fifo.rar_The Returned

#include<stdio.h> #include<stdlib.h> typedef struct { char * buf; int head; int tail; int size; } fifo_t; //This initializes the FIFO structure with the given buffer and size void fifo_init(fifo_t * f, char * buf, int size){ f->head = 0; f->tail = 0; f->size = size; f->buf = buf; } //This reads nbytes bytes from the FIFO //The number of bytes read is returned int fifo_read(fifo_t * f, void * buf, int nbytes){ int i; char * p; p = buf; for(i=0; i < nbytes; i++){ if( f->tail != f->head ){ //see if any data is available *p++ = f->buf[f->tail]; //grab a byte from the buffer f->tail++; //increment the tail if( f->tail == f->size ){ //check for wrap-around f->tail = 0; } } else { return i; //number of bytes read } } return nbytes; } //This writes up to nbytes bytes to the FIFO //If the head runs in to the tail, not all bytes are written //The number of bytes written is returned int fifo_write(fifo_t * f, const void * buf, int nbytes){ int i; const char * p; p = buf; for(i=0; i < nbytes; i++){ //first check to see if there is space in the buffer if( (f->head + 1 == f->tail) || ( (f->head+1 == f->size) && (f->tail == 0) )){ return i; //no more room } else { f->buf[f->head] = *p++; f->head++; //increment the head if( (f->head == f->size)){ //check for wrap-around f->head = 0; } } } return nbytes; } int main(){ fifo_t f; char wr_buffer[10]={'a','n','v','s','d'}; char rd_buffer[10]; char * fifo_buffer; int size, nb_wr, nb_rd, i; printf("donner la taille du buffer :\n"); scanf("%d",&size); fifo_buffer = malloc(size * sizeof(char)); fifo_init(&f, fifo_buffer, size); nb_wr = fifo_write(&f, wr_buffer, 4); nb_rd = fifo_read(&f, rd_buffer, 6); printf("\n nombre de trames ecrites : \t %d \n",nb_wr); for(i=0;i<nb_wr;i++){ printf("\t - trame %d : %c \n", i, f.buf[i]); } printf("\n nombre de trames lues : \t %d \n",nb_rd); for(i=0;i<nb_rd;i++){ printf("\t - trame %d : %c \n", i, rd_buffer[i]); } }