ram_file_drv.c

来自「OTP是开放电信平台的简称」· C语言 代码 · 共 712 行 · 第 1/2 页

	if (len > f->end-cur) len = f->end - cur;
    } else {
	len = 0; /* eof */
    }
    if ((bin = driver_alloc_binary(len)) == NULL) {
	*error = ENOMEM;
	return -1;
    }
    if (len) sys_memcpy(bin->orig_bytes, f->buf+cur, len);
    *bp = bin;
    if (! location) f->cur = cur + len;
    return len;
}

static int ram_file_seek(RamFile *f, int offset, int whence, int *error)
{
    int pos;

    if (f->flags == 0) {
	*error = EBADF;
	return -1;
    }	
    switch(whence) {
    case RAM_FILE_SEEK_SET: pos = offset; break;
    case RAM_FILE_SEEK_CUR: pos = f->cur + offset; break;
    case RAM_FILE_SEEK_END: pos = f->end + offset; break;
    default: *error = EINVAL; return -1;
    }
    if (pos < 0) {
	*error = EINVAL;
	return -1;
    }
    return f->cur = pos;
}

#define UUMASK(x)     ((x)&0x3F)
#define uu_encode(x)  (UUMASK(x)+32)

/* calculate max number of quadrauple bytes given max line length */
#define UULINE(n) ( (((n)-1) / 4) * 3)

#define UNIX_LINE 61  /* 61 character lines =>  45 uncoded => 60 coded */

#define uu_pack(p, c1, c2, c3) \
        (p)[0] = uu_encode((c1) >> 2), \
        (p)[1] = uu_encode(((c1) << 4) | ((c2) >> 4)), \
        (p)[2] = uu_encode(((c2) << 2) | ((c3) >> 6)), \
        (p)[3] = uu_encode(c3)

static int ram_file_uuencode(RamFile *f)
{
    int code_len = UULINE(UNIX_LINE);
    int len = f->end;
    int usize = (len*4+2)/3 + 2*(len/code_len+1) + 2 + 1;
    ErlDrvBinary* bin;
    uchar* inp;
    uchar* outp;
    int count = 0;

    if ((bin = driver_alloc_binary(usize)) == NULL)
	return error_reply(f, ENOMEM);
    outp = (unsigned char*)bin->orig_bytes;
    inp = f->buf;

    while(len > 0) {
        int c1, c2, c3;
        int n = (len >= code_len) ? code_len : len;

        len -= n;
        *outp++ = uu_encode(UUMASK(n));
        count++;
        while (n >= 3) {
            c1 = inp[0];
            c2 = inp[1];
            c3 = inp[2];
	    uu_pack(outp, c1, c2, c3);
            inp += 3; n -= 3;
            outp += 4; count += 4;
        }
        if (n == 2) {
            c1 = inp[0];
            c2 = inp[1];
	    uu_pack(outp, c1, c2, 0);
	    inp += 2;
            outp += 4; count += 4;
        }
        else if (n == 1) {
            c1 = inp[0];
	    uu_pack(outp, c1, 0, 0);
	    inp += 1;
            outp += 4; count += 4;
        }
        *outp++ = '\n';
        count++;
    }
    *outp++ = ' ';   /* this end of file 0 length !!! */
    *outp++ = '\n';
    count += 2;

    driver_free_binary(f->bin);
    ram_file_set(f, bin, usize, count);
    return numeric_reply(f, count);
}


#define uu_decode(x)  ((x)-32)

static int ram_file_uudecode(RamFile *f)
{
    int len = f->end;
    int usize = ( (len+3) / 4 ) * 3;
    ErlDrvBinary* bin;
    uchar* inp;
    uchar* outp;
    int count = 0;
    int n;

    if ((bin = driver_alloc_binary(usize)) == NULL)
	return error_reply(f, ENOMEM);
    outp = (unsigned char*)bin->orig_bytes;
    inp  = f->buf;

    while(len > 0) {
	if ((n = uu_decode(*inp++)) < 0)
	    goto error;
        len--;
	if ((n == 0) && (*inp == '\n'))
	    break;
        count += n;     /* count characters */
        while((n > 0) && (len >= 4)) {
            int c1, c2, c3, c4;
            c1 = uu_decode(inp[0]);
            c2 = uu_decode(inp[1]);
            c3 = uu_decode(inp[2]);
            c4 = uu_decode(inp[3]);
	    inp += 4;
            len -= 4;

            switch(n) {
            case 1:
                *outp++ = (c1 << 2) | (c2 >> 4);
		n = 0;
                break;
            case 2:
                *outp++ = (c1 << 2) | (c2 >> 4);
                *outp++ = (c2 << 4) | (c3 >> 2);
		n = 0;
                break;
            default:
                *outp++ = (c1 << 2) | (c2 >> 4);
                *outp++ = (c2 << 4) | (c3 >> 2);
                *outp++ = (c3 << 6) | c4;
                n -= 3;
                break;
            }
        }
	if ((n != 0) || (*inp++ != '\n'))
	    goto error;
        len--;
    }
    driver_free_binary(f->bin);
    ram_file_set(f, bin, usize, count);
    return numeric_reply(f, count);

 error:
    driver_free_binary(bin);
    return error_reply(f, EINVAL);
}


static int ram_file_compress(RamFile *f)
{
    int size = f->end;
    ErlDrvBinary* bin;

    if ((bin = erts_gzdeflate_buffer(f->buf, size)) == NULL) {
	return error_reply(f, EINVAL);
    }
    driver_free_binary(f->bin);
    size = bin->orig_size;
    ram_file_set(f, bin, size, size);
    return numeric_reply(f, size);
}

/* Tricky since we dont know the expanded size !!! */
/* First attempt is to double the size of input */
/* loop until we don't get Z_BUF_ERROR */

static int ram_file_uncompress(RamFile *f)
{
    int size = f->end;
    ErlDrvBinary* bin;

    if ((bin = erts_gzinflate_buffer(f->buf, size)) == NULL) {
	return error_reply(f, EINVAL);
    }
    driver_free_binary(f->bin);
    size = bin->orig_size;
    ram_file_set(f, bin, size, size);
    return numeric_reply(f, size);
}


static void rfile_command(ErlDrvData e, char* buf, int count)
{
    RamFile* f = (RamFile*)e;
    int error = 0;
    ErlDrvBinary* bin;
    char header[5];     /* result code + count */
    int offset;
    int origin;		/* Origin of seek. */
    int n;

    count--;
    switch(*(uchar*)buf++) {
    case RAM_FILE_OPEN:  /* args is initial data */
	f->flags = get_int32(buf);
	if (ram_file_init(f, buf+4, count-4, &error) < 0)
	    error_reply(f, error);
	else
	    numeric_reply(f, 0); /* 0 is not used */
	break;

    case RAM_FILE_FSYNC:
	if (f->flags == 0)
	    error_reply(f, EBADF);
	else
	    reply(f, 1, 0);
	break;

    case RAM_FILE_WRITE:
	if (ram_file_write(f, buf, count, NULL, &error) < 0)
	    error_reply(f, error);
	else
	    numeric_reply(f, count);
	break;

    case RAM_FILE_PWRITE:
        if ((offset = get_int32(buf)) < 0)
	    error_reply(f, EINVAL);
	else if (ram_file_write(f, buf+4, count-4, &offset, &error) < 0)
	    error_reply(f, error);
	else
	    numeric_reply(f, count-4);
	break;

    case RAM_FILE_LSEEK:
	offset = get_int32(buf);
	origin = get_int32(buf+4);
	if ((offset = ram_file_seek(f, offset, origin, &error)) < 0)
	    error_reply(f, error);
	else
	    numeric_reply(f, offset);
	break;

    case RAM_FILE_PREAD:
	if ((offset = get_int32(buf)) < 0) {
	    error_reply(f, EINVAL);
	    break;
	}
	
	count = get_int32(buf+4);
	if ((n = ram_file_read(f, count, &bin, &offset, &error)) < 0) {
	    error_reply(f, error);
	} else {
	    header[0] = RAM_FILE_RESP_DATA;
	    put_int32(n, header+1);
	    driver_output_binary(f->port, header, sizeof(header),
				 bin, 0, n);
	    driver_free_binary(bin);
	}
	break;

    case RAM_FILE_READ:
	count = get_int32(buf);
	if ((n = ram_file_read(f, count, &bin, NULL, &error)) < 0)
	    error_reply(f, error);
	else {
	    header[0] = RAM_FILE_RESP_DATA;
	    put_int32(n, header+1);
	    driver_output_binary(f->port, header, sizeof(header),
				 bin, 0, n);
	    driver_free_binary(bin);
	}
	break;

    case RAM_FILE_TRUNCATE:
	if (!(f->flags & RAM_FILE_MODE_WRITE)) {
	    error_reply(f, EACCES);
	    break;
	}
	if (f->end > f->cur)
	    sys_memzero(f->buf + f->cur, f->end - f->cur);
	f->end = f->cur;
	reply(f, 1, 0);
	break;

    case RAM_FILE_GET:        /* return a copy of the file */
	n = f->end;  /* length */
	if ((bin = driver_alloc_binary(n)) == NULL) {
	    error_reply(f, ENOMEM);
	    break;
	}
	sys_memcpy(bin->orig_bytes, f->buf, n);
	
	header[0] = RAM_FILE_RESP_DATA;
	put_int32(n, header+1);
	driver_output_binary(f->port, header, sizeof(header),
			     bin, 0, n);
	driver_free_binary(bin);
	break;

    case RAM_FILE_GET_CLOSE:  /* return the file and close driver */
	n = f->end;  /* length */
	bin = f->bin;
	f->bin = NULL;  /* NUKE IT */
	header[0] = RAM_FILE_RESP_DATA;
	put_int32(n, header+1);
	driver_output_binary(f->port, header, sizeof(header),
			     bin, 0, n);
	driver_free_binary(bin);
	driver_failure(f->port, 0);
	break;

    case RAM_FILE_SIZE:
	numeric_reply(f, f->end);
	break;
	
    case RAM_FILE_SET:        /* re-init file with new data */
	if ((n = ram_file_init(f, buf, count, &error)) < 0)
	    error_reply(f, error);
	else
	    numeric_reply(f, n); /* 0 is not used */
	break;
	
    case RAM_FILE_COMPRESS:   /* inline compress the file */
	ram_file_compress(f);
	break;

    case RAM_FILE_UNCOMPRESS: /* inline uncompress file */
	ram_file_uncompress(f);
	break;

    case RAM_FILE_UUENCODE:   /* uuencode file */
	ram_file_uuencode(f);
	break;
	
    case RAM_FILE_UUDECODE:   /* uudecode file */
	ram_file_uudecode(f);
	break;
    }
    /*
     * Ignore anything else -- let the caller hang.
     */
}