legacy/libburn/trunk/libburn/file.c

188 lines
4.1 KiB
C

/* -*- indent-tabs-mode: t; tab-width: 8; c-basic-offset: 8; -*- */
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include "source.h"
#include "libburn.h"
#include "file.h"
/* main channel data can be padded on read, but 0 padding the subs will make
an unreadable disc */
/* This is a generic OS oriented function wrapper which compensates
shortcommings of read() in respect to a guaranteed amount of return data.
See man 2 read , paragraph "RETURN VALUE".
Possibly libburn/file.c is not the right storage location for this.
To make it ready for a move, this function is not declared static.
*/
static int read_full_buffer(int fd, unsigned char *buffer, int size)
{
int ret,summed_ret = 0;
/* make safe against partial buffer returns */
while (1) {
ret = read(fd, buffer + summed_ret, size - summed_ret);
if (ret <= 0)
break;
summed_ret += ret;
if (summed_ret >= size)
break;
}
if (ret < 0) /* error encountered. abort immediately */
return ret;
return summed_ret;
}
static int file_read(struct burn_source *source,
unsigned char *buffer,
int size)
{
struct burn_source_fd *fs = source->data;
return read_full_buffer(fs->datafd, buffer, size);
}
static int file_read_sub(struct burn_source *source,
unsigned char *buffer,
int size)
{
struct burn_source_file *fs = source->data;
return read_full_buffer(fs->subfd, buffer, size);
}
static void file_free(struct burn_source *source)
{
struct burn_source_file *fs = source->data;
close(fs->datafd);
if (source->read_sub)
close(fs->subfd);
free(fs);
}
static off_t file_size(struct burn_source *source)
{
struct stat buf;
struct burn_source_file *fs = source->data;
if (fstat(fs->datafd, &buf) == -1)
return (off_t) 0;
/* for now we keep it compatible to the old (int) return value */
if(buf.st_size >= 1308622848) /* 2 GB - 800 MB to prevent rollover */
return (off_t) 1308622848;
return (off_t) buf.st_size;
}
struct burn_source *burn_file_source_new(const char *path, const char *subpath)
{
struct burn_source_file *fs;
struct burn_source *src;
int fd1, fd2 = 0;
if (!path)
return NULL;
fd1 = open(path, O_RDONLY);
if (fd1 == -1)
return NULL;
if (subpath) {
fd2 = open(subpath, O_RDONLY);
if (fd2 == -1) {
close(fd1);
return NULL;
}
}
fs = malloc(sizeof(struct burn_source_file));
fs->datafd = fd1;
if (subpath)
fs->subfd = fd2;
src = burn_source_new();
src->read = file_read;
if (subpath)
src->read_sub = file_read_sub;
src->get_size = file_size;
src->free_data = file_free;
src->data = fs;
return src;
}
/* ------ provisory location for the new source subclass fd --------- */
static off_t fd_get_size(struct burn_source *source)
{
struct stat buf;
struct burn_source_fd *fs = source->data;
if (fs->fixed_size > 0)
return fs->fixed_size;
if (fstat(fs->datafd, &buf) == -1)
return (off_t) 0;
/* for now we keep it compatible to the old (int) return value */
if (buf.st_size >= 1308622848) /* 2 GB - 800 MB to prevent rollover */
return (off_t) 1308622848;
return buf.st_size;
}
static int fd_read(struct burn_source *source,
unsigned char *buffer,
int size)
{
struct burn_source_fd *fs = source->data;
return read_full_buffer(fs->datafd, buffer, size);
}
static int fd_read_sub(struct burn_source *source,
unsigned char *buffer,
int size)
{
struct burn_source_fd *fs = source->data;
return read_full_buffer(fs->subfd, buffer, size);
}
static void fd_free_data(struct burn_source *source)
{
struct burn_source_fd *fs = source->data;
close(fs->datafd);
if (source->read_sub)
close(fs->subfd);
free(fs);
}
struct burn_source *burn_fd_source_new(int datafd, int subfd, off_t size)
{
struct burn_source_fd *fs;
struct burn_source *src;
if (datafd == -1)
return NULL;
fs = malloc(sizeof(struct burn_source_fd));
fs->datafd = datafd;
fs->subfd = subfd;
fs->fixed_size = size;
src = burn_source_new();
src->read = fd_read;
if(subfd != -1)
src->read = fd_read_sub;
src->get_size = fd_get_size;
src->free_data = fd_free_data;
src->data = fs;
return src;
}