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-rw-r--r--regexp.c826
1 files changed, 826 insertions, 0 deletions
diff --git a/regexp.c b/regexp.c
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+++ b/regexp.c
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+/* regexp.c */
+
+#include "internal.h"
+#include "regexp.h"
+#include <setjmp.h>
+#include <stdio.h>
+#include <ctype.h>
+
+
+#if ( defined BB_GREP || defined BB_FIND )
+
+/* This also tries to find a needle in a haystack, but uses
+ * real regular expressions.... The fake regular expression
+ * version of find_match lives in utility.c. Using this version
+ * will add 3.9k to busybox...
+ * -Erik Andersen
+ */
+extern int find_match(char *haystack, char *needle, int ignoreCase)
+{
+ int status;
+ struct regexp* re;
+ re = regcomp( needle);
+ status = regexec(re, haystack, FALSE, ignoreCase);
+ free( re);
+ return( status);
+}
+
+
+/* code swiped from elvis-tiny 1.4 (a clone of vi) and adjusted to
+ * suit the needs of busybox by Erik Andersen.
+ *
+ * From the README:
+ * "Elvis is freely redistributable, in either source form or executable form.
+ * There are no restrictions on how you may use it".
+ * Elvis was written by Steve Kirkendall <kirkenda@cs.pdx.edu>
+ *
+ *
+ * This file contains the code that compiles regular expressions and executes
+ * them. It supports the same syntax and features as vi's regular expression
+ * code. Specifically, the meta characters are:
+ * ^ matches the beginning of a line
+ * $ matches the end of a line
+ * \< matches the beginning of a word
+ * \> matches the end of a word
+ * . matches any single character
+ * [] matches any character in a character class
+ * \( delimits the start of a subexpression
+ * \) delimits the end of a subexpression
+ * * repeats the preceding 0 or more times
+ * NOTE: You cannot follow a \) with a *.
+ *
+ * The physical structure of a compiled RE is as follows:
+ * - First, there is a one-byte value that says how many character classes
+ * are used in this regular expression
+ * - Next, each character class is stored as a bitmap that is 256 bits
+ * (32 bytes) long.
+ * - A mixture of literal characters and compiled meta characters follows.
+ * This begins with M_BEGIN(0) and ends with M_END(0). All meta chars
+ * are stored as a \n followed by a one-byte code, so they take up two
+ * bytes apiece. Literal characters take up one byte apiece. \n can't
+ * be used as a literal character.
+ *
+ */
+
+
+
+static char *previous; /* the previous regexp, used when null regexp is given */
+static char *previous1; /* a copy of the text from the previous substitution for regsub()*/
+
+
+/* These are used to classify or recognize meta-characters */
+#define META '\0'
+#define BASE_META(m) ((m) - 256)
+#define INT_META(c) ((c) + 256)
+#define IS_META(m) ((m) >= 256)
+#define IS_CLASS(m) ((m) >= M_CLASS(0) && (m) <= M_CLASS(9))
+#define IS_START(m) ((m) >= M_START(0) && (m) <= M_START(9))
+#define IS_END(m) ((m) >= M_END(0) && (m) <= M_END(9))
+#define IS_CLOSURE(m) ((m) >= M_SPLAT && (m) <= M_QMARK)
+#define ADD_META(s,m) (*(s)++ = META, *(s)++ = BASE_META(m))
+#define GET_META(s) (*(s) == META ? INT_META(*++(s)) : *s)
+
+/* These are the internal codes used for each type of meta-character */
+#define M_BEGLINE 256 /* internal code for ^ */
+#define M_ENDLINE 257 /* internal code for $ */
+#define M_BEGWORD 258 /* internal code for \< */
+#define M_ENDWORD 259 /* internal code for \> */
+#define M_ANY 260 /* internal code for . */
+#define M_SPLAT 261 /* internal code for * */
+#define M_PLUS 262 /* internal code for \+ */
+#define M_QMARK 263 /* internal code for \? */
+#define M_CLASS(n) (264+(n)) /* internal code for [] */
+#define M_START(n) (274+(n)) /* internal code for \( */
+#define M_END(n) (284+(n)) /* internal code for \) */
+
+/* These are used during compilation */
+static int class_cnt; /* used to assign class IDs */
+static int start_cnt; /* used to assign start IDs */
+static int end_stk[NSUBEXP];/* used to assign end IDs */
+static int end_sp;
+static char *retext; /* points to the text being compiled */
+
+/* error-handling stuff */
+jmp_buf errorhandler;
+#define FAIL(why) fprintf(stderr, why); longjmp(errorhandler, 1)
+
+
+
+
+/* This function builds a bitmap for a particular class */
+/* text -- start of the class */
+/* bmap -- the bitmap */
+static char *makeclass(char* text, char* bmap)
+{
+ int i;
+ int complement = 0;
+
+
+ /* zero the bitmap */
+ for (i = 0; bmap && i < 32; i++)
+ {
+ bmap[i] = 0;
+ }
+
+ /* see if we're going to complement this class */
+ if (*text == '^')
+ {
+ text++;
+ complement = 1;
+ }
+
+ /* add in the characters */
+ while (*text && *text != ']')
+ {
+ /* is this a span of characters? */
+ if (text[1] == '-' && text[2])
+ {
+ /* spans can't be backwards */
+ if (text[0] > text[2])
+ {
+ FAIL("Backwards span in []");
+ }
+
+ /* add each character in the span to the bitmap */
+ for (i = text[0]; bmap && i <= text[2]; i++)
+ {
+ bmap[i >> 3] |= (1 << (i & 7));
+ }
+
+ /* move past this span */
+ text += 3;
+ }
+ else
+ {
+ /* add this single character to the span */
+ i = *text++;
+ if (bmap)
+ {
+ bmap[i >> 3] |= (1 << (i & 7));
+ }
+ }
+ }
+
+ /* make sure the closing ] is missing */
+ if (*text++ != ']')
+ {
+ FAIL("] missing");
+ }
+
+ /* if we're supposed to complement this class, then do so */
+ if (complement && bmap)
+ {
+ for (i = 0; i < 32; i++)
+ {
+ bmap[i] = ~bmap[i];
+ }
+ }
+
+ return text;
+}
+
+
+
+
+/* This function gets the next character or meta character from a string.
+ * The pointer is incremented by 1, or by 2 for \-quoted characters. For [],
+ * a bitmap is generated via makeclass() (if re is given), and the
+ * character-class text is skipped.
+ */
+static int gettoken(sptr, re)
+ char **sptr;
+ regexp *re;
+{
+ int c;
+
+ c = **sptr;
+ ++*sptr;
+ if (c == '\\')
+ {
+ c = **sptr;
+ ++*sptr;
+ switch (c)
+ {
+ case '<':
+ return M_BEGWORD;
+
+ case '>':
+ return M_ENDWORD;
+
+ case '(':
+ if (start_cnt >= NSUBEXP)
+ {
+ FAIL("Too many \\(s");
+ }
+ end_stk[end_sp++] = start_cnt;
+ return M_START(start_cnt++);
+
+ case ')':
+ if (end_sp <= 0)
+ {
+ FAIL("Mismatched \\)");
+ }
+ return M_END(end_stk[--end_sp]);
+
+ case '*':
+ return M_SPLAT;
+
+ case '.':
+ return M_ANY;
+
+ case '+':
+ return M_PLUS;
+
+ case '?':
+ return M_QMARK;
+
+ default:
+ return c;
+ }
+ }
+ else {
+ switch (c)
+ {
+ case '^':
+ if (*sptr == retext + 1)
+ {
+ return M_BEGLINE;
+ }
+ return c;
+
+ case '$':
+ if (!**sptr)
+ {
+ return M_ENDLINE;
+ }
+ return c;
+
+ case '.':
+ return M_ANY;
+
+ case '*':
+ return M_SPLAT;
+
+ case '[':
+ /* make sure we don't have too many classes */
+ if (class_cnt >= 10)
+ {
+ FAIL("Too many []s");
+ }
+
+ /* process the character list for this class */
+ if (re)
+ {
+ /* generate the bitmap for this class */
+ *sptr = makeclass(*sptr, re->program + 1 + 32 * class_cnt);
+ }
+ else
+ {
+ /* skip to end of the class */
+ *sptr = makeclass(*sptr, (char *)0);
+ }
+ return M_CLASS(class_cnt++);
+
+ default:
+ return c;
+ }
+ }
+ /*NOTREACHED*/
+}
+
+
+
+
+/* This function calculates the number of bytes that will be needed for a
+ * compiled RE. Its argument is the uncompiled version. It is not clever
+ * about catching syntax errors; that is done in a later pass.
+ */
+static unsigned calcsize(text)
+ char *text;
+{
+ unsigned size;
+ int token;
+
+ retext = text;
+ class_cnt = 0;
+ start_cnt = 1;
+ end_sp = 0;
+ size = 5;
+ while ((token = gettoken(&text, (regexp *)0)) != 0)
+ {
+ if (IS_CLASS(token))
+ {
+ size += 34;
+ }
+ else if (IS_META(token))
+ {
+ size += 2;
+ }
+ else
+ {
+ size++;
+ }
+ }
+
+ return size;
+}
+
+
+
+/*---------------------------------------------------------------------------*/
+
+
+/* This function checks for a match between a character and a token which is
+ * known to represent a single character. It returns 0 if they match, or
+ * 1 if they don't.
+ */
+static int match1(regexp* re, char ch, int token, int ignoreCase)
+{
+ if (!ch)
+ {
+ /* the end of a line can't match any RE of width 1 */
+ return 1;
+ }
+ if (token == M_ANY)
+ {
+ return 0;
+ }
+ else if (IS_CLASS(token))
+ {
+ if (re->program[1 + 32 * (token - M_CLASS(0)) + (ch >> 3)] & (1 << (ch & 7)))
+ return 0;
+ }
+ else if (ch == token
+ || (ignoreCase==TRUE && isupper(ch) && tolower(ch) == token))
+ {
+ return 0;
+ }
+ return 1;
+}
+
+
+
+/* This function checks characters up to and including the next closure, at
+ * which point it does a recursive call to check the rest of it. This function
+ * returns 0 if everything matches, or 1 if something doesn't match.
+ */
+/* re -- the regular expression */
+/* str -- the string */
+/* prog -- a portion of re->program, an compiled RE */
+/* here -- a portion of str, the string to compare it to */
+static int match(regexp* re, char* str, char* prog, char* here, int ignoreCase)
+{
+ int token;
+ int nmatched;
+ int closure;
+
+ for (token = GET_META(prog); !IS_CLOSURE(token); prog++, token = GET_META(prog))
+ {
+ switch (token)
+ {
+ /*case M_BEGLINE: can't happen; re->bol is used instead */
+ case M_ENDLINE:
+ if (*here)
+ return 1;
+ break;
+
+ case M_BEGWORD:
+ if (here != str &&
+ (here[-1] == '_' ||
+ (isascii(here[-1]) && isalnum(here[-1]))))
+ return 1;
+ break;
+
+ case M_ENDWORD:
+ if ((here[0] == '_' || isascii(here[0])) && isalnum(here[0]))
+ return 1;
+ break;
+
+ case M_START(0):
+ case M_START(1):
+ case M_START(2):
+ case M_START(3):
+ case M_START(4):
+ case M_START(5):
+ case M_START(6):
+ case M_START(7):
+ case M_START(8):
+ case M_START(9):
+ re->startp[token - M_START(0)] = (char *)here;
+ break;
+
+ case M_END(0):
+ case M_END(1):
+ case M_END(2):
+ case M_END(3):
+ case M_END(4):
+ case M_END(5):
+ case M_END(6):
+ case M_END(7):
+ case M_END(8):
+ case M_END(9):
+ re->endp[token - M_END(0)] = (char *)here;
+ if (token == M_END(0))
+ {
+ return 0;
+ }
+ break;
+
+ default: /* literal, M_CLASS(n), or M_ANY */
+ if (match1(re, *here, token, ignoreCase) != 0)
+ return 1;
+ here++;
+ }
+ }
+
+ /* C L O S U R E */
+
+ /* step 1: see what we have to match against, and move "prog" to point
+ * the the remainder of the compiled RE.
+ */
+ closure = token;
+ prog++, token = GET_META(prog);
+ prog++;
+
+ /* step 2: see how many times we can match that token against the string */
+ for (nmatched = 0;
+ (closure != M_QMARK || nmatched < 1) && *here && match1(re, *here, token, ignoreCase) == 0;
+ nmatched++, here++)
+ {
+ }
+
+ /* step 3: try to match the remainder, and back off if it doesn't */
+ while (nmatched >= 0 && match(re, str, prog, here, ignoreCase) != 0)
+ {
+ nmatched--;
+ here--;
+ }
+
+ /* so how did it work out? */
+ if (nmatched >= ((closure == M_PLUS) ? 1 : 0))
+ return 0;
+ return 1;
+}
+
+
+/* This function compiles a regexp. */
+extern regexp *regcomp(char* text)
+{
+ int needfirst;
+ unsigned size;
+ int token;
+ int peek;
+ char *build;
+ regexp *re;
+
+
+ /* prepare for error handling */
+ re = (regexp *)0;
+ if (setjmp(errorhandler))
+ {
+ if (re)
+ {
+ free(re);
+ }
+ return (regexp *)0;
+ }
+
+ /* if an empty regexp string was given, use the previous one */
+ if (*text == 0)
+ {
+ if (!previous)
+ {
+ FAIL("No previous RE");
+ }
+ text = previous;
+ }
+ else /* non-empty regexp given, so remember it */
+ {
+ if (previous)
+ free(previous);
+ previous = (char *)malloc((unsigned)(strlen(text) + 1));
+ if (previous)
+ strcpy(previous, text);
+ }
+
+ /* allocate memory */
+ class_cnt = 0;
+ start_cnt = 1;
+ end_sp = 0;
+ retext = text;
+ size = calcsize(text) + sizeof(regexp);
+ re = (regexp *)malloc((unsigned)size);
+
+ if (!re)
+ {
+ FAIL("Not enough memory for this RE");
+ }
+
+ /* compile it */
+ build = &re->program[1 + 32 * class_cnt];
+ re->program[0] = class_cnt;
+ for (token = 0; token < NSUBEXP; token++)
+ {
+ re->startp[token] = re->endp[token] = (char *)0;
+ }
+ re->first = 0;
+ re->bol = 0;
+ re->minlen = 0;
+ needfirst = 1;
+ class_cnt = 0;
+ start_cnt = 1;
+ end_sp = 0;
+ retext = text;
+ for (token = M_START(0), peek = gettoken(&text, re);
+ token;
+ token = peek, peek = gettoken(&text, re))
+ {
+ /* special processing for the closure operator */
+ if (IS_CLOSURE(peek))
+ {
+ /* detect misuse of closure operator */
+ if (IS_START(token))
+ {
+ FAIL("* or \\+ or \\? follows nothing");
+ }
+ else if (IS_META(token) && token != M_ANY && !IS_CLASS(token))
+ {
+ FAIL("* or \\+ or \\? can only follow a normal character or . or []");
+ }
+
+ /* it is okay -- make it prefix instead of postfix */
+ ADD_META(build, peek);
+
+ /* take care of "needfirst" - is this the first char? */
+ if (needfirst && peek == M_PLUS && !IS_META(token))
+ {
+ re->first = token;
+ }
+ needfirst = 0;
+
+ /* we used "peek" -- need to refill it */
+ peek = gettoken(&text, re);
+ if (IS_CLOSURE(peek))
+ {
+ FAIL("* or \\+ or \\? doubled up");
+ }
+ }
+ else if (!IS_META(token))
+ {
+ /* normal char is NOT argument of closure */
+ if (needfirst)
+ {
+ re->first = token;
+ needfirst = 0;
+ }
+ re->minlen++;
+ }
+ else if (token == M_ANY || IS_CLASS(token))
+ {
+ /* . or [] is NOT argument of closure */
+ needfirst = 0;
+ re->minlen++;
+ }
+
+ /* the "token" character is not closure -- process it normally */
+ if (token == M_BEGLINE)
+ {
+ /* set the BOL flag instead of storing M_BEGLINE */
+ re->bol = 1;
+ }
+ else if (IS_META(token))
+ {
+ ADD_META(build, token);
+ }
+ else
+ {
+ *build++ = token;
+ }
+ }
+
+ /* end it with a \) which MUST MATCH the opening \( */
+ ADD_META(build, M_END(0));
+ if (end_sp > 0)
+ {
+ FAIL("Not enough \\)s");
+ }
+
+ return re;
+}
+
+
+
+
+/* This function searches through a string for text that matches an RE. */
+/* re -- the compiled regexp to search for */
+/* str -- the string to search through */
+/* bol -- does str start at the beginning of a line? (boolean) */
+/* ignoreCase -- ignoreCase or not */
+extern int regexec(struct regexp* re, char* str, int bol, int ignoreCase)
+{
+ char *prog; /* the entry point of re->program */
+ int len; /* length of the string */
+ char *here;
+
+ /* if must start at the beginning of a line, and this isn't, then fail */
+ if (re->bol && bol==TRUE)
+ {
+ return FALSE;
+ }
+
+ len = strlen(str);
+ prog = re->program + 1 + 32 * re->program[0];
+
+ /* search for the RE in the string */
+ if (re->bol)
+ {
+ /* must occur at BOL */
+ if ((re->first
+ && match1(re, *(char *)str, re->first, ignoreCase))/* wrong first letter? */
+ || len < re->minlen /* not long enough? */
+ || match(re, (char *)str, prog, str, ignoreCase)) /* doesn't match? */
+ return FALSE; /* THEN FAIL! */
+ }
+ else if (ignoreCase == FALSE)
+ {
+ /* can occur anywhere in the line, noignorecase */
+ for (here = (char *)str;
+ (re->first && re->first != *here)
+ || match(re, (char *)str, prog, here, ignoreCase);
+ here++, len--)
+ {
+ if (len < re->minlen)
+ return FALSE;
+ }
+ }
+ else
+ {
+ /* can occur anywhere in the line, ignorecase */
+ for (here = (char *)str;
+ (re->first && match1(re, *here, (int)re->first, ignoreCase))
+ || match(re, (char *)str, prog, here, ignoreCase);
+ here++, len--)
+ {
+ if (len < re->minlen)
+ return FALSE;
+ }
+ }
+
+ /* if we didn't fail, then we must have succeeded */
+ return TRUE;
+}
+
+
+
+
+
+/* This performs substitutions after a regexp match has been found. */
+extern void regsub(regexp* re, char* src, char* dst)
+{
+ char *cpy;
+ char *end;
+ char c;
+ char *start;
+ int mod;
+
+ mod = 0;
+
+ start = src;
+ while ((c = *src++) != '\0')
+ {
+ /* recognize any meta characters */
+ if (c == '&')
+ {
+ cpy = re->startp[0];
+ end = re->endp[0];
+ }
+ else if (c == '~')
+ {
+ cpy = previous1;
+ if (cpy)
+ end = cpy + strlen(cpy);
+ }
+ else
+ if (c == '\\')
+ {
+ c = *src++;
+ switch (c)
+ {
+ case '0':
+ case '1':
+ case '2':
+ case '3':
+ case '4':
+ case '5':
+ case '6':
+ case '7':
+ case '8':
+ case '9':
+ /* \0 thru \9 mean "copy subexpression" */
+ c -= '0';
+ cpy = re->startp[(int)c];
+ end = re->endp[(int)c];
+ break;
+ case 'U':
+ case 'u':
+ case 'L':
+ case 'l':
+ /* \U and \L mean "convert to upper/lowercase" */
+ mod = c;
+ continue;
+
+ case 'E':
+ case 'e':
+ /* \E ends the \U or \L */
+ mod = 0;
+ continue;
+ case '&':
+ /* "\&" means "original text" */
+ *dst++ = c;
+ continue;
+
+ case '~':
+ /* "\~" means "previous text, if any" */
+ *dst++ = c;
+ continue;
+ default:
+ /* ordinary char preceded by backslash */
+ *dst++ = c;
+ continue;
+ }
+ }
+ else
+ {
+ /* ordinary character, so just copy it */
+ *dst++ = c;
+ continue;
+ }
+
+ /* Note: to reach this point in the code, we must have evaded
+ * all "continue" statements. To do that, we must have hit
+ * a metacharacter that involves copying.
+ */
+
+ /* if there is nothing to copy, loop */
+ if (!cpy)
+ continue;
+
+ /* copy over a portion of the original */
+ while (cpy < end)
+ {
+ switch (mod)
+ {
+ case 'U':
+ case 'u':
+ /* convert to uppercase */
+ if (isascii(*cpy) && islower(*cpy))
+ {
+ *dst++ = toupper(*cpy);
+ cpy++;
+ }
+ else
+ {
+ *dst++ = *cpy++;
+ }
+ break;
+
+ case 'L':
+ case 'l':
+ /* convert to lowercase */
+ if (isascii(*cpy) && isupper(*cpy))
+ {
+ *dst++ = tolower(*cpy);
+ cpy++;
+ }
+ else
+ {
+ *dst++ = *cpy++;
+ }
+ break;
+
+ default:
+ /* copy without any conversion */
+ *dst++ = *cpy++;
+ }
+
+ /* \u and \l end automatically after the first char */
+ if (mod && (mod == 'u' || mod == 'l'))
+ {
+ mod = 0;
+ }
+ }
+ }
+ *dst = '\0';
+
+ /* remember what text we inserted this time */
+ if (previous1)
+ free(previous1);
+ previous1 = (char *)malloc((unsigned)(strlen(start) + 1));
+ if (previous1)
+ strcpy(previous1, start);
+}
+
+
+#endif /* BB_REGEXP */
+
+
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