diff options
Diffstat (limited to 'src/mesa/program/hash_table.h')
-rw-r--r-- | src/mesa/program/hash_table.h | 79 |
1 files changed, 78 insertions, 1 deletions
diff --git a/src/mesa/program/hash_table.h b/src/mesa/program/hash_table.h index e7ab067a3bd..bfe221b242f 100644 --- a/src/mesa/program/hash_table.h +++ b/src/mesa/program/hash_table.h @@ -31,7 +31,13 @@ #ifndef HASH_TABLE_H #define HASH_TABLE_H +#include <string.h> +#include <stdint.h> +#include <limits.h> +#include <assert.h> + struct hash_table; +struct string_to_uint_map; typedef unsigned (*hash_func_t)(const void *key); typedef int (*hash_compare_func_t)(const void *key1, const void *key2); @@ -171,7 +177,78 @@ hash_table_call_foreach(struct hash_table *ht, void *closure), void *closure); +struct string_to_uint_map * +string_to_uint_map_ctor(); + +void +string_to_uint_map_dtor(struct string_to_uint_map *); + + #ifdef __cplusplus } -#endif + +/** + * Map from a string (name) to an unsigned integer value + * + * \note + * Because of the way this class interacts with the \c hash_table + * implementation, values of \c UINT_MAX cannot be stored in the map. + */ +struct string_to_uint_map { +public: + string_to_uint_map() + { + this->ht = hash_table_ctor(0, hash_table_string_hash, + hash_table_string_compare); + } + + ~string_to_uint_map() + { + hash_table_dtor(this->ht); + } + + /** + * Get the value associated with a particular key + * + * \return + * If \c key is found in the map, \c true is returned. Otherwise \c false + * is returned. + * + * \note + * If \c key is not found in the table, \c value is not modified. + */ + bool get(unsigned &value, const char *key) + { + const intptr_t v = + (intptr_t) hash_table_find(this->ht, (const void *) key); + + if (v == 0) + return false; + + value = (unsigned)(v - 1); + return true; + } + + void put(unsigned value, const char *key) + { + /* The low-level hash table structure returns NULL if key is not in the + * hash table. However, users of this map might want to store zero as a + * valid value in the table. Bias the value by +1 so that a + * user-specified zero is stored as 1. This enables ::get to tell the + * difference between a user-specified zero (returned as 1 by + * hash_table_find) and the key not in the table (returned as 0 by + * hash_table_find). + * + * The net effect is that we can't store UINT_MAX in the table. This is + * because UINT_MAX+1 = 0. + */ + assert(value != UINT_MAX); + hash_table_replace(ht, (void *) (intptr_t) (value + 1), key); + } + +private: + struct hash_table *ht; +}; + +#endif /* __cplusplus */ #endif /* HASH_TABLE_H */ |