Initial open sourcing of MuJoCo.

PiperOrigin-RevId: 450374687
Change-Id: Ie3225a46ce095fc28ae8e63c326a640261f562bb

src/engine/engine_vfs.c

@@ -0,0 +1,211 @@
+// Copyright 2021 DeepMind Technologies Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "engine/engine_vfs.h"
+
+#include <string.h>
+#include <stdlib.h>
+
+#include "engine/engine_array_safety.h"
+#include "engine/engine_file.h"
+#include "engine/engine_util_errmem.h"
+#include "engine/engine_util_misc.h"
+
+// strip path prefix from filename
+static void vfs_strippath(char* newname, const char* oldname) {
+  int i, sz = strlen(oldname);
+
+  // find last delimiter
+  for (i=sz-1; i>=0; i--) {
+    if (oldname[i]=='\\' || oldname[i]=='/') {
+      break;
+    }
+  }
+
+  // check resulting length
+  if (sz-(i+1)>=mjMAXVFSNAME) {
+    mju_error("Filename too long in VFS");
+  }
+  if (sz-(i+1)<=0) {
+    mju_error("Empty filename in VFS");
+  }
+
+  // copy
+  mju_strncpy(newname, oldname+i+1, mjMAXVFSNAME);
+
+  // make lowercase
+  for (i=strlen(newname)-1; i>=0; i--) {
+    if (newname[i]>='A' && newname[i]<='Z') {
+      newname[i] = (char)(((int)newname[i]) +'a' - 'A');
+    }
+  }
+}
+
+
+
+// initialize to empty (no deallocation)
+void mj_defaultVFS(mjVFS* vfs) {
+  memset(vfs, 0, sizeof(mjVFS));
+}
+
+
+
+// add file to VFS, return 0: success, 1: full, 2: repeated name, -1: failed to load
+int mj_addFileVFS(mjVFS* vfs, const char* directory, const char* filename) {
+  // check vfs size
+  if (vfs->nfile>=mjMAXVFS-1) {
+    return 1;
+  }
+
+  // make full name
+  char fullname[1000];
+  if (directory) {
+    mjSTRNCPY(fullname, directory);
+    mjSTRNCAT(fullname, filename);
+  } else {
+    mjSTRNCPY(fullname, filename);
+  }
+
+  // strip path
+  char newname[mjMAXVFSNAME];
+  vfs_strippath(newname, filename);
+
+  // check for repeated name
+  for (int i=0; i<vfs->nfile; i++) {
+    if (strncmp(newname, vfs->filename[i], mjMAXVFSNAME)==0) {
+      return 2;
+    }
+  }
+
+  // assign name
+  mjSTRNCPY(vfs->filename[vfs->nfile], newname);
+
+  // allocate and read
+  int filesize = 0;
+  vfs->filedata[vfs->nfile] = mju_fileToMemory(filename, &filesize);
+  if (!vfs->filedata[vfs->nfile]) {
+    return -1;
+  }
+  // assign size and count
+  vfs->filesize[vfs->nfile] = filesize;
+  vfs->nfile++;
+
+  return 0;
+}
+
+
+
+// make empty file in VFS, return 0: success, 1: full, 2: repeated name
+int mj_makeEmptyFileVFS(mjVFS* vfs, const char* filename, int filesize) {
+  // check vfs size
+  if (vfs->nfile>=mjMAXVFS-1) {
+    return 1;
+  }
+
+  // check filesize
+  if (filesize<=0) {
+    mju_error("mj_makeEmptyFileVFS expects positive filesize");
+  }
+
+  // strip path
+  char newname[mjMAXVFSNAME];
+  vfs_strippath(newname, filename);
+
+  // check for repeated name
+  for (int i=0; i<vfs->nfile; i++) {
+    if (strncmp(newname, vfs->filename[i], mjMAXVFSNAME)==0) {
+      return 2;
+    }
+  }
+
+  // assign name
+  mjSTRNCPY(vfs->filename[vfs->nfile], newname);
+
+  // allocate and clear
+  vfs->filedata[vfs->nfile] = mju_malloc(filesize);
+  if (!vfs->filedata[vfs->nfile]) {
+    mju_error("mj_makeEmptyFileVFS: could not allocate memory");
+  }
+  memset(vfs->filedata[vfs->nfile], 0, filesize);
+
+  // assign size and count
+  vfs->filesize[vfs->nfile] = filesize;
+  vfs->nfile++;
+
+  return 0;
+}
+
+
+
+// return file index in VFS, or -1 if not found in VFS
+int mj_findFileVFS(const mjVFS* vfs, const char* filename) {
+  // strip path
+  char newname[mjMAXVFSNAME];
+  vfs_strippath(newname, filename);
+
+  // find specific file
+  for (int i=0; i<vfs->nfile; i++) {
+    if (strncmp(newname, vfs->filename[i], mjMAXVFSNAME)==0) {
+      return i;
+    }
+  }
+
+  return -1;
+}
+
+
+
+// delete file from VFS, return 0: success, -1: not found in VFS
+int mj_deleteFileVFS(mjVFS* vfs, const char* filename) {
+  // strip path
+  char newname[mjMAXVFSNAME];
+  vfs_strippath(newname, filename);
+
+  // find specified file
+  for (int i=0; i<vfs->nfile; i++) {
+    if (strncmp(newname, vfs->filename[i], mjMAXVFSNAME)==0) {
+      // free buffer
+      mju_free(vfs->filedata[i]);
+
+      // scroll remaining files forward
+      while (i<vfs->nfile-1) {
+        mjSTRNCPY(vfs->filename[i], vfs->filename[i+1]);
+        vfs->filesize[i] = vfs->filesize[i+1];
+        vfs->filedata[i] = vfs->filedata[i+1];
+      }
+
+      // set last to 0, for style
+      vfs->filename[vfs->nfile-1][0] = 0;
+      vfs->filesize[vfs->nfile-1] = 0;
+      vfs->filedata[vfs->nfile-1] = NULL;
+
+      // decrease counter
+      vfs->nfile--;
+      return 0;
+    }
+  }
+
+  return -1;
+}
+
+
+
+// delete all files from VFS
+void mj_deleteVFS(mjVFS* vfs) {
+  for (int i=0; i<vfs->nfile; i++) {
+    mju_free(vfs->filedata[i]);
+  }
+
+  memset(vfs, 0, sizeof(mjVFS));
+}