diff options
Diffstat (limited to 'lib/sqfs/src/unix/istream.c')
-rw-r--r-- | lib/sqfs/src/unix/istream.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/lib/sqfs/src/unix/istream.c b/lib/sqfs/src/unix/istream.c new file mode 100644 index 0000000..fd2f120 --- /dev/null +++ b/lib/sqfs/src/unix/istream.c @@ -0,0 +1,169 @@ +/* SPDX-License-Identifier: LGPL-3.0-or-later */ +/* + * istream.c + * + * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at> + */ +#define SQFS_BUILDING_DLL +#include "config.h" + +#include "sqfs/io.h" +#include "sqfs/error.h" + +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <assert.h> +#include <errno.h> +#include <fcntl.h> + +#define BUFSZ (131072) + +typedef struct { + sqfs_istream_t base; + char *path; + int fd; + + bool eof; + size_t buffer_offset; + size_t buffer_used; + sqfs_u8 buffer[BUFSZ]; +} file_istream_t; + +static int precache(sqfs_istream_t *strm) +{ + file_istream_t *file = (file_istream_t *)strm; + + if (file->eof) + return 0; + + if (file->buffer_offset > 0 && + file->buffer_offset < file->buffer_used) { + memmove(file->buffer, file->buffer + file->buffer_offset, + file->buffer_used - file->buffer_offset); + } + + file->buffer_used -= file->buffer_offset; + file->buffer_offset = 0; + + while (file->buffer_used < BUFSZ) { + ssize_t ret = read(file->fd, file->buffer + file->buffer_used, + BUFSZ - file->buffer_used); + + if (ret == 0) { + file->eof = true; + break; + } + + if (ret < 0) { + if (errno == EINTR) + continue; + return SQFS_ERROR_IO; + } + + file->buffer_used += ret; + } + + return 0; +} + +static int file_get_buffered_data(sqfs_istream_t *strm, const sqfs_u8 **out, + size_t *size, size_t want) +{ + file_istream_t *file = (file_istream_t *)strm; + + if (want > BUFSZ) + want = BUFSZ; + + if (file->buffer_used == 0 || + (file->buffer_used - file->buffer_offset) < want) { + int ret = precache(strm); + if (ret) + return ret; + } + + *out = file->buffer + file->buffer_offset; + *size = file->buffer_used - file->buffer_offset; + return (file->eof && *size == 0) ? 1 : 0; +} + +static void file_advance_buffer(sqfs_istream_t *strm, size_t count) +{ + file_istream_t *file = (file_istream_t *)strm; + + assert(count <= file->buffer_used); + + file->buffer_offset += count; + + assert(file->buffer_offset <= file->buffer_used); +} + +static const char *file_get_filename(sqfs_istream_t *strm) +{ + return ((file_istream_t *)strm)->path; +} + +static void file_destroy(sqfs_object_t *obj) +{ + file_istream_t *file = (file_istream_t *)obj; + + close(file->fd); + free(file->path); + free(file); +} + +int sqfs_istream_open_handle(sqfs_istream_t **out, const char *path, + sqfs_file_handle_t fd) +{ + file_istream_t *file = calloc(1, sizeof(*file)); + sqfs_istream_t *strm = (sqfs_istream_t *)file; + + if (file == NULL) + return SQFS_ERROR_ALLOC; + + sqfs_object_init(file, file_destroy, NULL); + + file->path = strdup(path); + if (file->path == NULL) { + int temp = errno; + free(file); + errno = temp; + return SQFS_ERROR_ALLOC; + } + + file->fd = dup(fd); + if (file->fd < 0) { + int temp = errno; + free(file->path); + free(file); + errno = temp; + return SQFS_ERROR_IO; + } + close(fd); + + strm->get_buffered_data = file_get_buffered_data; + strm->advance_buffer = file_advance_buffer; + strm->get_filename = file_get_filename; + + *out = strm; + return 0; +} + +int sqfs_istream_open_file(sqfs_istream_t **out, const char *path) +{ + sqfs_file_handle_t fd; + int ret; + + ret = sqfs_open_native_file(&fd, path, SQFS_FILE_OPEN_READ_ONLY); + if (ret) + return ret; + + ret = sqfs_istream_open_handle(out, path, fd); + if (ret != 0) { + int temp = errno; + close(fd); + errno = temp; + } + + return ret; +} |