/* 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 tarball for details.
 *
 * See SuS3 sort standard at:
 * http://www.opengroup.org/onlinepubs/007904975/utilities/sort.html
 */

#include "busybox.h"

static int global_flags;

/*
	sort [-m][-o output][-bdfinru][-t char][-k keydef]... [file...]
	sort -c [-bdfinru][-t char][-k keydef][file]
*/

/* These are sort types */
#define FLAG_n			1		/* Numeric sort */
#define FLAG_g			2		/* Sort using strtod() */
#define FLAG_M			4		/* Sort date */
/* ucsz apply to root level only, not keys.  b at root level implies bb */
#define FLAG_u			8		/* Unique */
#define FLAG_c			16		/* Check: no output, exit(!ordered) */
#define FLAG_s			32		/* Stable sort, no ascii fallback at end */
#define FLAG_z			64		/* Input is null terminated, not \n */
/* These can be applied to search keys, the previous four can't */
#define FLAG_b			128		/* Ignore leading blanks */
#define FLAG_r			256		/* Reverse */
#define FLAG_d			512		/* Ignore !(isalnum()|isspace()) */
#define FLAG_f			1024	/* Force uppercase */
#define FLAG_i			2048	/* Ignore !isprint() */
#define FLAG_bb			32768	/* Ignore trailing blanks  */


#if ENABLE_FEATURE_SORT_BIG
static char key_separator;

static struct sort_key {
	struct sort_key *next_key;	/* linked list */
	unsigned short range[4];	/* start word, start char, end word, end char */
	int flags;
} *key_list;

static char *get_key(char *str, struct sort_key *key, int flags)
{
	int start = 0, end = 0, len, i, j;

	/* 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++) {
				/* Skip leading blanks or first separator */
				if (str[end]) {
					if (!key_separator)
						while (isspace(str[end])) end++;
				}
				/* Skip body of key */
				for (; str[end]; end++) {
					if (key_separator) {
						if (str[end] == key_separator)
							break;
					} else {
						if (isspace(str[end]))
							break;
					}
				}
			}
		}
		if (!j) start = end;
	}
	/* Key with explicit separator starts after separator */
	if (key_separator && str[start] == key_separator)
		start++;
	/* 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(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) \
	((global_flags & FLAG_z) \
	? bb_get_chunk_from_file(fp, NULL) \
	: xmalloc_getline(fp))
#else
#define GET_LINE(fp) xmalloc_getline(fp)
#endif

/* Iterate through keys list and perform comparisons */
static int compare_keys(const void *xarg, const void *yarg)
{
	int flags = global_flags, 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 : global_flags;
		/* 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:
			retval = strcmp(x, y);
			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
	}
	/* Perform fallback sort if necessary */
	if (!retval && !(global_flags & FLAG_s))
		retval = strcmp(*(char **)xarg, *(char **)yarg);

	if (flags & FLAG_r) return -retval;
	return retval;
}

int sort_main(int argc, char **argv)
{
	FILE *fp, *outfile = NULL;
	int linecount = 0, i, flag;
	char *line, **lines = NULL, *optlist = "ngMucszbrdfimS:T:o:k:t:";
	int c;

	xfunc_error_retval = 2;
	/* Parse command line options */
	while ((c = getopt(argc, argv, optlist)) > 0) {
		line = strchr(optlist, c);
		if (!line) bb_show_usage();
		switch (*line) {
#if ENABLE_FEATURE_SORT_BIG
		case 'o':
			if (outfile) bb_error_msg_and_die("too many -o");
			outfile = xfopen(optarg, "w");
			break;
		case 't':
			if (key_separator || optarg[1])
				bb_error_msg_and_die("too many -t");
			key_separator = *optarg;
			break;
		/* parse sort key */
		case 'k': {
			struct sort_key *key = add_key();
			char *temp, *temp2;

			temp = optarg;
			for (i = 0; *temp;) {
				/* Start of range */
				key->range[2*i] = (unsigned short)strtol(temp, &temp, 10);
				if (*temp == '.')
					key->range[(2*i)+1] = (unsigned short)strtol(temp+1, &temp, 10);
				for (; *temp; temp++) {
					if (*temp == ',' && !i++) {
						temp++;
						break;
					} /* no else needed: fall through to syntax error
						 because comma isn't in optlist */
					temp2 = strchr(optlist, *temp);
					flag = (1 << (temp2 - optlist));
					if (!temp2 || (flag > FLAG_M && flag < FLAG_b))
						bb_error_msg_and_die("unknown key option");
					/* b after ',' means strip _trailing_ space */
					if (i && flag == FLAG_b) flag = FLAG_bb;
					key->flags |= flag;
				}
			}
			break;
		}
#endif
		default:
			global_flags |= (1 << (line - optlist));
			/* global b strips leading and trailing spaces */
			if (global_flags & FLAG_b) global_flags |= FLAG_bb;
			break;
		}
	}
	/* Open input files and read data */
	for (i = argv[optind] ? optind : optind-1; argv[i]; i++) {
		fp = stdin;
		if (i >= optind && (argv[i][0] != '-' || argv[i][1]))
			fp = xfopen(argv[i], "r");
		for (;;) {
			line = GET_LINE(fp);
			if (!line) break;
			if (!(linecount & 63))
				lines = xrealloc(lines, sizeof(char *) * (linecount + 64));
			lines[linecount++] = line;
		}
		fclose(fp);
	}
#if ENABLE_FEATURE_SORT_BIG
	/* if no key, perform alphabetic sort */
	if (!key_list)
		add_key()->range[0] = 1;
	/* handle -c */
	if (global_flags & FLAG_c) {
		int j = (global_flags & FLAG_u) ? -1 : 0;
		for (i = 1; i < linecount; i++)
			if (compare_keys(&lines[i-1], &lines[i]) > j) {
				fprintf(stderr, "Check line %d\n", i);
				return 1;
			}
		return 0;
	}
#endif
	/* Perform the actual sort */
	qsort(lines, linecount, sizeof(char *), compare_keys);
	/* handle -u */
	if (global_flags & FLAG_u) {
		for (flag = 0, i = 1; i < linecount; i++) {
			if (!compare_keys(&lines[flag], &lines[i]))
				free(lines[i]);
			else
				lines[++flag] = lines[i];
		}
		if (linecount) linecount = flag+1;
	}
	/* Print it */
	if (!outfile) outfile = stdout;
	for (i = 0; i < linecount; i++)
		fprintf(outfile, "%s\n", lines[i]);

	fflush_stdout_and_exit(EXIT_SUCCESS);
}