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utility.h
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utility.h
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/* File: utility.h
* ---------------
* This file just includes a few support functions you might find
* helpful in writing the projects (error handling, debug printing)
*/
#ifndef _H_utility
#define _H_utility
#include <stdlib.h>
#include <stdio.h>
/* Function: Failure()
* Usage: Failure("Out of memory!");
* --------------------------------
* Reports an error and exits the program immediately. You should not
* need to call this since you should always try to continue parsing,
* even after an error is encountered. Some of the provided code calls
* this in unrecoverable error situations (cannot allocate memory, etc.)
* Failure accepts printf-style arguments in the message to be printed.
*/
void Failure(const char *format, ...);
/* Macro: Assert()
* Usage: Assert(num > 0);
* ----------------------
* This macro is designed to assert the truth of a necessary condition.
* It tests the given expression, and if it evalutes true, nothing happens.
* If it is false, it calls Failure to print a message and abort.
* For example: Assert(ptr != NULL)
* will print something similar to the following if ptr is NULL:
* *** Failure: Assertion failed: hashtable.cc, line 55:
* ptr != NULL
*/
#define Assert(expr) \
((expr) ? (void)0 : Failure("Assertion failed: %s, line %d:\n %s", __FILE__, __LINE__, #expr))
/* Function: PrintDebug()
* Usage: PrintDebug("parser", "found ident %s\n", ident);
* -------------------------------------------------------
* Print a message if we have turned debugging messages on for the given
* key. For example, the usage line shown above will only print a message
* if the call is preceded by a call to SetDebugForKey("parser",true).
* The function accepts printf arguments. The provided main.cc parses
* the command line to turn on debug flags.
*/
void PrintDebug(const char *key, const char *format, ...);
/* Function: SetDebugForKey()
* Usage: SetDebugForKey("scope", true);
* -------------------------------------
* Turn on debugging messages for the given key. See PrintDebug
* for an example. Can be called manually when desired and will
* be called from the provided main for flags passed with -d.
*/
void SetDebugForKey(const char *key, bool val);
/* Function: IsDebugOn()
* Usage: if (IsDebugOn("scope")) ...
* ----------------------------------
* Return true/false based on whether this key is currently on
* for debug printing.
*/
bool IsDebugOn(const char *key);
/* Function: ParseCommandLine
* --------------------------
* Turn on the debugging flags from the command line. Verifies that
* first argument is -d, and then interpret all the arguments that follow
* as being flags to turn on.
*/
void ParseCommandLine(int argc, char *argv[]);
#endif