toaruos/kernel/fs/pipe.c

141 lines
3.5 KiB
C
Raw Normal View History

2012-01-25 03:56:35 +04:00
/* vim: tabstop=4 shiftwidth=4 noexpandtab
* Buffered Pipe
*/
#include <system.h>
#include <fs.h>
#include <pipe.h>
uint32_t read_pipe(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
uint32_t write_pipe(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
void open_pipe(fs_node_t *node, uint8_t read, uint8_t write);
void close_pipe(fs_node_t *node);
static inline size_t pipe_unread(pipe_device_t * pipe) {
if (pipe->read_ptr > pipe->write_ptr) {
return (pipe->size - pipe->read_ptr) + pipe->write_ptr;
} else {
return (pipe->write_ptr - pipe->read_ptr);
}
}
static inline size_t pipe_available(pipe_device_t * pipe) {
if (pipe->read_ptr > pipe->write_ptr) {
return (pipe->read_ptr - pipe->write_ptr);
} else {
return (pipe->size - pipe->write_ptr)+ pipe->read_ptr;
}
}
static inline void pipe_increment_read(pipe_device_t * pipe) {
pipe->read_ptr++;
if (pipe->read_ptr == pipe->size) {
pipe->read_ptr = 0;
}
}
static inline void pipe_increment_write(pipe_device_t * pipe) {
pipe->write_ptr++;
if (pipe->write_ptr == pipe->size) {
pipe->write_ptr = 0;
}
}
uint32_t read_pipe(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
assert(node->inode != 0 && "Attempted to read from a fully-closed pipe.");
/* Retreive the pipe object associated with this file node */
pipe_device_t * pipe = (pipe_device_t *)node->inode;
size_t collected = 0;
while (collected < size) {
while (pipe_unread(pipe) > 0) {
buffer[collected] = pipe->buffer[pipe->read_ptr];
pipe_increment_read(pipe);
collected++;
}
switch_task();
}
return size;
}
uint32_t write_pipe(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
assert(node->inode != 0 && "Attempted to write to a fully-closed pipe.");
/* Retreive the pipe object associated with this file node */
pipe_device_t * pipe = (pipe_device_t *)node->inode;
size_t written = 0;
while (written < size) {
while (pipe_available(pipe) > 0) {
pipe->buffer[pipe->write_ptr] = buffer[written];
pipe_increment_write(pipe);
written++;
}
switch_task();
}
return size;
}
void open_pipe(fs_node_t * node, uint8_t read, uint8_t write) {
assert(node->inode != 0 && "Attempted to open a fully-closed pipe.");
/* Retreive the pipe object associated with this file node */
pipe_device_t * pipe = (pipe_device_t *)node->inode;
/* Add a reference */
pipe->refcount++;
return;
}
void close_pipe(fs_node_t * node) {
assert(node->inode != 0 && "Attempted to close an already fully-closed pipe.");
/* Retreive the pipe object associated with this file node */
pipe_device_t * pipe = (pipe_device_t *)node->inode;
/* Drop one reference */
pipe->refcount--;
/* Check the reference count number */
if (pipe->refcount == 0) {
/* No other references exist, free the pipe (but not its buffer) */
free(pipe);
/* And let the creator know there are no more references */
2012-01-25 03:58:19 +04:00
node->inode = 0;
2012-01-25 03:56:35 +04:00
}
return;
}
fs_node_t * make_pipe(uint8_t * buffer, size_t size) {
fs_node_t * fnode = malloc(sizeof(fs_node_t));
pipe_device_t * pipe = malloc(sizeof(fs_node_t));
fnode->inode = 0;
fnode->name[0] = '\0';
fnode->uid = 0;
fnode->gid = 0;
fnode->flags = 0;
fnode->read = read_pipe;
fnode->write = write_pipe;
fnode->open = open_pipe;
fnode->close = close_pipe;
fnode->readdir = NULL;
fnode->finddir = NULL;
fnode->inode = (uintptr_t)pipe;
pipe->buffer = buffer;
pipe->write_ptr = 0;
pipe->read_ptr = 0;
pipe->size = size;
pipe->refcount = 0;
pipe->lock = 0;
return fnode;
}