/*
 *
 * Copyright 2015, Google Inc.
 * 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.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * 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
 * OWNER 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 "test/core/util/slice_splitter.h"

#include <string.h>

#include <grpc/support/alloc.h>
#include <grpc/support/useful.h>

const char *grpc_slice_split_mode_name(grpc_slice_split_mode mode) {
  switch (mode) {
    case GRPC_SLICE_SPLIT_IDENTITY:
      return "identity";
    case GRPC_SLICE_SPLIT_MERGE_ALL:
      return "merge_all";
    case GRPC_SLICE_SPLIT_ONE_BYTE:
      return "one_byte";
  }
  return "error";
}

void grpc_split_slices(grpc_slice_split_mode mode, grpc_slice *src_slices,
                       size_t src_slice_count, grpc_slice **dst_slices,
                       size_t *dst_slice_count) {
  size_t i, j;
  size_t length;

  switch (mode) {
    case GRPC_SLICE_SPLIT_IDENTITY:
      *dst_slice_count = src_slice_count;
      *dst_slices = gpr_malloc(sizeof(grpc_slice) * src_slice_count);
      for (i = 0; i < src_slice_count; i++) {
        (*dst_slices)[i] = src_slices[i];
        grpc_slice_ref((*dst_slices)[i]);
      }
      break;
    case GRPC_SLICE_SPLIT_MERGE_ALL:
      *dst_slice_count = 1;
      length = 0;
      for (i = 0; i < src_slice_count; i++) {
        length += GPR_SLICE_LENGTH(src_slices[i]);
      }
      *dst_slices = gpr_malloc(sizeof(grpc_slice));
      **dst_slices = grpc_slice_malloc(length);
      length = 0;
      for (i = 0; i < src_slice_count; i++) {
        memcpy(GPR_SLICE_START_PTR(**dst_slices) + length,
               GPR_SLICE_START_PTR(src_slices[i]),
               GPR_SLICE_LENGTH(src_slices[i]));
        length += GPR_SLICE_LENGTH(src_slices[i]);
      }
      break;
    case GRPC_SLICE_SPLIT_ONE_BYTE:
      length = 0;
      for (i = 0; i < src_slice_count; i++) {
        length += GPR_SLICE_LENGTH(src_slices[i]);
      }
      *dst_slice_count = length;
      *dst_slices = gpr_malloc(sizeof(grpc_slice) * length);
      length = 0;
      for (i = 0; i < src_slice_count; i++) {
        for (j = 0; j < GPR_SLICE_LENGTH(src_slices[i]); j++) {
          (*dst_slices)[length] = grpc_slice_sub(src_slices[i], j, j + 1);
          length++;
        }
      }
      break;
  }
}

void grpc_split_slices_to_buffer(grpc_slice_split_mode mode,
                                 grpc_slice *src_slices, size_t src_slice_count,
                                 grpc_slice_buffer *dst) {
  grpc_slice *slices;
  size_t nslices;
  size_t i;
  grpc_split_slices(mode, src_slices, src_slice_count, &slices, &nslices);
  for (i = 0; i < nslices; i++) {
    /* add indexed to avoid re-merging split slices */
    grpc_slice_buffer_add_indexed(dst, slices[i]);
  }
  gpr_free(slices);
}

void grpc_split_slice_buffer(grpc_slice_split_mode mode, grpc_slice_buffer *src,
                             grpc_slice_buffer *dst) {
  grpc_split_slices_to_buffer(mode, src->slices, src->count, dst);
}

grpc_slice grpc_slice_merge(grpc_slice *slices, size_t nslices) {
  uint8_t *out = NULL;
  size_t length = 0;
  size_t capacity = 0;
  size_t i;

  for (i = 0; i < nslices; i++) {
    if (GPR_SLICE_LENGTH(slices[i]) + length > capacity) {
      capacity = GPR_MAX(capacity * 2, GPR_SLICE_LENGTH(slices[i]) + length);
      out = gpr_realloc(out, capacity);
    }
    memcpy(out + length, GPR_SLICE_START_PTR(slices[i]),
           GPR_SLICE_LENGTH(slices[i]));
    length += GPR_SLICE_LENGTH(slices[i]);
  }

  return grpc_slice_new(out, length, gpr_free);
}