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utils: implement NM_UTILS_STRING_LOOKUP_TABLE_DEFINE() as switch() statement

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The compiler will likely optimize a  switch() statement also to a table
lookup, but it also works for negative values and values with large
gaps.
This commit is contained in:
Thomas Haller
2016-01-24 13:33:48 +01:00
parent 3ed2488d74
commit b9df6009ff
1 changed files with 7 additions and 6 deletions
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13
src/NetworkManagerUtils.h
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@@ -260,19 +260,20 @@ const char *nm_utils_enum2str (const NMUtilsEnum2StrDesc *descs,
/*****************************************************************************/ /*****************************************************************************/
#define NM_UTILS_STRING_LOOKUP_TABLE_ITEM(v, n) [v] = n #define NM_UTILS_STRING_LOOKUP_TABLE_ITEM(v, n) (void) 0; case v: return (n); (void) 0
#define NM_UTILS_STRING_LOOKUP_TABLE_ITEM_S(v, n) NM_UTILS_STRING_LOOKUP_TABLE_ITEM(v, ""n"") #define NM_UTILS_STRING_LOOKUP_TABLE_ITEM_S(v, n) NM_UTILS_STRING_LOOKUP_TABLE_ITEM(v, ""n"")
#define _NM_UTILS_STRING_LOOKUP_TABLE_DEFINE(scope, fcn_name, lookup_type, unknown_val, ...) \ #define _NM_UTILS_STRING_LOOKUP_TABLE_DEFINE(scope, fcn_name, lookup_type, unknown_val, ...) \
scope const char * \ scope const char * \
fcn_name (lookup_type idx) \ fcn_name (lookup_type val) \
{ \ { \
static const char *const descs[] = { \ switch (val) { \
default: \
return (unknown_val); \
(void) 0, \
__VA_ARGS__ \ __VA_ARGS__ \
(void) 0; \
}; \ }; \
if ((gsize) idx < G_N_ELEMENTS (descs)) \
return descs[idx]; \
return unknown_val; \
} }
#define NM_UTILS_STRING_LOOKUP_TABLE_DEFINE(fcn_name, lookup_type, unknown_val, ...) \ #define NM_UTILS_STRING_LOOKUP_TABLE_DEFINE(fcn_name, lookup_type, unknown_val, ...) \