text: /* vi: set sw=4 ts=4: */
  /*
   * SuS3 compliant sort implementation for busybox
   *
   * Copyright (C) 2004 by Rob Landley <rob@landley.net>
   *
   * MAINTAINER: Rob Landley <rob@landley.net>
   *
   * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   *
   * See SuS3 sort standard at:
   * http://www.opengroup.org/onlinepubs/007904975/utilities/sort.html
   */
  
  #include "libbb.h"
  
  /* This is a NOEXEC applet. Be very careful! */
  
  
  /*
  	sort [-m][-o output][-bdfinru][-t char][-k keydef]... [file...]
  	sort -c [-bdfinru][-t char][-k keydef][file]
  */
  
  /* These are sort types */
  static const char OPT_STR[] ALIGN1 = "ngMucszbrdfimS:T:o:k:t:";
  enum {
  	FLAG_n  = 1,            /* Numeric sort */
  	FLAG_g  = 2,            /* Sort using strtod() */
  	FLAG_M  = 4,            /* Sort date */
  /* ucsz apply to root level only, not keys.  b at root level implies bb */
  	FLAG_u  = 8,            /* Unique */
  	FLAG_c  = 0x10,         /* Check: no output, exit(!ordered) */
  	FLAG_s  = 0x20,         /* Stable sort, no ascii fallback at end */
  	FLAG_z  = 0x40,         /* Input and output is NUL terminated, not \n */
  /* These can be applied to search keys, the previous four can't */
  	FLAG_b  = 0x80,         /* Ignore leading blanks */
  	FLAG_r  = 0x100,        /* Reverse */
  	FLAG_d  = 0x200,        /* Ignore !(isalnum()|isspace()) */
  	FLAG_f  = 0x400,        /* Force uppercase */
  	FLAG_i  = 0x800,        /* Ignore !isprint() */
  	FLAG_m  = 0x1000,       /* ignored: merge already sorted files; do not sort */
  	FLAG_S  = 0x2000,       /* ignored: -S, --buffer-size=SIZE */
  	FLAG_T  = 0x4000,       /* ignored: -T, --temporary-directory=DIR */
  	FLAG_o  = 0x8000,
  	FLAG_k  = 0x10000,
  	FLAG_t  = 0x20000,
  	FLAG_bb = 0x80000000,   /* Ignore trailing blanks  */
  };
  
  #if ENABLE_FEATURE_SORT_BIG
  static char key_separator;
  
  static struct sort_key {
  	struct sort_key *next_key;  /* linked list */
  	unsigned range[4];          /* start word, start char, end word, end char */
  	unsigned flags;
  } *key_list;
  
  static char *get_key(char *str, struct sort_key *key, int flags)
  {
  	int start = 0, end = 0, len, j;
  	unsigned i;
  
  	/* Special case whole string, so we don't have to make a copy */
  	if (key->range[0] == 1 && !key->range[1] && !key->range[2] && !key->range[3]
  	 && !(flags & (FLAG_b | FLAG_d | FLAG_f | FLAG_i | FLAG_bb))
  	) {
  		return str;
  	}
  
  	/* Find start of key on first pass, end on second pass */
  	len = strlen(str);
  	for (j = 0; j < 2; j++) {
  		if (!key->range[2*j])
  			end = len;
  		/* Loop through fields */
  		else {
  			end = 0;
  			for (i = 1; i < key->range[2*j] + j; i++) {
  				if (key_separator) {
  					/* Skip body of key and separator */
  					while (str[end]) {
  						if (str[end++] == key_separator)
  							break;
  					}
  				} else {
  					/* Skip leading blanks */
  					while (isspace(str[end]))
  						end++;
  					/* Skip body of key */
  					while (str[end]) {
  						if (isspace(str[end]))
  							break;
  						end++;
  					}
  				}
  			}
  		}
  		if (!j) start = end;
  	}
  	/* Strip leading whitespace if necessary */
  //XXX: skip_whitespace()
  	if (flags & FLAG_b)
  		while (isspace(str[start])) start++;
  	/* Strip trailing whitespace if necessary */
  	if (flags & FLAG_bb)
  		while (end > start && isspace(str[end-1])) end--;
  	/* Handle offsets on start and end */
  	if (key->range[3]) {
  		end += key->range[3] - 1;
  		if (end > len) end = len;
  	}
  	if (key->range[1]) {
  		start += key->range[1] - 1;
  		if (start > len) start = len;
  	}
  	/* Make the copy */
  	if (end < start) end = start;
  	str = xstrndup(str+start, end-start);
  	/* Handle -d */
  	if (flags & FLAG_d) {
  		for (start = end = 0; str[end]; end++)
  			if (isspace(str[end]) || isalnum(str[end]))
  				str[start++] = str[end];
  		str[start] = '\0';
  	}
  	/* Handle -i */
  	if (flags & FLAG_i) {
  		for (start = end = 0; str[end]; end++)
  			if (isprint_asciionly(str[end]))
  				str[start++] = str[end];
  		str[start] = '\0';
  	}
  	/* Handle -f */
  	if (flags & FLAG_f)
  		for (i = 0; str[i]; i++)
  			str[i] = toupper(str[i]);
  
  	return str;
  }
  
  static struct sort_key *add_key(void)
  {
  	struct sort_key **pkey = &key_list;
  	while (*pkey)
  		pkey = &((*pkey)->next_key);
  	return *pkey = xzalloc(sizeof(struct sort_key));
  }
  
  #define GET_LINE(fp) \
  	((option_mask32 & FLAG_z) \
  	? bb_get_chunk_from_file(fp, NULL) \
  	: xmalloc_fgetline(fp))
  #else
  #define GET_LINE(fp) xmalloc_fgetline(fp)
  #endif
  
  /* Iterate through keys list and perform comparisons */
  static int compare_keys(const void *xarg, const void *yarg)
  {
  	int flags = option_mask32, retval = 0;
  	char *x, *y;
  
  #if ENABLE_FEATURE_SORT_BIG
  	struct sort_key *key;
  
  	for (key = key_list; !retval && key; key = key->next_key) {
  		flags = key->flags ? key->flags : option_mask32;
  		/* Chop out and modify key chunks, handling -dfib */
  		x = get_key(*(char **)xarg, key, flags);
  		y = get_key(*(char **)yarg, key, flags);
  #else
  	/* This curly bracket serves no purpose but to match the nesting
  	   level of the for () loop we're not using */
  	{
  		x = *(char **)xarg;
  		y = *(char **)yarg;
  #endif
  		/* Perform actual comparison */
  		switch (flags & 7) {
  		default:
  			bb_error_msg_and_die("unknown sort type");
  			break;
  		/* Ascii sort */
  		case 0:
  #if ENABLE_LOCALE_SUPPORT
  			retval = strcoll(x, y);
  #else
  			retval = strcmp(x, y);
  #endif
  			break;
  #if ENABLE_FEATURE_SORT_BIG
  		case FLAG_g: {
  			char *xx, *yy;
  			double dx = strtod(x, &xx);
  			double dy = strtod(y, &yy);
  			/* not numbers < NaN < -infinity < numbers < +infinity) */
  			if (x == xx)
  				retval = (y == yy ? 0 : -1);
  			else if (y == yy)
  				retval = 1;
  			/* Check for isnan */
  			else if (dx != dx)
  				retval = (dy != dy) ? 0 : -1;
  			else if (dy != dy)
  				retval = 1;
  			/* Check for infinity.  Could underflow, but it avoids libm. */
  			else if (1.0 / dx == 0.0) {
  				if (dx < 0)
  					retval = (1.0 / dy == 0.0 && dy < 0) ? 0 : -1;
  				else
  					retval = (1.0 / dy == 0.0 && dy > 0) ? 0 : 1;
  			} else if (1.0 / dy == 0.0)
  				retval = (dy < 0) ? 1 : -1;
  			else
  				retval = (dx > dy) ? 1 : ((dx < dy) ? -1 : 0);
  			break;
  		}
  		case FLAG_M: {
  			struct tm thyme;
  			int dx;
  			char *xx, *yy;
  
  			xx = strptime(x, "%b", &thyme);
  			dx = thyme.tm_mon;
  			yy = strptime(y, "%b", &thyme);
  			if (!xx)
  				retval = (!yy) ? 0 : -1;
  			else if (!yy)
  				retval = 1;
  			else
  				retval = (dx == thyme.tm_mon) ? 0 : dx - thyme.tm_mon;
  			break;
  		}
  		/* Full floating point version of -n */
  		case FLAG_n: {
  			double dx = atof(x);
  			double dy = atof(y);
  			retval = (dx > dy) ? 1 : ((dx < dy) ? -1 : 0);
  			break;
  		}
  		} /* switch */
  		/* Free key copies. */
  		if (x != *(char **)xarg) free(x);
  		if (y != *(char **)yarg) free(y);
  		/* if (retval) break; - done by for () anyway */
  #else
  		/* Integer version of -n for tiny systems */
  		case FLAG_n:
  			retval = atoi(x) - atoi(y);
  			break;
  		} /* switch */
  #endif
  	} /* for */
  
  	/* Perform fallback sort if necessary */
  	if (!retval && !(option_mask32 & FLAG_s))
  		retval = strcmp(*(char **)xarg, *(char **)yarg);
  
  	if (flags & FLAG_r) return -retval;
  	return retval;
  }
  
  #if ENABLE_FEATURE_SORT_BIG
  static unsigned str2u(char **str)
  {
  	unsigned long lu;
  	if (!isdigit((*str)[0]))
  		bb_error_msg_and_die("bad field specification");
  	lu = strtoul(*str, str, 10);
  	if ((sizeof(long) > sizeof(int) && lu > INT_MAX) || !lu)
  		bb_error_msg_and_die("bad field specification");
  	return lu;
  }
  #endif
  
  int sort_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  int sort_main(int argc UNUSED_PARAM, char **argv)
  {
  	char *line, **lines;
  	char *str_ignored, *str_o, *str_t;
  	llist_t *lst_k = NULL;
  	int i, flag;
  	int linecount;
  	unsigned opts;
  
  	xfunc_error_retval = 2;
  
  	/* Parse command line options */
  	/* -o and -t can be given at most once */
  	opt_complementary = "o--o:t--t:" /* -t, -o: at most one of each */
  			"k::"; /* -k takes list */
  	opts = getopt32(argv, OPT_STR, &str_ignored, &str_ignored, &str_o, &lst_k, &str_t);
  	/* global b strips leading and trailing spaces */
  	if (opts & FLAG_b)
  		option_mask32 |= FLAG_bb;
  #if ENABLE_FEATURE_SORT_BIG
  	if (opts & FLAG_t) {
  		if (!str_t[0] || str_t[1])
  			bb_error_msg_and_die("bad -t parameter");
  		key_separator = str_t[0];
  	}
  	/* note: below this point we use option_mask32, not opts,
  	 * since that reduces register pressure and makes code smaller */
  
  	/* parse sort key */
  	while (lst_k) {
  		enum {
  			FLAG_allowed_for_k =
  				FLAG_n | /* Numeric sort */
  				FLAG_g | /* Sort using strtod() */
  				FLAG_M | /* Sort date */
  				FLAG_b | /* Ignore leading blanks */
  				FLAG_r | /* Reverse */
  				FLAG_d | /* Ignore !(isalnum()|isspace()) */
  				FLAG_f | /* Force uppercase */
  				FLAG_i | /* Ignore !isprint() */
  			0
  		};
  		struct sort_key *key = add_key();
  		char *str_k = llist_pop(&lst_k);
  
  		i = 0; /* i==0 before comma, 1 after (-k3,6) */
  		while (*str_k) {
  			/* Start of range */
  			/* Cannot use bb_strtou - suffix can be a letter */
  			key->range[2*i] = str2u(&str_k);
  			if (*str_k == '.') {
  				str_k++;
  				key->range[2*i+1] = str2u(&str_k);
  			}
  			while (*str_k) {
  				const char *temp2;
  
  				if (*str_k == ',' && !i++) {
  					str_k++;
  					break;
  				} /* no else needed: fall through to syntax error
  					because comma isn't in OPT_STR */
  				temp2 = strchr(OPT_STR, *str_k);
  				if (!temp2)
  					bb_error_msg_and_die("unknown key option");
  				flag = 1 << (temp2 - OPT_STR);
  				if (flag & ~FLAG_allowed_for_k)
  					bb_error_msg_and_die("unknown sort type");
  				/* b after ',' means strip _trailing_ space */
  				if (i && flag == FLAG_b)
  					flag = FLAG_bb;
  				key->flags |= flag;
  				str_k++;
  			}
  		}
  	}
  #endif
  
  	/* Open input files and read data */
  	argv += optind;
  	if (!*argv)
  		*--argv = (char*)"-";
  	linecount = 0;
  	lines = NULL;
  	do {
  		/* coreutils 6.9 compat: abort on first open error,
  		 * do not continue to next file: */
  		FILE *fp = xfopen_stdin(*argv);
  		for (;;) {
  			line = GET_LINE(fp);
  			if (!line)
  				break;
  			lines = xrealloc_vector(lines, 6, linecount);
  			lines[linecount++] = line;
  		}
  		fclose_if_not_stdin(fp);
  	} while (*++argv);
  
  #if ENABLE_FEATURE_SORT_BIG
  	/* if no key, perform alphabetic sort */
  	if (!key_list)
  		add_key()->range[0] = 1;
  	/* handle -c */
  	if (option_mask32 & FLAG_c) {
  		int j = (option_mask32 & FLAG_u) ? -1 : 0;
  		for (i = 1; i < linecount; i++) {
  			if (compare_keys(&lines[i-1], &lines[i]) > j) {
  				fprintf(stderr, "Check line %u\n", i);
  				return EXIT_FAILURE;
  			}
  		}
  		return EXIT_SUCCESS;
  	}
  #endif
  	/* Perform the actual sort */
  	qsort(lines, linecount, sizeof(lines[0]), compare_keys);
  	/* handle -u */
  	if (option_mask32 & FLAG_u) {
  		flag = 0;
  		/* coreutils 6.3 drop lines for which only key is the same */
  		/* -- disabling last-resort compare... */
  		option_mask32 |= FLAG_s;
  		for (i = 1; i < linecount; i++) {
  			if (compare_keys(&lines[flag], &lines[i]) == 0)
  				free(lines[i]);
  			else
  				lines[++flag] = lines[i];
  		}
  		if (linecount)
  			linecount = flag+1;
  	}
  
  	/* Print it */
  #if ENABLE_FEATURE_SORT_BIG
  	/* Open output file _after_ we read all input ones */
  	if (option_mask32 & FLAG_o)
  		xmove_fd(xopen(str_o, O_WRONLY|O_CREAT|O_TRUNC), STDOUT_FILENO);
  #endif
  	flag = (option_mask32 & FLAG_z) ? '\0' : '\n';
  	for (i = 0; i < linecount; i++)
  		printf("%s%c", lines[i], flag);
  
  	fflush_stdout_and_exit(EXIT_SUCCESS);
  }
  