// Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.

//

// 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

//

//     https://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.

#include <openssl/bio.h>

#include <limits.h>

#include <string.h>

#include "../internal.h"

namespace {

// hexdump_ctx contains the state of a hexdump.

struct hexdump_ctx {

  BIO *bio;

  char right_chars[18];  // the contents of the right-hand side, ASCII dump.

  unsigned used;         // number of bytes in the current line.

  size_t n;              // number of bytes total.

  unsigned indent;

};

}  // namespace

static void hexbyte(char *out, uint8_t b) {

  static const char hextable[] = "0123456789abcdef";

  out[0] = hextable[b >> 4];

  out[1] = hextable[b & 0x0f];

}

static char to_char(uint8_t b) {

  if (b < 32 || b > 126) {

    return '.';

  }

  return b;

}

// hexdump_write adds |len| bytes of |data| to the current hex dump described by

// |ctx|.

static int hexdump_write(struct hexdump_ctx *ctx, const uint8_t *data,

                         size_t len) {

  char buf[10];

  unsigned l;

  // Output lines look like:

  // 00000010  2e 2f 30 31 32 33 34 35  36 37 38 ... 3c 3d // |./0123456789:;<=|

  // ^ offset                          ^ extra space           ^ ASCII of line

  for (size_t i = 0; i < len; i++) {

    if (ctx->used == 0) {

      // The beginning of a line.

      BIO_indent(ctx->bio, ctx->indent, UINT_MAX);

      hexbyte(&buf[0], ctx->n >> 24);

      hexbyte(&buf[2], ctx->n >> 16);

      hexbyte(&buf[4], ctx->n >> 8);

      hexbyte(&buf[6], ctx->n);

      buf[8] = buf[9] = ' ';

      if (BIO_write(ctx->bio, buf, 10) < 0) {

        return 0;

      }

    }

    hexbyte(buf, data[i]);

    buf[2] = ' ';

    l = 3;

    if (ctx->used == 7) {

      // There's an additional space after the 8th byte.

      buf[3] = ' ';

      l = 4;

    } else if (ctx->used == 15) {

      // At the end of the line there's an extra space and the bar for the

      // right column.

      buf[3] = ' ';

      buf[4] = '|';

      l = 5;

    }

    if (BIO_write(ctx->bio, buf, l) < 0) {

      return 0;

    }

    ctx->right_chars[ctx->used] = to_char(data[i]);

    ctx->used++;

    ctx->n++;

    if (ctx->used == 16) {

      ctx->right_chars[16] = '|';

      ctx->right_chars[17] = '\n';

      if (BIO_write(ctx->bio, ctx->right_chars, sizeof(ctx->right_chars)) < 0) {

        return 0;

      }

      ctx->used = 0;

    }

  }

  return 1;

}

// finish flushes any buffered data in |ctx|.

static int finish(struct hexdump_ctx *ctx) {

  // See the comments in |hexdump| for the details of this format.

  const unsigned n_bytes = ctx->used;

  unsigned l;

  char buf[5];

  if (n_bytes == 0) {

    return 1;

  }

  OPENSSL_memset(buf, ' ', 4);

  buf[4] = '|';

  for (; ctx->used < 16; ctx->used++) {

    l = 3;

    if (ctx->used == 7) {

      l = 4;

    } else if (ctx->used == 15) {

      l = 5;

    }

    if (BIO_write(ctx->bio, buf, l) < 0) {

      return 0;

    }

  }

  ctx->right_chars[n_bytes] = '|';

  ctx->right_chars[n_bytes + 1] = '\n';

  if (BIO_write(ctx->bio, ctx->right_chars, n_bytes + 2) < 0) {

    return 0;

  }

  return 1;

}

int BIO_hexdump(BIO *bio, const uint8_t *data, size_t len, unsigned indent) {

  struct hexdump_ctx ctx;

  OPENSSL_memset(&ctx, 0, sizeof(ctx));

  ctx.bio = bio;

  ctx.indent = indent;

  if (!hexdump_write(&ctx, data, len) || !finish(&ctx)) {

    return 0;

  }

  return 1;

}