added assfile

[raydungeon] / libs / assfile / mod_archive.c

diff --git a/libs/assfile/mod_archive.c b/libs/assfile/mod_archive.c
new file mode 100644 (file)
index 0000000..43791cb
--- /dev/null
+++ b/libs/assfile/mod_archive.c
@@ -0,0 +1,157 @@
+/*
+assfile - library for accessing assets with an fopen/fread-like interface
+Copyright (C) 2018  John Tsiombikas <nuclear@member.fsf.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include "assfile_impl.h"
+#include "tar.h"
+
+struct file_info {
+       struct tar_entry *tarent;
+       long roffs;
+       int eof;
+};
+
+static void *fop_open(const char *fname, void *udata);
+static void fop_close(void *fp, void *udata);
+static long fop_seek(void *fp, long offs, int whence, void *udata);
+static long fop_read(void *fp, void *buf, long size, void *udata);
+
+
+struct ass_fileops *ass_alloc_archive(const char *fname)
+{
+       struct ass_fileops *fop;
+       struct tar *tar;
+
+       if(!(tar = malloc(sizeof *tar))) {
+               return 0;
+       }
+       if(load_tar(tar, fname) == -1) {
+               free(tar);
+               return 0;
+       }
+
+       if(!(fop = malloc(sizeof *fop))) {
+               return 0;
+       }
+       fop->udata = tar;
+       fop->open = fop_open;
+       fop->close = fop_close;
+       fop->seek = fop_seek;
+       fop->read = fop_read;
+       return fop;
+}
+
+void ass_free_archive(struct ass_fileops *fop)
+{
+       close_tar(fop->udata);
+       free(fop->udata);
+       fop->udata = 0;
+}
+
+static void *fop_open(const char *fname, void *udata)
+{
+       int i;
+       struct file_info *file;
+       struct tar *tar = udata;
+
+       for(i=0; i<tar->num_files; i++) {
+               if(strcmp(fname, tar->files[i].path) == 0) {
+                       if(!(file = malloc(sizeof *file))) {
+                               ass_errno = ENOMEM;
+                               return 0;
+                       }
+                       file->tarent = tar->files + i;
+                       file->roffs = 0;
+                       file->eof = 0;
+                       return file;
+               }
+       }
+
+       ass_errno = ENOENT;
+       return 0;
+}
+
+static void fop_close(void *fp, void *udata)
+{
+       free(fp);
+}
+
+static long fop_seek(void *fp, long offs, int whence, void *udata)
+{
+       long newoffs;
+       struct file_info *file = fp;
+
+       switch(whence) {
+       case SEEK_SET:
+               newoffs = offs;
+               break;
+
+       case SEEK_CUR:
+               newoffs = file->roffs + offs;
+               break;
+
+       case SEEK_END:
+               newoffs = file->tarent->size + offs;
+               break;
+
+       default:
+               ass_errno = EINVAL;
+               return -1;
+       }
+
+       if(newoffs < 0) {
+               ass_errno = EINVAL;
+               return -1;
+       }
+
+       file->eof = 0;
+       file->roffs = newoffs;
+       return newoffs;
+}
+
+static long fop_read(void *fp, void *buf, long size, void *udata)
+{
+       struct tar *tar = udata;
+       struct file_info *file = fp;
+       long newoffs = file->roffs + size;
+       size_t rdbytes;
+
+       if(file->roffs >= file->tarent->size) {
+               file->eof = 1;
+               return -1;
+       }
+
+       if(newoffs > file->tarent->size) {
+               size = file->tarent->size - file->roffs;
+               newoffs = file->tarent->size;
+       }
+
+       if(fseek(tar->fp, file->tarent->offset + file->roffs, SEEK_SET) == -1) {
+               fprintf(stderr, "assfile mod_archive: fop_read failed to seek to %ld (%ld + %ld)\n",
+                               file->tarent->offset + file->roffs, file->tarent->offset, file->roffs);
+               return -1;
+       }
+       if((rdbytes = fread(buf, 1, size, tar->fp)) < size) {
+               fprintf(stderr, "assfile mod_archive: fop_read unexpected EOF while trying to read %ld bytes\n", size);
+               size = rdbytes;
+       }
+       file->roffs = newoffs;
+       return size;
+}