1 files changed, 276 insertions, 0 deletions
diff --git a/Modules/_decimal/libmpdec/transpose.c b/Modules/_decimal/libmpdec/transpose.c
new file mode 100644
index 0000000000..55d6d89922
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+++ b/Modules/_decimal/libmpdec/transpose.c
@@ -0,0 +1,276 @@
+/*
+ * Copyright (c) 2008-2016 Stefan Krah. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+
+#include "mpdecimal.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <assert.h>
+#include "bits.h"
+#include "constants.h"
+#include "typearith.h"
+#include "transpose.h"
+
+
+#define BUFSIZE 4096
+#define SIDE 128
+
+
+/* Bignum: The transpose functions are used for very large transforms
+   in sixstep.c and fourstep.c. */
+
+
+/* Definition of the matrix transpose */
+void
+std_trans(mpd_uint_t dest[], mpd_uint_t src[], mpd_size_t rows, mpd_size_t cols)
+{
+    mpd_size_t idest, isrc;
+    mpd_size_t r, c;
+
+    for (r = 0; r < rows; r++) {
+        isrc = r * cols;
+        idest = r;
+        for (c = 0; c < cols; c++) {
+            dest[idest] = src[isrc];
+            isrc += 1;
+            idest += rows;
+        }
+    }
+}
+
+/*
+ * Swap half-rows of 2^n * (2*2^n) matrix.
+ * FORWARD_CYCLE: even/odd permutation of the halfrows.
+ * BACKWARD_CYCLE: reverse the even/odd permutation.
+ */
+static int
+swap_halfrows_pow2(mpd_uint_t *matrix, mpd_size_t rows, mpd_size_t cols, int dir)
+{
+    mpd_uint_t buf1[BUFSIZE];
+    mpd_uint_t buf2[BUFSIZE];
+    mpd_uint_t *readbuf, *writebuf, *hp;
+    mpd_size_t *done, dbits;
+    mpd_size_t b = BUFSIZE, stride;
+    mpd_size_t hn, hmax; /* halfrow number */
+    mpd_size_t m, r=0;
+    mpd_size_t offset;
+    mpd_size_t next;
+
+
+    assert(cols == mul_size_t(2, rows));
+
+    if (dir == FORWARD_CYCLE) {
+        r = rows;
+    }
+    else if (dir == BACKWARD_CYCLE) {
+        r = 2;
+    }
+    else {
+        abort(); /* GCOV_NOT_REACHED */
+    }
+
+    m = cols - 1;
+    hmax = rows; /* cycles start at odd halfrows */
+    dbits = 8 * sizeof *done;
+    if ((done = mpd_calloc(hmax/(sizeof *done) + 1, sizeof *done)) == NULL) {
+        return 0;
+    }
+
+    for (hn = 1; hn <= hmax; hn += 2) {
+
+        if (done[hn/dbits] & mpd_bits[hn%dbits]) {
+            continue;
+        }
+
+        readbuf = buf1; writebuf = buf2;
+
+        for (offset = 0; offset < cols/2; offset += b) {
+
+            stride = (offset + b < cols/2) ? b : cols/2-offset;
+
+            hp = matrix + hn*cols/2;
+            memcpy(readbuf, hp+offset, stride*(sizeof *readbuf));
+            pointerswap(&readbuf, &writebuf);
+
+            next = mulmod_size_t(hn, r, m);
+            hp = matrix + next*cols/2;
+
+            while (next != hn) {
+
+                memcpy(readbuf, hp+offset, stride*(sizeof *readbuf));
+                memcpy(hp+offset, writebuf, stride*(sizeof *writebuf));
+                pointerswap(&readbuf, &writebuf);
+
+                done[next/dbits] |= mpd_bits[next%dbits];
+
+                next = mulmod_size_t(next, r, m);
+                    hp = matrix + next*cols/2;
+
+            }
+
+            memcpy(hp+offset, writebuf, stride*(sizeof *writebuf));
+
+            done[hn/dbits] |= mpd_bits[hn%dbits];
+        }
+    }
+
+    mpd_free(done);
+    return 1;
+}
+
+/* In-place transpose of a square matrix */
+static inline void
+squaretrans(mpd_uint_t *buf, mpd_size_t cols)
+{
+    mpd_uint_t tmp;
+    mpd_size_t idest, isrc;
+    mpd_size_t r, c;
+
+    for (r = 0; r < cols; r++) {
+        c = r+1;
+        isrc = r*cols + c;
+        idest = c*cols + r;
+        for (c = r+1; c < cols; c++) {
+            tmp = buf[isrc];
+            buf[isrc] = buf[idest];
+            buf[idest] = tmp;
+            isrc += 1;
+            idest += cols;
+        }
+    }
+}
+
+/*
+ * Transpose 2^n * 2^n matrix. For cache efficiency, the matrix is split into
+ * square blocks with side length 'SIDE'. First, the blocks are transposed,
+ * then a square transposition is done on each individual block.
+ */
+static void
+squaretrans_pow2(mpd_uint_t *matrix, mpd_size_t size)
+{
+    mpd_uint_t buf1[SIDE*SIDE];
+    mpd_uint_t buf2[SIDE*SIDE];
+    mpd_uint_t *to, *from;
+    mpd_size_t b = size;
+    mpd_size_t r, c;
+    mpd_size_t i;
+
+    while (b > SIDE) b >>= 1;
+
+    for (r = 0; r < size; r += b) {
+
+        for (c = r; c < size; c += b) {
+
+            from = matrix + r*size + c;
+            to = buf1;
+            for (i = 0; i < b; i++) {
+                memcpy(to, from, b*(sizeof *to));
+                from += size;
+                to += b;
+            }
+            squaretrans(buf1, b);
+
+            if (r == c) {
+                to = matrix + r*size + c;
+                from = buf1;
+                for (i = 0; i < b; i++) {
+                    memcpy(to, from, b*(sizeof *to));
+                    from += b;
+                    to += size;
+                }
+                continue;
+            }
+            else {
+                from = matrix + c*size + r;
+                to = buf2;
+                for (i = 0; i < b; i++) {
+                    memcpy(to, from, b*(sizeof *to));
+                    from += size;
+                    to += b;
+                }
+                squaretrans(buf2, b);
+
+                to = matrix + c*size + r;
+                from = buf1;
+                for (i = 0; i < b; i++) {
+                    memcpy(to, from, b*(sizeof *to));
+                    from += b;
+                    to += size;
+                }
+
+                to = matrix + r*size + c;
+                from = buf2;
+                for (i = 0; i < b; i++) {
+                    memcpy(to, from, b*(sizeof *to));
+                    from += b;
+                    to += size;
+                }
+            }
+        }
+    }
+
+}
+
+/*
+ * In-place transposition of a 2^n x 2^n or a 2^n x (2*2^n)
+ * or a (2*2^n) x 2^n matrix.
+ */
+int
+transpose_pow2(mpd_uint_t *matrix, mpd_size_t rows, mpd_size_t cols)
+{
+    mpd_size_t size = mul_size_t(rows, cols);
+
+    assert(ispower2(rows));
+    assert(ispower2(cols));
+
+    if (cols == rows) {
+        squaretrans_pow2(matrix, rows);
+    }
+    else if (cols == mul_size_t(2, rows)) {
+        if (!swap_halfrows_pow2(matrix, rows, cols, FORWARD_CYCLE)) {
+            return 0;
+        }
+        squaretrans_pow2(matrix, rows);
+        squaretrans_pow2(matrix+(size/2), rows);
+    }
+    else if (rows == mul_size_t(2, cols)) {
+        squaretrans_pow2(matrix, cols);
+        squaretrans_pow2(matrix+(size/2), cols);
+        if (!swap_halfrows_pow2(matrix, cols, rows, BACKWARD_CYCLE)) {
+            return 0;
+        }
+    }
+    else {
+        abort(); /* GCOV_NOT_REACHED */
+    }
+
+    return 1;
+}
+
+