The .cc and .h file had different parameter names. Updated the header
to match.

Bug: None
Test: It builds.
Change-Id: Ib6df0b04595c3cb9df3b18351ce317b1126f9809

All clients now include "bsdiff/bsdiff.h" so no need for this export
path anymore.

Bug: None
Test: `make checkbuild`
Change-Id: I0cc7882a58905fcd276600ee2efa01620a7ab378

Add a new compressor interface; and the brotli compressor which is
similar to the existing bz2 one.

Also add a new CompressorType argument to PatchWriter's init function;
this allows us to choose the right compressor based on the input option
in the future.

Bug: 34220646
Test:  Run bsdiff/bspatch with brotli compressor/decompressor over a
list of files from angler's system image. Make succeeds.
Change-Id: Id9a3db2d7d051dcb751a1fc362f4c3b9226e878b

* changes:
  Pass the size of the new file to the PatchWriterInterface::Init()
  Cleanup bsdiff public API.
  Expose the PatchWriter generator in the public API.
  Correct SplitPatchWriter() comment.
  Add/remove includes to match used types.

Most patch formats include the size of the new file in the header.
To help streaming the patch to disk while generating it, this CL
passes the size of the new file to the patch writer on initialization.

To do this, we also move the Init() call to the patch writer to the
DiffEncoder, which makes more sense since the Close() call is also made
from the DiffEnconder.

Bug: None
Test: Updated tests to check for this value.
Change-Id: Idfaedbd492d68ab6e6cb2c1cb3883947f068c3aa

The original function used to generate a patch from two files is no
longer used elsewhere so this patch removes it in favour of the newer
version that takes the streams from memory buffers and uses a patch
writer to generate the patch.

Bug: None.
Test: Ran `bsdiff` manually, verified bspatch applied correctly.

Change-Id: I17aac1d3dd405d733ff6dc35abe8e683adea0d4f

We want to expose the patch writers constructors in the public API
without necesarily exposing the internal details. For that, we use a
factory in the public API so callers can create the PatchWriters they
need.

We will extend this file with new patch formats.

Bug: 34220646
Test: Used this interface from the bsdiff_main.cc (see follow up CL).
Change-Id: I1f005f103886579eacf37b7d9767b713e066030c

Bug: None
Test: Compiles.
Change-Id: I01eded0b094083eb79ccc4c59458e1b88952145d

uint64_t and similar types are defined in stdint.h, and size_t is
defined in stddef.h. While these headers are included virtually
everywhere anyways we should include what we use, specially in public
headers.

Bug: None
Test: still compiles.

Change-Id: I26846be960bf9c989372a05e9c4369caf02888cd

Add a wrapper class to separate the patch read from data stream
decompression. Therefore, bspatch will be able to process the patch
that is compressed with various tools.

Test: unittest pass
Change-Id: I5214e0451bde80366e8a70b960703afb2b2a7d97

Check that we don't attempt to use the region outside the old file.
While this is supported by our decoder, there's no reason why we should
do that and it often means a bug in the encoder.

Bug: None
Test: Added unittests that would fail without the fixes.
Change-Id: Ifd6d8763ae4e6b3f29a5a1289f22900a278dd1b0

am: 877a6678

Change-Id: Ib9004b35cc50111898510baef48864cbd6790a6c

The suffix array is used to search for strings from the new file in the
old file. The size of each element of the suffix array must be big
enough to hold the length of the old file. In most of the cases we use,
if not all of them, the old file is smaller than 2 GiB, which allows to
use 32-bit integers for the suffix array.

The previous code decided whether to use 64-bit or 32-bit integers
based on the large-file surpport, even in 32-bit computers architectures
which would not work in those cases; and would also use twice as much
memory when constructing the suffix array of inputs smaller than 2 GiB.

This patch selects the suffix array size based on the input size,
effectively using half the memory in the most common case. This also
improves the runtime performance due to lower cache pressure.

As a side effect, this patch hides the suffix array implementation
details from the public interface. This removes the limitation where
the caller of libbsdiff and libbsdiff needed to be compiled with the
same large-file support flags; and also hides the dependency on
libdivsufsort from the public interface.

While doing so, instead of re-implementing the suffix array search
algorithm (which had a history of bugs and corner cases) we re-use the
one from libdivsufsort, adapted to the bsdiff algorithm use-case.

The result is about 40% faster when diffing 10MiB files, and the patch
size is within 0.1%, due to differences in the position selected
whenever more than one match is available.

Bug: 34220646
Test: Added unittests for the suffix array.

Change-Id: Ib9dc85a83bbf10157a3937c5687e5663ab0d20d5

am: 52b6bae3

Change-Id: Ic5d3ea2844c9a0dede38492f42ea5e00366214b6

This new PatchWriterInterface derived class allows to split the
output patch of a bsdiff run into multiple files of a fixed new file
size. This allows to split long operations with minimal loss of patch
size due to splitting the compression blocks. For large enough new file
sections, this patch size reduction should be minimal.

Bug: 34220646
Test: Added unittests.
Change-Id: Ib90fddd5c55a38c87ce396f2792aa558ecd07b22

am: f356f501

Change-Id: I67fd6ee62c22784c228c21c8eac5d35c3e745e5e

The recently introduced PatchWriterInterface had both the patch file
format logic and the diff/extra streams selection from the control
entries. While this simplifies the bsdiff main algorithm and makes
invalid usages of the BsdiffPatchWriter evident, writing alternative
PatchWriterInterface classes required to replicate the diff/extra
stream selection logic.

This patch splits out the diff/extra stream generation and all the
checks around those to a new helper class DiffEncoder. The public
interface PatchWriterInterface now has two methods to accept the diff
and extra stream data, and does not compute them.

Bug: 34220646
Test: Added unittests. Ran bsdiff on some pairs of files obtaining the same result as before.
Change-Id: I5f303c06f1e10910eb00dcfda38c6811977a91cf

am: bfef6ef1

Change-Id: Ifb99ffacc3939fc15af6b00772e2e7b445006b22

* changes:
  Add unittest for the PatchWriter.
  Make BsdiffPatchWriter into an Interface.
  Update .gitignore to exclude tracked files.

Split the unittest logic between bsdiff() function and the PatchWriter.
This patch now tests individually the PatchWriter logic that writes to
disk and the bsdiff() logic to create patches in the same very simple
cases.

We also update the Android.bp file to only pass -DBSDIFF_TARGET_UNITTEST
when building for the target.

Bug: 34220646
Test: ran unittests.

Change-Id: I9350157ee4a0b5a617f44bb187bd7652f6d6f017

Currently, all bsdiff() functions take a filename for the patch, which
is called with a temporary file in all cases. To help expose an
interface that allows to write bsdiff patches in different formats (for
example, changing the compressor and header format) we expose the
PatchWriterInterface class in the public interface so callers can use
a different one or define their own to help experimenting with bsdiff
enconding improvements.

Bug: 34220646
Test: make bsdiff and update_engine; ran bsdiff_unittest

Change-Id: Ie450b2790137665bc033cb36d037171090b18a4b

.gitignore was ignoring all the files in the include/bsdiff/ directory
because the path includes "bsdiff". This fixes it to ignore only the
"bsdiff" path on the root directory.

Bug: None
Test: git ls-files -i --exclude-standard
Change-Id: Icc85d8b4b6214786cdf13b3e886e2d7240bbccdb

am: 97600586

Change-Id: I2ca100ea4498b41c3cda9e529c2342fa423dfd48

Include stdint.h for uint64_t. Also remove a redundant return at the
end of a function.

Bug: None
Test: make
Change-Id: I7712bd8020bc063463f5fee09fa05439b462cfac

am: cef30b31

Change-Id: I4b467e544ab95a571cec716162964a8ed5fb7208

am: b63fef9a

Change-Id: Ib94cdd5cf81fbf160991833c87e711879ca04354

We also remove the "using std::string" clause from the files that were
using it to simplify the integration with google's string type.

Bug: None
Test: Build and ran unittest.

Change-Id: I752040494f6a6bb8447d8ff6d7cc2cf2784085d6

This prevents accidentally including a header file from another project
that happens to have the same name.

Test: `make checkbuild`; emerge-${BOARD} bsdiff
Bug: None

Change-Id: I8af132ed388738c30a8e3d7434de70b1e9d2f924

am: 06c56a04

Change-Id: I4ba5b204dce9fd645697ddc8201ad1a50faf3455