你的解决方案已经很好了,因为它太简单了。我想问题是当枚举数变得很大的时候。我认为除了调用函数之外,没有其他方法可以在一行中完成这项工作。正如一些程序员所说,C没有内省功能。所以你得自己弥补。我做了一个枚举结构。它将处理枚举中的间距——但是您可能会意识到
仅仅是执行这个功能就变得多么复杂和可笑。
嗯
#ifndef __ENUM_H__
#define __ENUM_H__
#define null 0x00
#define ENUM_MAX_VALUES 4
#define ENUM_MAX_SCHEMA 4
#define ENUM_MAX_ENUM 4
#define ENUM_MAX_STRING_LEN 16
/**
* enum_key_value_t is essentially a key/value pair
* the key is the integer, the value is the string
*/
typedef struct
{
/** integer enum value */
int key;
/** string enum value */
char value[ENUM_MAX_STRING_LEN];
}enum_key_value_t;
/**
* An enum schema contains all possible string/int pairs
*/
typedef struct
{
/** all possible values of the enumerator object */
enum_key_value_t values[ENUM_MAX_VALUES];
/** the number of values used out of MAX_ENUM_VALUES */
int num_values;
}enum_schema_t;
typedef struct
{
/** current value of the enumerator object */
enum_key_value_t *value;
enum_schema_t *schema;
}enum_t;
enum_schema_t *new_EnumSchema(void);
void EnumSchema_AddValue(enum_schema_t *e, int key, const char *value);
enum_key_value_t *Enum_SetValue(enum_t *e, int key);
const char *Enum_GetValue(enum_t *e);
enum_t *new_Enum(enum_schema_t *schema, int initial_value);
#endif
C语言
#include "enum.h"
#include <string.h>
#include <stdio.h>
/** used in place of null strings etc. */
const char g_UNDEFINED[] = "<<UNDEFINED>>";
/** All enumerator objects */
static enum_schema_t g_EnumSchemas[ENUM_MAX_SCHEMA];
static enum_t g_Enums[ENUM_MAX_ENUM];
/** Current number of enumerator objects */
static int g_num_EnumSchemas = 0;
static int g_num_Enums = 0;
static enum_key_value_t *Enum_FindValue(enum_schema_t *e, int key);
/**
* new_Enum
*
* create a new enumerator
*
* @return pointer to the new enumerator
*/
enum_schema_t *new_EnumSchema(void)
{
if (g_num_EnumSchemas < ENUM_MAX_SCHEMA)
{
enum_schema_t *ret = &g_EnumSchemas[g_num_EnumSchemas++];
ret->num_values = 0;
return ret;
}
return null;
}
/**
* new_Enum
*
* create a new enumerator
*
* @return pointer to the new enumerator
*/
enum_t *new_Enum(enum_schema_t *schema, int initial_value)
{
if (g_num_Enums < ENUM_MAX_ENUM)
{
enum_t *ret = &g_Enums[g_num_Enums++];
ret->schema = schema;
ret->value = Enum_FindValue(schema, initial_value);
return ret;
}
return null;
}
/**
* Enum_AddValue
*
* adds a value/key key to a enumerator object
*
* @param e pointer to the enumerator object
* @param key the enumerated byte key
* @param value the value to show for this key
*/
void EnumSchema_AddValue(enum_schema_t *e, int key, const char *value)
{
if (e->num_values < ENUM_MAX_VALUES)
{
int i;
enum_key_value_t *val = &e->values[e->num_values++];
val->key = key;
strncpy(val->value, value, ENUM_MAX_STRING_LEN - 1);
val->value[ENUM_MAX_STRING_LEN - 1] = 0;
}
}
/**
* Enum_SetValue
*
* changes the enumerated key
*
* @param e pointer to the enumerator object
* @param key the new enumerated byte key
* @return pointer to the enum_key_value_t object that contains the key
*/
enum_key_value_t *Enum_SetValue(enum_t *e, int key)
{
enum_key_value_t *val = Enum_FindValue(e->schema, key);
if (val != null)
{
e->value = val;
return val;
}
return null;
}
/**
* Enum_GetValue
*
* gets the enumerated value key for enumerated key
*
* @param e pointer to the enumerator object
* @return value key
*/
const char *Enum_GetValue(enum_t *e)
{
if (e->value != null)
return e->value->value;
return g_UNDEFINED;
}
/*************************************
* STATIC FUNCTIONS (Local functions)
*************************************/
/**
* Enum_FindValue
*
* finds the enumerated key
*
* @param e pointer to the enumerator object
* @param key the enumerated byte key
* @return pointer to enum_key_value_t object that contains the key
*/
static enum_key_value_t *Enum_FindValue(enum_schema_t *e, int key)
{
int i;
for (i = 0; i < e->num_values; i++)
{
enum_key_value_t *val = &e->values[i];
if (val->key == key)
return val;
}
return null;
}
主C
#include <stdio.h>
#include "enum.h"
typedef enum
{
SUNDAY,
MONDAY,
FRIDAY = 6
}WEEK_DAY;
enum_schema_t *week_day_init()
{
enum_schema_t *enum_weekday = new_EnumSchema();
// add possible values
EnumSchema_AddValue(enum_weekday, SUNDAY, "SUNDAY");
EnumSchema_AddValue(enum_weekday, MONDAY, "MONDAY");
EnumSchema_AddValue(enum_weekday, FRIDAY, "FRIDAY");
return enum_weekday;
}
void main()
{
enum_schema_t *week_day_enum_t = week_day_init();
enum_t *weekday1 = new_Enum(week_day_enum_t, SUNDAY);
// the 'one-liner'
printf("weekday1 is currently '%s'\n",Enum_GetValue(weekday1));
Enum_SetValue(weekday1, FRIDAY);
printf("weekday1 is now '%s'\n", Enum_GetValue(weekday1));
}
输出
weekday1 is currently 'SUNDAY'
weekday1 is now 'FRIDAY'
