Merge pull request #1 from nuno-silva/ex1

Exercise 1

.gitignore

@@ -27,3 +27,18 @@
 *.i*86
 *.x86_64
 *.hex
+
+# Project Specific Files
+*.txt
+
+# temporary save files
+*.swp
+
+# c9.io folder
+.c9/*
+
+*.zip
+
+# binaries
+src/reader
+src/writer

src/Makefile

@@ -0,0 +1,26 @@
+CC = gcc
+CFLAGS = -g
+
+all: writer reader
+
+
+writer: writer_main.o writer.o shared_stuff.o
+
+writer_main.o: writer_main.c writer.h
+writer.o: writer.c writer.h shared_stuff.h
+
+
+
+reader: reader_main.o reader.o shared_stuff.o
+
+reader_main.o: reader_main.c reader.h
+reader.o: reader.c reader.h shared_stuff.h
+
+shared_stuff.o: shared_stuff.c shared_stuff.h
+
+clean:
+	rm -rf writer reader *.o *.txt
+
+zip:
+	rm -f grupo-46.zip
+	zip grupo-46.zip *.c *.h Makefile

src/reader.c

@@ -0,0 +1,84 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "shared_stuff.h"
+#include "reader.h"
+
+const static int reader_f_flags = O_RDONLY;
+
+
+int reader(int file_num){
+    char file_name[64];
+    int fd, file_value;
+    sprintf(file_name, FILENAME, file_num); // place file_num in FILENAME
+    fd = open(file_name, reader_f_flags);
+
+    if (fd == -1){ // error opening the file (does not exist?)
+        return FILE_IS_INVALID;
+    }
+
+    if ( file_contents_are_valid(fd, WRITER_STRING_LEN, LINES_PER_FILE) == TRUE ){
+        file_value = FILE_IS_VALID;
+    }else{
+        file_value =  FILE_IS_INVALID;
+    }
+
+    close(fd);
+    return file_value;
+}
+
+
+int file_contents_are_valid(int fd, int line_length, int line_count)
+{
+    // number of bytes to read at a time from the file
+    int line_size = line_length * sizeof(char);
+
+    char *first_line = (char*) malloc(line_size);
+
+    // try to read and validate the first line of the file
+    if ( read(fd, first_line, line_size) != line_size ) {
+        // the first line doesn't even have the correct number of characters
+        free(first_line);
+        return FALSE; // file is invalid
+    }
+    if ( !known_writer_string(first_line, line_size) ){
+        free(first_line);
+        return FALSE; // file is invalid
+    }
+
+    // the first line is valid, so we can compare it with all other lines
+    char *line_buffer = (char*) malloc(line_size);
+
+    // compare all lines with the first line
+    int i;
+    for ( i = 1 ; read(fd, line_buffer, line_size) == line_size; i++ )
+    {
+        if ( strncmp(line_buffer, first_line, line_size) != 0 || i >= line_count){
+            free(first_line);
+            free(line_buffer);
+            return FALSE; // file is invalid
+        }
+    }
+
+    free(first_line);
+    free(line_buffer);
+
+    if (i != line_count)
+        return FALSE;
+
+    return TRUE; // file is valid
+}
+
+int known_writer_string(char *str, int str_size){
+    int i;
+
+    for ( i = 0; i < WRITER_STRING_COUNT; i++ ){
+        if ( strncmp(str, writer_strings[i], str_size) == 0 ){
+            return TRUE;
+        }
+    }
+
+    return FALSE;
+}

src/reader.h

@@ -0,0 +1,13 @@
+#ifndef __READER_H__
+    #define __READER_H__
+
+
+    #define FILE_IS_VALID    0
+    #define FILE_IS_INVALID -1
+
+    int reader(int file_num);
+    int file_contents_are_valid(int fd, int line_length, int line_count);
+    int known_writer_string(char *str, int str_size);
+
+
+#endif

src/reader_main.c

@@ -0,0 +1,14 @@
+#include "shared_stuff.h"
+#include "reader.h"
+#include <time.h>
+#include <stdlib.h>
+
+int main () {
+    int file_num;
+
+    srand (time(NULL));
+
+    file_num = RANDOM_RANGE(0, 4);
+
+    return reader(file_num);
+}

src/shared_stuff.c

@@ -0,0 +1,14 @@
+#include "shared_stuff.h"
+
+char writer_strings [ WRITER_STRING_COUNT ][ WRITER_STRING_LEN + 1 ] = {
+	"aaaaaaaaa\n",
+	"bbbbbbbbb\n",
+	"ccccccccc\n",
+	"ddddddddd\n",
+	"eeeeeeeee\n",
+	"fffffffff\n",
+	"ggggggggg\n",
+	"hhhhhhhhh\n",
+	"iiiiiiiii\n",
+	"jjjjjjjjj\n"
+};

src/shared_stuff.h

@@ -0,0 +1,17 @@
+#ifndef __SHARED_STUFF_H__
+    #define __SHARED_STUFF_H__
+
+
+    #define WRITER_STRING_LEN   10
+    #define WRITER_STRING_COUNT 10
+    #define LINES_PER_FILE      1024
+
+    #define FILENAME "SO2014-%d.txt"
+
+    #define RANDOM_RANGE(MIN, MAX) (( rand() % ( MAX + 1 - MIN ) ) + MIN )
+
+    extern char writer_strings [ WRITER_STRING_COUNT ][ WRITER_STRING_LEN + 1 ];
+
+    #define TRUE    1
+    #define FALSE   0
+#endif

src/writer.c

@@ -0,0 +1,30 @@
+#include <stdio.h>
+#include <fcntl.h>
+
+
+#include "writer.h"
+#include "shared_stuff.h"
+
+
+const static int writer_f_flags = O_WRONLY | O_CREAT | O_TRUNC;
+const static int writer_f_mode  = S_IRUSR  | S_IWUSR | S_IROTH;
+
+void writer(int file_num, char *txt, int txt_len){
+	char file_name[64];
+	int fd, i, txt_size;
+
+	sprintf(file_name, FILENAME, file_num);	// place file_num in FILENAME
+	fd = open(file_name, writer_f_flags, writer_f_mode);
+
+	txt_len *= sizeof(char);
+	for (i = 0; i < LINES_PER_FILE; i++){
+		write(fd, txt, txt_len);
+	}
+
+	close(fd);
+}
+
+
+char *get_writer_string(int index){
+	return (char*) writer_strings[index];
+}

src/writer.h

@@ -0,0 +1,21 @@
+#ifndef __WRITER_H__
+    #define __WRITER_H__
+
+    #define CYCLE_COUNT 5120
+
+
+    /**
+     * @brief Opens the file specified by file_num and writes to it.
+     * @param file_nume the number of the file
+     * @param txt pointer to the string to write
+     * @param txt_size number of characters in txt to write
+     */
+    void writer(int file_num, char *txt, int txt_len);
+
+
+    /**
+     * @brief Get a writer string by its index
+     */
+    char * get_writer_string( int index );
+
+#endif //__WRITER_H__

src/writer_main.c

@@ -0,0 +1,19 @@
+#include "writer.h"
+#include <time.h>
+#include "shared_stuff.h"
+#include <stdlib.h>
+
+int main (int argc, char *argv[]){
+    int i, file_num;
+    char *rand_str;
+
+    srand (time(NULL));
+
+    for ( i = 0; i < CYCLE_COUNT; i++ ){
+    	file_num = RANDOM_RANGE(0, 4);
+    	rand_str = get_writer_string( RANDOM_RANGE(0, WRITER_STRING_COUNT - 1) );
+		writer(file_num, rand_str, WRITER_STRING_LEN);
+    }
+
+    return 0;
+}