1 files changed, 221 insertions, 0 deletions
diff --git a/subversion/libsvn_diff/binary_diff.c b/subversion/libsvn_diff/binary_diff.c
new file mode 100644
index 0000000..035794d
--- /dev/null
+++ b/subversion/libsvn_diff/binary_diff.c
@@ -0,0 +1,221 @@
+/*
+ * binary_diff.c:  handling of git like binary diffs
+ *
+ * ====================================================================
+ *    Licensed to the Apache Software Foundation (ASF) under one
+ *    or more contributor license agreements.  See the NOTICE file
+ *    distributed with this work for additional information
+ *    regarding copyright ownership.  The ASF licenses this file
+ *    to you 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 <apr.h>
+
+#include "svn_pools.h"
+#include "svn_error.h"
+#include "svn_diff.h"
+#include "svn_types.h"
+
+/* Copies the data from ORIGINAL_STREAM to a temporary file, returning both
+   the original and compressed size. */
+static svn_error_t *
+create_compressed(apr_file_t **result,
+                  svn_filesize_t *full_size,
+                  svn_filesize_t *compressed_size,
+                  svn_stream_t *original_stream,
+                  svn_cancel_func_t cancel_func,
+                  void *cancel_baton,
+                  apr_pool_t *result_pool,
+                  apr_pool_t *scratch_pool)
+{
+  svn_stream_t *compressed;
+  svn_filesize_t bytes_read = 0;
+  apr_finfo_t finfo;
+  apr_size_t rd;
+
+  SVN_ERR(svn_io_open_uniquely_named(result, NULL, NULL, "diffgz",
+                                     NULL, svn_io_file_del_on_pool_cleanup,
+                                     result_pool, scratch_pool));
+
+  compressed = svn_stream_compressed(
+                  svn_stream_from_aprfile2(*result, TRUE, scratch_pool),
+                  scratch_pool);
+
+  if (original_stream)
+    do
+    {
+      char buffer[SVN_STREAM_CHUNK_SIZE];
+      rd = sizeof(buffer);
+
+      if (cancel_func)
+        SVN_ERR(cancel_func(cancel_baton));
+
+      SVN_ERR(svn_stream_read_full(original_stream, buffer, &rd));
+
+      bytes_read += rd;
+      SVN_ERR(svn_stream_write(compressed, buffer, &rd));
+    }
+    while(rd == SVN_STREAM_CHUNK_SIZE);
+  else
+    {
+      apr_size_t zero = 0;
+      SVN_ERR(svn_stream_write(compressed, NULL, &zero));
+    }
+
+  SVN_ERR(svn_stream_close(compressed)); /* Flush compression */
+
+  *full_size = bytes_read;
+  SVN_ERR(svn_io_file_info_get(&finfo, APR_FINFO_SIZE, *result, scratch_pool));
+  *compressed_size = finfo.size;
+
+  return SVN_NO_ERROR;
+}
+
+#define GIT_BASE85_CHUNKSIZE 52
+
+/* Git Base-85 table for write_literal */
+static const char b85str[] =
+    "0123456789"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "abcdefghijklmnopqrstuvwxyz"
+    "!#$%&()*+-;<=>?@^_`{|}~";
+
+/* Git length encoding table for write_literal */
+static const char b85lenstr[] =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "abcdefghijklmnopqrstuvwxyz";
+
+/* Writes out a git-like literal output of the compressed data in
+   COMPRESSED_DATA to OUTPUT_STREAM, describing that its normal length is
+   UNCOMPRESSED_SIZE. */
+static svn_error_t *
+write_literal(svn_filesize_t uncompressed_size,
+              svn_stream_t *compressed_data,
+              svn_stream_t *output_stream,
+              svn_cancel_func_t cancel_func,
+              void *cancel_baton,
+              apr_pool_t *scratch_pool)
+{
+  apr_size_t rd;
+  SVN_ERR(svn_stream_seek(compressed_data, NULL)); /* Seek to start */
+
+  SVN_ERR(svn_stream_printf(output_stream, scratch_pool,
+                            "literal %" SVN_FILESIZE_T_FMT APR_EOL_STR,
+                            uncompressed_size));
+
+  do
+    {
+      char chunk[GIT_BASE85_CHUNKSIZE];
+      const unsigned char *next;
+      apr_size_t left;
+
+      rd = sizeof(chunk);
+
+      if (cancel_func)
+        SVN_ERR(cancel_func(cancel_baton));
+
+      SVN_ERR(svn_stream_read_full(compressed_data, chunk, &rd));
+
+      {
+        apr_size_t one = 1;
+        SVN_ERR(svn_stream_write(output_stream, &b85lenstr[rd-1], &one));
+      }
+
+      left = rd;
+      next = (void*)chunk;
+      while (left)
+      {
+        char five[5];
+        unsigned info = 0;
+        int n;
+        apr_size_t five_sz;
+
+        /* Push 4 bytes into the 32 bit info, when available */
+        for (n = 24; n >= 0 && left; n -= 8, next++, left--)
+        {
+            info |= (*next) << n;
+        }
+
+        /* Write out info as base85 */
+        for (n = 4; n >= 0; n--)
+        {
+            five[n] = b85str[info % 85];
+            info /= 85;
+        }
+
+        five_sz = 5;
+        SVN_ERR(svn_stream_write(output_stream, five, &five_sz));
+      }
+
+      SVN_ERR(svn_stream_puts(output_stream, APR_EOL_STR));
+    }
+  while (rd == GIT_BASE85_CHUNKSIZE);
+
+  return SVN_NO_ERROR;
+}
+
+svn_error_t *
+svn_diff_output_binary(svn_stream_t *output_stream,
+                       svn_stream_t *original,
+                       svn_stream_t *latest,
+                       svn_cancel_func_t cancel_func,
+                       void *cancel_baton,
+                       apr_pool_t *scratch_pool)
+{
+  apr_file_t *original_apr;
+  svn_filesize_t original_full;
+  svn_filesize_t original_deflated;
+  apr_file_t *latest_apr;
+  svn_filesize_t latest_full;
+  svn_filesize_t latest_deflated;
+  apr_pool_t *subpool = svn_pool_create(scratch_pool);
+
+  SVN_ERR(create_compressed(&original_apr, &original_full, &original_deflated,
+                            original, cancel_func, cancel_baton,
+                            scratch_pool, subpool));
+  svn_pool_clear(subpool);
+
+  SVN_ERR(create_compressed(&latest_apr, &latest_full, &latest_deflated,
+                            latest,  cancel_func, cancel_baton,
+                            scratch_pool, subpool));
+  svn_pool_clear(subpool);
+
+  SVN_ERR(svn_stream_puts(output_stream, "GIT binary patch" APR_EOL_STR));
+
+  /* ### git would first calculate if a git-delta latest->original would be
+         shorter than the zipped data. For now lets assume that it is not
+         and just dump the literal data */
+  SVN_ERR(write_literal(latest_full,
+                        svn_stream_from_aprfile2(latest_apr, FALSE, subpool),
+                        output_stream,
+                        cancel_func, cancel_baton,
+                        scratch_pool));
+  svn_pool_clear(subpool);
+  SVN_ERR(svn_stream_puts(output_stream, APR_EOL_STR));
+
+  /* ### git would first calculate if a git-delta original->latest would be
+         shorter than the zipped data. For now lets assume that it is not
+         and just dump the literal data */
+  SVN_ERR(write_literal(original_full,
+                        svn_stream_from_aprfile2(original_apr, FALSE, subpool),
+                        output_stream,
+                        cancel_func, cancel_baton,
+                        scratch_pool));
+  svn_pool_destroy(subpool);
+
+  SVN_ERR(svn_stream_puts(output_stream, APR_EOL_STR));
+
+  return SVN_NO_ERROR;
+}