1 files changed, 207 insertions, 0 deletions
diff --git a/Firebase/Utilities/NSData+zlib/GULNSData+zlib.m b/Firebase/Utilities/NSData+zlib/GULNSData+zlib.m
new file mode 100644
index 0000000..cd3394a
--- /dev/null
+++ b/Firebase/Utilities/NSData+zlib/GULNSData+zlib.m
@@ -0,0 +1,207 @@
+// Copyright 2018 Google
+//
+// 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.
+
+#import "GULNSData+zlib.h"
+
+#import <zlib.h>
+
+#define kChunkSize 1024
+#define Z_DEFAULT_COMPRESSION (-1)
+
+NSString *const GULNSDataZlibErrorDomain = @"com.google.GULNSDataZlibErrorDomain";
+NSString *const GULNSDataZlibErrorKey = @"GULNSDataZlibErrorKey";
+NSString *const GULNSDataZlibRemainingBytesKey = @"GULNSDataZlibRemainingBytesKey";
+
+@implementation NSData (GULGzip)
+
++ (NSData *)gul_dataByInflatingGzippedData:(NSData *)data error:(NSError **)error {
+  const void *bytes = [data bytes];
+  NSUInteger length = [data length];
+  if (!bytes || !length) {
+    return nil;
+  }
+
+#if defined(__LP64__) && __LP64__
+  // Don't support > 32bit length for 64 bit, see note in header.
+  if (length > UINT_MAX) {
+    return nil;
+  }
+#endif
+
+  z_stream strm;
+  bzero(&strm, sizeof(z_stream));
+
+  // Setup the input.
+  strm.avail_in = (unsigned int)length;
+  strm.next_in = (unsigned char *)bytes;
+
+  int windowBits = 15;  // 15 to enable any window size
+  windowBits += 32;     // and +32 to enable zlib or gzip header detection.
+
+  int retCode;
+  if ((retCode = inflateInit2(&strm, windowBits)) != Z_OK) {
+    if (error) {
+      NSDictionary *userInfo = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:retCode]
+                                                           forKey:GULNSDataZlibErrorKey];
+      *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain
+                                   code:GULNSDataZlibErrorInternal
+                               userInfo:userInfo];
+    }
+    return nil;
+  }
+
+  // Hint the size at 4x the input size.
+  NSMutableData *result = [NSMutableData dataWithCapacity:(length * 4)];
+  unsigned char output[kChunkSize];
+
+  // Loop to collect the data.
+  do {
+    // Update what we're passing in.
+    strm.avail_out = kChunkSize;
+    strm.next_out = output;
+    retCode = inflate(&strm, Z_NO_FLUSH);
+    if ((retCode != Z_OK) && (retCode != Z_STREAM_END)) {
+      if (error) {
+        NSMutableDictionary *userInfo =
+            [NSMutableDictionary dictionaryWithObject:[NSNumber numberWithInt:retCode]
+                                               forKey:GULNSDataZlibErrorKey];
+        if (strm.msg) {
+          NSString *message = [NSString stringWithUTF8String:strm.msg];
+          if (message) {
+            [userInfo setObject:message forKey:NSLocalizedDescriptionKey];
+          }
+        }
+        *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain
+                                     code:GULNSDataZlibErrorInternal
+                                 userInfo:userInfo];
+      }
+      inflateEnd(&strm);
+      return nil;
+    }
+    // Collect what we got.
+    unsigned gotBack = kChunkSize - strm.avail_out;
+    if (gotBack > 0) {
+      [result appendBytes:output length:gotBack];
+    }
+
+  } while (retCode == Z_OK);
+
+  // Make sure there wasn't more data tacked onto the end of a valid compressed stream.
+  if (strm.avail_in != 0) {
+    if (error) {
+      NSDictionary *userInfo =
+          [NSDictionary dictionaryWithObject:[NSNumber numberWithUnsignedInt:strm.avail_in]
+                                      forKey:GULNSDataZlibRemainingBytesKey];
+      *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain
+                                   code:GULNSDataZlibErrorDataRemaining
+                               userInfo:userInfo];
+    }
+    result = nil;
+  }
+  // The only way out of the loop was by hitting the end of the stream.
+  NSAssert(retCode == Z_STREAM_END,
+           @"Thought we finished inflate w/o getting a result of stream end, code %d", retCode);
+
+  // Clean up.
+  inflateEnd(&strm);
+
+  return result;
+}
+
++ (NSData *)gul_dataByGzippingData:(NSData *)data error:(NSError **)error {
+  const void *bytes = [data bytes];
+  NSUInteger length = [data length];
+
+  int level = Z_DEFAULT_COMPRESSION;
+  if (!bytes || !length) {
+    return nil;
+  }
+
+#if defined(__LP64__) && __LP64__
+  // Don't support > 32bit length for 64 bit, see note in header.
+  if (length > UINT_MAX) {
+    if (error) {
+      *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain
+                                   code:GULNSDataZlibErrorGreaterThan32BitsToCompress
+                               userInfo:nil];
+    }
+    return nil;
+  }
+#endif
+
+  z_stream strm;
+  bzero(&strm, sizeof(z_stream));
+
+  int memLevel = 8;          // Default.
+  int windowBits = 15 + 16;  // Enable gzip header instead of zlib header.
+
+  int retCode;
+  if ((retCode = deflateInit2(&strm, level, Z_DEFLATED, windowBits, memLevel,
+                              Z_DEFAULT_STRATEGY)) != Z_OK) {
+    if (error) {
+      NSDictionary *userInfo = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:retCode]
+                                                           forKey:GULNSDataZlibErrorKey];
+      *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain
+                                   code:GULNSDataZlibErrorInternal
+                               userInfo:userInfo];
+    }
+    return nil;
+  }
+
+  // Hint the size at 1/4 the input size.
+  NSMutableData *result = [NSMutableData dataWithCapacity:(length / 4)];
+  unsigned char output[kChunkSize];
+
+  // Setup the input.
+  strm.avail_in = (unsigned int)length;
+  strm.next_in = (unsigned char *)bytes;
+
+  // Collect the data.
+  do {
+    // update what we're passing in
+    strm.avail_out = kChunkSize;
+    strm.next_out = output;
+    retCode = deflate(&strm, Z_FINISH);
+    if ((retCode != Z_OK) && (retCode != Z_STREAM_END)) {
+      if (error) {
+        NSDictionary *userInfo = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:retCode]
+                                                             forKey:GULNSDataZlibErrorKey];
+        *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain
+                                     code:GULNSDataZlibErrorInternal
+                                 userInfo:userInfo];
+      }
+      deflateEnd(&strm);
+      return nil;
+    }
+    // Collect what we got.
+    unsigned gotBack = kChunkSize - strm.avail_out;
+    if (gotBack > 0) {
+      [result appendBytes:output length:gotBack];
+    }
+
+  } while (retCode == Z_OK);
+
+  // If the loop exits, it used all input and the stream ended.
+  NSAssert(strm.avail_in == 0,
+           @"Should have finished deflating without using all input, %u bytes left", strm.avail_in);
+  NSAssert(retCode == Z_STREAM_END,
+           @"thought we finished deflate w/o getting a result of stream end, code %d", retCode);
+
+  // Clean up.
+  deflateEnd(&strm);
+
+  return result;
+}
+
+@end