Little changes and debug

QAM/qamold/qam.c

@@ -5,11 +5,9 @@
 #include <complex.h>
 #include "../wav/wav.h"
 #include "../files/files.h"
-#include "../plot/plot_constellation.h"
 #include <string.h>
-#include <SDL2/SDL.h>
 
-#define A 10000
+#define A 1 
 
 struct qam_system_s {
     int M; // Nombre de symboles M-QAM
@@ -38,7 +36,7 @@ void init_constellation (qam_system* qam) {
         double complex ip = -(sm - 1) + 2 * i;
         for (int j = 0; j < sm; j++) {
             double complex qp = -(sm - 1) + 2 * j;
-            qam->constellation[i][j] = A * (ip + I * qp) / norm_factor; 
+            qam->constellation[i][j] = (ip + I * qp); 
         }
     }
 }
@@ -94,10 +92,9 @@ void demodulate(qam_system* qam, double complex* s, int nb_symbols, uint8_t* bit
         }
         r /= qam->N;
 
-        // Distance euclidien de Ir et Qr pour avoir le point le plus proche de la constellation
+        // Distance euclidien de Ir et Qr pour avoir le point le plus proche de la constellation (lent)
         
         int sm = (int)sqrt(qam->M);
-        /* TEMPS INFINI
         double min_d = INFINITY;
         int i_cl, j_cl = 0;
         for (int i = 0; i < sm; i++) {
@@ -110,39 +107,16 @@ void demodulate(qam_system* qam, double complex* s, int nb_symbols, uint8_t* bit
                 }
             }
         }
-        */
-        double norm_factor = sqrt((double)(qam->M - 1) / 3.0);
-        double Ir = creal(r) * norm_factor / A;
-        double Qr = cimag(r) * norm_factor / A;
 
-        int i = (int)round((Ir + (sm - 1)) / 2.0);
+                // index du symbole (id) : même mappage que dans bits_to_symbols()
-        int j = (int)round((Qr + (sm - 1)) / 2.0);
+        int id = i_cl * sm + j_cl;
 
-        i = (i < 0) ? 0 : ((i >= sm) ? sm - 1 : i);
-        j = (j < 0) ? 0 : ((j >= sm) ? sm - 1 : j);
-
-        int id = i * sm + j;
-
-        //int id = i_cl * sm + j_cl;
         for (int b = 0; b < qam->k; b++) {
-            bits_hat[k * qam->k + (qam->k - 1 - b)] = (id >> b) & 1;
+            bits_hat[k * qam->k + b] = (id >> (qam->k - 1 - b)) & 1;
         }
     }
 }
 
-double complex* demodulate_points(qam_system* qam, double complex* s, int nb_symbols) {
-    double complex* points = malloc(sizeof(double complex) * nb_symbols);
-    for (int k = 0; k < nb_symbols; k++) {
-        double complex r = 0;
-        for (int n = 0; n < qam->N; n++) {
-            r += s[k * qam->N + n] * cexp(-2 * I * M_PI * qam->Fc * ((double)n / qam->Fs));
-        }
-        r /= qam->N;
-        points[k] = r;
-    }
-    return points;
-}
-
 // Libération de la mémoire
 void free_constellation(qam_system* qam) {
     int sm = (int)sqrt(qam->M);
@@ -151,6 +125,36 @@ void free_constellation(qam_system* qam) {
     free(qam->constellation);
 }
 
+// Compare deux tableaux de bits (0/1) et retourne le pourcentage de fiabilité.
+double compare_bits(const uint8_t *in_bits, size_t nb_bits_in, const uint8_t *out_bits, size_t nb_bits_out, size_t *erreurs) {
+    if (!in_bits || !out_bits) {
+        if (erreurs) *erreurs = (nb_bits_in < nb_bits_out) ? nb_bits_out : nb_bits_in;
+        return 0.0;
+    }
+
+    size_t n_min = (nb_bits_in < nb_bits_out) ? nb_bits_in : nb_bits_out;
+    size_t n_max = (nb_bits_in > nb_bits_out) ? nb_bits_in : nb_bits_out;
+
+    size_t err = 0;
+    for (size_t i = 0; i < n_min; ++i) {
+        if ((in_bits[i] & 1) != (out_bits[i] & 1)) err++;
+    }
+
+    if (n_max != n_min) {
+        err += (n_max - n_min);
+    }
+
+    if (erreurs) *erreurs = err;
+
+    double total_compared = (double)n_max;
+    if (total_compared == 0.0) return 0.0;
+
+    double ber = (double)err / total_compared;
+    double reliability_percent = (1.0 - ber) * 100.0;
+    return reliability_percent;
+}
+
+
 int main (int argc, char *argv[]) {
     if (argc < 2) {
         fprintf(stderr, "Utilisation: %s <fichier_entree>\n", argv[0]);
@@ -158,7 +162,7 @@ int main (int argc, char *argv[]) {
     }
 
     qam_system qam;
-    qam.M = 64;
+    qam.M = 16;
     qam.k = (int)log2((double)(qam.M));
     qam.Fs = 44100;
     qam.Ts = 0.0003;
@@ -185,18 +189,18 @@ int main (int argc, char *argv[]) {
 
     // Ajout du bruit 
     double signal_power = (2.0/3.0)*(qam.M-1); // puissance moyenne avant échelle
-    double snr_dB = -27; // Signal to noise ratio
+    double snr_dB = 10; // Signal to noise ratio
     double snr_lin = pow(10.0, snr_dB / 10.0);
     double sigma = sqrt(signal_power / snr_lin);
     printf("Ajout du bruit... \n       puissance du signal : %f\n       SNR db : %f\n       sigma : %f\n", signal_power, snr_dB, sigma);
-    add_noise(s, total_samples, 1875);
+    add_noise(s, total_samples, 0);
 
     printf("Demodulation...\n");
 
     // Demodulation QAM
     bit_array output_bits;
     output_bits.nb_bits = input_bits.nb_bits;
-    output_bits.bits = (uint8_t*)malloc(output_bits.nb_bits);
+    output_bits.bits = (uint8_t*)malloc(output_bits.nb_bits * sizeof(uint8_t));
     demodulate(&qam, s, nb_symbols, output_bits.bits);
 
     printf("Ecriture...\n");
@@ -204,24 +208,25 @@ int main (int argc, char *argv[]) {
     char *output_filename = make_output_filename(input_filename);
     bits_to_file(output_filename, &output_bits);
 
-
     // Affichage du signal dans un .wav
+    /*
     double* si = (double*)malloc(sizeof(double) * total_samples);
     for (int i = 0; i < total_samples; i++) {
        si[i] = cimag(s[i]); 
     }
     write_wav("output.wav", si, total_samples);
+    */
 
-    // Plot
+    size_t erreurs = 0; 
-    printf("Ploting...");
+    double fiabilite = compare_bits( input_bits.bits, input_bits.nb_bits, output_bits.bits, output_bits.nb_bits, &erreurs);
-    plot_t plot;
+
-    plot_init(&plot, 1400, 1400, 0.04);
+    printf("Comparaison :\n");
-    plot_draw_constellation(&plot, qam.constellation, qam.M);
+    printf("    Bits d'entrée : %zu\n", input_bits.nb_bits);
-    SDL_Color red = {255, 0, 0, 255};
+    printf("    Bits de sortie: %zu\n", output_bits.nb_bits);
-    plot_draw_points_animated(&plot, demodulate_points(&qam, s, nb_symbols), nb_symbols, red, 5);
+    printf("    Erreurs       : %zu\n", erreurs);
+    printf("    Fiabilité     : %.4f %%\n", fiabilite);
 
     // Libération mémoire
-    plot_close(&plot);
     free_bit_array(&input_bits);
     free_bit_array(&output_bits);
     free(symbols);

QAM/qamold/qambis.c

@@ -0,0 +1,237 @@
+#include <math.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <complex.h>
+#include "../wav/wav.h"
+#include "../files/files.h"
+#include "../plot/plot_constellation.h"
+#include <string.h>
+#include <SDL2/SDL.h>
+
+#define A 1 
+
+struct qam_system_s {
+    int M; // Nombre de symboles M-QAM
+    int k; // Nombre de bits/symboles
+    double Fs; // Fréquence d'échantillionage
+    double Ts; // Temps d'échantillionage
+    int N; // Nombre d'échantillions
+    double Fc; // Fréquence de la porteuse
+    double complex** constellation; // Tableau de symboles I + j Q
+};
+typedef struct qam_system_s qam_system;
+
+// Initialisation de la constellation (double tableau de taille sqrt(M)), 
+// ToDo : changer à un tableau à 1 dimension pour éviter de calculer sqrt(M)
+void init_constellation (qam_system* qam) {
+    int sm = (int)sqrt(qam->M);
+    qam->constellation = (double complex**)malloc(sizeof(double complex*) * sm);
+    
+    for (int i = 0; i < sm; i++) {
+       qam->constellation[i] = (double complex*)malloc(sizeof(double complex) * sm);
+    }
+
+    double norm_factor = sqrt((double)(qam->M - 1) / 3.0); // Pour puissance unitaire
+
+    for (int i = 0; i < sm; i++) {
+        double complex ip = -(sm - 1) + 2 * i;
+        for (int j = 0; j < sm; j++) {
+            double complex qp = -(sm - 1) + 2 * j;
+            qam->constellation[i][j] = (ip + I * qp); 
+        }
+    }
+}
+
+// Calcul du bruit gaussien pour un sigma donné
+// Formule de Box-Muller
+double gaussian_noise (double sigma) {
+    double u1 = (rand() + 1) / ((double)RAND_MAX + 2);
+    double u2 = (rand() + 1) / ((double)RAND_MAX + 2);
+    return sigma * sqrt(-2 * log(u1)) * cos(2 * M_PI * u2);
+}
+
+// Ajout du bruit
+void add_noise (double complex* s, int len, double sigma) {
+    for (int i = 0; i < len; i++) {
+        double nr = gaussian_noise(sigma);
+        double ni = gaussian_noise(sigma);
+        s[i] += nr + I * ni;
+    }
+}
+
+// Changer le tableau de bits en boolen ou alors la represenation binaire et shifter pour extraire les bits (pas bien si M plus grand)
+void bits_to_symbols (qam_system* qam, uint8_t* bits, int nb_bits, double complex* symbols) {
+    int nb_symbols = nb_bits / qam->k;
+    int sm = sqrt(qam->M);
+    for (int k = 0; k < nb_symbols; k++) {
+        int id = 0;
+        for (int b = 0 ; b < qam->k; b++) {
+            id = id * 2 + bits[k * qam->k + b];
+        }
+        int i = id / sm; 
+        int j = id % sm;
+        symbols[k] = qam->constellation[i][j];
+    }
+}
+
+// Modulation QAM 
+void modulate (qam_system* qam, double complex* symbols, int nb_symbols, double complex* s) {
+    for (int k = 0; k < nb_symbols; k++) {
+        double complex iq = symbols[k];
+        for (int n = 0; n < qam->N; n++) {
+            s[k * qam->N + n] = iq * cexp(2 * I * M_PI * qam->Fc * ((double)n / qam->Fs)); 
+        }
+    }
+}
+
+// Demodulation QAM 
+void demodulate(qam_system* qam, double complex* s, int nb_symbols, uint8_t* bits_hat) {
+    for (int k = 0; k < nb_symbols; k++) {
+        double complex r = 0;
+        for (int n = 0; n < qam->N; n++) {
+            r += s[k * qam->N + n] * cexp(-2 * I * M_PI * qam->Fc * ((double)n / qam->Fs));
+        }
+        r /= qam->N;
+
+        // Distance euclidien de Ir et Qr pour avoir le point le plus proche de la constellation
+        
+        int sm = (int)sqrt(qam->M);
+        double min_d = INFINITY;
+        int i_cl, j_cl = 0;
+        for (int i = 0; i < sm; i++) {
+            for (int j = 0; j < sm; j++) {
+                double d = cabs(r - qam->constellation[i][j]);
+                if (d < min_d) {
+                    min_d = d;
+                    i_cl = i;
+                    j_cl = j;
+                }
+            }
+        }
+        /*
+        double norm_factor = sqrt((double)(qam->M - 1) / 3.0);
+        double Ir = creal(r) * norm_factor / A;
+        double Qr = cimag(r) * norm_factor / A;
+
+        int i = (int)round((Ir + (sm - 1)) / 2.0);
+        int j = (int)round((Qr + (sm - 1)) / 2.0);
+
+        i = (i < 0) ? 0 : ((i >= sm) ? sm - 1 : i);
+        j = (j < 0) ? 0 : ((j >= sm) ? sm - 1 : j);
+
+        int id = i * sm + j;
+        */
+
+        int id = i_cl * sm + j_cl;
+        for (int b = 0; b < qam->k; b++) {
+            bits_hat[k * qam->k + (qam->k - 1 - b)] = (id >> b) & 1;
+        }
+    }
+}
+
+double complex* demodulate_points(qam_system* qam, double complex* s, int nb_symbols) {
+    double complex* points = malloc(sizeof(double complex) * nb_symbols);
+    for (int k = 0; k < nb_symbols; k++) {
+        double complex r = 0;
+        for (int n = 0; n < qam->N; n++) {
+            r += s[k * qam->N + n] * cexp(-2 * I * M_PI * qam->Fc * ((double)n / qam->Fs));
+        }
+        r /= qam->N;
+        double norm_factor = sqrt((double)(qam->M - 1) / 3.0);
+        double Ir = creal(r);
+        double Qr = cimag(r);
+
+        points[k] = Ir + I * Qr;
+    }
+    return points;
+}
+
+// Libération de la mémoire
+void free_constellation(qam_system* qam) {
+    int sm = (int)sqrt(qam->M);
+    for (int i = 0; i < sm; i++)
+        free(qam->constellation[i]);
+    free(qam->constellation);
+}
+
+int main (int argc, char *argv[]) {
+    if (argc < 2) {
+        fprintf(stderr, "Utilisation: %s <fichier_entree>\n", argv[0]);
+        return 1;
+    }
+
+    qam_system qam;
+    qam.M = 16;
+    qam.k = (int)log2((double)(qam.M));
+    qam.Fs = 44100;
+    qam.Ts = 0.0003;
+    qam.N = (int)qam.Fs * qam.Ts;
+    qam.Fc = 2000;
+    init_constellation(&qam);
+
+    printf("Lecture du fichier...\n");
+    // Lecture du fichier et conversion en bits
+    const char *input_filename = argv[1];
+    bit_array input_bits = file_to_bits(input_filename);
+    size_t nb_symbols = input_bits.nb_bits / qam.k;
+
+    printf("Mise en forme des symboles...\n");
+    // Mise en forme des symboles
+    double complex *symbols = malloc(sizeof(double complex) * nb_symbols);
+    bits_to_symbols(&qam, input_bits.bits, input_bits.nb_bits, symbols);
+
+    printf("Modulation...\n");
+    // Modulation QAM 
+    int total_samples = qam.N * nb_symbols;
+    double complex* s = (double complex*)malloc(sizeof(double complex) * total_samples);
+    modulate(&qam, symbols, nb_symbols, s);
+
+    // Ajout du bruit 
+    double signal_power = (2.0/3.0)*(qam.M-1); // puissance moyenne avant échelle
+    double snr_dB = 10; // Signal to noise ratio
+    double snr_lin = pow(10.0, snr_dB / 10.0);
+    double sigma = sqrt(signal_power / snr_lin);
+    printf("Ajout du bruit... \n       puissance du signal : %f\n       SNR db : %f\n       sigma : %f\n", signal_power, snr_dB, sigma);
+    add_noise(s, total_samples, sigma);
+
+    printf("Demodulation...\n");
+
+    // Demodulation QAM
+    bit_array output_bits;
+    output_bits.nb_bits = input_bits.nb_bits;
+    output_bits.bits = (uint8_t*)malloc(output_bits.nb_bits);
+    demodulate(&qam, s, nb_symbols, output_bits.bits);
+
+    printf("Ecriture...\n");
+    // Ecriture du fichier de Demodulation
+    char *output_filename = make_output_filename(input_filename);
+    bits_to_file(output_filename, &output_bits);
+
+
+    // Affichage du signal dans un .wav
+    double* si = (double*)malloc(sizeof(double) * total_samples);
+    for (int i = 0; i < total_samples; i++) {
+       si[i] = cimag(s[i]); 
+    }
+    write_wav("output.wav", si, total_samples);
+
+    // Plot
+    printf("Ploting...");
+    plot_t plot;
+    plot_init(&plot, 1400, 1400, 0.04);
+    plot_draw_constellation(&plot, qam.constellation, qam.M);
+    SDL_Color red = {255, 0, 0, 255};
+    plot_draw_points_animated(&plot, demodulate_points(&qam, s, nb_symbols), nb_symbols, red, 5);
+
+    // Libération mémoire
+    plot_close(&plot);
+    free_bit_array(&input_bits);
+    free_bit_array(&output_bits);
+    free(symbols);
+    free(s);
+    free_constellation(&qam);
+    free(output_filename);
+
+    return 0;
+}

QAM/qamold/qambisbis.c

@@ -0,0 +1,324 @@
+#include <math.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <complex.h>
+#include "../wav/wav.h"
+#include "../files/files.h"
+#include <string.h>
+
+#define A 1 
+
+struct qam_system_s {
+    int M; // Nombre de symboles M-QAM
+    int k; // Nombre de bits/symboles
+    double Fs; // Fréquence d'échantillionage
+    double Ts; // Temps d'échantillionage
+    int N; // Nombre d'échantillions
+    double Fc; // Fréquence de la porteuse
+    double complex** constellation; // Tableau de symboles I + j Q
+};
+typedef struct qam_system_s qam_system;
+
+// Initialisation de la constellation (double tableau de taille sqrt(M)), 
+// ToDo : changer à un tableau à 1 dimension pour éviter de calculer sqrt(M)
+void init_constellation (qam_system* qam) {
+    int sm = (int)sqrt(qam->M);
+    qam->constellation = (double complex**)malloc(sizeof(double complex*) * sm);
+    
+    for (int i = 0; i < sm; i++) {
+       qam->constellation[i] = (double complex*)malloc(sizeof(double complex) * sm);
+    }
+
+    double norm_factor = sqrt((double)(qam->M - 1) / 3.0); // Pour puissance unitaire
+
+    for (int i = 0; i < sm; i++) {
+        double complex ip = -(sm - 1) + 2 * i;
+        for (int j = 0; j < sm; j++) {
+            double complex qp = -(sm - 1) + 2 * j;
+            qam->constellation[i][j] = (ip + I * qp); 
+        }
+    }
+}
+
+// Calcul du bruit gaussien pour un sigma donné
+// Formule de Box-Muller
+double gaussian_noise (double sigma) {
+    double u1 = (rand() + 1) / ((double)RAND_MAX + 2);
+    double u2 = (rand() + 1) / ((double)RAND_MAX + 2);
+    return sigma * sqrt(-2 * log(u1)) * cos(2 * M_PI * u2);
+}
+
+// Ajout du bruit
+void add_noise (double complex* s, int len, double sigma) {
+    for (int i = 0; i < len; i++) {
+        double nr = gaussian_noise(sigma);
+        double ni = gaussian_noise(sigma);
+        s[i] += nr + I * ni;
+    }
+}
+
+// Changer le tableau de bits en boolen ou alors la represenation binaire et shifter pour extraire les bits (pas bien si M plus grand)
+void bits_to_symbols (qam_system* qam, uint8_t* bits, int nb_bits, double complex* symbols) {
+    int nb_symbols = nb_bits / qam->k;
+    int sm = sqrt(qam->M);
+    for (int k = 0; k < nb_symbols; k++) {
+        int id = 0;
+        for (int b = 0 ; b < qam->k; b++) {
+            id = id * 2 + bits[k * qam->k + b];
+        }
+        int i = id / sm; 
+        int j = id % sm;
+        symbols[k] = qam->constellation[i][j];
+    }
+}
+
+// Modulation QAM 
+void modulate (qam_system* qam, double complex* symbols, int nb_symbols, double complex* s) {
+    for (int k = 0; k < nb_symbols; k++) {
+        double complex iq = symbols[k];
+        for (int n = 0; n < qam->N; n++) {
+            s[k * qam->N + n] = iq * cexp(2 * I * M_PI * qam->Fc * ((double)n / qam->Fs)); 
+        }
+    }
+}
+
+// Demodulation QAM 
+void demodulate(qam_system* qam, double complex* s, int nb_symbols, uint8_t* bits_hat) {
+    for (int k = 0; k < nb_symbols; k++) {
+        double complex r = 0;
+        for (int n = 0; n < qam->N; n++) {
+            r += s[k * qam->N + n] * cexp(-2 * I * M_PI * qam->Fc * ((double)n / qam->Fs));
+            //int i = k * qam->N + n;
+            //r += s[i] * cexp(-2 * I * M_PI * qam->Fc * ((double)i / qam->Fs));
+        }
+        r /= qam->N;
+
+        // Distance euclidien de Ir et Qr pour avoir le point le plus proche de la constellation
+        
+        int sm = (int)sqrt(qam->M);
+        double min_d = INFINITY;
+        int i_cl, j_cl = 0;
+        for (int i = 0; i < sm; i++) {
+            for (int j = 0; j < sm; j++) {
+                double d = cabs(r - qam->constellation[i][j]);
+                if (d < min_d) {
+                    min_d = d;
+                    i_cl = i;
+                    j_cl = j;
+                }
+            }
+        }
+
+                // index du symbole (id) : même mappage que dans bits_to_symbols()
+        int id = i_cl * sm + j_cl;
+
+        for (int b = 0; b < qam->k; b++) {
+            bits_hat[k * qam->k + b] = (id >> (qam->k - 1 - b)) & 1;
+        }
+
+        /*
+        double norm_factor = sqrt((double)(qam->M - 1) / 3.0);
+        double Ir = creal(r) * norm_factor / A;
+        double Qr = cimag(r) * norm_factor / A;
+
+        int i = (int)round((Ir + (sm - 1)) / 2.0);
+        int j = (int)round((Qr + (sm - 1)) / 2.0);
+
+        i = (i < 0) ? 0 : ((i >= sm) ? sm - 1 : i);
+        j = (j < 0) ? 0 : ((j >= sm) ? sm - 1 : j);
+
+        int id = i * sm + j;
+
+        int id = i_cl * sm + j_cl;
+        for (int b = 0; b < qam->k; b++) {
+            bits_hat[k * qam->k + (qam->k - 1 - b)] = (id >> b) & 1;
+        }
+        */
+    }
+}
+
+double complex* demodulate_points(qam_system* qam, double complex* s, int nb_symbols) {
+    double complex* points = malloc(sizeof(double complex) * nb_symbols);
+    for (int k = 0; k < nb_symbols; k++) {
+        double complex r = 0;
+        for (int n = 0; n < qam->N; n++) {
+            int i = k * qam->N + n;
+            r += s[i] * cexp(-2 * I * M_PI * qam->Fc * ((double)i / qam->Fs));
+        }
+        r /= qam->N;
+        double norm_factor = sqrt((double)(qam->M - 1) / 3.0);
+        double Ir = creal(r);
+        double Qr = cimag(r);
+
+        
+        int sm = (int)sqrt(qam->M);
+        double min_d = INFINITY;
+        int i_cl, j_cl = 0;
+        for (int i = 0; i < sm; i++) {
+            for (int j = 0; j < sm; j++) {
+                double d = cabs(r - qam->constellation[i][j]);
+                if (d < min_d) {
+                    min_d = d;
+                    i_cl = i;
+                    j_cl = j;
+                }
+            }
+        }
+
+        double complex p = qam->constellation[i_cl][j_cl];
+        points[k] = creal(p) + I * cimag(p);
+         
+        //points[k] = (int)Ir + I * (int)Qr;
+    }
+    return points;
+}
+
+// Libération de la mémoire
+void free_constellation(qam_system* qam) {
+    int sm = (int)sqrt(qam->M);
+    for (int i = 0; i < sm; i++)
+        free(qam->constellation[i]);
+    free(qam->constellation);
+}
+
+#include <stddef.h>  // pour size_t
+
+// Compare deux tableaux de bits (0/1) et retourne le pourcentage de fiabilité.
+double compare_bits_and_get_reliability(const uint8_t *in_bits, size_t nb_bits_in, const uint8_t *out_bits, size_t nb_bits_out, size_t *erreurs) {
+    if (!in_bits || !out_bits) {
+        if (erreurs) *erreurs = (nb_bits_in < nb_bits_out) ? nb_bits_out : nb_bits_in;
+        return 0.0;
+    }
+
+    size_t n_min = (nb_bits_in < nb_bits_out) ? nb_bits_in : nb_bits_out;
+    size_t n_max = (nb_bits_in > nb_bits_out) ? nb_bits_in : nb_bits_out;
+
+    size_t err = 0;
+    for (size_t i = 0; i < n_min; ++i) {
+        if ((in_bits[i] & 1) != (out_bits[i] & 1)) err++;
+    }
+
+    if (n_max != n_min) {
+        err += (n_max - n_min);
+    }
+
+    if (erreurs) *erreurs = err;
+
+    double total_compared = (double)n_max;
+    if (total_compared == 0.0) return 0.0;
+
+    double ber = (double)err / total_compared;
+    double reliability_percent = (1.0 - ber) * 100.0;
+    return reliability_percent;
+}
+
+
+void affiche_constellation(qam_system* qam) {
+    int sm = (int)sqrt(qam->M);
+    for (int i = 0; i < sm; i++) {
+        for (int j = 0; j < sm; j++) {
+            double complex p = qam->constellation[i][j];
+            printf("(%d,%d) ", (int)creal(p), (int)cimag(p));
+        }
+        printf("\n");
+    }
+}
+
+void affiche_points(double complex* r, int len, int len_samples) {
+    for (int i = 0; i < len; i += len_samples) {
+        for (int j = 0; j < len_samples; j++) {
+            double complex p = r[i + j];
+            printf("(%f,%f) ", (float)creal(p), (float)cimag(p));
+        }
+        printf("\n");
+    }
+}
+
+int main (int argc, char *argv[]) {
+    if (argc < 2) {
+        fprintf(stderr, "Utilisation: %s <fichier_entree>\n", argv[0]);
+        return 1;
+    }
+
+    qam_system qam;
+    qam.M = 16;
+    qam.k = (int)log2((double)(qam.M));
+    qam.Fs = 44100;
+    qam.Ts = 0.0003;
+    qam.N = (int)qam.Fs * qam.Ts;
+    qam.Fc = 2000;
+    init_constellation(&qam);
+
+    printf("Lecture du fichier...\n");
+    // Lecture du fichier et conversion en bits
+    const char *input_filename = argv[1];
+    bit_array input_bits = file_to_bits(input_filename);
+    size_t nb_symbols = input_bits.nb_bits / qam.k;
+
+    printf("Mise en forme des symboles...\n");
+    // Mise en forme des symboles
+    double complex *symbols = malloc(sizeof(double complex) * nb_symbols);
+    bits_to_symbols(&qam, input_bits.bits, input_bits.nb_bits, symbols);
+
+    printf("Modulation...\n");
+    // Modulation QAM 
+    int total_samples = qam.N * nb_symbols;
+    double complex* s = (double complex*)malloc(sizeof(double complex) * total_samples);
+    modulate(&qam, symbols, nb_symbols, s);
+
+    // Ajout du bruit 
+    double signal_power = (2.0/3.0)*(qam.M-1); // puissance moyenne avant échelle
+    double snr_dB = 10; // Signal to noise ratio
+    double snr_lin = pow(10.0, snr_dB / 10.0);
+    double sigma = sqrt(signal_power / snr_lin);
+    printf("Ajout du bruit... \n       puissance du signal : %f\n       SNR db : %f\n       sigma : %f\n", signal_power, snr_dB, sigma);
+    add_noise(s, total_samples, 5);
+
+    printf("Demodulation...\n");
+
+    // Demodulation QAM
+    bit_array output_bits;
+    output_bits.nb_bits = input_bits.nb_bits;
+    output_bits.bits = (uint8_t*)malloc(output_bits.nb_bits);
+    demodulate(&qam, s, nb_symbols, output_bits.bits);
+
+    printf("Ecriture...\n");
+    // Ecriture du fichier de Demodulation
+    char *output_filename = make_output_filename(input_filename);
+    bits_to_file(output_filename, &output_bits);
+
+    //printf("Constelattion :\n");
+    //affiche_constellation(&qam);
+    //printf("Points de demodulation :\n");
+    //affiche_points(demodulate_points(&qam, s, nb_symbols), nb_symbols, qam.N);
+
+    // Affichage du signal dans un .wav
+    /*
+    double* si = (double*)malloc(sizeof(double) * total_samples);
+    for (int i = 0; i < total_samples; i++) {
+       si[i] = cimag(s[i]); 
+    }
+    write_wav("output.wav", si, total_samples);
+    */
+
+
+    size_t erreurs = 0;
+    double fiabilite = compare_bits_and_get_reliability( input_bits.bits, input_bits.nb_bits, output_bits.bits, output_bits.nb_bits, &erreurs);
+
+    printf("Résultat de la comparaison :\n");
+    printf("  Bits d'entrée : %zu\n", input_bits.nb_bits);
+    printf("  Bits de sortie: %zu\n", output_bits.nb_bits);
+    printf("  Erreurs       : %zu\n", erreurs);
+    printf("  Fiabilité     : %.4f %%\n", fiabilite);
+
+    // Libération mémoire
+    free_bit_array(&input_bits);
+    free_bit_array(&output_bits);
+    free(symbols);
+    free(s);
+    free_constellation(&qam);
+    free(output_filename);
+
+    return 0;
+}

files/files.c

@@ -3,7 +3,8 @@
 #include <stdlib.h>
 #include <string.h>
 
-// Lire un fichier binaire et en faire un tableau de bits (0/1)
+// files.c corrections : MSB-first within each byte
+
 bit_array file_to_bits(const char *filename) {
     bit_array arr = {0};
 
@@ -13,7 +14,6 @@ bit_array file_to_bits(const char *filename) {
         return arr;
     }
 
-    // Taille fichier
     fseek(f, 0, SEEK_END);
     long file_size = ftell(f);
     rewind(f);
@@ -23,27 +23,19 @@ bit_array file_to_bits(const char *filename) {
         return arr;
     }
 
-    // Lire tous les octets
     uint8_t *raw = (uint8_t*)malloc(file_size);
-    if (!raw) {
+    if (!raw) { fclose(f); return arr; }
-        fclose(f);
-        return arr;
-    }
     fread(raw, 1, file_size, f);
     fclose(f);
 
-    // Convertir en bits (0/1 dans uint8_t)
     arr.nb_bits = (size_t)file_size * 8;
-    arr.bits = (uint8_t*)malloc(arr.nb_bits);
+    arr.bits = (uint8_t*)malloc(arr.nb_bits * sizeof(uint8_t));
-    if (!arr.bits) {
+    if (!arr.bits) { free(raw); arr.nb_bits = 0; return arr; }
-        free(raw);
-        arr.nb_bits = 0;
-        return arr;
-    }
 
+    // MSB-first in each byte: bit 7 -> index 0, bit 0 -> index 7
     for (size_t i = 0; i < (size_t)file_size; i++) {
         for (int b = 0; b < 8; b++) {
-            arr.bits[i * 8 + b] = (raw[i] >> b) & 1u;
+            arr.bits[i * 8 + b] = (raw[i] >> (7 - b)) & 1u;
         }
     }
 
@@ -51,7 +43,6 @@ bit_array file_to_bits(const char *filename) {
     return arr;
 }
 
-// Transformer un tableau de bits (0/1) en fichier binaire
 int bits_to_file(const char *filename, const bit_array *arr) {
     if (!arr || !arr->bits) return -1;
 
@@ -59,19 +50,17 @@ int bits_to_file(const char *filename, const bit_array *arr) {
     uint8_t *raw = (uint8_t*)calloc(nb_bytes, 1);
     if (!raw) return -1;
 
+    // MSB-first packing: index bit 0 -> place at position 7 of first byte
     for (size_t i = 0; i < arr->nb_bits; i++) {
         if (arr->bits[i]) {
-            raw[i / 8] |= (1u << (i % 8));
+            size_t byte_idx = i / 8;
+            int bit_in_byte = i % 8; // 0..7
+            raw[byte_idx] |= (1u << (7 - bit_in_byte));
         }
     }
 
     FILE *f = fopen(filename, "wb");
-    if (!f) {
+    if (!f) { perror("fopen"); free(raw); return -1; }
-        perror("fopen");
-        free(raw);
-        return -1;
-    }
-
     fwrite(raw, 1, nb_bytes, f);
     fclose(f);
     free(raw);

files/files.h

@@ -19,3 +19,4 @@ char* make_output_filename(const char *input_filename);
 
 // Libérer la mémoire du bit_array
 void free_bit_array(bit_array *arr);
+