fix: implementations of FromHexString() for md5 and crc32c (#246)

Author: frankyn

google-cloud-storage/src/main/java/com/google/cloud/storage/BlobInfo.java

@@ -34,8 +34,8 @@
 import com.google.common.io.BaseEncoding;
 import java.io.Serializable;
 import java.math.BigInteger;
+import java.nio.ByteBuffer;
 import java.util.AbstractMap;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
@@ -232,6 +232,7 @@ public abstract static class Builder {
  *
  * @see <a href="https://cloud.google.com/storage/docs/hashes-etags#_JSONAPI">Hashes and ETags:
  * Best Practices</a>
+ * @throws IllegalArgumentException when given an invalid hexadecimal value.
  */
  public abstract Builder setMd5FromHexString(String md5HexString);
 
@@ -252,6 +253,7 @@ public abstract static class Builder {
  *
  * @see <a href="https://cloud.google.com/storage/docs/hashes-etags#_JSONAPI">Hashes and ETags:
  * Best Practices</a>
+ * @throws IllegalArgumentException when given an invalid hexadecimal value.
  */
  public abstract Builder setCrc32cFromHexString(String crc32cHexString);
 
@@ -293,7 +295,7 @@ public abstract static class Builder {
  }
 
  static final class BuilderImpl extends Builder {
-
+ private final String hexDecimalValues = "0123456789abcdef";
  private BlobId blobId;
  private String generatedId;
  private String contentType;
@@ -442,16 +444,27 @@ public Builder setMd5(String md5) {
  return this;
  }
 
+ @Override
  public Builder setMd5FromHexString(String md5HexString) {
  if (md5HexString == null) {
  return this;
  }
- byte[] bytes = new BigInteger(md5HexString, 16).toByteArray();
- int leadingEmptyBytes = bytes.length - md5HexString.length() / 2;
- if (leadingEmptyBytes > 0) {
- bytes = Arrays.copyOfRange(bytes, leadingEmptyBytes, bytes.length);
+ if (md5HexString.length() % 2 != 0) {
+ throw new IllegalArgumentException(
+ "each byte must be represented by 2 valid hexadecimal characters");
+ }
+ String md5HexStringLower = md5HexString.toLowerCase();
+ ByteBuffer md5ByteBuffer = ByteBuffer.allocate(md5HexStringLower.length() / 2);
+ for (int charIndex = 0; charIndex < md5HexStringLower.length(); charIndex += 2) {
+ int higherOrderBits = this.hexDecimalValues.indexOf(md5HexStringLower.charAt(charIndex));
+ int lowerOrderBits = this.hexDecimalValues.indexOf(md5HexStringLower.charAt(charIndex + 1));
+ if (higherOrderBits == -1 || lowerOrderBits == -1) {
+ throw new IllegalArgumentException(
+ "each byte must be represented by 2 valid hexadecimal characters");
+ }
+ md5ByteBuffer.put((byte) (higherOrderBits << 4 | lowerOrderBits));
  }
- this.md5 = BaseEncoding.base64().encode(bytes);
+ this.md5 = BaseEncoding.base64().encode(md5ByteBuffer.array());
  return this;
  }
 
@@ -466,12 +479,23 @@ public Builder setCrc32cFromHexString(String crc32cHexString) {
  if (crc32cHexString == null) {
  return this;
  }
- byte[] bytes = new BigInteger(crc32cHexString, 16).toByteArray();
- int leadingEmptyBytes = bytes.length - crc32cHexString.length() / 2;
- if (leadingEmptyBytes > 0) {
- bytes = Arrays.copyOfRange(bytes, leadingEmptyBytes, bytes.length);
+ if (crc32cHexString.length() % 2 != 0) {
+ throw new IllegalArgumentException(
+ "each byte must be represented by 2 valid hexadecimal characters");
+ }
+ String crc32cHexStringLower = crc32cHexString.toLowerCase();
+ ByteBuffer crc32cByteBuffer = ByteBuffer.allocate(crc32cHexStringLower.length() / 2);
+ for (int charIndex = 0; charIndex < crc32cHexStringLower.length(); charIndex += 2) {
+ int higherOrderBits = this.hexDecimalValues.indexOf(crc32cHexStringLower.charAt(charIndex));
+ int lowerOrderBits =
+ this.hexDecimalValues.indexOf(crc32cHexStringLower.charAt(charIndex + 1));
+ if (higherOrderBits == -1 || lowerOrderBits == -1) {
+ throw new IllegalArgumentException(
+ "each byte must be represented by 2 valid hexadecimal characters");
+ }
+ crc32cByteBuffer.put((byte) (higherOrderBits << 4 | lowerOrderBits));
  }
- this.crc32c = BaseEncoding.base64().encode(bytes);
+ this.crc32c = BaseEncoding.base64().encode(crc32cByteBuffer.array());
  return this;
  }
 

google-cloud-storage/src/test/java/com/google/cloud/storage/BlobInfoTest.java

@@ -49,12 +49,16 @@ public class BlobInfoTest {
  private static final String CONTENT_LANGUAGE = "En";
  private static final String CRC32 = "FF00";
  private static final String CRC32_HEX_STRING = "145d34";
+ private static final String CRC32_HEX_STRING_LEADING_ZEROS = "005d34";
+ private static final String CRC32_BASE64_LEADING_ZEROS = "AF00";
  private static final Long DELETE_TIME = System.currentTimeMillis();
  private static final String ETAG = "0xFF00";
  private static final Long GENERATION = 1L;
  private static final String GENERATED_ID = "B/N:1";
  private static final String MD5 = "FF00";
  private static final String MD5_HEX_STRING = "145d34";
+ private static final String MD5_HEX_STRING_LEADING_ZEROS = "0006a7de52b4e0b82602ce09809523ca";
+ private static final String MD5_BASE64_LEADING_ZEROS = "AAan3lK04LgmAs4JgJUjyg==";
  private static final String MEDIA_LINK = "http://media/b/n";
  private static final Map<String, String> METADATA = ImmutableMap.of("n1", "v1", "n2", "v2");
  private static final Long META_GENERATION = 10L;
@@ -132,13 +136,31 @@ public void testToBuilderSetMd5FromHexString() {
  assertEquals(MD5, blobInfo.getMd5());
  }
 
+ @Test
+ public void testToBuilderSetMd5FromHexStringLeadingZeros() {
+ BlobInfo blobInfo =
+ BlobInfo.newBuilder(BlobId.of("b2", "n2"))
+ .setMd5FromHexString(MD5_HEX_STRING_LEADING_ZEROS)
+ .build();
+ assertEquals(MD5_BASE64_LEADING_ZEROS, blobInfo.getMd5());
+ }
+
  @Test
  public void testToBuilderSetCrc32cFromHexString() {
  BlobInfo blobInfo =
  BlobInfo.newBuilder(BlobId.of("b2", "n2")).setCrc32cFromHexString(CRC32_HEX_STRING).build();
  assertEquals(CRC32, blobInfo.getCrc32c());
  }
 
+ @Test
+ public void testToBuilderSetCrc32cFromHexStringLeadingZeros() {
+ BlobInfo blobInfo =
+ BlobInfo.newBuilder(BlobId.of("b2", "n2"))
+ .setCrc32cFromHexString(CRC32_HEX_STRING_LEADING_ZEROS)
+ .build();
+ assertEquals(CRC32_BASE64_LEADING_ZEROS, blobInfo.getCrc32c());
+ }
+
  @Test
  public void testToBuilderIncomplete() {
  BlobInfo incompleteBlobInfo = BlobInfo.newBuilder(BlobId.of("b2", "n2")).build();