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Diffstat (limited to 'libjava/jni/classpath/native_state.c')
| -rw-r--r-- | libjava/jni/classpath/native_state.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/libjava/jni/classpath/native_state.c b/libjava/jni/classpath/native_state.c new file mode 100644 index 0000000..746686e --- /dev/null +++ b/libjava/jni/classpath/native_state.c @@ -0,0 +1,247 @@ +/* Magical NSA API -- Associate a C ptr with an instance of an object + Copyright (C) 1998, 2002 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA +02111-1307 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +#include <stdlib.h> +#include <jni.h> +#include "native_state.h" + +#define DEFAULT_TABLE_SIZE 97 + +struct state_table * +init_state_table_with_size (JNIEnv *env, jclass clazz, jint size) +{ + struct state_table *table; + jfieldID hash; + jclass clazz_g; + + hash = (*env)->GetFieldID (env, clazz, "native_state", "I"); + if (hash == NULL) + return NULL; + + clazz_g = (*env)->NewGlobalRef (env, clazz); + if (clazz_g == NULL) + return NULL; + + table = (struct state_table *) malloc (sizeof (struct state_table)); + table->size = size; + table->head = (struct state_node **) calloc (sizeof (struct state_node *), + table->size); + table->hash = hash; + table->clazz = clazz_g; + + return table; +} + +struct state_table * +init_state_table (JNIEnv *env, jclass clazz) +{ + return init_state_table_with_size (env, clazz, DEFAULT_TABLE_SIZE); +} + +static void * +remove_node (struct state_node **head, jint obj_id) +{ + struct state_node *back_ptr = NULL; + struct state_node *node = *head; + + while (node != NULL) + { + if (node->key == obj_id) + { + void *return_value; + if (back_ptr == NULL) + *head = node->next; + else + back_ptr->next = node->next; + return_value = node->c_state; + free (node); + return return_value; + } + back_ptr = node; + node = node->next; + } + + return NULL; +} + +static void * +get_node (struct state_node **head, jint obj_id) +{ + struct state_node *back_ptr = NULL; + struct state_node *node = *head; + + while (node != NULL) + { + if (node->key == obj_id) + { + /* Move the node we found to the front of the list. */ + if (back_ptr != NULL) + { + back_ptr->next = node->next; + node->next = *head; + *head = node; + } + + /* Return the match. */ + return node->c_state; + } + + back_ptr = node; + node = node->next; + } + + return NULL; +} + +static void +add_node (struct state_node **head, jint obj_id, void *state) +{ + struct state_node *node = *head; + struct state_node *back_ptr = NULL; + + struct state_node *new_node; + + if (node != NULL) + { + while (node->next != NULL && obj_id != node->key) + { + back_ptr = node; + node = node->next; + } + + if (node->key == obj_id) + { + /* If we're updating a node, move it to the front of the + list. */ + if (back_ptr != NULL) + { + back_ptr->next = node->next; + node->next = *head; + } + node->c_state = state; + return; + } + } + + new_node = (struct state_node *) malloc (sizeof (struct state_node)); + new_node->key = obj_id; + new_node->c_state = state; + new_node->next = *head; + *head = new_node; +} + +void +set_state_oid (JNIEnv *env, jobject lock, struct state_table *table, + jint obj_id, void *state) +{ + jint hash; + + hash = obj_id % table->size; + + (*env)->MonitorEnter (env, lock); + add_node (&table->head[hash], obj_id, state); + (*env)->MonitorExit (env, lock); +} + +void * +get_state_oid (JNIEnv *env, jobject lock, struct state_table *table, + jint obj_id) +{ + jint hash; + void *return_value; + + hash = obj_id % table->size; + + (*env)->MonitorEnter (env, lock); + return_value = get_node (&table->head[hash], obj_id); + (*env)->MonitorExit (env, lock); + + return return_value; +} + +void * +remove_state_oid (JNIEnv *env, jobject lock, struct state_table *table, + jint obj_id) +{ + jint hash; + void *return_value; + + hash = obj_id % table->size; + + (*env)->MonitorEnter (env, lock); + return_value = remove_node (&table->head[hash], obj_id); + (*env)->MonitorExit (env, lock); + + return return_value; +} + +int +set_state (JNIEnv *env, jobject obj, struct state_table *table, void *state) +{ + jint obj_id; + obj_id = (*env)->GetIntField (env, obj, table->hash); + + if ((*env)->ExceptionOccurred (env) != NULL) + return -1; + + set_state_oid (env, table->clazz, table, obj_id, state); + return 0; +} + +void * +get_state (JNIEnv *env, jobject obj, struct state_table *table) +{ + jint obj_id; + obj_id = (*env)->GetIntField (env, obj, table->hash); + + if ((*env)->ExceptionOccurred (env) != NULL) + return NULL; + + return get_state_oid (env, table->clazz, table, obj_id); +} + +void * +remove_state_slot (JNIEnv *env, jobject obj, struct state_table *table) +{ + jint obj_id; + obj_id = (*env)->GetIntField (env, obj, table->hash); + + if ((*env)->ExceptionOccurred (env) != NULL) + return NULL; + + return remove_state_oid (env, table->clazz, table, obj_id); +} |