text: #define LENGTH 16
  /* md4hl.c
   * ----------------------------------------------------------------------------
   * "THE BEER-WARE LICENSE" (Revision 42):
   * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
   * can do whatever you want with this stuff. If we meet some day, and you think
   * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
   * ----------------------------------------------------------------------------
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD: releng/11.1/lib/libmd/md4hl.c 310372 2016-12-21 18:42:04Z emaste $");
  
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  #include <unistd.h>
  
  #include <errno.h>
  #include <stdio.h>
  #include <stdlib.h>
  
  #include "md4.h"
  
  char *
  MD4End(MD4_CTX *ctx, char *buf)
  {
  	int i;
  	unsigned char digest[LENGTH];
  	static const char hex[]="0123456789abcdef";
  
  	if (!buf)
  		buf = malloc(2*LENGTH + 1);
  	if (!buf)
  		return 0;
  	MD4Final(digest, ctx);
  	for (i = 0; i < LENGTH; i++) {
  		buf[i+i] = hex[digest[i] >> 4];
  		buf[i+i+1] = hex[digest[i] & 0x0f];
  	}
  	buf[i+i] = '\0';
  	return buf;
  }
  
  char *
  MD4Fd(int fd, char *buf)
  {
  	return MD4FdChunk(fd, buf, 0, 0);
  }
  
  char *
  MD4FdChunk(int fd, char *buf, off_t ofs, off_t len)
  {
  	unsigned char buffer[16*1024];
  	MD4_CTX ctx;
  	struct stat stbuf;
  	int readrv, e;
  	off_t remain;
  
  	if (len < 0) {
  		errno = EINVAL;
  		return NULL;
  	}
  
  	MD4Init(&ctx);
  	if (ofs != 0) {
  		errno = 0;
  		if (lseek(fd, ofs, SEEK_SET) != ofs ||
  		    (ofs == -1 && errno != 0)) {
  			readrv = -1;
  			goto error;
  		}
  	}
  	remain = len;
  	readrv = 0;
  	while (len == 0 || remain > 0) {
  		if (len == 0 || remain > sizeof(buffer))
  			readrv = read(fd, buffer, sizeof(buffer));
  		else
  			readrv = read(fd, buffer, remain);
  		if (readrv <= 0) 
  			break;
  		MD4Update(&ctx, buffer, readrv);
  		remain -= readrv;
  	} 
  error:
  	if (readrv < 0)
  		return NULL;
  	return (MD4End(&ctx, buf));
  }
  
  char *
  MD4File(const char *filename, char *buf)
  {
  	return (MD4FileChunk(filename, buf, 0, 0));
  }
  
  char *
  MD4FileChunk(const char *filename, char *buf, off_t ofs, off_t len)
  {
  	char *ret;
  	int e, fd;
  
  	fd = open(filename, O_RDONLY);
  	if (fd < 0)
  		return NULL;
  	ret = MD4FdChunk(fd, buf, ofs, len);
  	e = errno;
  	close (fd);
  	errno = e;
  	return ret;
  }
  
  char *
  MD4Data (const void *data, unsigned int len, char *buf)
  {
  	MD4_CTX ctx;
  
  	MD4Init(&ctx);
  	MD4Update(&ctx,data,len);
  	return (MD4End(&ctx, buf));
  }
  
  #ifdef WEAK_REFS
  /* When building libmd, provide weak references. Note: this is not
     activated in the context of compiling these sources for internal
     use in libcrypt.
   */
  #undef MD4End
  __weak_reference(_libmd_MD4End, MD4End);
  #undef MD4File
  __weak_reference(_libmd_MD4File, MD4File);
  #undef MD4FileChunk
  __weak_reference(_libmd_MD4FileChunk, MD4FileChunk);
  #undef MD4Data
  __weak_reference(_libmd_MD4Data, MD4Data);
  #endif
  