1 files changed, 382 insertions, 0 deletions
diff --git a/src/c/liberasurecode/src/builtin/xor_codes/xor_code.c b/src/c/liberasurecode/src/builtin/xor_codes/xor_code.c
new file mode 100644
index 0000000..3e7db21
--- /dev/null
+++ b/src/c/liberasurecode/src/builtin/xor_codes/xor_code.c
@@ -0,0 +1,382 @@
+/* * Copyright (c) 2013, Kevin Greenan (kmgreen2@gmail.com)
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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 <emmintrin.h>  //SSE2
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include "xor_code.h"
+
+const int g_bit_lookup[] = {0x1, 0x2, 0x4, 0x8,
+                                 0x10, 0x20, 0x40, 0x80,
+                                 0x100, 0x200, 0x400, 0x800,
+                                 0x1000, 0x2000, 0x4000, 0x8000,
+                                 0x10000, 0x20000, 0x40000, 0x80000,
+                                 0x100000, 0x200000, 0x400000, 0x800000,
+                                 0x1000000, 0x2000000, 0x4000000, 0x8000000,
+                                 0x10000000, 0x20000000, 0x40000000, 0x80000000};
+
+int is_data_in_parity(int data_idx, unsigned int parity_bm)
+{
+  return ((g_bit_lookup[data_idx] & parity_bm) == g_bit_lookup[data_idx]);
+}
+
+int does_parity_have_data(int parity_idx, unsigned int data_bm)
+{
+  return ((g_bit_lookup[parity_idx] & data_bm) == g_bit_lookup[parity_idx]);
+}
+
+int parity_bit_lookup(xor_code_t *code_desc, int index)
+{
+  return g_bit_lookup[code_desc->k - index];
+}
+
+int data_bit_lookup(xor_code_t *code_desc, int index)
+{
+  return g_bit_lookup[index];
+}
+
+int missing_elements_bm(xor_code_t *code_desc, int *missing_elements, int (*bit_lookup_func)(xor_code_t *code_desc, int index))
+{
+  int i = 0;
+  int bm = 0;
+
+  while (missing_elements[i] > -1) {
+    bm |= bit_lookup_func(code_desc, missing_elements[i]);
+    i++;
+  }
+
+  return bm;
+}
+
+failure_pattern_t get_failure_pattern(xor_code_t *code_desc, int *missing_idxs)
+{
+  int i = 0;
+  int num_failures = 0;
+  failure_pattern_t pattern = FAIL_PATTERN_0D_0P;
+
+  while (missing_idxs[i] > -1) {
+    if (num_failures >= code_desc->hd) {
+      pattern = FAIL_PATTERN_GE_HD;
+    }
+    switch(pattern) {
+      case FAIL_PATTERN_0D_0P:
+        pattern = (missing_idxs[i] < code_desc->k) ? FAIL_PATTERN_1D_0P : FAIL_PATTERN_0D_1P;
+        break;
+      case FAIL_PATTERN_1D_0P:
+        pattern = (missing_idxs[i] < code_desc->k) ? FAIL_PATTERN_2D_0P : FAIL_PATTERN_1D_1P;
+        break;
+      case FAIL_PATTERN_2D_0P:
+        pattern = (missing_idxs[i] < code_desc->k) ? FAIL_PATTERN_3D_0P : FAIL_PATTERN_2D_1P;
+        break;
+      case FAIL_PATTERN_3D_0P:
+        pattern = FAIL_PATTERN_GE_HD;
+        break;
+      case FAIL_PATTERN_1D_1P:
+        pattern = (missing_idxs[i] < code_desc->k) ? FAIL_PATTERN_2D_1P : FAIL_PATTERN_1D_2P;
+        break;
+      case FAIL_PATTERN_1D_2P:
+        pattern = FAIL_PATTERN_GE_HD;
+        break;
+      case FAIL_PATTERN_2D_1P:
+        pattern = FAIL_PATTERN_GE_HD;
+        break;
+      case FAIL_PATTERN_0D_1P:
+        pattern = (missing_idxs[i] < code_desc->k) ? FAIL_PATTERN_1D_1P : FAIL_PATTERN_0D_2P;
+        break;
+      case FAIL_PATTERN_0D_2P:
+        pattern = (missing_idxs[i] < code_desc->k) ? FAIL_PATTERN_1D_2P : FAIL_PATTERN_0D_3P;
+        break;
+      case FAIL_PATTERN_0D_3P:
+        pattern = FAIL_PATTERN_GE_HD;
+        break;
+      case FAIL_PATTERN_GE_HD:
+      default:
+        break;
+    }
+    if (pattern == FAIL_PATTERN_GE_HD) {
+      break;
+    }
+    i++;
+  }
+
+  return pattern;
+}
+
+void fast_memcpy(char *dst, char *src, int size)
+{
+    // Use _mm_stream_si128((__m128i*) _buf2, sum);
+    memcpy(dst, src, size);
+}
+
+/*
+ * Buffers must be aligned to 16-byte boundaries
+ *
+ * Store in buf2 (opposite of memcpy convention...  Maybe change?)
+ */
+void xor_bufs_and_store(char *buf1, char *buf2, int blocksize)
+{
+#ifdef INTEL_SSE2
+  int residual_bytes = num_unaligned_end(blocksize);
+  int fast_blocksize = blocksize > residual_bytes ? (blocksize - residual_bytes) : 0;
+  int fast_int_blocksize = fast_blocksize / sizeof(__m128i);
+  int i;
+  __m128i *_buf1 = (__m128i*)buf1;
+  __m128i *_buf2 = (__m128i*)buf2;
+
+  /*
+   * XOR aligned region using 128-bit XOR
+   */
+  for (i=0; i < fast_int_blocksize; i++) {
+    _buf2[i] = _mm_xor_si128(_buf1[i], _buf2[i]);
+  }
+#else
+  int residual_bytes = num_unaligned_end(blocksize);
+  int fast_blocksize = blocksize > residual_bytes ? (blocksize - residual_bytes) : 0;
+  int fast_int_blocksize = fast_blocksize / sizeof(unsigned long);
+  int i;
+
+  unsigned long*_buf1 = (unsigned long*)buf1;
+  unsigned long*_buf2 = (unsigned long*)buf2;
+
+  for (i=0; i < fast_int_blocksize; i++) {
+    _buf2[i] = _buf1[i] ^ _buf2[i];
+  }
+#endif
+
+  /*
+   * XOR unaligned end of region
+   */
+  for (i=fast_blocksize; i < blocksize; i++)
+  {
+    buf2[i] ^= buf1[i];
+  }
+}
+
+void xor_code_encode(xor_code_t *code_desc, char **data, char **parity, int blocksize)
+{
+  int i, j;
+
+  for (i=0; i < code_desc->k; i++) {
+    for (j=0; j < code_desc->m; j++) {
+      if (is_data_in_parity(i, code_desc->parity_bms[j])) {
+        xor_bufs_and_store(data[i], parity[j], blocksize);
+      }
+    }
+  }
+}
+
+void selective_encode(xor_code_t *code_desc, char **data, char **parity, int *missing_parity, int blocksize)
+{
+  int i;
+  for (i=0; i < code_desc->k; i++) {
+    int j=0;
+    while (missing_parity[j] > -1) {
+      int parity_index = missing_parity[j] - code_desc->k;
+      if (is_data_in_parity(i, code_desc->parity_bms[parity_index])) {
+        xor_bufs_and_store(data[i], parity[parity_index], blocksize);
+      }
+      j++;
+    }
+  }
+}
+
+int * get_missing_parity(xor_code_t *code_desc, int *missing_idxs)
+{
+  int *missing_parity = (int*)malloc(sizeof(int)*MAX_PARITY);
+  int i = 0, j = 0;
+
+  while (missing_idxs[i] > -1) {
+    if (missing_idxs[i] >= code_desc->k) {
+      missing_parity[j] = missing_idxs[i];
+      j++;
+    }
+    i++;
+  }
+
+  missing_parity[j] = -1;
+  return missing_parity;
+}
+
+int * get_missing_data(xor_code_t *code_desc, int *missing_idxs)
+{
+  int *missing_data = (int*)malloc(sizeof(int)*MAX_DATA);
+  int i = 0, j = 0;
+
+  while (missing_idxs[i] > -1) {
+    if (missing_idxs[i] < code_desc->k) {
+      missing_data[j] = missing_idxs[i];
+      j++;
+    }
+    i++;
+  }
+
+  missing_data[j] = -1;
+  return missing_data;
+}
+
+/*
+ * Reconstruct a single missing symbol, given other symbols may be missing
+ */
+void xor_reconstruct_one(xor_code_t *code_desc, char **data, char **parity, int *missing_idxs, int index_to_reconstruct, int blocksize)
+{
+  int *missing_data = get_missing_data(code_desc, missing_idxs);
+  int *missing_parity = get_missing_parity(code_desc, missing_idxs);
+  int i;
+
+  // If it is a data symbol, we need to figure out
+  // what data+parity symbols are needed to reconstruct
+  // If there is not at least one parity equation with
+  // one missing data element (the index to resonstruct),
+  // just call the underlying decode function
+  if (index_to_reconstruct < code_desc->k) {
+    int connected_parity_idx = index_of_connected_parity(code_desc, index_to_reconstruct, missing_parity, missing_data);
+
+    if (connected_parity_idx >= 0) {
+      // Can do a cheap reoncstruction!
+      int relative_parity_idx = connected_parity_idx - code_desc->k;
+      int parity_bm = code_desc->parity_bms[relative_parity_idx];
+
+      fast_memcpy(data[index_to_reconstruct], parity[relative_parity_idx], blocksize);
+
+      for (i=0; i < code_desc->k; i++) {
+        if (parity_bm & (1 << i)) {
+          if (i != index_to_reconstruct) {
+            xor_bufs_and_store(data[i], data[index_to_reconstruct], blocksize);
+          }
+        }
+      }
+
+    } else {
+      // Just call decode
+      code_desc->decode(code_desc, data, parity, missing_idxs, blocksize, 1);
+    }
+
+  } else {
+
+    // If it is a parity symbol, we need to figure out
+    // what data symbols are needed to reconstruct the
+    // parity.  If *any* data symbols in the parity
+    // equation are missing, we are better off calling
+    // the underlying decode function.
+    int num_data_missing = num_missing_data_in_parity(code_desc, index_to_reconstruct, missing_data);
+
+    if (num_data_missing == 0) {
+      int relative_parity_idx = index_to_reconstruct - code_desc->k;
+      int parity_bm = code_desc->parity_bms[relative_parity_idx];
+
+      memset(parity[relative_parity_idx], 0, blocksize);
+
+      for (i=0; i < code_desc->k; i++) {
+        if (parity_bm & (1 << i)) {
+          xor_bufs_and_store(data[i], parity[relative_parity_idx], blocksize);
+        }
+      }
+
+    } else {
+      // Just call decode
+      code_desc->decode(code_desc, data, parity, missing_idxs, blocksize, 1);
+    }
+  }
+  free(missing_data);
+  free(missing_parity);
+}
+
+int num_missing_data_in_parity(xor_code_t *code_desc, int parity_idx, int *missing_data)
+{
+  int i = 0;
+  int num_missing_data = 0;
+  int relative_parity_index = parity_idx - code_desc->k;
+  if (missing_data == NULL) {
+    return 0;
+  }
+
+  while (missing_data[i] > -1) {
+    if (does_parity_have_data(relative_parity_index, code_desc->data_bms[missing_data[i]]) > 0) {
+      num_missing_data++;
+    }
+    i++;
+  }
+
+  return num_missing_data;
+}
+
+int index_of_connected_parity(xor_code_t *code_desc, int data_index, int *missing_parity, int *missing_data)
+{
+  int parity_index = -1;
+  int i;
+
+  for (i=0; i < code_desc->m; i++) {
+    if (num_missing_data_in_parity(code_desc, i + code_desc->k, missing_data) > 1) {
+      continue;
+    }
+    if (is_data_in_parity(data_index, code_desc->parity_bms[i])) {
+      int j=0;
+      int is_missing = 0;
+      if (missing_parity == NULL) {
+        parity_index = i;
+        break;
+      }
+      while (missing_parity[j] > -1) {
+        if ((code_desc->k + i) == missing_parity[j]) {
+          is_missing = 1;
+          break;
+        }
+        j++;
+      }
+      if (!is_missing) {
+        parity_index = i;
+        break;
+      }
+    }
+  }
+
+  // Must add k to get the absolute
+  // index of the parity in the stripe
+  return parity_index > -1 ? parity_index + code_desc->k : parity_index;
+}
+
+void remove_from_missing_list(int element, int *missing_list)
+{
+  int i = 0;
+  int elem_idx = -1;
+  int num_elems = 0;
+
+  while (missing_list[i] > -1) {
+    if (missing_list[i] == element) {
+      elem_idx = i;
+      missing_list[i] = -1;
+    }
+    i++;
+  }
+
+  num_elems = i;
+
+  for (i=elem_idx;i < num_elems-1;i++) {
+    int tmp = missing_list[i+1];
+    missing_list[i+1] = missing_list[i];
+    missing_list[i] = tmp;
+  }
+}