--- /dev/null
+package javajs.util;
+
+/**
+ * byte converter
+ *
+ *
+ * @author Bob Hanson hansonr@stolaf.edu
+ *
+ */
+public class BC {
+
+ public BC() {
+ // unnecessary to instantialize unless subclassed
+ }
+
+ public static float bytesToFloat(byte[] bytes, int j, boolean isBigEndian) throws Exception {
+ return intToFloat(bytesToInt(bytes, j, isBigEndian));
+ }
+
+ public static int bytesToShort(byte[] bytes, int j, boolean isBigEndian) {
+ int n = (isBigEndian ? (bytes[j + 1] & 0xff) | (bytes[j] & 0xff) << 8
+ : (bytes[j++] & 0xff) | (bytes[j++] & 0xff) << 8);
+ return (n > 0x7FFF ? n - 0x10000 : n);
+ }
+
+ public static int bytesToInt(byte[] bytes, int j, boolean isBigEndian) {
+ int n = (isBigEndian ? (bytes[j + 3] & 0xff) | (bytes[j + 2] & 0xff) << 8
+ | (bytes[j + 1] & 0xff) << 16 | (bytes[j] & 0xff) << 24
+ : (bytes[j++] & 0xff) | (bytes[j++] & 0xff) << 8
+ | (bytes[j++] & 0xff) << 16 | (bytes[j++] & 0xff) << 24);
+
+ return (/** @j2sNative (n|0) || */ n);
+// /**
+// * xxxxxxj2sNative
+// *
+// * return (n > 0x7FFFFFFF ? n - 0x100000000 : n);
+// *
+// */
+// {
+// return n;
+// }
+ }
+
+ public static int intToSignedInt(int n) {
+
+ return (/** @j2sNative n || */ n);
+
+// /**
+// * xxxxxxj2sNative
+// *
+// * return (n > 0x7FFFFFFF ? n - 0x100000000 : n);
+// *
+// */
+// {
+// return n;
+// }
+ }
+ public static float intToFloat(int x) throws Exception {
+
+// // see http://en.wikipedia.org/wiki/Binary32
+// //
+// // [sign] [8 bits power] [23 bits fraction]
+// // 0x80000000 0x7F800000 0x7FFFFF
+// //
+// // (untested)
+// if (x == 0)
+// return 0;
+// boolean isJS = /** xxxxxxj2sNative true | */false;
+//
+//
+// if (isJS) {
+// if (fracIEEE == null)
+// setFracIEEE();
+// int m = ((x & 0x7F800000) >> 23);
+// * return ((x & 0x80000000) == 0 ? 1 : -1) * o.shiftIEEE$D$I((x & 0x7FFFFF) | 0x800000, m - 149);
+//
+// }
+// /**
+// *
+// * xxxxxxj2sNative
+// *
+// * if (x == 0) return 0;
+// * var o = javajs.util.BC;
+// * if (o.fracIEEE$ == null)
+// * o.setFracIEEE$();
+// * var m = ((x & 0x7F800000) >> 23);
+// * return ((x & 0x80000000) == 0 ? 1 : -1) * o.shiftIEEE$D$I((x & 0x7FFFFF) | 0x800000, m - 149);
+// *
+// */
+// {
+ return Float.intBitsToFloat(x);
+ // }
+ }
+
+ /**
+ * see http://en.wikipedia.org/wiki/Binary64
+ *
+ * not concerning ourselves with very small or very large numbers and getting
+ * this exactly right. Just need a float here.
+ *
+ * @param bytes
+ * @param j
+ * @param isBigEndian
+ * @return float
+ */
+ public static float bytesToDoubleToFloat(byte[] bytes, int j, boolean isBigEndian) {
+ {
+ // IEEE754: sign (1 bit), exponent (11 bits), fraction (52 bits).
+ // seeeeeee eeeeffff ffffffff ffffffff ffffffff xxxxxxxx xxxxxxxx xxxxxxxx
+ // b1 b2 b3 b4 b5 ---------float ignores----
+
+ if (fracIEEE == null)
+ setFracIEEE();
+
+ /**
+ * @j2sNative
+ * var b1, b2, b3, b4, b5;
+ *
+ * if (isBigEndian) {
+ * b1 = bytes[j] & 0xFF;
+ * b2 = bytes[j + 1] & 0xFF;
+ * b3 = bytes[j + 2] & 0xFF;
+ * b4 = bytes[j + 3] & 0xFF;
+ * b5 = bytes[j + 4] & 0xFF;
+ * } else {
+ * b1 = bytes[j + 7] & 0xFF;
+ * b2 = bytes[j + 6] & 0xFF;
+ * b3 = bytes[j + 5] & 0xFF;
+ * b4 = bytes[j + 4] & 0xFF;
+ * b5 = bytes[j + 3] & 0xFF;
+ * }
+ * var s = ((b1 & 0x80) == 0 ? 1 : -1);
+ * var e = (((b1 & 0x7F) << 4) | (b2 >> 4)) - 1026;
+ * b2 = (b2 & 0xF) | 0x10;
+ * return s * (C$.shiftIEEE$D$I(b2, e) +C$.shiftIEEE$D$I(b3, e - 8) + C$.shiftIEEE$D$I(b4, e - 16)
+ * + C$.shiftIEEE$D$I(b5, e - 24));
+ */
+ {
+ double d;
+
+ if (isBigEndian)
+ d = Double.longBitsToDouble((((long) bytes[j]) & 0xff) << 56
+ | (((long) bytes[j + 1]) & 0xff) << 48
+ | (((long) bytes[j + 2]) & 0xff) << 40
+ | (((long) bytes[j + 3]) & 0xff) << 32
+ | (((long) bytes[j + 4]) & 0xff) << 24
+ | (((long) bytes[j + 5]) & 0xff) << 16
+ | (((long) bytes[j + 6]) & 0xff) << 8
+ | (((long) bytes[7]) & 0xff));
+ else
+ d = Double.longBitsToDouble((((long) bytes[j + 7]) & 0xff) << 56
+ | (((long) bytes[j + 6]) & 0xff) << 48
+ | (((long) bytes[j + 5]) & 0xff) << 40
+ | (((long) bytes[j + 4]) & 0xff) << 32
+ | (((long) bytes[j + 3]) & 0xff) << 24
+ | (((long) bytes[j + 2]) & 0xff) << 16
+ | (((long) bytes[j + 1]) & 0xff) << 8
+ | (((long) bytes[j]) & 0xff));
+ return (float) d;
+ }
+
+ }
+ }
+
+ private static float[] fracIEEE;
+
+ private static void setFracIEEE() {
+ fracIEEE = new float[270];
+ for (int i = 0; i < 270; i++)
+ fracIEEE[i] = (float) Math.pow(2, i - 141);
+ // System.out.println(fracIEEE[0] + " " + Parser.FLOAT_MIN_SAFE);
+ // System.out.println(fracIEEE[269] + " " + Float.MAX_VALUE);
+ }
+
+ /**
+ * only concerned about reasonable float values here -- private but not designated; called by JavaScript
+ *
+ * @param f
+ * @param i
+ * @return f * 2^i
+ */
+ static double shiftIEEE(double f, int i) {
+ if (f == 0 || i < -140)
+ return 0;
+ if (i > 128)
+ return Float.MAX_VALUE;
+ return f * fracIEEE[i + 140];
+ }
+
+// static {
+// setFracIEEE();
+// for (int i = -50; i < 50; i++) {
+// float f = i * (float) (Math.random() * Math.pow(2, Math.random() * 100 - 50));
+// int x = Float.floatToIntBits(f);
+// int m = ((x & 0x7F800000) >> 23);
+// float f1 = (float) (f == 0 ? 0 : ((x & 0x80000000) == 0 ? 1 : -1) * shiftIEEE((x & 0x7FFFFF) | 0x800000, m - 149));
+// System.out.println(f + " " + f1);
+// }
+// System.out.println("binarydo");
+// }
+
+
+
+}
git://source.jalview.org / jalview.git / blobdiff