/*
   BLAKE2 reference source code package - b2sum tool
  
   Copyright 2012, Samuel Neves <sneves@dei.uc.pt>.  You may use this under the
   terms of the CC0, the OpenSSL Licence, or the Apache Public License 2.0, at
   your option.  The terms of these licenses can be found at:
  
   - CC0 1.0 Universal : http://creativecommons.org/publicdomain/zero/1.0
   - OpenSSL license   : https://www.openssl.org/source/license.html
   - Apache 2.0        : http://www.apache.org/licenses/LICENSE-2.0
  
   More information about the BLAKE2 hash function can be found at
   https://blake2.net.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>

#include <ctype.h>
#include <unistd.h>
#include <getopt.h>
#include <stdbool.h>

#include "blake2.h"

/* This will help compatibility with coreutils */
int blake2s_stream( FILE *stream, void *resstream, size_t outbytes )
{
  int ret = -1;
  size_t sum, n;
  blake2s_state S[1];
  static const size_t buffer_length = 32768;
  uint8_t *buffer = ( uint8_t * )malloc( buffer_length );

  if( !buffer ) return -1;

  blake2s_init( S, outbytes );

  while( 1 )
  {
    sum = 0;

    while( 1 )
    {
      n = fread( buffer + sum, 1, buffer_length - sum, stream );
      sum += n;

      if( buffer_length == sum )
        break;

      if( 0 == n )
      {
        if( ferror( stream ) )
          goto cleanup_buffer;

        goto final_process;
      }

      if( feof( stream ) )
        goto final_process;
    }

    blake2s_update( S, buffer, buffer_length );
  }

final_process:;

  if( sum > 0 ) blake2s_update( S, buffer, sum );

  blake2s_final( S, resstream, outbytes );
  ret = 0;
cleanup_buffer:
  free( buffer );
  return ret;
}

int blake2b_stream( FILE *stream, void *resstream, size_t outbytes )
{
  int ret = -1;
  size_t sum, n;
  blake2b_state S[1];
  static const size_t buffer_length = 32768;
  uint8_t *buffer = ( uint8_t * )malloc( buffer_length );

  if( !buffer ) return -1;

  blake2b_init( S, outbytes );

  while( 1 )
  {
    sum = 0;

    while( 1 )
    {
      n = fread( buffer + sum, 1, buffer_length - sum, stream );
      sum += n;

      if( buffer_length == sum )
        break;

      if( 0 == n )
      {
        if( ferror( stream ) )
          goto cleanup_buffer;

        goto final_process;
      }

      if( feof( stream ) )
        goto final_process;
    }

    blake2b_update( S, buffer, buffer_length );
  }

final_process:;

  if( sum > 0 ) blake2b_update( S, buffer, sum );

  blake2b_final( S, resstream, outbytes );
  ret = 0;
cleanup_buffer:
  free( buffer );
  return ret;
}

int blake2sp_stream( FILE *stream, void *resstream, size_t outbytes )
{
  int ret = -1;
  size_t sum, n;
  blake2sp_state S[1];
  static const size_t buffer_length = 16 * ( 1UL << 20 );
  uint8_t *buffer = ( uint8_t * )malloc( buffer_length );

  if( !buffer ) return -1;

  blake2sp_init( S, outbytes );

  while( 1 )
  {
    sum = 0;

    while( 1 )
    {
      n = fread( buffer + sum, 1, buffer_length - sum, stream );
      sum += n;

      if( buffer_length == sum )
        break;

      if( 0 == n )
      {
        if( ferror( stream ) )
          goto cleanup_buffer;

        goto final_process;
      }

      if( feof( stream ) )
        goto final_process;
    }

    blake2sp_update( S, buffer, buffer_length );
  }

final_process:;

  if( sum > 0 ) blake2sp_update( S, buffer, sum );

  blake2sp_final( S, resstream, outbytes );
  ret = 0;
cleanup_buffer:
  free( buffer );
  return ret;
}


int blake2bp_stream( FILE *stream, void *resstream, size_t outbytes )
{
  int ret = -1;
  size_t sum, n;
  blake2bp_state S[1];
  static const size_t buffer_length = 16 * ( 1UL << 20 );
  uint8_t *buffer = ( uint8_t * )malloc( buffer_length );

  if( !buffer ) return -1;

  blake2bp_init( S, outbytes );

  while( 1 )
  {
    sum = 0;

    while( 1 )
    {
      n = fread( buffer + sum, 1, buffer_length - sum, stream );
      sum += n;

      if( buffer_length == sum )
        break;

      if( 0 == n )
      {
        if( ferror( stream ) )
          goto cleanup_buffer;

        goto final_process;
      }

      if( feof( stream ) )
        goto final_process;
    }

    blake2bp_update( S, buffer, buffer_length );
  }

final_process:;

  if( sum > 0 ) blake2bp_update( S, buffer, sum );

  blake2bp_final( S, resstream, outbytes );
  ret = 0;
cleanup_buffer:
  free( buffer );
  return ret;
}

typedef int ( *blake2fn )( FILE *, void *, size_t );


static void usage( char **argv, int errcode )
{
  FILE *out = errcode ? stderr : stdout;
  fprintf( out, "Usage: %s [OPTION]... [FILE]...\n", argv[0] );
  fprintf( out, "\n" );
  fprintf( out, "With no FILE, or when FILE is -, read standard input.\n" );
  fprintf( out, "\n" );
  fprintf( out, "  -a <algo>    hash algorithm (blake2b is default): \n"
                "               [blake2b|blake2s|blake2bp|blake2sp]\n" );
  fprintf( out, "  -l <length>  digest length in bits, must not exceed the maximum for\n"
                "               the selected algorithm and must be a multiple of 8\n" );
  fprintf( out, "  --tag        create a BSD-style checksum\n" );
  fprintf( out, "  --help       display this help and exit\n" );
  exit( errcode );
}


int main( int argc, char **argv )
{
  blake2fn blake2_stream = blake2b_stream;
  unsigned long maxbytes = BLAKE2B_OUTBYTES;
  const char *algorithm = "BLAKE2b";
  unsigned long outbytes = 0;
  unsigned char hash[BLAKE2B_OUTBYTES] = {0};
  bool bsdstyle = false;
  int c;
  opterr = 1;

  while( 1 )
  {
    int this_option_optind = optind ? optind : 1;
    int option_index = 0;
    char *end = NULL;
    unsigned long outbits;
    static struct option long_options[] = {
      { "help",  no_argument, 0,  0  },
      { "tag",   no_argument, 0,  0  },
      { NULL, 0, NULL, 0 }
    };

    c = getopt_long( argc, argv, "a:l:", long_options, &option_index );
    if( c == -1 ) break;
    switch( c )
    {
    case 'a':
      if( 0 == strcmp( optarg, "blake2b" ) )
      {
        blake2_stream = blake2b_stream;
        maxbytes = BLAKE2B_OUTBYTES;
        algorithm = "BLAKE2b";
      }
      else if ( 0 == strcmp( optarg, "blake2s" ) )
      {
        blake2_stream = blake2s_stream;
        maxbytes = BLAKE2S_OUTBYTES;
        algorithm = "BLAKE2s";
      }
      else if ( 0 == strcmp( optarg, "blake2bp" ) )
      {
        blake2_stream = blake2bp_stream;
        maxbytes = BLAKE2B_OUTBYTES;
        algorithm = "BLAKE2bp";
      }
      else if ( 0 == strcmp( optarg, "blake2sp" ) )
      {
        blake2_stream = blake2sp_stream;
        maxbytes = BLAKE2S_OUTBYTES;
        algorithm = "BLAKE2sp";
      }
      else
      {
        printf( "Invalid function name: `%s'\n", optarg );
        usage( argv, 111 );
      }

      break;

    case 'l':
      outbits = strtoul(optarg, &end, 10);
      if( !end || *end != '\0' || outbits % 8 != 0)
      {
        printf( "Invalid length argument: `%s'\n", optarg);
        usage( argv, 111 );
      }
      outbytes = outbits / 8;
      break;

    case 0:
      if( 0 == strcmp( "help", long_options[option_index].name ) )
        usage( argv, 0 );
      else if( 0 == strcmp( "tag", long_options[option_index].name ) )
        bsdstyle = true;
      break;

    case '?':
      usage( argv, 1 );
      break;
    }
  }

  if(outbytes > maxbytes)
  {
    printf( "Invalid length argument: %lu\n", outbytes * 8 );
    printf( "Maximum digest length for %s is %lu\n", algorithm, maxbytes * 8 );
    usage( argv, 111 );
  }
  else if( outbytes == 0 )
    outbytes = maxbytes;

  if( optind == argc )
    argv[argc++] = (char *) "-";

  for( int i = optind; i < argc; ++i )
  {
    FILE *f = NULL;
    if( argv[i][0] == '-' && argv[i][1] == '\0' )
      f = stdin;
    else
      f = fopen( argv[i], "rb" );

    if( !f )
    {
      fprintf( stderr, "Could not open `%s': %s\n", argv[i], strerror( errno ) );
      continue;
    }

    if( blake2_stream( f, hash, outbytes ) < 0 )
    {
      fprintf( stderr, "Failed to hash `%s'\n", argv[i] );
    }
    else
    {
      if( bsdstyle )
      {
        if( outbytes < maxbytes )
          printf( "%s-%lu (%s) = ", algorithm, outbytes * 8, argv[i] );
        else
          printf( "%s (%s) = ", algorithm, argv[i] );
      }

      for( size_t j = 0; j < outbytes; ++j )
        printf( "%02x", hash[j] );

      if( bsdstyle )
        printf( "\n" );
      else
        printf( "  %s\n", argv[i] );
    }

    if( f != stdin ) fclose( f );
  }

  return 0;
}

