/*
 * Copyright (C) 2009-2011 the libgit2 contributors
 *
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
 */

/*
 * Function fnmatch() as specified in POSIX 1003.2-1992, section B.6.
 * Compares a filename or pathname to a pattern.
 */

#include <ctype.h>
#include <stdio.h>
#include <string.h>

#include "fnmatch.h"

#define EOS		'\0'

#define RANGE_MATCH		1
#define RANGE_NOMATCH		0
#define RANGE_ERROR		(-1)

static int rangematch(const char *, char, int, char **);

int
p_fnmatch(const char *pattern, const char *string, int flags)
{
		const char *stringstart;
		char *newp;
		char c, test;

		for (stringstart = string;;)
				switch (c = *pattern++) {
				case EOS:
						if ((flags & FNM_LEADING_DIR) && *string == '/')
								return (0);
						return (*string == EOS ? 0 : FNM_NOMATCH);
				case '?':
						if (*string == EOS)
								return (FNM_NOMATCH);
						if (*string == '/' && (flags & FNM_PATHNAME))
								return (FNM_NOMATCH);
						if (*string == '.' && (flags & FNM_PERIOD) &&
							(string == stringstart ||
							((flags & FNM_PATHNAME) && *(string - 1) == '/')))
								return (FNM_NOMATCH);
						++string;
						break;
				case '*':
						c = *pattern;
						/* Collapse multiple stars. */
						while (c == '*')
								c = *++pattern;

						if (*string == '.' && (flags & FNM_PERIOD) &&
							(string == stringstart ||
							((flags & FNM_PATHNAME) && *(string - 1) == '/')))
								return (FNM_NOMATCH);

						/* Optimize for pattern with * at end or before /. */
						if (c == EOS) {
								if (flags & FNM_PATHNAME)
										return ((flags & FNM_LEADING_DIR) ||
											strchr(string, '/') == NULL ?
											0 : FNM_NOMATCH);
								else
										return (0);
						} else if (c == '/' && (flags & FNM_PATHNAME)) {
								if ((string = strchr(string, '/')) == NULL)
										return (FNM_NOMATCH);
								break;
						}

						/* General case, use recursion. */
						while ((test = *string) != EOS) {
								if (!p_fnmatch(pattern, string, flags & ~FNM_PERIOD))
										return (0);
								if (test == '/' && (flags & FNM_PATHNAME))
										break;
								++string;
						}
						return (FNM_NOMATCH);
				case '[':
						if (*string == EOS)
								return (FNM_NOMATCH);
						if (*string == '/' && (flags & FNM_PATHNAME))
								return (FNM_NOMATCH);
						if (*string == '.' && (flags & FNM_PERIOD) &&
							(string == stringstart ||
							((flags & FNM_PATHNAME) && *(string - 1) == '/')))
								return (FNM_NOMATCH);

						switch (rangematch(pattern, *string, flags, &newp)) {
						case RANGE_ERROR:
								/* not a good range, treat as normal text */
								goto normal;
						case RANGE_MATCH:
								pattern = newp;
								break;
						case RANGE_NOMATCH:
								return (FNM_NOMATCH);
						}
						++string;
						break;
				case '\\':
						if (!(flags & FNM_NOESCAPE)) {
								if ((c = *pattern++) == EOS) {
										c = '\\';
										--pattern;
								}
						}
						/* FALLTHROUGH */
				default:
				normal:
						if (c != *string && !((flags & FNM_CASEFOLD) &&
									(tolower((unsigned char)c) ==
									tolower((unsigned char)*string))))
								return (FNM_NOMATCH);
						++string;
						break;
				}
		/* NOTREACHED */
}

static int
rangematch(const char *pattern, char test, int flags, char **newp)
{
		int negate, ok;
		char c, c2;

		/*
			* A bracket expression starting with an unquoted circumflex
			* character produces unspecified results (IEEE 1003.2-1992,
			* 3.13.2). This implementation treats it like '!', for
			* consistency with the regular expression syntax.
			* J.T. Conklin (conklin@ngai.kaleida.com)
			*/
		if ((negate = (*pattern == '!' || *pattern == '^')) != 0)
				++pattern;

		if (flags & FNM_CASEFOLD)
				test = (char)tolower((unsigned char)test);

		/*
			* A right bracket shall lose its special meaning and represent
			* itself in a bracket expression if it occurs first in the list.
			* -- POSIX.2 2.8.3.2
			*/
		ok = 0;
		c = *pattern++;
		do {
				if (c == '\\' && !(flags & FNM_NOESCAPE))
						c = *pattern++;
				if (c == EOS)
						return (RANGE_ERROR);
				if (c == '/' && (flags & FNM_PATHNAME))
						return (RANGE_NOMATCH);
				if ((flags & FNM_CASEFOLD))
						c = (char)tolower((unsigned char)c);
				if (*pattern == '-'
					&& (c2 = *(pattern+1)) != EOS && c2 != ']') {
						pattern += 2;
						if (c2 == '\\' && !(flags & FNM_NOESCAPE))
								c2 = *pattern++;
						if (c2 == EOS)
								return (RANGE_ERROR);
						if (flags & FNM_CASEFOLD)
								c2 = (char)tolower((unsigned char)c2);
						if (c <= test && test <= c2)
								ok = 1;
				} else if (c == test)
						ok = 1;
		} while ((c = *pattern++) != ']');

		*newp = (char *)pattern;
		return (ok == negate ? RANGE_NOMATCH : RANGE_MATCH);
}