CToolBox/include/toolbox/cstring.h

#ifndef CSTRING_H
#define CSTRING_H

/* CSTRING RETURN CODE */
#define CSTRING_RC_TYPE unsigned char
extern __thread CSTRING_RC_TYPE logger_errno;
#define CSTRING_RC_OK   ((CSTRING_RC_TYPE) 0L) /* No Error */
#define CSTRING_RC_EVN  ((CSTRING_RC_TYPE) 1L) /* Value is Null */

#include <stddef.h>

__attribute__((__pure__))
size_t
cstring_len(const char *cstring);

__attribute__((__pure__))
_Bool
cstring_equal(const char *restrict cstring_1, const char *restrict cstring_2);

#define IMPLEMENTATIONS
#if defined(CSTRING_IMP) || defined(IMPLEMENTATIONS)

#include <stddef.h>
#include <stdlib.h>

#if defined(CSTRING_LOG) || defined(LOGS)
  #define __LOG(OUT, PFX, TXT) fprintf(OUT, PFX" %s: %s", __func__, TXT)
  #define LOG_ERROR(TXT) __LOG(stderr, "[ERROR]", TXT)
#else
  #define LOG_ERROR(TXT) ;
#endif	/* CSTRING_LOG */

#define true  ((unsigned char) 1L)
#define false ((unsigned char) 0L)

#define TEST_FOR_NULL(POINTER)						\
	if ( POINTER == NULL ) {					\
		LOG_ERROR("Null Pointer Not Expected");		\
		logger_errno = CSTRING_RC_EVN;				\
		return logger_errno;					\
	}

size_t
cstring_len(const char *p_cstr) {
	TEST_FOR_NULL(p_cstr);
	size_t len = 0;
	while ( *(p_cstr + len++) ) {}
	return --len;
}

_Bool
cstring_equal(const char *restrict p_cstr1, const char *restrict p_cstr2) {
	TEST_FOR_NULL(p_cstr1);
	TEST_FOR_NULL(p_cstr2);

	const size_t cstr1_size = cstring_len(p_cstr1);
	const size_t cstr2_size = cstring_len(p_cstr2);

	if ( cstr1_size != cstr2_size ) {
		return false;
	}

	for ( size_t i = 0; i < cstr1_size; ++i ) {
		if ( p_cstr1[i] != p_cstr2[i] ) {
			return false;
		}
	}

	return true;
}

#undef true
#undef false

#undef LOG_ERROR
#undef TEST_FOR_NULL

#endif /* CSTRING_IMP || IMPLEMENTATIONS */

#endif	/* CSTRING_H */