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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* io_stdin.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "common.h"
#include <stdlib.h>
#include <string.h>
#include <errno.h>
typedef struct {
sqfs_file_t base;
const sparse_map_t *map;
sqfs_u64 offset;
sqfs_u64 real_size;
sqfs_u64 apparent_size;
FILE *fp;
} sqfs_file_stdinout_t;
static void stdinout_destroy(sqfs_object_t *base)
{
free(base);
}
static sqfs_u64 stdinout_get_size(const sqfs_file_t *base)
{
return ((const sqfs_file_stdinout_t *)base)->apparent_size;
}
static int stdinout_truncate(sqfs_file_t *base, sqfs_u64 size)
{
(void)base; (void)size;
return SQFS_ERROR_IO;
}
static int stdin_read_at(sqfs_file_t *base, sqfs_u64 offset,
void *buffer, size_t size)
{
sqfs_file_stdinout_t *file = (sqfs_file_stdinout_t *)base;
size_t temp_size = 0;
sqfs_u8 *temp = NULL;
sqfs_u64 diff;
size_t ret;
if (offset < file->offset)
return SQFS_ERROR_IO;
if (offset > file->offset) {
temp_size = 1024;
temp = alloca(temp_size);
}
if (offset >= file->real_size || (offset + size) > file->real_size)
return SQFS_ERROR_OUT_OF_BOUNDS;
while (size > 0) {
if (ferror(file->fp))
return SQFS_ERROR_IO;
if (feof(file->fp))
return SQFS_ERROR_OUT_OF_BOUNDS;
if (offset > file->offset) {
diff = file->offset - offset;
diff = diff > (sqfs_u64)temp_size ? temp_size : diff;
ret = fread(temp, 1, diff, file->fp);
} else {
ret = fread(buffer, 1, size, file->fp);
}
if (offset <= file->offset) {
buffer = (char *)buffer + ret;
size -= ret;
offset += ret;
}
file->offset += ret;
}
return 0;
}
static int stdin_read_condensed(sqfs_file_t *base, sqfs_u64 offset,
void *buffer, size_t size)
{
sqfs_file_stdinout_t *file = (sqfs_file_stdinout_t *)base;
sqfs_u64 poffset = 0, src_start;
size_t dst_start, diff, count;
const sparse_map_t *it;
int err;
memset(buffer, 0, size);
for (it = file->map; it != NULL; it = it->next) {
if (it->offset + it->count <= offset) {
poffset += it->count;
continue;
}
if (it->offset >= offset + size) {
poffset += it->count;
continue;
}
count = size;
if (offset + count >= it->offset + it->count)
count = it->offset + it->count - offset;
if (it->offset < offset) {
diff = offset - it->offset;
src_start = poffset + diff;
dst_start = 0;
count -= diff;
} else if (it->offset > offset) {
diff = it->offset - offset;
src_start = poffset;
dst_start = diff;
} else {
src_start = poffset;
dst_start = 0;
}
err = stdin_read_at(base, src_start,
(char *)buffer + dst_start, count);
if (err)
return err;
poffset += it->count;
}
return 0;
}
static int stdin_write_at(sqfs_file_t *base, sqfs_u64 offset,
const void *buffer, size_t size)
{
(void)base; (void)offset; (void)buffer; (void)size;
return SQFS_ERROR_IO;
}
sqfs_file_t *sqfs_get_stdin_file(FILE *fp, const sparse_map_t *map,
sqfs_u64 size)
{
sqfs_file_stdinout_t *file = calloc(1, sizeof(*file));
sqfs_file_t *base = (sqfs_file_t *)file;
const sparse_map_t *it;
if (file == NULL)
return NULL;
file->apparent_size = size;
file->map = map;
file->fp = fp;
if (map != NULL) {
for (it = map; it != NULL; it = it->next)
file->real_size += map->count;
} else {
file->real_size = size;
}
((sqfs_object_t *)base)->destroy = stdinout_destroy;
base->write_at = stdin_write_at;
base->get_size = stdinout_get_size;
base->truncate = stdinout_truncate;
if (map == NULL) {
base->read_at = stdin_read_at;
} else {
base->read_at = stdin_read_condensed;
}
return base;
}
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