cmpsc311.c

/* CMPSC 311, Spring 2013, Project 5 solution
 *
 */

/* base library for CMPSC 311 projects
 * version of 25 Feb. 2013
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdbool.h>
#include <errno.h>
#include <string.h>

#include "cmpsc311.h"
#include "hake.h"

//------------------------------------------------------------------------------

// global variables set from the command line

//char *prog = "[no name]";	// program name
//int verbose = 0;		// -v option, extra output
				// -v can be repeated for even more output

  // verbosity levels
  // 0  off, default
  // 1  normal, behavioral info
  // 2  extra, functionality info
  // 3  memory allocation info, from Malloc(), Strdup()
  // 4  too much, information overload

//------------------------------------------------------------------------------

// utility functions
//   safe_string(() -- guard against null pointer for character string output

const char *safe_string(const char *str)
{
  if (str == NULL) return "(null)";
  else return str;
}

/* The Solaris C library doesn't like printf("%s", p) when p is a null pointer.
 * It will generate a segmentation fault, and end the program.  This is
 * an acceptable implementation according to the C and Posix Standards.
 * The GNU C library (on Linux and Mac OS X) is more generous; it will print
 * the string "(null)" and keep going.
 * If you compile with GCC with all the warnings turned on, there are complaints
 * about printf("%s", NULL); but none about printf("%s", p) when p happens to be
 * a null pointer.
 * With the safe_string() function, we can act like the GNU C library version of
 * printf(), even on Solaris.
 * Of course, we could also use assert() or verify() to catch NULL pointers,
 * which is often a better idea, unless you really want the program to keep
 * going.
 */

//------------------------------------------------------------------------------

// check function arguments
//   verify() -- tf is expected to be true; if not, print msg and quit

// #define verify(tf, msg) cmpsc311_verify(tf, msg, __func__, __LINE__)

void cmpsc311_verify(const bool tf, const char *msg,
	const char *func, const int line)
{
  if (tf == false)
    {
      fprintf(stderr, "%s: %s() at line %d failed: %s\n", prog, func, line, msg);
      exit(EXIT_FAILURE);
    }
}

//------------------------------------------------------------------------------

// check function return values
//   function	standards
//   malloc	C and Posix
//   strdup	      Posix
//   fopen	C and Posix
// We follow the standard protoypes of the original functions.
// Compare these to the error-checking wrappers in CS:APP, csapp.h and csapp.c.

// #define Malloc(size) cmpsc311_malloc(size, __func__, __LINE__)

void *cmpsc311_malloc(size_t size,
	const char *func, const int line)
{
  void *p = malloc(size);
  if (p == NULL)
    {
      fprintf(stderr, "%s: %s() at line %d failed: malloc(): %s\n",
	prog, func, line, strerror(errno));
      exit(EXIT_FAILURE);
    }

  if (v_flag)
    { // which address?
      fprintf(stderr, "%s: malloc(%zd) at %p from %s line %d\n",
	prog, size, p, func, line);
    }

  return p;
}

// #define Strdup(s) cmpsc311_strdup(s, __func__, __LINE__)

char *cmpsc311_strdup(const char *s,
	const char *func, const int line)
{
  char *p = strdup(s);
  if (p == NULL)
    {
      fprintf(stderr, "%s: %s() at line %d failed: strdup(): %s\n",
	prog, func, line, strerror(errno));
      exit(EXIT_FAILURE);
    }

  if (v_flag)
    { // which address?
      fprintf(stderr, "%s: strdup(%zd) at %p from %s line %d\n",
	prog, strlen(s)+1, (void *) p, func, line);
    }

  return p;
}

// #define Fopen(filename,mode) cmpsc311_fopen(filename, mode, __func__, __LINE__)

FILE *cmpsc311_fopen(const char * restrict filename, const char * restrict mode,
	const char *func, const int line)
{
  FILE *f = fopen(filename, mode);
  if (f == NULL)
    {
      fprintf(stderr, "%s: %s() at line %d failed: fopen(%s): %s\n",
	prog, func, line, filename, strerror(errno));
      exit(EXIT_FAILURE);
    }

  return f;
}

//------------------------------------------------------------------------------