Change assets to use 64-bit API

The asset system and supporting libraries were using off_t instead of
off64_t to access files larger than 2GB (32-bit signed). This change
replaces all off_t with off64_t and lseek64.

There is a new utils/Compat.h added for Mac OS compatibility.

Also fixed some size-related compiler warnings.

Bug: 3205336
Change-Id: I9097b3cb7a602e811fe52f245939d8975da55e9e
diff --git a/libs/utils/ObbFile.cpp b/libs/utils/ObbFile.cpp
index 2c3724c..2907b56 100644
--- a/libs/utils/ObbFile.cpp
+++ b/libs/utils/ObbFile.cpp
@@ -22,6 +22,8 @@
 #include <unistd.h>
 
 #define LOG_TAG "ObbFile"
+
+#include <utils/Compat.h>
 #include <utils/Log.h>
 #include <utils/ObbFile.h>
 
@@ -67,17 +69,6 @@
     _rc; })
 #endif
 
-/*
- * Work around situations where off_t is 64-bit and use off64_t in
- * situations where it's 32-bit.
- */
-#ifdef OFF_T_IS_64_BIT
-#define my_lseek64 lseek
-typedef off_t my_off64_t;
-#else
-#define my_lseek64 lseek64
-typedef off64_t my_off64_t;
-#endif
 
 namespace android {
 
@@ -125,7 +116,7 @@
 
 bool ObbFile::parseObbFile(int fd)
 {
-    my_off64_t fileLength = my_lseek64(fd, 0, SEEK_END);
+    off64_t fileLength = lseek64(fd, 0, SEEK_END);
 
     if (fileLength < kFooterMinSize) {
         if (fileLength < 0) {
@@ -140,7 +131,7 @@
     size_t footerSize;
 
     {
-        my_lseek64(fd, fileLength - kFooterTagSize, SEEK_SET);
+        lseek64(fd, fileLength - kFooterTagSize, SEEK_SET);
 
         char *footer = new char[kFooterTagSize];
         actual = TEMP_FAILURE_RETRY(read(fd, footer, kFooterTagSize));
@@ -171,8 +162,8 @@
         }
     }
 
-    my_off64_t fileOffset = fileLength - footerSize - kFooterTagSize;
-    if (my_lseek64(fd, fileOffset, SEEK_SET) != fileOffset) {
+    off64_t fileOffset = fileLength - footerSize - kFooterTagSize;
+    if (lseek64(fd, fileOffset, SEEK_SET) != fileOffset) {
         LOGW("seek %lld failed: %s\n", fileOffset, strerror(errno));
         return false;
     }
@@ -211,10 +202,10 @@
 
     memcpy(&mSalt, (unsigned char*)scanBuf + kSaltOffset, sizeof(mSalt));
 
-    uint32_t packageNameLen = get4LE((unsigned char*)scanBuf + kPackageNameLenOffset);
-    if (packageNameLen <= 0
+    size_t packageNameLen = get4LE((unsigned char*)scanBuf + kPackageNameLenOffset);
+    if (packageNameLen == 0
             || packageNameLen > (footerSize - kPackageNameOffset)) {
-        LOGW("bad ObbFile package name length (0x%04x; 0x%04x possible)\n",
+        LOGW("bad ObbFile package name length (0x%04zx; 0x%04zx possible)\n",
                 packageNameLen, footerSize - kPackageNameOffset);
         free(scanBuf);
         return false;
@@ -257,7 +248,7 @@
         return false;
     }
 
-    my_lseek64(fd, 0, SEEK_END);
+    lseek64(fd, 0, SEEK_END);
 
     if (mPackageName.size() == 0 || mVersion == -1) {
         LOGW("tried to write uninitialized ObbFile data\n");