netlab/lab8/sockio.c

#include "sockio.h"

// get char from client socket
int sgetc(int clnt_sock, struct buffer *recv_buf)
{
    if (recv_buf->ptr == recv_buf->len)
    {
        ssize_t n = read(clnt_sock, recv_buf->buf, BUF_SIZE);
        if (n == -1)
        {
            return -1;
        }
        if (n == 0) // avoid confusion with '\0'
        {
            return -2;
        }

        recv_buf->ptr = 0;
        recv_buf->len = n;
    }

    return (uint8_t)recv_buf->buf[recv_buf->ptr++]; // avoid confusion with '\xff'
}

// get line from client socket
int sgetline(int clnt_sock, struct buffer *recv_buf, struct buffer *line_buf)
{
    int cr = 0;

    for (line_buf->len = 0;;)
    {
        int c = sgetc(clnt_sock, recv_buf);
        if (c < 0)
        {
            return c;
        }

        line_buf->buf[line_buf->len++] = c;

        if (c == '\r')
        {
            cr = 1;
        }
        else if (c == '\n' && cr)
        {
            break;
        }
        else
        {
            cr = 0;
        }
    }

    line_buf->buf[line_buf->len] = '\0';

    return line_buf->len;
}

// flush send buffer
int sflush(int clnt_sock, struct buffer *send_buf)
{
    uint16_t len = send_buf->len;

    for (; send_buf->len;)
    {
        ssize_t n = write(clnt_sock, send_buf->buf + len - send_buf->len, send_buf->len);
        if (n == -1)
        {
            return -1;
        }

        send_buf->len -= n;
    }

    return len;
}

// put char to client socket
int sputc(int clnt_sock, struct buffer *send_buf, char c)
{
    if (send_buf->len == BUF_SIZE && sflush(clnt_sock, send_buf) == -1)
    {
        return -1;
    }

    send_buf->buf[send_buf->len++] = c;

    return (uint8_t)c; // avoid confusion with '\xff'
}

// put line to client socket
int sputline(int clnt_sock, struct buffer *send_buf, struct buffer *line_buf)
{
    for (char *s = line_buf->buf; s < line_buf->buf + line_buf->len; s++)
    {
        int c = sputc(clnt_sock, send_buf, *s);
        if (c == -1)
        {
            return -1;
        }
    }

    return line_buf->len;
}