Begin porting qrcode

src/qrcode/decoder/mode.rs

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2007 ZXing authors
+ *
+ * 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.
+ */
+
+/**
+ * <p>See ISO 18004:2006, 6.4.1, Tables 2 and 3. This enum encapsulates the various modes in which
+ * data can be encoded to bits in the QR code standard.</p>
+ *
+ * @author Sean Owen
+ */
+public enum Mode {
+
+  TERMINATOR(new int[]{0, 0, 0}, 0x00), // Not really a mode...
+  NUMERIC(new int[]{10, 12, 14}, 0x01),
+  ALPHANUMERIC(new int[]{9, 11, 13}, 0x02),
+  STRUCTURED_APPEND(new int[]{0, 0, 0}, 0x03), // Not supported
+  BYTE(new int[]{8, 16, 16}, 0x04),
+  ECI(new int[]{0, 0, 0}, 0x07), // character counts don't apply
+  KANJI(new int[]{8, 10, 12}, 0x08),
+  FNC1_FIRST_POSITION(new int[]{0, 0, 0}, 0x05),
+  FNC1_SECOND_POSITION(new int[]{0, 0, 0}, 0x09),
+  /** See GBT 18284-2000; "Hanzi" is a transliteration of this mode name. */
+  HANZI(new int[]{8, 10, 12}, 0x0D);
+
+  private final int[] characterCountBitsForVersions;
+  private final int bits;
+
+  Mode(int[] characterCountBitsForVersions, int bits) {
+    this.characterCountBitsForVersions = characterCountBitsForVersions;
+    this.bits = bits;
+  }
+
+  /**
+   * @param bits four bits encoding a QR Code data mode
+   * @return Mode encoded by these bits
+   * @throws IllegalArgumentException if bits do not correspond to a known mode
+   */
+  public static Mode forBits(int bits) {
+    switch (bits) {
+      case 0x0:
+        return TERMINATOR;
+      case 0x1:
+        return NUMERIC;
+      case 0x2:
+        return ALPHANUMERIC;
+      case 0x3:
+        return STRUCTURED_APPEND;
+      case 0x4:
+        return BYTE;
+      case 0x5:
+        return FNC1_FIRST_POSITION;
+      case 0x7:
+        return ECI;
+      case 0x8:
+        return KANJI;
+      case 0x9:
+        return FNC1_SECOND_POSITION;
+      case 0xD:
+        // 0xD is defined in GBT 18284-2000, may not be supported in foreign country
+        return HANZI;
+      default:
+        throw new IllegalArgumentException();
+    }
+  }
+
+  /**
+   * @param version version in question
+   * @return number of bits used, in this QR Code symbol {@link Version}, to encode the
+   *         count of characters that will follow encoded in this Mode
+   */
+  public int getCharacterCountBits(Version version) {
+    int number = version.getVersionNumber();
+    int offset;
+    if (number <= 9) {
+      offset = 0;
+    } else if (number <= 26) {
+      offset = 1;
+    } else {
+      offset = 2;
+    }
+    return characterCountBitsForVersions[offset];
+  }
+
+  public int getBits() {
+    return bits;
+  }
+
+}