Initial

1 files changed, 142 insertions, 0 deletions

diff --git a/Firebase/Messaging/FIRMessagingCodedInputStream.m b/Firebase/Messaging/FIRMessagingCodedInputStream.m
new file mode 100644
index 0000000..82c0677
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+++ b/Firebase/Messaging/FIRMessagingCodedInputStream.m
@@ -0,0 +1,142 @@
+/*
+ * Copyright 2017 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 "FIRMessagingCodedInputStream.h"
+#import "FIRMessagingDefines.h"
+
+typedef struct {
+  const void *bytes;
+  size_t bufferSize;
+  size_t bufferPos;
+} BufferState;
+
+static BOOL CheckSize(BufferState *state, size_t size) {
+  size_t newSize = state->bufferPos + size;
+  if (newSize > state->bufferSize) {
+    return NO;
+  }
+  return YES;
+}
+
+static BOOL ReadRawByte(BufferState *state, int8_t *output) {
+  _FIRMessagingDevAssert(output != NULL && state != NULL, @"Invalid parameters");
+
+  if (CheckSize(state, sizeof(int8_t))) {
+    *output = ((int8_t *)state->bytes)[state->bufferPos++];
+    return YES;
+  }
+  return NO;
+}
+
+static BOOL ReadRawVarInt32(BufferState *state, int32_t *output) {
+  _FIRMessagingDevAssert(output != NULL && state != NULL, @"Invalid parameters");
+
+  int8_t tmp = 0;
+  if (!ReadRawByte(state, &tmp)) {
+    return NO;
+  }
+  if (tmp >= 0) {
+    *output = tmp;
+    return YES;
+  }
+  int32_t result = tmp & 0x7f;
+  if (!ReadRawByte(state, &tmp)) {
+    return NO;
+  }
+  if (tmp >= 0) {
+    result |= tmp << 7;
+  } else {
+    result |= (tmp & 0x7f) << 7;
+    if (!ReadRawByte(state, &tmp)) {
+      return NO;
+    }
+    if (tmp >= 0) {
+      result |= tmp << 14;
+    } else {
+      result |= (tmp & 0x7f) << 14;
+      if (!ReadRawByte(state, &tmp)) {
+        return NO;
+      }
+      if (tmp >= 0) {
+        result |= tmp << 21;
+      } else {
+        result |= (tmp & 0x7f) << 21;
+        if (!ReadRawByte(state, &tmp)) {
+          return NO;
+        }
+        result |= tmp << 28;
+        if (tmp < 0) {
+          // Discard upper 32 bits.
+          for (int i = 0; i < 5; ++i) {
+            if (!ReadRawByte(state, &tmp)) {
+              return NO;
+            }
+            if (tmp >= 0) {
+              *output = result;
+              return YES;
+            }
+          }
+          return NO;
+        }
+      }
+    }
+  }
+  *output = result;
+  return YES;
+}
+
+@interface FIRMessagingCodedInputStream()
+
+@property(nonatomic, readwrite, strong) NSData *buffer;
+@property(nonatomic, readwrite, assign) BufferState state;
+
+@end
+
+@implementation FIRMessagingCodedInputStream;
+
+- (instancetype)initWithData:(NSData *)data {
+  self = [super init];
+  if (self) {
+    _buffer = data;
+    _state.bytes = _buffer.bytes;
+    _state.bufferSize = _buffer.length;
+  }
+  return self;
+}
+
+- (size_t)offset {
+  return _state.bufferPos;
+}
+
+- (BOOL)readTag:(int8_t *)tag {
+  return ReadRawByte(&_state, tag);
+}
+
+- (BOOL)readLength:(int32_t *)length {
+  return ReadRawVarInt32(&_state, length);
+}
+
+- (NSData *)readDataWithLength:(uint32_t)length {
+  if (!CheckSize(&_state, length)) {
+    return nil;
+  }
+  const void *bytesToRead = _state.bytes + _state.bufferPos;
+  NSData *result = [NSData dataWithBytes:bytesToRead length:length];
+  _state.bufferPos += length;
+  return result;
+}
+
+@end