Add iteration 1 report

.gitignore

@@ -0,0 +1,6 @@
+*/**/*.swp
+*/**/.DStore
+.DStore
+*/**/*.dSYM
+*.dSYM
+*.swp

Common/Makefile

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+CC = gcc
+CFLAGS = -g -o
+LDFLAGS = -lncurses
+EXECS = exec
+FILE = *.c
+
+all: compile clean
+
+compile: $(FILE)
+	$(CC) $(CFLAGS) $(EXECS) $(FILE) $(LDFLAGS)
+
+clean: 
+	-rm -rf *.dSYM
+
+spotless: 
+	-rm $(EXECS)

Common/Queue.c

@@ -0,0 +1,134 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "common.h"
+
+/* initialize a Queue data structure */
+int init(Queue_t *queue)
+{
+	int all_ok = 0;
+
+	if (queue != NULL)
+	{
+		queue->head = NULL;
+		queue->tail = NULL;
+		queue->size = 0;
+		all_ok = 1;
+	}
+	return all_ok;
+}
+
+/* delete all elements in a queue */
+
+void destroy(Queue_t *queue)
+{
+	Node_t *tmp = NULL;
+
+	if (queue->head != NULL)
+	{
+		while (queue->head != NULL)
+		{
+			tmp = queue->head;
+			queue->head = queue->head->next;
+			free(tmp);
+		}
+		queue->head = NULL;
+		queue->tail = NULL;
+	}
+}
+
+/* add an element to the end of the queue */
+int enqueue(Queue_t *queue, void *data)
+{
+	int all_ok = 0;
+	if (queue != NULL)
+	{
+		Node_t *n= (Node_t *) malloc(sizeof(Node_t));
+		n->next = NULL;
+		n->prev = NULL;
+		n->data = data;
+		if (queue != NULL && n != NULL)
+		{
+			n->next = NULL;
+			n->prev = queue->tail;
+
+			if (queue->tail == NULL)
+				queue->head = n;
+			else
+				queue->tail->next = n;
+			queue->size += 1;
+			all_ok = 1;
+		}
+	}
+	return all_ok;
+}
+
+/* remove the first element in a queue */
+int dequeue(Queue_t *queue, void **data)
+{
+	int all_ok = 0;
+
+	Node_t *tmp = NULL;
+
+	if (queue != NULL && data != NULL)
+	{
+		if (queue->head != NULL)
+		{
+			/* get the data */
+			*data = queue->head->data;
+
+			/* remove the node */
+			tmp = queue->head;
+			queue->head = queue->head->next;
+			if (queue->head == NULL)
+				queue->tail = NULL;
+			else
+				queue->head->prev = NULL;
+
+			free(tmp);
+			all_ok = 1;
+		}
+		else
+			*data = NULL;
+		queue->size -= 1;
+	}
+
+	return all_ok;
+}
+
+/* Allow code to traverse through a queue linearly.  The context
+   parameter is state that the calling program stores for the
+   traversal.  It indicates the last node in the queue that was
+   reported by the traversal.  To begin a traversal, pass a NULL
+   value as the context content (but not the context variable itself). */
+
+int next(Queue_t *queue, void **context, void **data)
+{
+	int all_ok = 1;
+
+	Node_t **curr = (Node_t **) context;
+
+	/* determine the next node to report in the queue */
+	if (*curr == NULL)
+		*curr = queue->head;
+	else
+		*curr = (*curr)->next;
+
+	/* if we haven't hit the end of the queue, report the data */
+
+	*data = NULL;
+	if (*curr != NULL)
+		*data = (*curr)->data;
+
+	return all_ok;
+}
+
+/* return the size of the queue */
+int size(Queue_t *queue) { return queue->size; }
+
+/* determine if the queue is empty */
+int isEmpty(Queue_t *queue) { return (queue->size == 0); }
+
+
+
+

Common/Queue.h

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+#ifndef _Queue_h_
+#define _Queue_h_
+
+typedef struct Node_t {
+	void *data;
+	struct Node_t *prev, *next;
+} Node_t;
+
+typedef struct Queue_t {
+	Node_t *head;
+	Node_t *tail;
+	int size;
+} Queue_t;
+
+
+int init(Queue_t *);
+void destroy(Queue_t *);
+int enqueue(Queue_t *, void *);
+int dequeue(Queue_t *, void **);
+int next(Queue_t *, void **, void **);
+int size(Queue_t *);
+int ieEmpty(Queue_t *);
+
+
+#endif
+

Common/common.h

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+#ifndef _common_h_
+#define _common_h_
+
+#include <stdio.h>
+#include <stdlib.h>
+#define MAXCRS 7
+#define MAXLEN 20
+#define MAXQUERY 1024
+
+/* Queue Data Structure */
+typedef struct Node_t {
+	void *data;
+	struct Node_t *prev, *next;
+} Node_t;
+
+typedef struct Queue_t {
+	Node_t *head;
+	Node_t *tail;
+	int size;
+} Queue_t;
+
+
+int init(Queue_t *);
+void destroy(Queue_t *);
+int enqueue(Queue_t *, void *);
+int dequeue(Queue_t *, void **);
+int next(Queue_t *, void **, void **);
+int size(Queue_t *);
+int ieEmpty(Queue_t *);
+/* End of Queue Data Structure */
+
+
+/* Database Integration */
+
+/* End of Database Itegration */
+
+
+
+
+#endif

Queue.md

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+Accessing the inside of the queue
+--------------------------------
+
+- `next` -- for iterating over the queue
+  where the position was found using `next`
+
+The function use a "context" parameter to let the queue.c
+functions remember where they are within the queue. `next`
+changes the context variable.
+
+To iterate through the linked queue, begin with the context as a
+NULL value.  Sample iteration code is:
+
+    Queue_t the_queue;
+    void *context = NULL;
+    void *mydata;
+
+    /* Assume that the queue has been inialized and data has been added to it. */
+
+    while ( next( &the_queue, &context, &mydata ) && (mydata != NULL)) {
+      /* Do something with the data pointed to by mydata. */
+    }
+

README.md

@@ -2,3 +2,58 @@
 ===============
 
 CSCI 3431 Project: Creating A Shell 
+
+This is the reporsitory for our CSCI 3134 project.
+
+The header files are all in the headers folder, all other header files in other folders are symbolic links.
+
+***
+
+Group Members
+-------------
+
+Tsubasa Hirooka (Pipe)
+
+Lianzhu Shi
+
+Yucheng Liu
+
+Yiying Zhang
+
+***
+
+Functions
+---------
+
+In this projcet we want to implement a simple shell which has basically 4 functions.
+
+1. History
+
+2. Pipe 
+
+3. Tab Completion Function
+
+4. Database
+
+***
+
+Usage
+---------
+
+When first use this program, use the command `make`, it will compile the program and create an executable call "exec". When you want to delete the executable, use the command `make spotless`.
+
+TBA
+
+***
+
+Data Structure
+---------
+- Queue:
+  - For more information, please refer to [Queue.md] [1]
+
+
+TBA
+
+
+
+[1]: Queue.md

Sample Codes/Makefile

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+
+EXECS = pipe1 pipe2 popen1 popen2
+CC = gcc
+
+all: $(EXECS)
+
+pipe1: pipe1.c
+pipe2: pipe2.c
+popen1: popen1.c
+popen2: popen2.c
+
+clean:
+
+spotless:  clean
+	-rm $(EXECS)
+

Sample Codes/README.md

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+Sample Code Folder
+===
+
+This folder contains the sample codes for various libraries, function, etc. It now only have codes for pipes, which can be later used for implementing pipe-like commands in the shell we are to implement.
+
+***
+
+Sample codes
+------
+
+- `pipe1.c`: The parent process closes the pipe after the child process is terminated.
+
+- `pipe2.c`: The parent process closes the pipe before the child process is terminated and after the message is sent.
+
+- `popen1.c`: Execute `ls` command in another process
+
+- `popen2.c`: Execute `sort` command in another process
+	1. create a file with words
+	2. open a pipe and sort the words in the file
+	3. get rid of the file now that it's done
+
+***
+
+Know Issues
+------
+
+TBA
+