#include <stddef.h>
#include <string.h>
#include <ctype.h>
#include "global.h"

#define SPC_GRAN 16
#define LINEBUF 128

char *the_comment;
size_t len_comment;

/*
   find_start_comment() -- return a pointer to the first comment-start
   sequence after |s|, or |NULL| if none is found
*/
static char *find_start_comment(s)
  register char *s;
{
  int in_dq = 0, in_sq = 0;

  for (;;) {
    switch (*s++) {
    case '\0':
      return NULL;
    case '\\':
      s++;
      continue;
    case '"':
      if (!in_sq)
	in_dq ^= 1;
      break;
    case '\'':
      if (!in_dq)
	in_sq ^= 1;
      break;
    case '/':
      if (!in_dq && !in_sq && *s == '*')
	return s - 1;
    }
  }
}

/*
   find_end_comment() -- return a pointer to the first character after the
   current comment, or end of line if the comment does not end on this line.
   Modifies |in_comment| appropriately.
*/
static char *find_end_comment(s)
  register char *s;
{
  for (; *s; s++) {
    if (*s == '*' && s[1] == '/')
      return s + 2;
  }
  return NULL;
}

/*
   nest_check() -- examine the body of a comment for comment-start sequences.
   Return 1 if one is found, 0 if not.
*/
static int nest_check(s, t)
  char *s, *t;
{
  register char *u;

  if (!t)
    t = s + strlen(s);
  if (f_cpp_cmts) {
    for (u = s; u < t - 1; u++)
      if (*u == '/' && (u[1] == '*' || u[1] == '/'))
	return 1;
  } else {
    for (u = s; u < t - 1; u++)
      if (*u == '/' && u[1] == '*')
	return 1;
  }
  return 0;
}

/*
   copy_comment() -- place a malloc()'ed copy of the comment beginning at |s|
   into the global pointer |the_comment|.  Return a pointer to the first
   character after the comment.
*/
static char *copy_comment(s)
  char *s;
{
  register char *in_com, *t;
  int n;
  unsigned long in_comment;

  in_comment = this_line;
  in_com = the_comment = mallok(len_comment = LINEBUF);
  if (s[1] == '/') {
    free(the_comment);
    the_comment = strdup(s);
    if (w_nest_cmts && nest_check(s + 2, NULL))
      warning("nested comment (began at line %lu)", in_comment);
    return s + strlen(s);
  }
  for (;;) {
    t = find_end_comment(s);
    n = (!t ? strlen(s) + 2 : (int)(t - s) + 1);
    in_com = grow(&the_comment, &len_comment, in_com, n);
    strncpy(in_com, s, n);
    in_com += n;
    if (!t)
      *in_com++ = '\n';
    *in_com = '\0';
    if (w_nest_cmts && nest_check(s, t))
      warning("nested comment (began at line %lu)", in_comment);
    if (t)
      break;
    s = getline();
    if (!s) {
      error("unterminated comment (began at line %ld)", in_comment);
      in_com = grow(&the_comment, &len_comment, in_com, 3);
      *in_com++ = '*';
      *in_com++ = '/';
      *in_com = '\0';
      t = NULL;
      break;
    }
  }
  return t;
}

/*
   suck_comment() -- Skip over the comment beginning at |s|.  Return a
   pointer to the first character after the comment.
*/
static char *suck_comment(s)
  char *s;
{
  register char *t;
  unsigned long in_comment;

  if (keep_comments)
    return copy_comment(s);
  in_comment = this_line;
  /* C++ comments end at the end of the line */
  if (s[1] == '/') {
    if (w_nest_cmts && nest_check(s + 2, NULL))
      warning("nested comment (began at line %lu)", in_comment);
    return s + strlen(s);
  }
  for (;;) {
    t = find_end_comment(s);
    if (w_nest_cmts && nest_check(s, t))
      warning("nested comment (began at line %lu)", in_comment);
    if (t) {
      return t;
    }
    s = getline();
    if (!s) {
      error("unterminated comment (began at line %ld)", in_comment);
      return NULL;
    }
  }
}

/*
   suck_ws() -- skip over whitespace characters after |S|, placing a
   malloc()'ed copy of same in |*spc|.  Return a pointer to the first
   non-whitespace character after |s|.
*/
char *suck_ws(s, spc)
  register char *s;
  char **spc;
{
  register char *t, *u;
  char *spc_buf;
  size_t sz_spc_buf;
  int n;
  extern char *the_comment;

  u = spc_buf = mallok(sz_spc_buf = SPC_GRAN);
  for (;;) {
    t = s;
    while (isspace(*s))
      *s++;
    n = s - t;
    u = grow(&spc_buf, &sz_spc_buf, u, n + 2);
    strncpy(u, t, n);
    u += n;
    *u = '\0';
    if (!(*s == '/' && (s[1] == '*' || (f_cpp_cmts && s[1] == '/'))))
      break;
    s = suck_comment(s);
    if (!keep_comments)
      *u++ = ' ';
    else {
      n = strlen(the_comment);
      u = grow(&spc_buf, &sz_spc_buf, u, n + 1);
      strcpy(u, the_comment);
      u += n;
    }
    if (!s)
      break;
  }
  *u = '\0';
  *spc = spc_buf;
  return s;
}