/* $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 * 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 __RCSID("$NetBSD: fastgrep.c,v 1.5 2011/04/18 03:27:40 joerg Exp $"); #include #include #include #include #include #include #include "grep.h" static inline int grep_cmp(const unsigned char *, const unsigned char *, size_t); static inline void grep_revstr(unsigned char *, int); void fgrepcomp(fastgrep_t *fg, const char *pat) { unsigned int i; /* Initialize. */ fg->len = strlen(pat); fg->bol = false; fg->eol = false; fg->reversed = false; fg->pattern = (unsigned char *)grep_strdup(pat); /* Preprocess pattern. */ for (i = 0; i <= UCHAR_MAX; i++) fg->qsBc[i] = fg->len; for (i = 1; i < fg->len; i++) fg->qsBc[fg->pattern[i]] = fg->len - i; } /* * Returns: -1 on failure, 0 on success */ int fastcomp(fastgrep_t *fg, const char *pat) { unsigned int i; int firstHalfDot = -1; int firstLastHalfDot = -1; int hasDot = 0; int lastHalfDot = 0; int shiftPatternLen; /* Initialize. */ fg->len = strlen(pat); fg->bol = false; fg->eol = false; fg->reversed = false; fg->word = wflag; /* Remove end-of-line character ('$'). */ 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; } }