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#include <stdio.h>
#include <string.h>
#include "erl_driver.h"
#define put_int32(i, s) {((char*)(s))[0] = (char)((i) >> 24) & 0xff; \
((char*)(s))[1] = (char)((i) >> 16) & 0xff; \
((char*)(s))[2] = (char)((i) >> 8) & 0xff; \
((char*)(s))[3] = (char)((i) & 0xff);}
#define get_int32(s) ((((unsigned char*) (s))[0] << 24) | \
(((unsigned char*) (s))[1] << 16) | \
(((unsigned char*) (s))[2] << 8) | \
(((unsigned char*) (s))[3]))
/*
* Data operations. To use, send code using erlang:port_control/2,
* then send the data to the port.
*/
#define PUSHQ 0
#define ENQ 1
#define PUSHQ_BIN 2
#define ENQ_BIN 3
#define PUSHQV 4
#define ENQV 5
/*
* Control operations. Data is returned directly.
*/
#define DEQ 6
#define BYTES_QUEUED 7
#define READ_HEAD 8
static ErlDrvPort erlang_port;
static unsigned opcode; /* Opcode for next operation. */
static ErlDrvData queue_start(ErlDrvPort, char*);
static void queue_stop(ErlDrvData), queue_read(ErlDrvData, char*, ErlDrvSizeT);
static void queue_outputv(ErlDrvData, ErlIOVec*);
static ErlDrvSSizeT control(ErlDrvData, unsigned int,
char*, ErlDrvSizeT, char**, ErlDrvSizeT);
static ErlDrvBinary* read_head(ErlDrvPort, int bytes);
static ErlDrvEntry queue_driver_entry =
{
NULL,
queue_start,
queue_stop,
queue_read,
NULL,
NULL,
"queue_drv",
NULL,
NULL,
control,
NULL,
queue_outputv,
NULL,
NULL,
NULL,
NULL,
ERL_DRV_EXTENDED_MARKER,
ERL_DRV_EXTENDED_MAJOR_VERSION,
ERL_DRV_EXTENDED_MINOR_VERSION,
0,
NULL,
NULL,
NULL
};
DRIVER_INIT(queue_drv)
{
erlang_port = (ErlDrvPort) -1;
return &queue_driver_entry;
}
static ErlDrvData queue_start(ErlDrvPort port, char *buf)
{
if (erlang_port != (ErlDrvPort)-1) {
return ERL_DRV_ERROR_GENERAL;
}
erlang_port = port;
opcode = 0xFFFFFFFF;
set_port_control_flags(erlang_port, PORT_CONTROL_FLAG_BINARY);
return (ErlDrvData)port;
}
/* messages from Erlang */
static void queue_read(ErlDrvData port, char *buf, ErlDrvSizeT len)
{
}
static void queue_stop(ErlDrvData port)
{
erlang_port = (ErlDrvPort) -1;
}
static ErlDrvSSizeT
control(ErlDrvData drv_data, unsigned command,
char* buf, ErlDrvSizeT len, char** rbuf, ErlDrvSizeT rlen)
{
ErlDrvBinary* b;
switch (command) {
case PUSHQ:
case ENQ:
case PUSHQ_BIN:
case ENQ_BIN:
case PUSHQV:
case ENQV:
opcode = command;
*rbuf = NULL;
return 0;
case DEQ:
*rbuf = NULL;
if (len != 4) {
driver_failure_atom(erlang_port, "deq: bad length");
} else {
int n = get_int32(buf);
driver_deq(erlang_port, n);
}
return 0;
case BYTES_QUEUED:
*rbuf = (char*)(b = driver_alloc_binary(4));
put_int32(driver_sizeq(erlang_port), b->orig_bytes);
return 0;
case READ_HEAD:
if (len != 4) {
driver_failure_atom(erlang_port, "read_head: bad length");
return 0;
} else {
int n = get_int32(buf);
*rbuf = (char *) read_head(erlang_port, n);
return 0; /* Ignored anyway */
}
default:
driver_failure_atom(erlang_port, "bad opcode to control()");
return 0;
}
}
static void
queue_outputv(ErlDrvData drv_data, ErlIOVec* ev)
{
ErlDrvBinary* bin;
ErlDrvPort ix = (ErlDrvPort) drv_data;
int i = ev->vsize - 1;
int offset;
switch (opcode) {
case PUSHQ:
driver_pushq(ix, ev->iov[i].iov_base, ev->iov[i].iov_len);
break;
case ENQ:
driver_enq(ix, ev->iov[i].iov_base, ev->iov[i].iov_len);
break;
case PUSHQ_BIN:
case ENQ_BIN:
if (ev->binv[i] != NULL) {
bin = ev->binv[i];
offset = ev->iov[i].iov_base - bin->orig_bytes;
} else {
bin = driver_alloc_binary(ev->iov[i].iov_len);
memcpy(bin->orig_bytes, ev->iov[i].iov_base, ev->iov[i].iov_len);
offset = 0;
}
if (opcode == PUSHQ_BIN) {
driver_pushq_bin(ix, bin, offset, ev->iov[i].iov_len);
} else {
driver_enq_bin(ix, bin, offset, ev->iov[i].iov_len);
}
if (ev->binv[i] == NULL) {
driver_free_binary(bin);
}
break;
case PUSHQV:
driver_pushqv(ix, ev, 0);
break;
case ENQV:
driver_enqv(ix, ev, 0);
break;
default:
fprintf(stderr, "[queue_drv] Bad opcode %d\n", opcode);
driver_failure_atom(ix, "bad_opcode");
break;
}
}
static ErlDrvBinary*
read_head(ErlDrvPort ix, int bytes)
{
int len_io_queue;
SysIOVec* iov = driver_peekq(ix, &len_io_queue);
int bytes_left = bytes;
int copied = 0;
ErlDrvBinary* b;
int iv;
b = driver_alloc_binary(bytes);
iv = 0;
while (bytes_left > 0 && iv < len_io_queue) {
int n = (iov[iv].iov_len < bytes_left) ? iov[iv].iov_len : bytes_left;
memcpy(b->orig_bytes+copied, iov[iv].iov_base, n);
copied += n;
bytes_left -= n;
iv++;
}
return b;
}
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