ardupilot/libraries/AP_ROMFS/AP_ROMFS.cpp

149 lines
4.0 KiB
C++

/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
implement a file store for embedded firmware images
*/
#include "AP_ROMFS.h"
#include "tinf.h"
#include <AP_Math/crc.h>
#include <AP_Common/AP_Common.h>
#include <AP_HAL/AP_HAL_Boards.h>
#include <string.h>
#ifdef HAL_HAVE_AP_ROMFS_EMBEDDED_H
#include <ap_romfs_embedded.h>
#else
const AP_ROMFS::embedded_file AP_ROMFS::files[] = {};
#endif
/*
find an embedded file
*/
const AP_ROMFS::embedded_file *AP_ROMFS::find_file(const char *name)
{
for (uint16_t i=0; i<ARRAY_SIZE(files); i++) {
if (strcmp(name, files[i].filename) == 0) {
return &files[i];
}
}
return nullptr;
}
/*
find a compressed file and uncompress it. Space for decompressed data comes
from malloc. Caller must be careful to free the resulting data after use. The
file data buffer is guaranteed to contain at least one null (though it may be
at buf[size]).
*/
const uint8_t *AP_ROMFS::find_decompress(const char *name, uint32_t &size)
{
const struct embedded_file *f = find_file(name);
if (!f) {
return nullptr;
}
#ifdef HAL_ROMFS_UNCOMPRESSED
size = f->decompressed_size;
return f->contents;
#else
uint8_t *decompressed_data = (uint8_t *)malloc(f->decompressed_size+1);
if (!decompressed_data) {
return nullptr;
}
if (f->decompressed_size == 0) {
// empty file
size = 0;
return decompressed_data;
}
// explicitly null-terminate the data
decompressed_data[f->decompressed_size] = 0;
TINF_DATA *d = (TINF_DATA *)malloc(sizeof(TINF_DATA));
if (!d) {
::free(decompressed_data);
return nullptr;
}
uzlib_uncompress_init(d, NULL, 0);
d->source = f->contents;
d->source_limit = f->contents + f->compressed_size;
d->dest = decompressed_data;
d->destSize = f->decompressed_size;
int res = uzlib_uncompress(d);
::free(d);
if (res != TINF_OK) {
::free(decompressed_data);
return nullptr;
}
if (crc32_small(0, decompressed_data, f->decompressed_size) != f->crc) {
::free(decompressed_data);
return nullptr;
}
size = f->decompressed_size;
return decompressed_data;
#endif
}
// free returned data
void AP_ROMFS::free(const uint8_t *data)
{
#ifndef HAL_ROMFS_UNCOMPRESSED
::free(const_cast<uint8_t *>(data));
#endif
}
/*
directory listing interface. Start with ofs=0. Returns pathnames
that match dirname prefix. Ends with nullptr return when no more
files found
*/
const char *AP_ROMFS::dir_list(const char *dirname, uint16_t &ofs)
{
const size_t dlen = strlen(dirname);
for ( ; ofs < ARRAY_SIZE(files); ofs++) {
if (strncmp(dirname, files[ofs].filename, dlen) == 0) {
const char last_char = files[ofs].filename[dlen];
if (dlen != 0 && last_char != '/' && last_char != 0) {
// only a partial match, skip
continue;
}
/*
prevent duplicate directories
*/
const char *start_name = files[ofs].filename + dlen + 1;
const char *slash = strchr(start_name, '/');
if (ofs > 0 && slash != nullptr) {
auto len = slash - start_name;
if (memcmp(files[ofs].filename, files[ofs-1].filename, len+dlen+1) == 0) {
continue;
}
}
// found one
return files[ofs++].filename;
}
}
return nullptr;
}