entry point */
    if(!gunderscript_function(&ginst, argv[2], strlen(argv[2]))) {
      print_error(&ginst);
      gunderscript_free(&ginst);
      return 1;
    }
    gunderscript_free(&ginst);
    return 0;

  } else if(strcmp(argv[1], GXSMAIN_RUN_BYTECODE) == 0) {

    /* initialize gunderscript object */
    if(!gunderscript_new_vm(&ginst, stackSize, callbacksSize)) {
      print_alloc_error();
      return 1;
    }

    /* import the compiled code from a BIN file */
    if(!gunderscript_import_bytecode(&ginst, argv[3])) {
      print_error(&ginst);
      gunderscript_free(&ginst);
      return 1;
    }
    
    /* execute the desired entry point */
    if(!gunderscript_function(&ginst, argv[2], strlen(argv[2]))) {
      print_error(&ginst);
      gunderscript_free(&ginst);
      return 1;
    }
    gunderscript_free(&ginst);
    return 0;

  } else {
    print_help();
    return 1;
  }
  return 0;
}