ProvaPratica 2013.09.13 - Revision history

FedericoB: Aggiunte soluzione di un'altro studente

2017-05-10T07:42:09Z

Aggiunte soluzione di un'altro studente

FedericoB: Aggiunte soluzioni da altre pagine, uniformato

2017-05-09T08:10:22Z

Aggiunte soluzioni da altre pagine, uniformato

Pirata at 13:34, 23 March 2014

2014-03-23T13:34:42Z

Edu san at 18:31, 9 March 2014

2014-03-09T18:31:28Z

Edu san: Created page with "[C esercizio 1 e 2] /*********************************************************************** * Prova Pratica di Laboratorio di Sistemi Operativi ..."

2014-03-04T23:58:31Z

Created page with "[C esercizio 1 e 2] <syntaxhighlight lang="C"> /*********************************************************************** * Prova Pratica di Laboratorio di Sistemi Operativi ..."

New page

[C esercizio 1 e 2]
<syntaxhighlight lang="C">

/***********************************************************************
* Prova Pratica di Laboratorio di Sistemi Operativi *
* 13 settembre 2013 *
* Esercizio 1+2 *
* *
* URL: http://www.cs.unibo.it/~renzo/so/pratiche/2013.09.13.pdf *
* Autore: Eduardo Santarelli *
************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <unistd.h>

/* An entry in the hash table. */
typedef struct fileEntry{

const char *filename;
struct fileEntry *next;

} fileEntry;

/* Global variables */
fileEntry **table = NULL;
int table_size;

/* Hash function. Calculates XOR of 8-bytes blocks *
* (actually, sizeof(long int)) read from the input file */
unsigned int hash(const char *fname){

FILE *f;
unsigned long int hash_val = 0;
unsigned long int tmp = 0;

f = fopen(fname, "r");
fread(&hash_val, sizeof(unsigned long int), 1, f);

while((fread(&tmp, sizeof(unsigned long int), 1, f) == 1))
hash_val = hash_val^tmp;

fclose(f);
return hash_val;

}

/* Creates a table of struct fileEntry elements, based on the hash values of the files *
* detected by scandir. If a collision is detected, the new entry is pointed by the *
* 'next' field of the current last element*/
void populate_table(struct dirent *dir_list[], int n){

int i;

table_size = 2*n;
table = (fileEntry**)calloc(table_size, sizeof(fileEntry));
if(!table) abort();

for(i=0; i<n; i++){
unsigned int index;
fileEntry *entry = NULL;

entry = (fileEntry*)malloc(sizeof(fileEntry));
if(!entry) abort();

index = hash(dir_list[i]->d_name)%table_size;
if(table[index] == NULL){
entry->filename = dir_list[i]->d_name;
entry->next = NULL;
table[index] = entry;
}
else{
entry->filename = dir_list[i]->d_name;
entry->next = table[index];
table[index] = entry;
}
}

}

/* Compares two files */
int fcompare(const char *f1, const char *f2){

FILE *f, *g;
int file1, file2;

f = fopen(f1, "r");
g = fopen(f2, "r");

while(fread(&file1, sizeof(int), 1, f) && fread(&file2, sizeof(int), 1, g)){
if(file1!=file2){
fclose(f);
fclose(g);
return 0;
}
}
fclose(f);
fclose(g);
return 1;

}

/* This function scans the file table. If an entry contains more than one file, *
* it compares all them. If a duplicate is found, the first file is removed, *
* and a hard link is created with the deleted file's name, pointing to the *
* second, identical, file. */
void deduplicate(){

int i;

for(i=0; i<table_size; i++){
while(table[i] != NULL && table[i]->next != NULL){

fileEntry *file1, *file2;
file1 = table[i];
file2 = table[i]->next;
while(file2 != NULL){
if(fcompare(file1->filename, file2->filename)){
unlink(file1->filename);
link(file2->filename, file1->filename);
printf("%s -> %s\n", file1->filename, file2->filename);
break;
}
file2 = file2->next;
}
table[i] = table[i]->next;
}
}
}

/*selector function for scandir() */
int exclude(const struct dirent *dir){

if(dir->d_type != DT_REG)
return 0;
else
return 1;

}

int main(int argc, char *argv[]){

struct dirent **entries = NULL;
int num_files;

num_files = scandir(".", &entries, exclude, alphasort);

populate_table(entries, num_files);
deduplicate();

return EXIT_SUCCESS;

}
</syntaxhighlight>

@@ Line 162: / Line 162: @@
+}
 </syntaxhighlight>
 ==Esercizio 3==

@@ Line 1: / Line 1: @@
-[C esercizio 1 e 2]
+==Esercizio 1 e 2==
 <syntaxhighlight lang="C">
@@ Line 162: / Line 163: @@
 </syntaxhighlight>
+==Esercizio 3==
-------
+===Soluzione di Edu San===
 <syntaxhighlight lang="Python">
 #!/usr/bin/env python3
@@ Line 227: / Line 226: @@
-[Bash esercizio 3]
+===Soluzione di Pirata===
 <syntaxhighlight lang="Bash">
 #Esercizio 3: Script bash o Python: (10 punti):
@@ Line 254: / Line 253: @@
 rm fileresult
 </syntaxhighlight>
-Pirata

← Older revision		Revision as of 13:34, 23 March 2014
Line 225:		Line 225:
	lc.printLines()		lc.printLines()
	</syntaxhighlight>		</syntaxhighlight>
		+
		+
		+	[Bash esercizio 3]
		+	<syntaxhighlight lang="Bash">
		+	#Esercizio 3: Script bash o Python: (10 punti):
		+	#Sia data una directory che contiene file di testo.
		+	#Scopo dell'esercizio e' di contare i caratteri delle corrispondenti righe di testo di tutti i file della directory, si vuole cioe' sapere
		+	#il numero totale di caratteri presenti nelle prime righe di tutti i file, nelle seconde linee, ecc.
		+	#$ ccpl mydir
		+	#1 234
		+	#2 21
		+	#3 333
		+	# .....
		+	#l'ouput significa che se contiamo tutti i caratteri contenuti nella prima riga di tutti i file in mydir otteniamo 234 (mydir/file1
		+	#puo' avere 40 caratteri nella prima riga, mydir/file2 ne puo' avere 20, ecc... procedendo per tutti i file di mydir la somma fa 234)
		+
		+	#! bin/bash
		+
		+
		+	nline=1
		+	touch fileresult
		+	paste $1/* > fileresult #merges every file's line from the directory passed to the file fileresult
		+	while read line; do
		+	count=$(echo $line \| wc -m) #counts the number of char in each line of fileresult
		+	echo $nline $count
		+	nline=$(($nline + 1))
		+	done < fileresult
		+	rm fileresult
		+	</syntaxhighlight>
		+	Pirata

← Older revision		Revision as of 18:31, 9 March 2014
Line 160:		Line 160:

	}		}
		+	</syntaxhighlight>
		+
		+
		+	------
		+
		+	[Python esercizio 3]
		+	<syntaxhighlight lang="Python">
		+	#!/usr/bin/env python3
		+
		+	# Prova Pratica di Laboratorio di Sistemi Operativi
		+	# 13 settembre 2013
		+	# Esercizio 3
		+	#
		+	# URL: http://www.cs.unibo.it/~renzo/so/pratiche/2013.09.13.pdf *
		+	# Autore: Eduardo Santarelli
		+
		+
		+	class LineCounter:
		+
		+	def __init__(self, fileList):
		+	# A list containing the char-per-line
		+	# count for the specified files.
		+	# Value for line 1 is in result[0] and so on.
		+	self.result = []
		+	self.files = fileList # List of files to elaborate.
		+	self.getLinesCount()
		+
		+	# Count the chars for each lines of specified file,
		+	# add the result to the relevant field in self.result,
		+	# if already present, append the value to the
		+	# end of the list if not.
		+	def countLines(self, file):
		+	i = 0
		+	fd = open(file)
		+	for line in fd:
		+	lineLength = len(line)
		+	# If an entry for the current line does
		+	# not exist, append the value to the end of the list
		+	try:
		+	self.result[i] += lineLength
		+	except IndexError:
		+	self.result.append(lineLength)
		+	i = i+1
		+	fd.close()
		+
		+	# Call self.countLines() for each file in self.files
		+	# in order to build the self.result list
		+	def getLinesCount(self):
		+	for entry in self.files:
		+	self.countLines(entry)
		+
		+	# Print the items in self.result, each preceded by the
		+	# corresponding line number.
		+	def printLines(self):
		+	i = 1
		+	for value in self.result:
		+	print("{:d}: {:d}".format(i, value))
		+	i = i+1
		+
		+
		+	import os
		+
		+	lc = LineCounter(os.listdir(os.getcwd()))
		+	lc.printLines()
	</syntaxhighlight>		</syntaxhighlight>