diff --git a/libsparse/output_file.cpp b/libsparse/output_file.cpp
index e35cb0d..b883c13 100644
--- a/libsparse/output_file.cpp
+++ b/libsparse/output_file.cpp
@@ -35,8 +35,9 @@
 #include "sparse_crc32.h"
 #include "sparse_format.h"
 
+#include <android-base/mapped_file.h>
+
 #ifndef _WIN32
-#include <sys/mman.h>
 #define O_BINARY 0
 #else
 #define ftruncate64 ftruncate
@@ -45,7 +46,6 @@
 #if defined(__APPLE__) && defined(__MACH__)
 #define lseek64 lseek
 #define ftruncate64 ftruncate
-#define mmap64 mmap
 #define off64_t off_t
 #endif
 
@@ -649,52 +649,10 @@
 }
 
 int write_fd_chunk(struct output_file* out, unsigned int len, int fd, int64_t offset) {
-  int ret;
-  int64_t aligned_offset;
-  int aligned_diff;
-  uint64_t buffer_size;
-  char* ptr;
+  auto m = android::base::MappedFile::FromFd(fd, offset, len, PROT_READ);
+  if (!m) return -errno;
 
-  aligned_offset = offset & ~(4096 - 1);
-  aligned_diff = offset - aligned_offset;
-  buffer_size = (uint64_t)len + (uint64_t)aligned_diff;
-
-#ifndef _WIN32
-  if (buffer_size > SIZE_MAX) return -E2BIG;
-  char* data =
-      reinterpret_cast<char*>(mmap64(nullptr, buffer_size, PROT_READ, MAP_SHARED, fd, aligned_offset));
-  if (data == MAP_FAILED) {
-    return -errno;
-  }
-  ptr = data + aligned_diff;
-#else
-  off64_t pos;
-  char* data = reinterpret_cast<char*>(malloc(len));
-  if (!data) {
-    return -errno;
-  }
-  pos = lseek64(fd, offset, SEEK_SET);
-  if (pos < 0) {
-    free(data);
-    return -errno;
-  }
-  ret = read_all(fd, data, len);
-  if (ret < 0) {
-    free(data);
-    return ret;
-  }
-  ptr = data;
-#endif
-
-  ret = out->sparse_ops->write_data_chunk(out, len, ptr);
-
-#ifndef _WIN32
-  munmap(data, buffer_size);
-#else
-  free(data);
-#endif
-
-  return ret;
+  return out->sparse_ops->write_data_chunk(out, m->size(), m->data());
 }
 
 /* Write a contiguous region of data blocks from a file */