Add iso_file_src default implementation.
This will be the base class for file content writting, with support for on-the-file file modification, useful for things like compression or encryption.
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@ -32,6 +32,8 @@ libisofs_libisofs_la_SOURCES = \
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libisofs/hash.c \
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libisofs/file.h \
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libisofs/file.c \
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libisofs/file_src.h \
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libisofs/file_src.c \
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libisofs/eltorito.h \
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libisofs/eltorito.c \
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libisofs/data_source.c \
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163
libisofs/trunk/libisofs/file_src.c
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163
libisofs/trunk/libisofs/file_src.c
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#include <stdlib.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <assert.h>
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#include <string.h>
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#include <limits.h>
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#include "file_src.h"
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#include "messages.h"
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#define BLOCK_SIZE 2048
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struct local_file_data {
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int fd; /* the file descriptor, once the file is opened */
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off_t size; /* file size */
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off_t bytes_read; /* bytes already read from file */
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int error;
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char *path; /* path of the file on local filesystem */
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};
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static
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int lf_open(struct iso_file_src *src)
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{
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struct local_file_data *data;
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assert(src);
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data = (struct local_file_data*) src->data;
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assert(data->fd == -1);
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data->fd = open(data->path, O_RDONLY);
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data->bytes_read = (off_t) 0;
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data->error = 0;
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return (data->fd != -1 ? 1 : 0);
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}
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static
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void lf_close(struct iso_file_src *src)
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{
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struct local_file_data *data;
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assert(src);
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data = (struct local_file_data*) src->data;
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assert(data->fd != -1);
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close(data->fd);
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data->fd = -1;
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}
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static
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int lf_read_block(struct iso_file_src *src, unsigned char *buffer)
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{
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ssize_t bytes;
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struct local_file_data *data;
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assert(src);
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assert(buffer);
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data = (struct local_file_data*) src->data;
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assert(data->fd != -1);
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if (data->bytes_read >= data->size) {
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return 0;
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}
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if (data->error) {
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memset(buffer, 0, BLOCK_SIZE);
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data->bytes_read += BLOCK_SIZE;
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return -2;
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}
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bytes = 0;
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do {
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ssize_t result;
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result = read(data->fd, buffer + bytes, BLOCK_SIZE - bytes);
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if (result < 0) {
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char msg[PATH_MAX + 32];
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sprintf(msg, "Problem reading from %s", data->path);
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iso_msg_sorry(LIBISO_CANT_READ_FILE, msg);
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/* fill buffer with 0s and return */
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memset(buffer + bytes, 0, BLOCK_SIZE - bytes);
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data->bytes_read += BLOCK_SIZE;
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return -1;
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}
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if (!result)
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break;
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bytes += result;
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} while (bytes < BLOCK_SIZE);
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if (bytes < BLOCK_SIZE) {
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/* eof */
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memset(buffer + bytes, 0, BLOCK_SIZE - bytes);
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}
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data->bytes_read += (off_t) bytes;
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if (data->bytes_read >= data->size) {
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return 0;
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} else {
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return 1;
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}
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}
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static
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off_t lf_get_size(struct iso_file_src *src)
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{
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struct local_file_data *data;
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assert(src);
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data = (struct local_file_data*) src->data;
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return data->size;
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}
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static
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void lf_free_data(struct iso_file_src *src)
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{
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free(src->data);
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}
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struct iso_file_src*
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iso_file_src_from_path(const char *path)
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{
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struct stat info;
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struct iso_file_src *src;
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struct local_file_data *data;
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assert(path);
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if (lstat(path, &info) < 0) {
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iso_msg_fatal(LIBISO_FILE_DOESNT_EXIST, "File doesn't exist");
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return NULL;
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}
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if (access(path, R_OK) < 0) {
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iso_msg_fatal(LIBISO_FILE_NO_READ_ACCESS, "No read access");
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return NULL;
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}
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data = malloc(sizeof(struct local_file_data));
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if (!data)
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return NULL;
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src = malloc(sizeof(struct iso_file_src));
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if (!src) {
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free(data);
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return NULL;
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}
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data->fd = -1;
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data->path = strdup(path);
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data->size = info.st_size;
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src->open = lf_open;
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src->close = lf_close;
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src->read_block = lf_read_block;
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src->get_size = lf_get_size;
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src->free_data = lf_free_data;
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src->data = data;
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return src;
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}
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82
libisofs/trunk/libisofs/file_src.h
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82
libisofs/trunk/libisofs/file_src.h
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@ -0,0 +1,82 @@
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/*
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* Class for reading data from files, with base implementations
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* for reading local filesystem files and previous session files.
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*
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* TODO this is kept private for now, it can be useful to make that
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* public later.
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*/
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#ifndef FILE_SRC_H_
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#define FILE_SRC_H_
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#include <sys/types.h>
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struct iso_file_src {
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/**
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* Opens the file.
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* This should be called before any call to read_block().
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* @return 1 on success, <= 0 on error
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*/
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int (*open)(struct iso_file_src *src);
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/**
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* Close the file.
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* This should be called when the iso_file_src is no more needed.
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*/
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void (*close)(struct iso_file_src *src);
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/**
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* Read data from the file in 2048 bytes chunks.
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*
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* A pointer to the contents of the file will be updated, in such a way
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* that each time this function is called, new data is read to the buffer.
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* It behaves in the same way as usual read(2) call this way.
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*
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* This always reads 2048 bytes, unless an EOF is found, or we reach the
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* size previously returned by get_size(). In this case, the buffer is
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* completed with 0s.
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*
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* @param buffer Buffer where the data will be written. Its size must
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* be at least 2048 bytes.
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* @return
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* 1 if file contains more data. If we reach EOF before the expected
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* size, this keeps returning 1, and next blocks are filled with 0s.
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* 0 when we reach the expected size, that in normal usage is also EOF
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* on file.
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* < 0 on error. If such case, next calls to read_block will keep
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* returning < 0 until we reach the expected size, filling blocks with
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* 0s.
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*/
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int (*read_block)(struct iso_file_src *src, unsigned char *buffer);
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/**
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* Get the size in bytes of the file.
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*
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* This is set when the iso_file_src is created, and should not change. If
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* the actual file size changes, it will be truncated or padding with 0s
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* when the block is read
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*/
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off_t (*get_size)(struct iso_file_src *);
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/** Clean up the source specific data */
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void (*free_data)(struct iso_file_src *);
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/** Source specific data */
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void *data;
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};
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/**
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* Get a iso_file_src() for reading from a local filesystem file.
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*/
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struct iso_file_src* iso_file_src_from_path(const char *path);
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/**
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* close and free a iso_file_src
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*/
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void iso_file_src_free(struct iso_file_src *src);
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#endif /*FILE_SRC_H_*/
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@ -385,6 +385,8 @@ Range "vreixo" : 0x00030000 to 0x0003ffff
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General:
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0x00031001 (SORRY,HIGH) = Can't read file (ignored)
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0x00031002 (FATAL,HIGH) = Can't read file (operation canceled)
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0x00031003 (FATAL,HIGH) = File doesn't exist
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0x00031004 (FATAL,HIGH) = Read access denied
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Image reading:
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0x00031000 (FATAL,HIGH) = Unsupported ISO-9660 image
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#define LIBISO_CANT_READ_FILE 0x00031001
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/** Can't read file (operation canceled) */
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#define LIBISO_FILE_READ_ERROR 0x00031002
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/** File doesn't exist */
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#define LIBISO_FILE_DOESNT_EXIST 0x00031003
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/** Read access denied */
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#define LIBISO_FILE_NO_READ_ACCESS 0x00031004
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/** Unsupported image feature */
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#define LIBISO_IMG_UNSUPPORTED 0x00031000
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