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Diffstat (limited to 'package/toolbox/src/grep/fastgrep.c')
| -rw-r--r-- | package/toolbox/src/grep/fastgrep.c | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/package/toolbox/src/grep/fastgrep.c b/package/toolbox/src/grep/fastgrep.c new file mode 100644 index 000000000..2fcd864e2 --- /dev/null +++ b/package/toolbox/src/grep/fastgrep.c @@ -0,0 +1,336 @@ +/* $OpenBSD: util.c,v 1.36 2007/10/02 17:59:18 otto Exp $ */ +/* $FreeBSD: head/usr.bin/grep/fastgrep.c 211496 2010-08-19 09:28:59Z des $ */ + +/*- + * Copyright (c) 1999 James Howard and Dag-Erling Coïdan Smørgrav + * Copyright (C) 2008 Gabor Kovesdan <gabor@FreeBSD.org> + * All rights reserved. + * + * 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. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +/* + * XXX: This file is a speed up for grep to cover the defects of the + * regex library. These optimizations should practically be implemented + * there keeping this code clean. This is a future TODO, but for the + * meantime, we need to use this workaround. + */ + +#if HAVE_NBTOOL_CONFIG_H +#include "nbtool_config.h" +#endif + +#include <sys/cdefs.h> +__RCSID("$NetBSD: fastgrep.c,v 1.5 2011/04/18 03:27:40 joerg Exp $"); + +#include <limits.h> +#include <stdbool.h> +#include <stdlib.h> +#include <string.h> +#include <wchar.h> +#include <wctype.h> + +#include "grep.h" + +static inline int grep_cmp(const unsigned char *, const unsigned char *, size_t); +static inline void grep_revstr(unsigned char *, int); + +void +fgrepcomp(fastgrep_t *fg, const char *pat) +{ + unsigned int i; + + /* Initialize. */ + fg->len = strlen(pat); + fg->bol = false; + fg->eol = false; + fg->reversed = false; + + fg->pattern = (unsigned char *)grep_strdup(pat); + + /* Preprocess pattern. */ + for (i = 0; i <= UCHAR_MAX; i++) + fg->qsBc[i] = fg->len; + for (i = 1; i < fg->len; i++) + fg->qsBc[fg->pattern[i]] = fg->len - i; +} + +/* + * Returns: -1 on failure, 0 on success + */ +int +fastcomp(fastgrep_t *fg, const char *pat) +{ + unsigned int i; + int firstHalfDot = -1; + int firstLastHalfDot = -1; + int hasDot = 0; + int lastHalfDot = 0; + int shiftPatternLen; + + /* Initialize. */ + fg->len = strlen(pat); + fg->bol = false; + fg->eol = false; + fg->reversed = false; + fg->word = wflag; + + /* Remove end-of-line character ('$'). */ + if (fg->len > 0 && pat[fg->len - 1] == '$') { + fg->eol = true; + fg->len--; + } + + /* Remove beginning-of-line character ('^'). */ + if (pat[0] == '^') { + fg->bol = true; + fg->len--; + pat++; + } + + if (fg->len >= 14 && + memcmp(pat, "[[:<:]]", 7) == 0 && + memcmp(pat + fg->len - 7, "[[:>:]]", 7) == 0) { + fg->len -= 14; + pat += 7; + /* Word boundary is handled separately in util.c */ + fg->word = true; + } + + /* + * pat has been adjusted earlier to not include '^', '$' or + * the word match character classes at the beginning and ending + * of the string respectively. + */ + fg->pattern = grep_malloc(fg->len + 1); + memcpy(fg->pattern, pat, fg->len); + fg->pattern[fg->len] = '\0'; + + /* Look for ways to cheat...er...avoid the full regex engine. */ + for (i = 0; i < fg->len; i++) { + /* Can still cheat? */ + if (fg->pattern[i] == '.') { + hasDot = i; + if (i < fg->len / 2) { + if (firstHalfDot < 0) + /* Closest dot to the beginning */ + firstHalfDot = i; + } else { + /* Closest dot to the end of the pattern. */ + lastHalfDot = i; + if (firstLastHalfDot < 0) + firstLastHalfDot = i; + } + } else { + /* Free memory and let others know this is empty. */ + free(fg->pattern); + fg->pattern = NULL; + return (-1); + } + } + + /* + * Determine if a reverse search would be faster based on the placement + * of the dots. + */ + if ((!(lflag || cflag)) && ((!(fg->bol || fg->eol)) && + ((lastHalfDot) && ((firstHalfDot < 0) || + ((fg->len - (lastHalfDot + 1)) < (size_t)firstHalfDot)))) && + !oflag && !color) { + fg->reversed = true; + hasDot = fg->len - (firstHalfDot < 0 ? + firstLastHalfDot : firstHalfDot) - 1; + grep_revstr(fg->pattern, fg->len); + } + + /* + * Normal Quick Search would require a shift based on the position the + * next character after the comparison is within the pattern. With + * wildcards, the position of the last dot effects the maximum shift + * distance. + * The closer to the end the wild card is the slower the search. A + * reverse version of this algorithm would be useful for wildcards near + * the end of the string. + * + * Examples: + * Pattern Max shift + * ------- --------- + * this 5 + * .his 4 + * t.is 3 + * th.s 2 + * thi. 1 + */ + + /* Adjust the shift based on location of the last dot ('.'). */ + shiftPatternLen = fg->len - hasDot; + + /* Preprocess pattern. */ + for (i = 0; i <= (signed)UCHAR_MAX; i++) + fg->qsBc[i] = shiftPatternLen; + for (i = hasDot + 1; i < fg->len; i++) { + fg->qsBc[fg->pattern[i]] = fg->len - i; + } + + /* + * Put pattern back to normal after pre-processing to allow for easy + * comparisons later. + */ + if (fg->reversed) + grep_revstr(fg->pattern, fg->len); + + return (0); +} + +int +grep_search(fastgrep_t *fg, const unsigned char *data, size_t len, regmatch_t *pmatch) +{ + unsigned int j; + int ret = REG_NOMATCH; + + if (pmatch->rm_so == (ssize_t)len) + return (ret); + + if (fg->bol && pmatch->rm_so != 0) { + pmatch->rm_so = len; + pmatch->rm_eo = len; + return (ret); + } + + /* No point in going farther if we do not have enough data. */ + if (len < fg->len) + return (ret); + + /* Only try once at the beginning or ending of the line. */ + if (fg->bol || fg->eol) { + /* Simple text comparison. */ + /* Verify data is >= pattern length before searching on it. */ + if (len >= fg->len) { + /* Determine where in data to start search at. */ + j = fg->eol ? len - fg->len : 0; + if (!((fg->bol && fg->eol) && (len != fg->len))) + if (grep_cmp(fg->pattern, data + j, + fg->len) == -1) { + pmatch->rm_so = j; + pmatch->rm_eo = j + fg->len; + ret = 0; + } + } + } else if (fg->reversed) { + /* Quick Search algorithm. */ + j = len; + do { + if (grep_cmp(fg->pattern, data + j - fg->len, + fg->len) == -1) { + pmatch->rm_so = j - fg->len; + pmatch->rm_eo = j; + ret = 0; + break; + } + /* Shift if within bounds, otherwise, we are done. */ + if (j == fg->len) + break; + j -= fg->qsBc[data[j - fg->len - 1]]; + } while (j >= fg->len); + } else { + /* Quick Search algorithm. */ + j = pmatch->rm_so; + do { + if (grep_cmp(fg->pattern, data + j, fg->len) == -1) { + pmatch->rm_so = j; + pmatch->rm_eo = j + fg->len; + ret = 0; + break; + } + + /* Shift if within bounds, otherwise, we are done. */ + if (j + fg->len == len) + break; + else + j += fg->qsBc[data[j + fg->len]]; + } while (j <= (len - fg->len)); + } + + return (ret); +} + +/* + * Returns: i >= 0 on failure (position that it failed) + * -1 on success + */ +static inline int +grep_cmp(const unsigned char *pat, const unsigned char *data, size_t len) +{ + size_t size; + wchar_t *wdata, *wpat; + unsigned int i; + + if (iflag) { + if ((size = mbstowcs(NULL, (const char *)data, 0)) == + ((size_t) - 1)) + return (-1); + + wdata = grep_malloc(size * sizeof(wint_t)); + + if (mbstowcs(wdata, (const char *)data, size) == + ((size_t) - 1)) + return (-1); + + if ((size = mbstowcs(NULL, (const char *)pat, 0)) == + ((size_t) - 1)) + return (-1); + + wpat = grep_malloc(size * sizeof(wint_t)); + + if (mbstowcs(wpat, (const char *)pat, size) == ((size_t) - 1)) + return (-1); + for (i = 0; i < len; i++) { + if ((towlower(wpat[i]) == towlower(wdata[i])) || + ((grepbehave != GREP_FIXED) && wpat[i] == L'.')) + continue; + free(wpat); + free(wdata); + return (i); + } + } else { + for (i = 0; i < len; i++) { + if ((pat[i] == data[i]) || ((grepbehave != GREP_FIXED) && + pat[i] == '.')) + continue; + return (i); + } + } + return (-1); +} + +static inline void +grep_revstr(unsigned char *str, int len) +{ + int i; + char c; + + for (i = 0; i < len / 2; i++) { + c = str[i]; + str[i] = str[len - i - 1]; + str[len - i - 1] = c; + } +} |