nuttx/tools/nxstyle.c

/****************************************************************************
 * tools/nxstyle.c
 *
 *   Copyright (C) 2015, 2018-2020 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name NuttX 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  ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <stdlib.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <strings.h>
#include <ctype.h>
#include <limits.h>
#include <unistd.h>
#include <libgen.h>

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

#define NXSTYLE_VERSION "0.01"

#define LINE_SIZE      512
#define RANGE_NUMBER   4096
#define DEFAULT_WIDTH  78

#define FIRST_SECTION  INCLUDED_FILES
#define LAST_SECTION   PUBLIC_FUNCTION_PROTOTYPES

#define FATAL(m, l, o) message(FATAL, (m), (l), (o))
#define FATALFL(m, s)  message(FATAL, (m), -1, -1)
#define WARN(m, l, o)  message(WARN, (m), (l), (o))
#define ERROR(m, l, o) message(ERROR, (m), (l), (o))
#define ERRORFL(m, s)  message(ERROR, (m), -1, -1)
#define INFO(m, l, o)  message(INFO, (m), (l), (o))
#define INFOFL(m, s)   message(INFO, (m), -1, -1)

/****************************************************************************
 * Private types
 ****************************************************************************/

enum class_e
{
  INFO,
  WARN,
  ERROR,
  FATAL
};

const char *class_text[] =
{
  "info",
  "warning",
  "error",
  "fatal"
};

enum file_e
{
  UNKNOWN  = 0x00,
  C_HEADER = 0x01,
  C_SOURCE = 0x02
};

enum section_s
{
  NO_SECTION = 0,
  INCLUDED_FILES,
  PRE_PROCESSOR_DEFINITIONS,
  PUBLIC_TYPES,
  PRIVATE_TYPES,
  PRIVATE_DATA,
  PUBLIC_DATA,
  PRIVATE_FUNCTIONS,
  PRIVATE_FUNCTION_PROTOTYPES,
  INLINE_FUNCTIONS,
  PUBLIC_FUNCTIONS,
  PUBLIC_FUNCTION_PROTOTYPES
};

struct file_section_s
{
  const char *name;   /* File section name */
  uint8_t     ftype;  /* File type where section found */
};

/****************************************************************************
 * Private data
 ****************************************************************************/

static char *g_file_name        = "";
static enum file_e g_file_type  = UNKNOWN;
static enum section_s g_section = NO_SECTION;
static int g_maxline            = DEFAULT_WIDTH;
static int g_status             = 0;
static int g_verbose            = 2;
static int g_rangenumber        = 0;
static int g_rangestart[RANGE_NUMBER];
static int g_rangecount[RANGE_NUMBER];

static const struct file_section_s g_section_info[] =
{
  {
    " *\n",                             /* Index: NO_SECTION */
    C_SOURCE | C_HEADER
  },
  {
    " * Included Files\n",              /* Index: INCLUDED_FILES */
    C_SOURCE | C_HEADER
  },
  {
    " * Pre-processor Definitions\n",   /* Index: PRE_PROCESSOR_DEFINITIONS */
    C_SOURCE | C_HEADER
  },
  {
    " * Public Types\n",                /* Index: PUBLIC_TYPES */
    C_HEADER
  },
  {
    " * Private Types\n",               /* Index: PRIVATE_TYPES */
    C_SOURCE
  },
  {
    " * Private Data\n",                /* Index: PRIVATE_DATA */
    C_SOURCE
  },
  {
    " * Public Data\n",                 /* Index: PUBLIC_DATA */
    C_SOURCE | C_HEADER
  },
  {
    " * Private Functions\n",           /* Index: PRIVATE_FUNCTIONS */
    C_SOURCE
  },
  {
    " * Private Function Prototypes\n", /* Index: PRIVATE_FUNCTION_PROTOTYPES */
    C_SOURCE
  },
  {
    " * Inline Functions\n",            /* Index: INLINE_FUNCTIONS */
    C_SOURCE | C_HEADER
  },
  {
    " * Public Functions\n",            /* Index: PUBLIC_FUNCTIONS */
    C_SOURCE
  },
  {
    " * Public Function Prototypes\n",  /* Index: PUBLIC_FUNCTION_PROTOTYPES */
    C_HEADER
  }
};

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: show_usage
 *
 * Description:
 *
 ****************************************************************************/

static void show_usage(char *progname, int exitcode, char *what)
{
  fprintf(stderr, "%s version %s\n\n", basename(progname), NXSTYLE_VERSION);
  if (what)
    {
      fprintf(stderr, "%s\n", what);
    }

  fprintf(stderr, "Usage:  %s [-m <excess>] [-v <level>] [-r <start,count>] <filename>\n",
          basename(progname));
  fprintf(stderr, "        %s -h this help\n", basename(progname));
  fprintf(stderr, "        %s -v <level> where level is\n", basename(progname));
  fprintf(stderr, "                   0 - no output\n");
  fprintf(stderr, "                   1 - PASS/FAIL\n");
  fprintf(stderr, "                   2 - output each line (default)\n");
  exit(exitcode);
}

/****************************************************************************
 * Name: skip
 *
 * Description:
 *
 ****************************************************************************/

static int skip(int lineno)
{
  int i;

  for (i = 0; i < g_rangenumber; i++)
    {
      if (lineno >= g_rangestart[i] && lineno < g_rangestart[i] + g_rangecount[i])
        {
          return 0;
        }
    }

  return g_rangenumber != 0;
}

/****************************************************************************
 * Name: message
 *
 * Description:
 *
 ****************************************************************************/

static int message(enum class_e class, const char *text, int lineno, int ndx)
{
  FILE *out = stdout;

  if (skip(lineno))
    {
      return g_status;
    }

  if (class > INFO)
    {
      out = stderr;
      g_status |= 1;
    }

  if (g_verbose == 2)
    {
      if (lineno == -1 && ndx == -1)
        {
          fprintf(out, "%s: %s: %s\n", g_file_name, class_text[class], text);
        }
      else
        {
          fprintf(out, "%s:%d:%d: %s: %s\n", g_file_name, lineno, ndx,
                  class_text[class], text);
        }
    }

  return g_status;
}

/****************************************************************************
 * Name: check_spaces_left
 *
 * Description:
 *
 ****************************************************************************/

static void check_spaces_left(char *line, int lineno, int ndx)
{
  /* Unary operator should generally be preceded by a space but make also
   * follow a left parenthesis at the beginning of a parenthetical list or
   * expression or follow a right parentheses in the case of a cast.
   */

  if (ndx-- > 0 && line[ndx] != ' ' && line[ndx] != '(' && line[ndx] != ')')
    {
       ERROR("Operator/assignment must be preceded with whitespace",
             lineno, ndx);
    }
}

/****************************************************************************
 * Name: check_spaces_leftright
 *
 * Description:
 *
 ****************************************************************************/

static void check_spaces_leftright(char *line, int lineno, int ndx1, int ndx2)
{
  if (ndx1 > 0 && line[ndx1 - 1] != ' ')
    {
       ERROR("Operator/assignment must be preceded with whitespace",
             lineno, ndx1);
    }

  if (line[ndx2 + 1] != '\0' && line[ndx2 + 1] != '\n' && line[ndx2 + 1] != ' ')
    {
       ERROR("Operator/assignment must be followed with whitespace",
             lineno, ndx2);
    }
}

/****************************************************************************
 * Name: block_comment_width
 *
 * Description:
 *   Get the width of a block comment
 *
 ****************************************************************************/

static int block_comment_width(char *line)
{
  int b;
  int e;
  int n;

  /* Skip over any leading whitespace on the line */

  for (b = 0; isspace(line[b]); b++)
    {
    }

  /* Skip over any trailing whitespace at the end of the line */

  for (e = strlen(line) - 1; isspace(line[e]); e--)
    {
    }

  /* Number of characters on the line */

  n = e - b + 1;
  if (n < 4)
    {
      return 0;
    }

  /* The first line of a block comment starts with "[slash]***" and ends with
   * "***"
   */

  if (strncmp(&line[b], "/***", 4) == 0 &&
      strncmp(&line[e - 2], "***", 3) == 0)
    {
      /* Return the the length of the line up to the final '*' */

      return e + 1;
    }

  /* The last line of a block begins with whitespace then "***" and ends
   * with "***[slash]"
   */

  if (strncmp(&line[b], "***", 3) == 0 &&
      strncmp(&line[e - 3], "***/", 4) == 0)
    {
      /* Return the the length of the line up to the final '*' */

      return e;
    }

  /* But there is also a special single line comment that begins with "[slash]* "
   * and ends with "***[slash]"
   */

  if (strncmp(&line[b], "/*", 2) == 0 &&
      strncmp(&line[e - 3], "***/", 4) == 0)
    {
      /* Return the the length of the line up to the final '*' */

      return e;
    }

  /* Return zero if the line is not the first or last line of a block
   * comment.
   */

  return 0;
}

/****************************************************************************
 * Name: get_line_width
 *
 * Description:
 *   Get the maximum line width by examining the width of the block comments.
 *
 ****************************************************************************/

static int get_line_width(FILE *instream)
{
  char line[LINE_SIZE]; /* The current line being examined */
  int max = 0;
  int min = INT_MAX;
  int len;

  while (fgets(line, LINE_SIZE, instream))
    {
      len = block_comment_width(line);
      if (len > 0)
        {
          if (len > max)
            {
              max = len;
            }

          if (len < min)
            {
              min = len;
            }
        }
    }

  if (max < min)
    {
      ERRORFL("No block comments found", g_file_name);
      return DEFAULT_WIDTH;
    }
  else if (max != min)
    {
      ERRORFL("Block comments have different lengths", g_file_name);
      return DEFAULT_WIDTH;
    }

  return min;
}

/****************************************************************************
 * Name:  check_section_header
 *
 * Description:
 *   Check if the current line holds a section header
 *
 ****************************************************************************/

static bool check_section_header(const char *line, int lineno)
{
  int i;

  /* Search g_section_info[] to find a matching section header line */

  for (i = FIRST_SECTION; i <= LAST_SECTION; i++)
    {
      if (strcmp(line, g_section_info[i].name) == 0)
        {
          g_section = (enum section_s)i;

          /* Verify that this section is appropriate for this file type */

          if ((g_file_type & g_section_info[i].ftype) == 0)
            {
              ERROR("Invalid section for this file type", lineno, 3);
            }

          return true;
        }
    }

  return false;
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

int main(int argc, char **argv, char **envp)
{
  FILE *instream;       /* File input stream */
  char line[LINE_SIZE]; /* The current line being examined */
  char buffer[100];     /* Localy format error strings */
  char *lptr;           /* Temporary pointer into line[] */
  char *ext;            /* Temporary file extension */
  bool btabs;           /* True: TAB characters found on the line */
  bool bcrs;            /* True: Carriage return found on the line */
  bool bfunctions;      /* True: In private or public functions */
  bool bstatm;          /* True: This line is beginning of a statement */
  bool bfor;            /* True: This line is beginning of a 'for' statement */
  bool bswitch;         /* True: Within a switch statement */
  bool bstring;         /* True: Within a string */
  bool bquote;          /* True: Backslash quoted character next */
  bool bblank;          /* Used to verify block comment terminator */
  bool ppline;          /* True: The next line the continuation of a pre-processor command */
  bool bexternc;        /* True: Within 'extern "C"' */
  bool brhcomment;      /* True: Comment to the right of code */
  bool prevbrhcmt;      /* True: previous line had comment to the right of code */
  int lineno;           /* Current line number */
  int indent;           /* Indentation level */
  int ncomment;         /* Comment nesting level on this line */
  int prevncomment;     /* Comment nesting level on the previous line */
  int bnest;            /* Brace nesting level on this line */
  int prevbnest;        /* Brace nesting level on the previous line */
  int dnest;            /* Data declaration nesting level on this line */
  int prevdnest;        /* Data declaration nesting level on the previous line */
  int pnest;            /* Parenthesis nesting level on this line */
  int comment_lineno;   /* Line on which the last comment was closed */
  int blank_lineno;     /* Line number of the last blank line */
  int noblank_lineno;   /* A blank line is not needed after this line */
  int lbrace_lineno;    /* Line number of last left brace */
  int rbrace_lineno;    /* Last line containing a right brace */
  int externc_lineno;   /* Last line where 'extern "C"' declared */
  int linelen;          /* Length of the line */
  int excess;
  int n;
  int i;
  int c;

  excess = 0;
  while ((c = getopt(argc, argv, ":hv:gm:r:")) != -1)
    {
      switch (c)
      {
      case 'm':
        excess = atoi(optarg);
        if (excess < 1)
          {
            show_usage(argv[0], 1, "Bad value for <excess>.");
            excess = 0;
          }

        break;

      case 'v':
        g_verbose = atoi(optarg);
        if (g_verbose < 0 || g_verbose > 2)
          {
            show_usage(argv[0], 1, "Bad value for <level>.");
          }

        break;

      case 'r':
        g_rangestart[g_rangenumber] = atoi(strtok(optarg, ","));
        g_rangecount[g_rangenumber++] = atoi(strtok(NULL, ","));
        break;

      case 'h':
        show_usage(argv[0], 0, NULL);
        break;

      case ':':
        show_usage(argv[0], 1, "Missing argument.");
        break;

      case '?':
        show_usage(argv[0], 1, "Unrecognized option.");
        break;

      default:
        show_usage(argv[0], 0, NULL);
        break;
      }
  }

  if (optind < argc - 1 || argv[optind] == NULL)
    {
      show_usage(argv[0], 1, "No file name given.");
    }

  g_file_name = argv[optind];
  instream = fopen(g_file_name, "r");

  if (!instream)
    {
      FATALFL("Failed to open", g_file_name);
      return 1;
    }

  /* Determine the line width */

  g_maxline = get_line_width(instream) + excess;
  rewind(instream);

  /* Are we parsing a header file? */

  ext = strrchr(g_file_name, '.');

  if (ext == 0)
    {
      INFOFL("No file extension", g_file_name);
    }
  else if (strcmp(ext, ".h") == 0)
    {
      g_file_type = C_HEADER;
    }
  else if (strcmp(ext, ".c") == 0)
    {
      g_file_type = C_SOURCE;
    }

  if (g_file_type == UNKNOWN)
    {
      INFOFL("Unknown file extension", g_file_name);
      return 0;
    }

  btabs          = false; /* True: TAB characters found on the line */
  bcrs           = false; /* True: Carriage return found on the line */
  bfunctions     = false; /* True: In private or public functions */
  bswitch        = false; /* True: Within a switch statement */
  bstring        = false; /* True: Within a string */
  ppline         = false; /* True: Continuation of a pre-processor line */
  bexternc       = false; /* True: Within 'extern "C"' */
  brhcomment     = false; /* True: Comment to the right of code */
  prevbrhcmt     = false; /* True: Previous line had comment to the right of code */
  lineno         = 0;     /* Current line number */
  ncomment       = 0;     /* Comment nesting level on this line */
  bnest          = 0;     /* Brace nesting level on this line */
  dnest          = 0;     /* Data declaration nesting level on this line */
  pnest          = 0;     /* Parenthesis nesting level on this line */
  comment_lineno = -1;    /* Line on which the last comment was closed */
  blank_lineno   = -1;    /* Line number of the last blank line */
  noblank_lineno = -1;    /* A blank line is not needed after this line */
  lbrace_lineno  = -1;    /* Line number of last left brace */
  rbrace_lineno  = -1;    /* Last line containing a right brace */
  externc_lineno = -1;    /* Last line where 'extern "C"' declared */

  /* Process each line in the input stream */

  while (fgets(line, LINE_SIZE, instream))
    {
      lineno++;
      indent       = 0;
      prevbnest    = bnest;    /* Brace nesting level on the previous line */
      prevdnest    = dnest;    /* Data declaration nesting level on the previous line */
      prevncomment = ncomment; /* Comment nesting level on the previous line */
      bstatm       = false;    /* True: This line is beginning of a statement */
      bfor         = false;    /* REVISIT: Implies for() is all on one line */

      /* If we are not in a comment, then this certainly is not a right-hand comment. */

      prevbrhcmt   = brhcomment;
      if (ncomment <= 0)
        {
          brhcomment = false;
        }

      /* Check for a blank line */

      for (n = 0; line[n] != '\n' && isspace((int)line[n]); n++)
        {
        }

      if (line[n] == '\n')
        {
          if (n > 0)
            {
              ERROR("Blank line contains whitespace", lineno, 1);
            }

          if (lineno == 1)
            {
              ERROR("File begins with a blank line", 1, 1);
            }
          else if (lineno == blank_lineno + 1)
            {
              ERROR("Too many blank lines", lineno, 1);
            }
          else if (lineno == lbrace_lineno + 1)
            {
              ERROR("Blank line follows left brace", lineno, 1);
            }

          blank_lineno = lineno;
          continue;
        }
      else /* This line is non-blank */
        {
          /* Check for a missing blank line after a comment */

          if (lineno == comment_lineno + 1)
            {
              /* No blank line should be present if the current line contains
               * a right brace, a pre-processor line, the start of another
               * comment.
               *
               * REVISIT: Generates a false alarm if the current line is also
               * a comment.  Generally it is acceptable for one comment to
               * follow another with no space separation.
               *
               * REVISIT: prevbrhcmt is tested to case the preceding line
               * contained comments to the right of the code.  In such cases,
               * the comments are normally aligned and do not follow normal
               * indentation rules.  However, this code will generate a false
               * alarm if the comments are aligned to the right BUT the
               * preceding line has no comment.
               */

              if (line[n] != '}' /* && line[n] != '#' */ && !prevbrhcmt)
                {
                   ERROR("Missing blank line after comment", comment_lineno,
                         1);
                }
            }

          /* Files must begin with a comment (the file header).
           * REVISIT:  Logically, this belongs in the STEP 2 operations
           * below.
           */

          if (lineno == 1 && (line[n] != '/' || line[n + 1] != '*'))
            {
               ERROR("Missing file header comment block", lineno, 1);
            }

          /* Check for a blank line following a right brace */

          if (bfunctions && lineno == rbrace_lineno + 1)
            {
              /* Check if this line contains a right brace.  A right brace
               * must be followed by 'else', 'while', 'break', a blank line,
               * another right brace, or a pre-processor directive like #endif
               */

              if (strchr(line, '}') == NULL && line[n] != '#' &&
                  strncmp(&line[n], "else", 4) != 0 &&
                  strncmp(&line[n], "while", 5) != 0 &&
                  strncmp(&line[n], "break", 5) != 0)
                {
                   ERROR("Right brace must be followed by a blank line",
                         rbrace_lineno, n + 1);
                }

              /* If the right brace is followed by a pre-processor command
               * like #endif (but not #else or #elif), then set the right
               * brace line number to the line number of the pre-processor
               * command (it then must be followed by a blank line)
               */

              if (line[n] == '#')
                {
                  int ii;

                  for (ii = n + 1; line[ii] != '\0' && isspace(line[ii]); ii++)
                    {
                    }

                  if (strncmp(&line[ii], "else", 4) != 0 &&
                      strncmp(&line[ii], "elif", 4) != 0)
                    {
                      rbrace_lineno = lineno;
                    }
                }
            }
        }

      /* STEP 1: Find the indentation level and the start of real stuff on
       * the line.
       */

      for (n = 0; line[n] != '\n' && isspace((int)line[n]); n++)
        {
          switch (line[n])
            {
            case ' ':
              {
                indent++;
              }
              break;

            case '\t':
              {
                if (!btabs)
                  {
                    ERROR("TABs found.  First detected", lineno, n);
                    btabs = true;
                  }

                indent = (indent + 4) & ~3;
              }
              break;

            case '\r':
              {
                if (!bcrs)
                  {
                    ERROR("Carriage returns found.  "
                            "First detected", lineno, n);
                    bcrs = true;
                  }
              }
              break;

            default:
              {
                 snprintf(buffer, sizeof(buffer),
                          "Unexpected white space character %02x found",
                          line[n]);
                 ERROR(buffer, lineno, n);
              }
              break;
            }
        }

      /* STEP 2: Detect some certain start of line conditions */

      /* Skip over pre-processor lines (or continuations of pre-processor
       * lines as indicated by ppline)
       */

      if (line[indent] == '#' || ppline)
        {
          int len;
          int ii;

          /* Suppress error for comment following conditional compilation */

          noblank_lineno = lineno;

          /* Check pre-processor commands if this is not a continuation
           * line.
           */

          if (!ppline)
            {
              /* Skip to the pre-processor command following the '#' */

               for (ii = indent + 1;
                    line[ii] != '\0' && isspace(line[ii]);
                    ii++)
                 {
                 }

               if (line[ii] != '\0')
                 {
                   /* Make sure that pre-processor definitions are all in
                    * the pre-processor definitions section.
                    */

                   if (strncmp(&line[ii], "define", 6) == 0)
                     {
                       if (g_section != PRE_PROCESSOR_DEFINITIONS)
                         {
                           /* A complication is the header files always have
                            * the idempotence guard definitions before the
                            * "Pre-processor Definitions section".
                            */

                           if (g_section == NO_SECTION &&
                               g_file_type != C_HEADER)
                             {
                               /* Only a warning because there is some usage
                                * of define outside the Pre-processor
                                * Definitions section which is justifiable.
                                * Should be manually checked.
                                */

                               WARN("#define outside of 'Pre-processor "
                                    "Definitions' section",
                                    lineno, ii);
                             }
                         }
                     }

                   /* Make sure that files are included only in the Included
                    * Files section.
                    */

                   else if (strncmp(&line[ii], "include", 7) == 0)
                     {
                       if (g_section != INCLUDED_FILES)
                         {
                           /* Only a warning because there is some usage of
                            * include outside the Included Files section
                            * which may be is justifiable.  Should be
                            * manually checked.
                            */

                           WARN("#include outside of 'Included Files' "
                                "section",
                                lineno, ii);
                         }
                     }
                 }
            }

          /* Check if the next line will be a continuation of the pre-
           * processor command.
           */

          len = strlen(&line[indent]) + indent - 1;
          if (line[len] == '\n')
            {
              len--;
            }

          ppline = (line[len] == '\\');
          continue;
        }

      /* Check for a single line comment */

      linelen = strlen(line);
      if (linelen >= 5)      /* Minimum is slash, star, star, slash, newline */
        {
          lptr = strstr(line, "*/");
          if (line[indent] == '/' && line[indent + 1] == '*' &&
              lptr - line == linelen - 3)
            {
              /* If preceding comments were to the right of code, then we can
               * assume that there is a columnar alignment of columns that do
               * no follow the usual alignment.  So the brhcomment flag
               * should propagate.
               */

              brhcomment = prevbrhcmt;

              /* Check if there should be a blank line before the comment */

              if (lineno > 1 &&
                  comment_lineno != lineno - 1 &&
                  blank_lineno   != lineno - 1 &&
                  noblank_lineno != lineno - 1 &&
                  !brhcomment)
                {
                  /* TODO:  This generates a false alarm if preceded by a label. */

                   ERROR("Missing blank line before comment found", lineno, 1);
                }

              /* 'comment_lineno 'holds the line number of the last closing
               * comment.  It is used only to verify that the comment is
               * followed by a blank line.
               */

              comment_lineno = lineno;
            }
        }

      /* Check for the comment block indicating the beginning of a new file
       * section.
       */

      if (check_section_header(line, lineno))
        {
          if (g_section == PRIVATE_FUNCTIONS || g_section == PUBLIC_FUNCTIONS)
            {
              bfunctions = true;  /* Latched */
            }
        }

      /* Check for some kind of declaration.
       * REVISIT: The following logic fails for any non-standard types.
       * REVISIT: Terminator after keyword might not be a space.  Might be
       * a newline, for example.  struct and unions are often unnamed, for
       * example.
       */

      else if (strncmp(&line[indent], "auto ", 5) == 0 ||
               strncmp(&line[indent], "bool ", 5) == 0 ||
               strncmp(&line[indent], "char ", 5) == 0 ||
               strncmp(&line[indent], "CODE ", 5) == 0 ||
               strncmp(&line[indent], "const ", 6) == 0 ||
               strncmp(&line[indent], "double ", 7) == 0 ||
               strncmp(&line[indent], "struct ", 7) == 0 ||
               strncmp(&line[indent], "struct\n", 7) == 0 ||      /* May be unnamed */
               strncmp(&line[indent], "enum ", 5) == 0 ||
               strncmp(&line[indent], "extern ", 7) == 0 ||
               strncmp(&line[indent], "EXTERN ", 7) == 0 ||
               strncmp(&line[indent], "FAR ", 4) == 0 ||
               strncmp(&line[indent], "float ", 6) == 0 ||
               strncmp(&line[indent], "int ", 4) == 0 ||
               strncmp(&line[indent], "int16_t ", 8) == 0 ||
               strncmp(&line[indent], "int32_t ", 8) == 0 ||
               strncmp(&line[indent], "long ", 5) == 0 ||
               strncmp(&line[indent], "off_t ", 6) == 0 ||
               strncmp(&line[indent], "register ", 9) == 0 ||
               strncmp(&line[indent], "short ", 6) == 0 ||
               strncmp(&line[indent], "signed ", 7) == 0 ||
               strncmp(&line[indent], "size_t ", 7) == 0 ||
               strncmp(&line[indent], "ssize_t ", 8) == 0 ||
               strncmp(&line[indent], "static ", 7) == 0 ||
               strncmp(&line[indent], "time_t ", 7) == 0 ||
               strncmp(&line[indent], "typedef ", 8) == 0 ||
               strncmp(&line[indent], "uint8_t ", 8) == 0 ||
               strncmp(&line[indent], "uint16_t ", 9) == 0 ||
               strncmp(&line[indent], "uint32_t ", 9) == 0 ||
               strncmp(&line[indent], "union ", 6) == 0 ||
               strncmp(&line[indent], "union\n", 6) == 0 ||      /* May be unnamed */
               strncmp(&line[indent], "unsigned ", 9) == 0 ||
               strncmp(&line[indent], "void ", 5) == 0 ||
               strncmp(&line[indent], "volatile ", 9) == 0)
        {
          /* Check if this is extern "C";  We don't typically indent following
           * this.
           */

          if (strncmp(&line[indent], "extern \"C\"", 10) == 0)
            {
              externc_lineno = lineno;
            }

          /* bfunctions:  True:  Processing private or public functions.
           * bnest:       Brace nesting level on this line
           * dnest:       Data declaration nesting level on this line
           */

          /* REVISIT: Also picks up function return types */

          /* REVISIT: Logic problem for nested data/function declarations */

          if ((!bfunctions || bnest > 0) && dnest == 0)
            {
              dnest = 1;
            }

          /* Check for multiple definitions of variables on the line.
           * Ignores declarations within parentheses which are probably
           * formal parameters.
           */

          if (pnest == 0)
            {
              int tmppnest;

              /* Note, we have not yet parsed each character on the line so
               * a comma have have been be preceded by '(' on the same line.
               * We will have parse up to any comma to see if that is the
               * case.
               */

              for (i = indent, tmppnest = 0;
                   line[i] != '\n' && line[i] != '\0';
                   i++)
                {
                  if (tmppnest == 0 && line[i] == ',')
                    {
                       ERROR("Multiple data definitions", lineno, i + 1);
                      break;
                    }
                  else if (line[i] == '(')
                    {
                      tmppnest++;
                    }
                  else if (line[i] == ')')
                    {
                      if (tmppnest < 1)
                        {
                          /* We should catch this later */

                          break;
                        }

                      tmppnest--;
                    }
                  else if (line[i] == ';')
                    {
                      /* Break out if the semicolon terminates the
                       * declaration is found.  Avoids processing any
                       * righthand comments in most cases.
                       */

                      break;
                    }
                }
            }
        }

      /* Check for a keyword indicating the beginning of a statement.
       * REVISIT:  This, obviously, will not detect statements that do not
       * begin with a C keyword (such as assignment statements).
       */

      else if (strncmp(&line[indent], "break ", 6) == 0 ||
               strncmp(&line[indent], "case ", 5) == 0 ||
#if 0 /* Part of switch */
               strncmp(&line[indent], "case ", 5) == 0 ||
#endif
               strncmp(&line[indent], "continue ", 9) == 0 ||

#if 0 /* Part of switch */
               strncmp(&line[indent], "default ", 8) == 0 ||
#endif
               strncmp(&line[indent], "do ", 3) == 0 ||
               strncmp(&line[indent], "else ", 5) == 0 ||
               strncmp(&line[indent], "goto ", 5) == 0 ||
               strncmp(&line[indent], "if ", 3) == 0 ||
               strncmp(&line[indent], "return ", 7) == 0 ||
#if 0 /*  Doesn't follow pattern */
               strncmp(&line[indent], "switch ", 7) == 0 ||
#endif
               strncmp(&line[indent], "while ", 6) == 0)
        {
          bstatm = true;
        }

      /* Spacing works a little differently for and switch statements */

      else if (strncmp(&line[indent], "for ", 4) == 0)
        {
          bfor   = true;
          bstatm = true;
        }
      else if (strncmp(&line[indent], "switch ", 7) == 0)
        {
          bswitch = true;
        }

      /* Also check for C keywords with missing white space */

      else if (strncmp(&line[indent], "do(", 3) == 0 ||
               strncmp(&line[indent], "if(", 3) == 0 ||
               strncmp(&line[indent], "while(", 6) == 0)
        {
          ERROR("Missing whitespace after keyword", lineno, n);
          bstatm = true;
        }
      else if (strncmp(&line[indent], "for(", 4) == 0)
        {
          ERROR("Missing whitespace after keyword", lineno, n);
          bfor   = true;
          bstatm = true;
        }
      else if (strncmp(&line[indent], "switch(", 7) == 0)
        {
          ERROR("Missing whitespace after keyword", lineno, n);
          bswitch = true;
        }

      /* STEP 3: Parse each character on the line */

      bquote = false;   /* True: Backslash quoted character next */
      bblank = true;    /* Used to verify block comment terminator */

      for (; line[n] != '\n' && line[n] != '\0'; n++)
        {
          /* Report any use of non-standard white space characters */

          if (isspace(line[n]))
            {
              if (line[n] == '\t')
                {
                  if (!btabs)
                    {
                      ERROR("TABs found.  First detected", lineno, n);
                      btabs = true;
                    }
                }
              else if (line[n] == '\r')
                {
                  if (!bcrs)
                    {
                      ERROR("Carriage returns found.  "
                              "First detected", lineno, n);
                      bcrs = true;
                    }
                }
              else if (line[n] != ' ')
                {
                  snprintf(buffer, sizeof(buffer),
                           "Unexpected white space character %02x found",
                           line[n]);
                  ERROR(buffer, lineno, n);
                }
            }

          /* Skip over identifiers */

          if (ncomment == 0 && !bstring && (line[n] == '_' || isalpha(line[n])))
            {
              bool have_upper = false;
              bool have_lower = false;
              int ident_index = n;

              /* Parse over the identifier.  Check if it contains mixed upper-
               * and lower-case characters.
               */

              do
                {
                  have_upper |= isupper(line[n]);

                  /* The coding standard provides for some exceptions of lower
                   * case characters in pre-processor strings:
                   *
                   *   IPv[4|6]    as an IP version number
                   *   ICMPv6      as an ICMP version number
                   *   IGMPv2      as an IGMP version number
                   *   [0-9]p[0-9] as a decimal point
                   *   d[0-9]      as a divisor
                   */

                   if (!have_lower && islower(line[n]))
                     {
                       switch (line[n])
                       {
                         /* A sequence containing 'v' may occur at the
                          * beginning of the identifier.
                          */

                         case 'v':
                           if (n > 1 &&
                               line[n - 2] == 'I' &&
                               line[n - 1] == 'P' &&
                               (line[n + 1] == '4' ||
                                line[n + 1] == '6'))
                             {
                             }
                           else if (n > 3 &&
                                    line[n - 4] == 'I' &&
                                    line[n - 3] == 'C' &&
                                    line[n - 2] == 'M' &&
                                    line[n - 1] == 'P' &&
                                    line[n + 1] == '6')
                             {
                             }
                           else if (n > 3 &&
                                    line[n - 4] == 'I' &&
                                    line[n - 3] == 'G' &&
                                    line[n - 2] == 'M' &&
                                    line[n - 1] == 'P' &&
                                    line[n + 1] == '2')
                             {
                             }
                           else
                             {
                               have_lower = true;
                             }
                           break;

                         /* Sequences containing 'p' or 'd' must have been
                          * preceded by upper case characters.
                          */

                         case 'p':
                           if (!have_upper || n < 1 ||
                               !isdigit(line[n - 1]) ||
                               !isdigit(line[n + 1]))
                             {
                               have_lower = true;
                             }
                             break;

                         case 'd':
                           if (!have_upper || !isdigit(line[n + 1]))
                             {
                               have_lower = true;
                             }
                             break;

                         default:
                           have_lower = true;
                           break;
                       }
                     }

                  n++;
                }
              while (line[n] == '_' || isalnum(line[n]));

              /* Check for mixed upper and lower case */

              if (have_upper && have_lower)
                {
                  /* REVISIT:  Although pre-processor definitions are
                   * supposed to be all upper-case, there are exceptions
                   * such as using 'p' for a decimal point or 'MHz'.
                   * Those will be reported here, but probably should be
                   * considered false alarms.
                   */

                  /* Ignore inttype.h strings beginning with PRIx and
                   * system calls beginning with SYS_
                   */

                  if ((strncmp(&line[ident_index], "PRIx", 4) == 0) ||
                      (strncmp(&line[ident_index], "SYS_", 4) == 0))
                    {
                      /* No error */
                    }

                  /* Special case hex constants.  These will look like
                   * identifiers starting with 'x' or 'X' but preceded
                   * with '0'
                   */

                  else if (ident_index < 1 ||
                           (line[ident_index] != 'x' &&
                            line[ident_index] != 'X') ||
                           line[ident_index - 1] != '0')
                    {
                       ERROR("Mixed case identifier found",
                             lineno, ident_index);
                    }
                  else if (have_upper)
                    {
                       ERROR("Upper case hex constant found",
                             lineno, ident_index);
                    }
                }

              /* Check if the identifier is the last thing on the line */

              if (line[n] == '\n' || line[n] == '\0')
                {
                  break;
                }
            }

          /* Handle comments */

          if (line[n] == '/' && !bstring)
            {
              /* Check for start of a C comment */

              if (line[n + 1] == '*')
                {
                  if (line[n + 2] == '\n')
                    {
                      ERROR("C comment opening on separate line", lineno, n);
                    }
                  else if (!isspace((int)line[n + 2]) && line[n + 2] != '*')
                    {
                       ERROR("Missing space after opening C comment", lineno, n);
                    }

                  /* Increment the count of nested comments */

                  ncomment++;

                  /* If there is anything to the left of the left brace, then
                   * this must be a comment to the right of code.
                   * Also if preceding comments were to the right of code, then
                   * we can assume that there is a columnar alignment of columns
                   * that do no follow the usual alignment.  So the brhcomment
                   * flag should propagate.
                   */

                  brhcomment = ((n != indent) || prevbrhcmt);

                  n++;
                  continue;
                }

              /* Check for end of a C comment */

              else if (n > 0 && line[n - 1] == '*')
                {
                  if (n < 2)
                    {
                      ERROR("Closing C comment not indented", lineno, n);
                    }
                  else if (!isspace((int)line[n + 1]) && line[n - 2] != '*')
                    {
                       ERROR("Missing space before closing C comment", lineno,
                             n);
                    }

                  /* Check for block comments that are not on a separate line.
                   * This would be the case if we are we are within a comment
                   * that did not start on this line and the current line is
                   * not blank up to the point where the comment was closed.
                   */

                  if (prevncomment > 0 && !bblank && !brhcomment)
                    {
                       ERROR("Block comment terminator must be on a "
                              "separate line", lineno, n);
                    }

#if 0
                  /* REVISIT: Generates false alarms when portions of an
                   * expression are commented out within the expression.
                   */

                  if (line[n + 1] != '\n')
                    {
                       ERROR("Garbage on line after C comment", lineno, n);
                    }
#endif

                  /* Handle nested comments */

                  if (ncomment > 0)
                    {
                      /* Remember the line number of the line containing the
                       * closing of the outermost comment.
                       */

                      if (--ncomment == 0)
                        {
                          /* 'comment_lineno 'holds the line number of the
                           * last closing comment.  It is used only to
                           * verify that the comment is followed by a blank
                           * line.
                           */

                          comment_lineno = lineno;

                          /* Note that brhcomment must persist to support a
                           * later test for comment alignment.  We will fix
                           * that at the top of the loop when ncomment == 0.
                           */
                        }
                    }
                  else
                    {
                      /* Note that brhcomment must persist to support a later
                       * test for comment alignment.  We will will fix that
                       * at the top of the loop when ncomment == 0.
                       */

                      ncomment = 0;
                       ERROR("Closing without opening comment", lineno, n);
                    }

                  n++;
                  continue;
                }

              /* Check for C++ style comments */

              else if (line[n + 1] == '/')
                {
                  /* Check for "http://" or "https://" */

                  if ((n < 5 || strncmp(&line[n - 5], "http://", 7) != 0) &&
                      (n < 6 || strncmp(&line[n - 6], "https://", 8) != 0))
                    {
                      ERROR("C++ style comment", lineno, n);
                      n++;
                      continue;
                    }
                }
            }

          /* Check if the line is blank so far.  This is only used to
           * to verify the the closing of a block comment is on a separate
           * line.  So we also need to treat '*' as a 'blank'.
           */

          if (!isblank(line[n]) && line[n] != '*')
            {
              bblank = false;
            }

          /* Check for a string... ignore if we are in the middle of a
           * comment.
           */

          if (ncomment == 0)
            {
              /* Backslash quoted character */

              if (line[n] == '\\')
                {
                  bquote = true;
                  n++;
                }

              /* Check for quoted characters: \" in string */

              if (line[n] == '"' && !bquote)
                {
                  bstring = !bstring;
                }

              bquote = false;
            }

          /* The reset of the line is only examined of we are not in a comment
           * or a string.
           *
           * REVISIT: Should still check for whitespace at the end of the
           * line.
           */

          if (ncomment == 0 && !bstring)
            {
              switch (line[n])
                {
                /* Handle logic nested with curly braces */

                case '{':
                  {
                    if (n > indent)
                      {
                        /* REVISIT: dnest is always > 0 here if bfunctions == false */

                        if (dnest == 0 || !bfunctions)
                          {
                             ERROR("Left bracket not on separate line", lineno,
                                   n);
                          }
                      }
                    else if (line[n + 1] != '\n')
                      {
                        if (dnest == 0)
                          {
                             ERROR("Garbage follows left bracket", lineno, n);
                          }
                      }

                    bnest++;
                    if (dnest > 0)
                      {
                        dnest++;
                      }

                    /* Check if we are within 'extern "C"', we don't
                     * normally indent in that case because the 'extern "C"'
                     * is conditioned on __cplusplus.
                     */

                    if (lineno == externc_lineno ||
                        lineno - 1 == externc_lineno)
                      {
                        bexternc = true;
                      }

                    /* Suppress error for comment following a left brace */

                    noblank_lineno = lineno;
                    lbrace_lineno  = lineno;
                  }
                  break;

                case '}':
                  {
                   /* Decrement the brace nesting level */

                   if (bnest < 1)
                     {
                       ERROR("Unmatched right brace", lineno, n);
                     }
                   else
                     {
                       bnest--;
                       if (bnest < 1)
                         {
                           bnest = 0;
                           bswitch = false;
                         }
                     }

                    /* Decrement the declaration nesting level */

                    if (dnest < 3)
                      {
                        dnest = 0;
                        bexternc = false;
                      }
                    else
                      {
                        dnest--;
                      }

                    /* The right brace should be on a separate line */

                    if (n > indent)
                      {
                        if (dnest == 0)
                          {
                             ERROR("Right bracket not on separate line",
                                   lineno, n);
                          }
                      }

                    /* Check for garbage following the left brace */

                    if (line[n + 1] != '\n' &&
                        line[n + 1] != ',' &&
                        line[n + 1] != ';')
                      {
                        int sndx = n + 1;
                        bool whitespace = false;

                        /* Skip over spaces */

                        while (line[sndx] == ' ')
                          {
                            sndx++;
                          }

                        /* One possibility is that the right bracket is
                         * followed by an identifier then a semi-colon.
                         * Comma is possible to but would be a case of
                         * multiple declaration of multiple instances.
                         */

                        if (line[sndx] == '_' || isalpha(line[sndx]))
                          {
                            int endx = sndx;

                            /* Skip to the end of the identifier.  Checking
                             * for mixed case identifiers will be done
                             * elsewhere.
                             */

                            while (line[endx] == '_' ||
                                   isalnum(line[endx]))
                              {
                                endx++;
                              }

                            /* Skip over spaces */

                            while (line[endx] == ' ')
                              {
                                whitespace = true;
                                endx++;
                              }

                            /* Handle according to what comes after the
                             * identifier.
                             */

                            if (strncmp(&line[sndx], "while", 5) == 0)
                              {
                                 ERROR("'while' must be on a separate line",
                                        lineno, sndx);
                              }
                            else if (line[endx] == ',')
                              {
                                 ERROR("Multiple data definitions on line",
                                        lineno, endx);
                              }
                            else if (line[endx] == ';')
                              {
                                if (whitespace)
                                  {
                                     ERROR("Space precedes semi-colon",
                                           lineno, endx);
                                  }
                              }
                            else
                              {
                                 ERROR("Garbage follows right bracket",
                                       lineno, n);
                              }
                          }
                        else
                          {
                             ERROR("Garbage follows right bracket", lineno, n);
                          }
                      }

                    /* The right brace should not be preceded with a a blank line */

                    if (lineno == blank_lineno + 1)
                      {
                         ERROR("Blank line precedes right brace at line",
                                lineno, 1);
                      }

                    rbrace_lineno  = lineno;
                  }
                  break;

                /* Handle logic with parentheses */

                case '(':
                  {
                    /* Increase the parenthetical nesting level */

                    pnest++;

                   /* Check for inappropriate space around parentheses */

                    if (line[n + 1] == ' ')  /* && !bfor */
                      {
                         ERROR("Space follows left parenthesis", lineno, n);
                      }
                  }
                  break;

                case ')':
                  {
                    /* Decrease the parenthetical nesting level */

                    if (pnest < 1)
                     {
                       ERROR("Unmatched right parentheses", lineno, n);
                       pnest = 0;
                     }
                   else
                     {
                       pnest--;
                     }

                    /* Allow ')' as first thing on the line (n == indent)
                     * Allow "for (xx; xx; )" (bfor == true)
                     */

                    if (n > 0 && n != indent && line[n - 1] == ' ' && !bfor)
                      {
                         ERROR("Space precedes right parenthesis", lineno, n);
                      }
                  }
                  break;

                /* Check for inappropriate space around square brackets */

                case '[':
                  {
                    if (line[n + 1] == ' ')
                      {
                         ERROR("Space follows left bracket", lineno, n);
                      }
                  }
                  break;

                case ']':
                  {
                    if (n > 0 && line[n - 1] == ' ')
                      {
                         ERROR("Space precedes right bracket", lineno, n);
                      }
                  }
                  break;

                /* Semi-colon may terminate a declaration */

                case ';':
                  {
                    if (!isspace((int)line[n + 1]))
                      {
                        ERROR("Missing whitespace after semicolon", lineno, n);
                      }

                    /* Semicolon terminates a declaration/definition if there
                     * was no left curly brace (i.e., dnest is only 1).
                     */

                    if (dnest == 1)
                      {
                        dnest = 0;
                      }
                  }
                  break;

                /* Semi-colon may terminate a declaration */

                case ',':
                  {
                    if (!isspace((int)line[n + 1]))
                      {
                        ERROR("Missing whitespace after comma", lineno, n);
                      }
                  }
                  break;

                /* Skip over character constants */

                case '\'':
                  {
                    int endndx = n + 2;

                    if (line[n + 1] != '\n' && line[n + 1] != '\0')
                      {
                        if (line[n + 1] == '\\')
                          {
                            for (;
                                 line[endndx] != '\n' &&
                                 line[endndx] != '\0' &&
                                 line[endndx] != '\'';
                                 endndx++);
                          }

                        n = endndx + 1;
                      }
                  }
                  break;

                /* Check for space around various operators */

                case '-':

                  /* ->, -- */

                  if (line[n + 1] == '>' || line[n + 1] == '-')
                    {
                      n++;
                    }

                  /* -= */

                  else if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else
                    {
                      /* '-' may function as a unary operator and snuggle
                       * on the left.
                       */

                      check_spaces_left(line, lineno, n);
                    }

                  break;

                case '+':

                  /* ++ */

                  if (line[n + 1] == '+')
                    {
                      n++;
                    }

                  /* += */

                  else if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else
                    {
                      /* '+' may function as a unary operator and snuggle
                       * on the left.
                       */

                      check_spaces_left(line, lineno, n);
                    }

                  break;

                case '&':

                  /* &<variable> OR &(<expression>) */

                  if (isalpha((int)line[n + 1]) || line[n + 1] == '_' ||
                      line[n + 1] == '(')
                    {
                    }

                  /* &&, &= */

                  else if (line[n + 1] == '=' || line[n + 1] == '&')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else
                    {
                      check_spaces_leftright(line, lineno, n, n);
                    }

                  break;

                case '/':

                  /* C comment terminator*/

                  if (line[n - 1] == '*')
                    {
                      n++;
                    }

                    /* C++-style comment */

                  else if (line[n + 1] == '/')
                    {
                      /* Check for "http://" or "https://" */

                      if ((n < 5 || strncmp(&line[n - 5], "http://", 7) != 0) &&
                          (n < 6 || strncmp(&line[n - 6], "https://", 8) != 0))
                        {
                          ERROR("C++ style comment on at %d:%d\n",
                                lineno, n);
                        }

                      n++;
                    }

                  /* /= */

                  else if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }

                  /* Division operator */

                  else
                    {
                      check_spaces_leftright(line, lineno, n, n);
                    }

                  break;

                case '*':

                  /* *\/, ** */

                  if (line[n] == '*' &&
                      (line[n + 1] == '/' ||
                       line[n + 1] == '*'))
                    {
                     n++;
                     break;
                    }

                  /* *<variable>, *(<expression>) */

                  else if (isalpha((int)line[n + 1]) ||
                           line[n + 1] == '_' ||
                           line[n + 1] == '(')
                    {
                      break;
                    }

                  /* (<type> *) */

                  else if (line[n + 1] == ')')
                    {
                      /* REVISIT: This gives false alarms on syntax like *--ptr */

                      if (line[n - 1] != ' ')
                        {
                           ERROR("Operator/assignment must be preceded "
                                  "with whitespace", lineno, n);
                        }

                      break;
                    }

                  /* *= */

                  else if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else
                    {
                      /* A single '*' may be an binary operator, but
                       * it could also be a unary operator when used to deference
                       * a pointer.
                       */

                      check_spaces_left(line, lineno, n);
                    }

                  break;

                case '%':

                  /* %= */

                  if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else
                    {
                      check_spaces_leftright(line, lineno, n, n);
                    }

                  break;

                case '<':

                  /* <=, <<, <<= */

                  if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else if (line[n + 1] == '<')
                    {
                      if (line[n + 2] == '=')
                        {
                          check_spaces_leftright(line, lineno, n, n + 2);
                          n += 2;
                        }
                      else
                        {
                          check_spaces_leftright(line, lineno, n, n + 1);
                          n++;
                        }
                    }
                  else
                    {
                      check_spaces_leftright(line, lineno, n, n);
                    }

                  break;

                case '>':

                  /* >=, >>, >>= */

                  if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else if (line[n + 1] == '>')
                    {
                      if (line[n + 2] == '=')
                        {
                          check_spaces_leftright(line, lineno, n, n + 2);
                          n += 2;
                        }
                      else
                        {
                          check_spaces_leftright(line, lineno, n, n + 1);
                          n++;
                        }
                    }
                  else
                    {
                      check_spaces_leftright(line, lineno, n, n);
                    }

                  break;

                case '|':

                  /* |=, || */

                  if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else if (line[n + 1] == '|')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else
                    {
                      check_spaces_leftright(line, lineno, n, n);
                    }

                  break;

                case '^':

                  /* ^= */

                  if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else
                    {
                      check_spaces_leftright(line, lineno, n, n);
                    }

                  break;

                case '=':

                  /* == */

                  if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }
                  else
                    {
                      check_spaces_leftright(line, lineno, n, n);
                    }

                  break;

                case '~':
                  check_spaces_left(line, lineno, n);
                  break;

                case '!':

                  /* != */

                  if (line[n + 1] == '=')
                    {
                      check_spaces_leftright(line, lineno, n, n + 1);
                      n++;
                    }

                  /* !! */

                  else if (line[n + 1] == '!')
                    {
                      check_spaces_left(line, lineno, n);
                      n++;
                    }
                  else
                    {
                      check_spaces_left(line, lineno, n);
                    }

                  break;

                default:
                  break;
                }
            }
        }

      /* Loop terminates when NUL or newline character found */

      if (line[n] == '\n')
        {
          /* Check for space at the end of the line.  Except for carriage
           * returns which we have already reported (one time) above.
           */

          if (n > 1 && isspace((int)line[n - 1]) && line[n - 1] != '\r')
            {
               ERROR("Dangling whitespace at the end of line", lineno, n);
            }

          /* Check for long lines */

          if (n > g_maxline)
            {
              if (g_file_type == C_SOURCE)
                {
                  ERROR("Long line found", lineno, n);
                }
              else if (g_file_type == C_HEADER)

                {
                  WARN("Long line found", lineno, n);
                }
            }
        }

      /* STEP 4: Check alignment */

      /* Within a comment block, we need only check on the alignment of the
       * comment.
       */

      if ((ncomment > 0 || prevncomment > 0) && !bstring)
        {
          /* Nothing should begin in comment zero */

          if (indent == 0 && line[0] != '/' && !bexternc)
            {
              /* NOTE:  if this line contains a comment to the right of the
               * code, then ncomment will be misleading because it was
               * already incremented above.
               */

              if (ncomment > 1 || !brhcomment)
                {
                  ERROR("No indentation line", lineno, indent);
                }
            }
          else if (indent == 1 && line[0] == ' ' && line[1] == '*')
            {
              /* Good indentation */
            }
          else if (indent > 0 && line[indent] == '\n')
            {
              ERROR("Whitespace on blank line", lineno, indent);
            }
          else if (indent > 0 && indent < 2)
            {
              if (bnest > 0)
                {
                  ERROR("Insufficient indentation", lineno, indent);
                }
              else
                {
                  ERROR("Expected indentation line", lineno, indent);
                }
            }
          else if (indent > 0 && !bswitch)
            {
              if (line[indent] == '/')
                {
                  /* Comments should like at offsets 2, 6, 10, ...
                   * This rule is not followed, however, if the comments are
                   * aligned to the right of the code.
                   */

                  if ((indent & 3) != 2 && !brhcomment)
                    {
                       ERROR("Bad comment alignment", lineno, indent);
                    }

                  /* REVISIT:  This screws up in cases where there is C code,
                   * followed by a comment that continues on the next line.
                   */

                  else if (line[indent + 1] != '*')
                    {
                       ERROR("Missing asterisk in comment", lineno, indent);
                    }
                }
              else if (line[indent] == '*')
                {
                  /* REVISIT: Generates false alarms on comments at the end of
                   * the line if there is nothing preceding (such as the aligned
                   * comments with a structure field definition).  So disabled for
                   * comments before beginning of function definitions.
                   *
                   * Suppress this error if this is a comment to the right of code.
                   * Those may be unaligned.
                   */

                  if ((indent & 3) != 3 && bfunctions && dnest == 0 &&
                      !brhcomment)
                    {
                       ERROR("Bad comment block alignment", lineno, indent);
                    }

                  if (line[indent + 1] != ' ' &&
                      line[indent + 1] != '*' &&
                      line[indent + 1] != '\n' &&
                      line[indent + 1] != '/')
                    {
                       ERROR("Invalid character after asterisk "
                             "in comment block", lineno, indent);
                    }
                }

              /* If this is not the line containing the comment start, then this
               * line should begin with '*'
               */

              else if (prevncomment > 0)
                {
                  ERROR("Missing asterisk in comment block", lineno, indent);
                }
            }
        }

      /* Check for various alignment outside of the comment block */

      else if ((ncomment == 0 && prevncomment == 0) && !bstring)
        {
          if (indent == 0 && strchr("\n#{}", line[0]) == NULL)
            {
               /* Ignore if we are at global scope */

               if (prevbnest > 0)
                {
                  bool blabel = false;

                  if (isalpha((int)line[indent]))
                    {
                      for (i = indent + 1; isalnum((int)line[i]) ||
                           line[i] == '_'; i++);
                      blabel = (line[i] == ':');
                    }

                  if (!blabel && !bexternc)
                    {
                      ERROR("No indentation line", lineno, indent);
                    }
                }
            }
          else if (indent == 1 && line[0] == ' ' && line[1] == '*')
            {
              /* Good indentation */
            }
          else if (indent > 0 && line[indent] == '\n')
            {
              ERROR("Whitespace on blank line", lineno, indent);
            }
          else if (indent > 0 && indent < 2)
            {
              ERROR("Insufficient indentation line", lineno, indent);
            }
          else if (line[indent] == '{')
            {
              /* Check for left brace in first column, but preceded by a
               * blank line.  Should never happen (but could happen with
               * internal compound statements).
               */

              if (indent == 0 && lineno == blank_lineno + 1)
                {
                  ERROR("Blank line before opening left brace", lineno, indent);
                }

              /* REVISIT:  Possible false alarms in compound statements
               * without a preceding conditional.  That usage often violates
               * the coding standard.
               */

              else if (!bfunctions && (indent & 1) != 0)
                {
                  ERROR("Bad left brace alignment", lineno, indent);
                }
              else if ((indent & 3) != 0 && !bswitch && dnest == 0)
                {
                  ERROR("Bad left brace alignment", lineno, indent);
                }
            }
          else if (line[indent] == '}')
            {
              /* REVISIT:  Possible false alarms in compound statements
               * without a preceding conditional.  That usage often violates
               * the coding standard.
               */

              if (!bfunctions && (indent & 1) != 0)
                {
                  ERROR("right left brace alignment", lineno, indent);
                }
              else if ((indent & 3) != 0 && !bswitch && prevdnest == 0)
                {
                  ERROR("Bad right brace alignment", lineno, indent);
                }
            }
          else if (indent > 0)
            {
              /* REVISIT: Generates false alarms when a statement continues on
               * the next line.  The bstatm check limits to lines beginning
               * with C keywords.
               * REVISIT:  The bstatm check will not detect statements that
               * do not begin with a C keyword (such as assignment statements).
               * REVISIT: Generates false alarms on comments at the end of
               * the line if there is nothing preceding (such as the aligned
               * comments with a structure field definition).  So disabled for
               * comments before beginning of function definitions.
               */

              if ((bstatm ||                              /* Begins with C keyword */
                  (line[indent] == '/' && bfunctions)) && /* Comment in functions */
                  !bswitch &&                             /* Not in a switch */
                  dnest == 0)                             /* Not a data definition */
                {
                  if ((indent & 3) != 2)
                    {
                      ERROR("Bad alignment", lineno, indent);
                    }
                }

              /* Crazy cases.  There should be no small odd alignments
               * outside of comment/string.  Odd alignments are possible
               * on continued lines, but not if they are small.
               */

              else if (indent == 1 || indent == 3)
                {
                  ERROR("Small odd alignment", lineno, indent);
                }
            }
        }
    }

  if (!bfunctions && g_file_type == C_SOURCE)
    {
      ERROR("\"Private/Public Functions\" not found!"
            " File was not be checked", lineno, 1);
    }

  if (ncomment > 0 || bstring)
    {
      ERROR("Comment or string found at end of file", lineno, 1);
    }

  fclose(instream);
  if (g_verbose == 1)
    {
      fprintf(stderr, "%s: %s nxstyle check\n", g_file_name,
              g_status == 0 ? "PASSED" : "FAILED");
    }

  return g_status;
}