fnv32.c

/*
 * fnv32 - 32 bit Fowler/Noll/Vo hash of a buffer or string
 *
 * @(#) $Revision: 5.5 $
 * @(#) $Id: fnv32.c,v 5.5 2012/03/21 01:38:12 chongo Exp $
 * @(#) $Source: /usr/local/src/cmd/fnv/RCS/fnv32.c,v $
 *
 ***
 *
 * Fowler/Noll/Vo hash
 *
 * The basis of this hash algorithm was taken from an idea sent
 * as reviewer comments to the IEEE POSIX P1003.2 committee by:
 *
 *      Phong Vo (http://www.research.att.com/info/kpv/)
 *      Glenn Fowler (http://www.research.att.com/~gsf/)
 *
 * In a subsequent ballot round:
 *
 *      Landon Curt Noll (http://www.isthe.com/chongo/)
 *
 * improved on their algorithm.  Some people tried this hash
 * and found that it worked rather well.  In an EMail message
 * to Landon, they named it the ``Fowler/Noll/Vo'' or FNV hash.
 *
 * FNV hashes are designed to be fast while maintaining a low
 * collision rate. The FNV speed allows one to quickly hash lots
 * of data while maintaining a reasonable collision rate.  See:
 *
 *      http://www.isthe.com/chongo/tech/comp/fnv/index.html
 *
 * for more details as well as other forms of the FNV hash.
 *
 ***
 *
 * Please do not copyright this code.  This code is in the public domain.
 *
 * LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
 * EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 *
 * By:
 *  chongo <Landon Curt Noll> /\oo/\
 *      http://www.isthe.com/chongo/
 *
 * Share and Enjoy! :-)
 */

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>

#include "fnv.h"

#define WIDTH 32    /* bit width of hash */

#define BUF_SIZE (32*1024)  /* number of bytes to hash at a time */

static char *usage =
"usage: %s [-b bcnt] [-m] [-s arg] [-t code] [-v] [arg ...]\n"
"\n"
"\t-b bcnt\tmask off all but the lower bcnt bits (default 32)\n"
"\t-m\tmultiple hashes, one per line for each arg\n"
"\t-s\thash arg as a string (ignoring terminating NUL bytes)\n"
"\t-t code\t  test hash code: (0 ==> generate test vectors\n"
"\t\t\t\t   1 ==> validate against FNV test vectors)\n"
"\t-v\tverbose mode, print arg after hash (implies -m)\n"
"\targ\tstring (if -s was given) or filename (default stdin)\n"
"\n"
"\tNOTE: Programs that begin with fnv0 implement the FNV-0 hash.\n"
"\t      The FNV-0 hash is historic FNV algorithm that is now deprecated.\n"
"\n"
"\tSee http://www.isthe.com/chongo/tech/comp/fnv/index.html for more info.\n"
"\n"
"\t@(#) FNV Version: %s\n";
static char *program; /* our name */


/*
 * test_fnv32 - test the FNV32 hash
 *
 * given:
 *  hash_type type of FNV hash to test
 *  init_hval initial hash value
 *  mask      lower bit mask
 *  v_flag      1 => print test failure info on stderr
 *  code    0 ==> generate FNV test vectors
 *      1 ==> validate against FNV test vectors
 *
 * returns: 0 ==> OK, else test vector failure number
 */
static int
test_fnv32(enum fnv_type hash_type, Fnv32_t init_hval,
     Fnv32_t mask, int v_flag, int code)
{
    struct test_vector *t;  /* FNV test vestor */
    Fnv32_t hval;   /* current hash value */
    int tstnum;     /* test vector that failed, starting at 1 */

    /*
     * print preamble if generating test vectors
     */
    if (code == 0) {
  switch (hash_type) {
  case FNV0_32:
      printf("struct fnv0_32_test_vector fnv0_32_vector[] = {\n");
      break;
  case FNV1_32:
      printf("struct fnv1_32_test_vector fnv1_32_vector[] = {\n");
      break;
  case FNV1a_32:
      printf("struct fnv1a_32_test_vector fnv1a_32_vector[] = {\n");
      break;
  default:
      unknown_hash_type(program, hash_type, 12);  /* exit(12) */
      /*NOTREACHED*/
      }
    }

    /*
     * loop thru all test vectors
     */
    for (t = fnv_test_str, tstnum = 1; t->buf != NULL; ++t, ++tstnum) {

        /*
   * compute the FNV hash
   */
  hval = init_hval;
  switch (hash_type) {
  case FNV0_32:
  case FNV1_32:
      hval = fnv_32_buf(t->buf, t->len, hval);
      break;
  case FNV1a_32:
      hval = fnv_32a_buf(t->buf, t->len, hval);
      break;
  default:
      unknown_hash_type(program, hash_type, 13);  /* exit(13) */
      /*NOTREACHED*/
  }

  /*
   * print the vector
   */
  switch (code) {
  case 0:   /* generate the test vector */
      printf("    { &fnv_test_str[%d], (Fnv32_t) 0x%08lxUL },\n",
            tstnum-1, hval & mask);
          break;
  case 1:   /* validate against test vector */
      switch (hash_type) {
      case FNV0_32:
    if ((hval&mask) != (fnv0_32_vector[tstnum-1].fnv0_32 & mask)) {
        if (v_flag) {
          fprintf(stderr, "%s: failed fnv0_32 test # %d\n",
        program, tstnum);
          fprintf(stderr, "%s: test # 1 is 1st test\n", program);
      fprintf(stderr,
          "%s: expected 0x%08lx != generated: 0x%08lx\n",
          program, (hval&mask),
          (fnv0_32_vector[tstnum-1].fnv0_32 & mask));
        }
        return tstnum;
    }
        break;
      case FNV1_32:
    if ((hval&mask) != (fnv1_32_vector[tstnum-1].fnv1_32 & mask)) {
        if (v_flag) {
          fprintf(stderr, "%s: failed fnv1_32 test # %d\n",
        program, tstnum);
          fprintf(stderr, "%s: test # 1 is 1st test\n", program);
      fprintf(stderr,
          "%s: expected 0x%08lx != generated: 0x%08lx\n",
          program, (hval&mask),
          (fnv1_32_vector[tstnum-1].fnv1_32 & mask));
        }
        return tstnum;
    }
        break;
      case FNV1a_32:
    if ((hval&mask) != (fnv1a_32_vector[tstnum-1].fnv1a_32 &mask)) {
        if (v_flag) {
          fprintf(stderr, "%s: failed fnv1a_32 test # %d\n",
        program, tstnum);
          fprintf(stderr, "%s: test # 1 is 1st test\n", program);
      fprintf(stderr,
          "%s: expected 0x%08lx != generated: 0x%08lx\n",
          program, (hval&mask),
          (fnv1a_32_vector[tstnum-1].fnv1a_32 & mask));
        }
        return tstnum;
    }
        break;
      }
      break;
      default:
      fprintf(stderr, "%s: -m %d not implemented yet\n", program, code);
      exit(14);
      }
    }

    /*
     * print completion if generating test vectors
     */
    if (code == 0) {
  printf("    { NULL, 0 }\n");
  printf("};\n");
    }

    /*
     * no failures, return code 0 ==> all OK
     */
    return 0;
}


/*
 * main - the main function
 *
 * See the above usage for details.
 */
int
main(int argc, char *argv[])
{
    char buf[BUF_SIZE+1]; /* read buffer */
    int readcnt;    /* number of characters written */
    Fnv32_t hval;   /* current hash value */
    int s_flag = 0;   /* 1 => -s was given, hash args as strings */
    int m_flag = 0;   /* 1 => print multiple hashes, one per arg */
    int v_flag = 0;   /* 1 => verbose hash print */
    int b_flag = WIDTH;   /* -b flag value */
    int t_flag = -1;    /* FNV test vector code (0=>print, 1=>test) */
    enum fnv_type hash_type = FNV_NONE; /* type of FNV hash to perform */
    Fnv32_t bmask;    /* mask to apply to output */
    extern char *optarg;  /* option argument */
    extern int optind;    /* argv index of the next arg */
    int fd;     /* open file to process */
    char *p;
    int i;

    /*
     * parse args
     */
    program = argv[0];
    while ((i = getopt(argc, argv, "b:mst:v")) != -1) {
  switch (i) {
  case 'b': /* bcnt bit mask count */
      b_flag = atoi(optarg);
      break;
  case 'm': /* print multiple hashes, one per arg */
      m_flag = 1;
      break;
  case 's': /* hash args as strings */
      s_flag = 1;
      break;
  case 't': /* FNV test vector code */
      t_flag = atoi(optarg);
      if (t_flag < 0 || t_flag > 1) {
    fprintf(stderr, "%s: -t code must be 0 or 1\n", program);
    fprintf(stderr, usage, program, FNV_VERSION);
    exit(1);
      }
      m_flag = 1;
      break;
  case 'v': /* verbose hash print */
      m_flag = 1;
      v_flag = 1;
      break;
  default:
      fprintf(stderr, usage, program, FNV_VERSION);
      exit(1);
  }
    }
    /* -t code incompatible with -b, -m and args */
    if (t_flag >= 0) {
      if (b_flag != WIDTH) {
      fprintf(stderr, "%s: -t code incompatible with -b\n", program);
      exit(2);
  }
      if (s_flag != 0) {
      fprintf(stderr, "%s: -t code incompatible with -s\n", program);
      exit(3);
  }
  if (optind < argc) {
      fprintf(stderr, "%s: -t code incompatible args\n", program);
      exit(4);
  }
    }
    /* -s requires at least 1 arg */
    if (s_flag && optind >= argc) {
  fprintf(stderr, usage, program, FNV_VERSION);
  exit(5);
    }
    /* limit -b values */
    if (b_flag < 0 || b_flag > WIDTH) {
  fprintf(stderr, "%s: -b bcnt: %d must be >= 0 and < %d\n",
    program, b_flag, WIDTH);
  exit(6);
    }
    if (b_flag == WIDTH) {
  bmask = (Fnv32_t)0xffffffff;
    } else {
  bmask = (Fnv32_t)((1 << b_flag) - 1);
    }

    /*
     * start with the initial basis depending on the hash type
     */
    p = strrchr(program, '/');
    if (p == NULL) {
  p = program;
    } else {
  ++p;
    }
    if (strcmp(p, "fnv032") == 0) {
  /* using non-recommended FNV-0 and zero initial basis */
  hval = FNV0_32_INIT;
  hash_type = FNV0_32;
    } else if (strcmp(p, "fnv132") == 0) {
  /* using FNV-1 and non-zero initial basis */
  hval = FNV1_32_INIT;
  hash_type = FNV1_32;
    } else if (strcmp(p, "fnv1a32") == 0) {
   /* start with the FNV-1a initial basis */
  hval = FNV1_32A_INIT;
  hash_type = FNV1a_32;
    } else {
  fprintf(stderr, "%s: unknown program name, unknown hash type\n",
    program);
  exit(7);
    }

    /*
     * FNV test vector processing, if needed
     */
    if (t_flag >= 0) {
  int code;   /* test vector that failed, starting at 1 */

  /*
   * perform all tests
   */
  code = test_fnv32(hash_type, hval, bmask, v_flag, t_flag);

  /*
   * evaluate the tests
   */
  if (code == 0) {
      if (v_flag) {
        printf("passed\n");
      }
      exit(0);
  } else {
      printf("failed vector (1 is 1st test): %d\n", code);
      exit(8);
  }
    }

    /*
     * string hashing
     */
    if (s_flag) {

  /* hash any other strings */
  for (i=optind; i < argc; ++i) {
      switch (hash_type) {
      case FNV0_32:
      case FNV1_32:
    hval = fnv_32_str(argv[i], hval);
        break;
      case FNV1a_32:
    hval = fnv_32a_str(argv[i], hval);
    break;
      default:
    unknown_hash_type(program, hash_type, 9); /* exit(9) */
    /*NOTREACHED*/
      }
      if (m_flag) {
    print_fnv32(hval, bmask, v_flag, argv[i]);
      }
  }


    /*
     * file hashing
     */
    } else {

  /*
   * case: process only stdin
   */
  if (optind >= argc) {

      /* case: process only stdin */
      while ((readcnt = read(0, buf, BUF_SIZE)) > 0) {
    switch (hash_type) {
    case FNV0_32:
    case FNV1_32:
        hval = fnv_32_buf(buf, readcnt, hval);
        break;
    case FNV1a_32:
        hval = fnv_32a_buf(buf, readcnt, hval);
        break;
    default:
        unknown_hash_type(program, hash_type, 10);  /* exit(10) */
        /*NOTREACHED*/
    }
      }
      if (m_flag) {
    print_fnv32(hval, bmask, v_flag, "(stdin)");
      }

  } else {

      /*
       * process any other files
       */
      for (i=optind; i < argc; ++i) {

    /* open the file */
    fd = open(argv[i], O_RDONLY);
    if (fd < 0) {
        fprintf(stderr, "%s: unable to open file: %s\n",
          program, argv[i]);
        exit(4);
    }

    /*  hash the file */
    while ((readcnt = read(fd, buf, BUF_SIZE)) > 0) {
        switch (hash_type) {
        case FNV0_32:
        case FNV1_32:
      hval = fnv_32_buf(buf, readcnt, hval);
      break;
        case FNV1a_32:
      hval = fnv_32a_buf(buf, readcnt, hval);
      break;
        default:
      unknown_hash_type(program, hash_type, 11);/* exit(11) */
      /*NOTREACHED*/
        }
    }

    /* finish processing the file */
    if (m_flag) {
        print_fnv32(hval, bmask, v_flag, argv[i]);
    }
    close(fd);
      }
  }
    }

    /*
     * report hash and exit
     */
    if (!m_flag) {
  print_fnv32(hval, bmask, v_flag, "");
    }
    return 0; /* exit(0); */
}