Linux_sys_prog

gluethread/glthreads/Makefile

@@ -0,0 +1,14 @@
+LIBNAME=libglthread.a
+TARGET:${LIBNAME} exe
+${LIBNAME}:glthread.o
+	ar rs ${LIBNAME} glthread.o
+exe:main.o ${LIBNAME}
+	gcc -g main.o -o exe -L . -lglthread
+glthread.o:glthread.c
+	gcc -g -c -I . glthread.c -o glthread.o
+main.o:main.c
+	gcc -g -c -I . main.c -o main.o
+clean:
+	rm *.o
+	rm exe
+	rm ${LIBNAME}

gluethread/glthreads/glthread.c

@@ -0,0 +1,81 @@
+#include "glthread.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+/*Private function to add a new_node right after curr_node*/
+static void
+_glthread_add_next(glthread_node_t *curr_node, 
+                   glthread_node_t *new_node){
+
+    if(!curr_node->right){
+        curr_node->right = new_node;
+        new_node->left = curr_node;
+        return;
+    }
+
+    glthread_node_t *temp = curr_node->right;
+    curr_node->right = new_node;
+    new_node->left = curr_node;
+    new_node->right = temp;
+    temp->left = new_node;
+}
+
+/*Fn to insert a new GLnode into a glthread at the first position
+ * in a glthread i.e. new node becomes a head
+ * */
+void
+glthread_add (glthread_t *lst, glthread_node_t *glnode){
+
+    glnode->left = NULL;
+    glnode->right = NULL;
+    if(!lst->head){
+        lst->head = glnode;
+        return;
+    }
+    glthread_node_t *head = lst->head;
+    _glthread_add_next(glnode, head);
+    lst->head = glnode;
+}
+
+static void
+_remove_glthread(glthread_node_t *glnode){
+
+    if(!glnode->left){
+        if(glnode->right){
+            glnode->right->left = NULL;
+            glnode->right = 0;
+            return;
+        }
+        return;
+    }
+    if(!glnode->right){
+        glnode->left->right = NULL;
+        glnode->left = NULL;
+        return;
+    }
+
+    glnode->left->right = glnode->right;
+    glnode->right->left = glnode->left;
+    glnode->left = 0;
+    glnode->right = 0;
+}
+
+/*API to remove a glnode from glthread*/
+void
+glthread_remove(glthread_t *lst, glthread_node_t *glnode){
+
+    glthread_node_t *head = lst->head;
+    /*If the node being removed is the head node itself, then update the 
+     * head*/
+    if(head == glnode){
+        lst->head = head->right;
+    }
+    _remove_glthread(glnode);
+}
+
+void
+init_glthread(glthread_t *glthread, unsigned int offset){
+
+    glthread->head = NULL;
+    glthread->offset = offset;
+}

gluethread/glthreads/glthread.h

@@ -0,0 +1,42 @@
+#ifndef __GLTHREADS__
+#define __GLTHREADS__
+
+typedef struct glthread_node_ {
+
+    struct glthread_node_ *left;
+    struct glthread_node_ *right;
+} glthread_node_t; 
+
+typedef struct glthread_ {
+
+    glthread_node_t *head;
+    unsigned int offset;
+} glthread_t;
+
+void
+glthread_add (glthread_t *lst, glthread_node_t *glnode);
+
+void
+glthread_remove(glthread_t *lst, glthread_node_t *glnode);
+
+/*Iterative macro to Iterate Over GLTHhreads*/
+#define ITERATE_GL_THREADS_BEGIN(lstptr, struct_type, ptr)      \
+{                                                               \
+    glthread_node_t *_glnode = NULL, *_next = NULL;             \
+    for(_glnode = lstptr->head; _glnode; _glnode = _next){      \
+        _next = _glnode->right;                                 \
+        ptr = (struct_type *)((char *)_glnode - lstptr->offset);
+
+#define ITERATE_GL_THREADS_ENDS }}
+
+#define glthread_node_init(glnode)  \
+    glnode->left = NULL;            \
+    glnode->right = NULL;
+
+void
+init_glthread(glthread_t *glthread, unsigned int offset);
+
+#define offsetof(struct_name, field_name)   \
+    ((unsigned int)&((struct_name *)0)->field_name)
+
+#endif /* __GLTHREADS__ */

gluethread/glthreads/main.c

@@ -0,0 +1,87 @@
+#include "glthread.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <memory.h>
+
+typedef struct emp_ {
+
+    char name[30];
+    unsigned int salary;
+    char designation[30];
+    unsigned int emp_id;
+    glthread_node_t glnode;
+} emp_t; 
+
+void
+print_emp_details(emp_t *emp){
+
+    printf("Employee name = %s\n", emp->name);
+    printf("salary = %u\n", emp->salary);
+    printf("designation = %s\n", emp->designation);
+    printf("emp_id = %u\n", emp->emp_id);
+}
+
+
+int 
+main(int argc, char **argv){
+
+    emp_t *emp1  = calloc(1, sizeof(emp_t));
+    strncpy(emp1->name, "Neha", strlen("Neha"));
+    emp1->salary = 50000;
+    strncpy(emp1->designation, "HR", strlen("HR"));
+    emp1->emp_id = 21;
+    glthread_node_init((&emp1->glnode));
+
+    emp_t *emp2  = calloc(1, sizeof(emp_t));
+    strncpy(emp2->name, "Abhishek", strlen("Abhishek"));
+    emp1->salary = 150000;
+    strncpy(emp2->designation, "SE3", strlen("SE3"));
+    emp2->emp_id = 32;
+    glthread_node_init((&emp2->glnode));
+
+    emp_t *emp3  = calloc(1, sizeof(emp_t));
+    strncpy(emp3->name, "Arun", strlen("Arun"));
+    emp3->salary = 60000;
+    strncpy(emp3->designation, "SE4", strlen("SE4"));
+    emp3->emp_id = 27;
+    glthread_node_init((&emp3->glnode));
+
+
+    /*Now Create a glthread*/
+    glthread_t *emp_list = calloc(1, sizeof(glthread_t));
+    init_glthread(emp_list, offsetof(emp_t, glnode));
+
+    /*Now insert the records in glthread*/
+    glthread_add(emp_list, &emp1->glnode);
+    glthread_add(emp_list, &emp2->glnode);
+    glthread_add(emp_list, &emp3->glnode);
+
+
+    /*Walk over glthread*/
+    emp_t *ptr = NULL;
+    ITERATE_GL_THREADS_BEGIN(emp_list, emp_t, ptr){
+
+        print_emp_details(ptr);
+    } ITERATE_GL_THREADS_ENDS;
+
+    /*Let us remove one record at random*/
+
+    glthread_remove(emp_list, &emp2->glnode);
+    printf("\nprinting again . . . \n");
+
+    ITERATE_GL_THREADS_BEGIN(emp_list, emp_t, ptr){
+
+        print_emp_details(ptr);
+    } ITERATE_GL_THREADS_ENDS;
+
+
+    /*Free all Dynamicall allocations*/
+    ITERATE_GL_THREADS_BEGIN(emp_list, emp_t, ptr){
+        
+         glthread_remove(emp_list, &ptr->glnode);
+         free(ptr);
+    } ITERATE_GL_THREADS_ENDS;
+    free(emp_list);
+
+    return 0;
+}

gluethread/glthreads/main2.c

@@ -0,0 +1,87 @@
+#include "glthread.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <memory.h>
+
+typedef struct emp_ {
+
+    char name[30];
+    unsigned int salary;
+    char designation[30];
+    unsigned int emp_id;
+    glthread_node_t glnode;
+} emp_t; 
+
+void
+print_emp_details(emp_t *emp){
+
+    printf("Employee name = %s\n", emp->name);
+    printf("salary = %u\n", emp->salary);
+    printf("designation = %s\n", emp->designation);
+    printf("emp_id = %u\n", emp->emp_id);
+}
+
+
+int 
+main(int argc, char **argv){
+
+    emp_t *emp1  = calloc(1, sizeof(emp_t));
+    strncpy(emp1->name, "Neha", strlen("Neha"));
+    emp1->salary = 50000;
+    strncpy(emp1->designation, "HR", strlen("HR"));
+    emp1->emp_id = 21;
+    glthread_node_init((&emp1->glnode));
+
+    emp_t *emp2  = calloc(1, sizeof(emp_t));
+    strncpy(emp2->name, "Abhishek", strlen("Abhishek"));
+    emp1->salary = 150000;
+    strncpy(emp2->designation, "SE3", strlen("SE3"));
+    emp2->emp_id = 32;
+    glthread_node_init((&emp2->glnode));
+
+    emp_t *emp3  = calloc(1, sizeof(emp_t));
+    strncpy(emp3->name, "Arun", strlen("Arun"));
+    emp3->salary = 60000;
+    strncpy(emp3->designation, "SE4", strlen("SE4"));
+    emp3->emp_id = 27;
+    glthread_node_init((&emp3->glnode));
+
+
+    /*Now Create a glthread*/
+    glthread_t *emp_list = calloc(1, sizeof(glthread_t));
+    init_glthread(emp_list, offsetof(emp_t, glnode));
+
+    /*Now insert the records in glthread*/
+    glthread_add(emp_list, &emp1->glnode);
+    glthread_add(emp_list, &emp2->glnode);
+    glthread_add(emp_list, &emp3->glnode);
+
+
+    /*Walk over glthread*/
+    emp_t *ptr = NULL;
+    ITERATE_GL_THREADS_BEGIN(emp_list, emp_t, ptr){
+
+        print_emp_details(ptr);
+    } ITERATE_GL_THREADS_ENDS;
+
+    /*Let us remove one record at random*/
+
+    glthread_remove(emp_list, &emp2->glnode);
+    printf("\nprinting again . . . \n");
+
+    ITERATE_GL_THREADS_BEGIN(emp_list, emp_t, ptr){
+
+        print_emp_details(ptr);
+    } ITERATE_GL_THREADS_ENDS;
+
+
+    /*Free all Dynamicall allocations*/
+    ITERATE_GL_THREADS_BEGIN(emp_list, emp_t, ptr){
+        
+         glthread_remove(emp_list, &ptr->glnode);
+         free(ptr);
+    } ITERATE_GL_THREADS_ENDS;
+    free(emp_list);
+
+    return 0;
+}