761 lines
23 KiB
C
761 lines
23 KiB
C
/*
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** 2012-11-13
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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******************************************************************************
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**
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** The code in this file implements a compact but reasonably
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** efficient regular-expression matcher for posix extended regular
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** expressions against UTF8 text.
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**
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** This file is an SQLite extension. It registers a single function
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** named "regexp(A,B)" where A is the regular expression and B is the
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** string to be matched. By registering this function, SQLite will also
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** then implement the "B regexp A" operator. Note that with the function
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** the regular expression comes first, but with the operator it comes
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** second.
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**
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** The following regular expression syntax is supported:
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**
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** X* zero or more occurrences of X
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** X+ one or more occurrences of X
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** X? zero or one occurrences of X
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** X{p,q} between p and q occurrences of X
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** (X) match X
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** X|Y X or Y
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** ^X X occurring at the beginning of the string
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** X$ X occurring at the end of the string
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** . Match any single character
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** \c Character c where c is one of \{}()[]|*+?.
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** \c C-language escapes for c in afnrtv. ex: \t or \n
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** \uXXXX Where XXXX is exactly 4 hex digits, unicode value XXXX
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** \xXX Where XX is exactly 2 hex digits, unicode value XX
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** [abc] Any single character from the set abc
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** [^abc] Any single character not in the set abc
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** [a-z] Any single character in the range a-z
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** [^a-z] Any single character not in the range a-z
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** \b Word boundary
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** \w Word character. [A-Za-z0-9_]
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** \W Non-word character
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** \d Digit
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** \D Non-digit
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** \s Whitespace character
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** \S Non-whitespace character
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**
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** A nondeterministic finite automaton (NFA) is used for matching, so the
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** performance is bounded by O(N*M) where N is the size of the regular
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** expression and M is the size of the input string. The matcher never
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** exhibits exponential behavior. Note that the X{p,q} operator expands
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** to p copies of X following by q-p copies of X? and that the size of the
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** regular expression in the O(N*M) performance bound is computed after
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** this expansion.
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*/
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#include <string.h>
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#include <stdlib.h>
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#include "sqlite3ext.h"
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SQLITE_EXTENSION_INIT1
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/*
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** The following #defines change the names of some functions implemented in
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** this file to prevent name collisions with C-library functions of the
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** same name.
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*/
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#define re_match sqlite3re_match
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#define re_compile sqlite3re_compile
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#define re_free sqlite3re_free
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/* The end-of-input character */
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#define RE_EOF 0 /* End of input */
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/* The NFA is implemented as sequence of opcodes taken from the following
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** set. Each opcode has a single integer argument.
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*/
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#define RE_OP_MATCH 1 /* Match the one character in the argument */
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#define RE_OP_ANY 2 /* Match any one character. (Implements ".") */
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#define RE_OP_ANYSTAR 3 /* Special optimized version of .* */
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#define RE_OP_FORK 4 /* Continue to both next and opcode at iArg */
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#define RE_OP_GOTO 5 /* Jump to opcode at iArg */
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#define RE_OP_ACCEPT 6 /* Halt and indicate a successful match */
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#define RE_OP_CC_INC 7 /* Beginning of a [...] character class */
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#define RE_OP_CC_EXC 8 /* Beginning of a [^...] character class */
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#define RE_OP_CC_VALUE 9 /* Single value in a character class */
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#define RE_OP_CC_RANGE 10 /* Range of values in a character class */
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#define RE_OP_WORD 11 /* Perl word character [A-Za-z0-9_] */
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#define RE_OP_NOTWORD 12 /* Not a perl word character */
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#define RE_OP_DIGIT 13 /* digit: [0-9] */
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#define RE_OP_NOTDIGIT 14 /* Not a digit */
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#define RE_OP_SPACE 15 /* space: [ \t\n\r\v\f] */
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#define RE_OP_NOTSPACE 16 /* Not a digit */
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#define RE_OP_BOUNDARY 17 /* Boundary between word and non-word */
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/* Each opcode is a "state" in the NFA */
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typedef unsigned short ReStateNumber;
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/* Because this is an NFA and not a DFA, multiple states can be active at
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** once. An instance of the following object records all active states in
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** the NFA. The implementation is optimized for the common case where the
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** number of actives states is small.
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*/
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typedef struct ReStateSet {
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unsigned nState; /* Number of current states */
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ReStateNumber *aState; /* Current states */
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} ReStateSet;
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/* An input string read one character at a time.
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*/
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typedef struct ReInput ReInput;
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struct ReInput {
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const unsigned char *z; /* All text */
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int i; /* Next byte to read */
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int mx; /* EOF when i>=mx */
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};
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/* A compiled NFA (or an NFA that is in the process of being compiled) is
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** an instance of the following object.
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*/
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typedef struct ReCompiled ReCompiled;
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struct ReCompiled {
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ReInput sIn; /* Regular expression text */
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const char *zErr; /* Error message to return */
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char *aOp; /* Operators for the virtual machine */
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int *aArg; /* Arguments to each operator */
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unsigned (*xNextChar)(ReInput*); /* Next character function */
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unsigned char zInit[12]; /* Initial text to match */
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int nInit; /* Number of characters in zInit */
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unsigned nState; /* Number of entries in aOp[] and aArg[] */
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unsigned nAlloc; /* Slots allocated for aOp[] and aArg[] */
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};
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/* Add a state to the given state set if it is not already there */
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static void re_add_state(ReStateSet *pSet, int newState){
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unsigned i;
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for(i=0; i<pSet->nState; i++) if( pSet->aState[i]==newState ) return;
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pSet->aState[pSet->nState++] = newState;
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}
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/* Extract the next unicode character from *pzIn and return it. Advance
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** *pzIn to the first byte past the end of the character returned. To
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** be clear: this routine converts utf8 to unicode. This routine is
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** optimized for the common case where the next character is a single byte.
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*/
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static unsigned re_next_char(ReInput *p){
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unsigned c;
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if( p->i>=p->mx ) return 0;
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c = p->z[p->i++];
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if( c>=0x80 ){
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if( (c&0xe0)==0xc0 && p->i<p->mx && (p->z[p->i]&0xc0)==0x80 ){
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c = (c&0x1f)<<6 | (p->z[p->i++]&0x3f);
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if( c<0x80 ) c = 0xfffd;
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}else if( (c&0xf0)==0xe0 && p->i+1<p->mx && (p->z[p->i]&0xc0)==0x80
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&& (p->z[p->i+1]&0xc0)==0x80 ){
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c = (c&0x0f)<<12 | ((p->z[p->i]&0x3f)<<6) | (p->z[p->i+1]&0x3f);
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p->i += 2;
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if( c<=0x3ff || (c>=0xd800 && c<=0xdfff) ) c = 0xfffd;
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}else if( (c&0xf8)==0xf0 && p->i+3<p->mx && (p->z[p->i]&0xc0)==0x80
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&& (p->z[p->i+1]&0xc0)==0x80 && (p->z[p->i+2]&0xc0)==0x80 ){
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c = (c&0x07)<<18 | ((p->z[p->i]&0x3f)<<12) | ((p->z[p->i+1]&0x3f)<<6)
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| (p->z[p->i+2]&0x3f);
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p->i += 3;
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if( c<=0xffff || c>0x10ffff ) c = 0xfffd;
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}else{
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c = 0xfffd;
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}
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}
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return c;
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}
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static unsigned re_next_char_nocase(ReInput *p){
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unsigned c = re_next_char(p);
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if( c>='A' && c<='Z' ) c += 'a' - 'A';
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return c;
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}
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/* Return true if c is a perl "word" character: [A-Za-z0-9_] */
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static int re_word_char(int c){
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return (c>='0' && c<='9') || (c>='a' && c<='z')
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|| (c>='A' && c<='Z') || c=='_';
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}
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/* Return true if c is a "digit" character: [0-9] */
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static int re_digit_char(int c){
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return (c>='0' && c<='9');
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}
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/* Return true if c is a perl "space" character: [ \t\r\n\v\f] */
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static int re_space_char(int c){
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return c==' ' || c=='\t' || c=='\n' || c=='\r' || c=='\v' || c=='\f';
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}
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/* Run a compiled regular expression on the zero-terminated input
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** string zIn[]. Return true on a match and false if there is no match.
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*/
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static int re_match(ReCompiled *pRe, const unsigned char *zIn, int nIn){
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ReStateSet aStateSet[2], *pThis, *pNext;
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ReStateNumber aSpace[100];
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ReStateNumber *pToFree;
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unsigned int i = 0;
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unsigned int iSwap = 0;
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int c = RE_EOF+1;
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int cPrev = 0;
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int rc = 0;
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ReInput in;
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in.z = zIn;
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in.i = 0;
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in.mx = nIn>=0 ? nIn : (int)strlen((char const*)zIn);
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/* Look for the initial prefix match, if there is one. */
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if( pRe->nInit ){
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unsigned char x = pRe->zInit[0];
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while( in.i+pRe->nInit<=in.mx
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&& (zIn[in.i]!=x ||
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strncmp((const char*)zIn+in.i, (const char*)pRe->zInit, pRe->nInit)!=0)
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){
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in.i++;
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}
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if( in.i+pRe->nInit>in.mx ) return 0;
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}
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if( pRe->nState<=(sizeof(aSpace)/(sizeof(aSpace[0])*2)) ){
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pToFree = 0;
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aStateSet[0].aState = aSpace;
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}else{
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pToFree = sqlite3_malloc( sizeof(ReStateNumber)*2*pRe->nState );
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if( pToFree==0 ) return -1;
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aStateSet[0].aState = pToFree;
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}
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aStateSet[1].aState = &aStateSet[0].aState[pRe->nState];
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pNext = &aStateSet[1];
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pNext->nState = 0;
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re_add_state(pNext, 0);
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while( c!=RE_EOF && pNext->nState>0 ){
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cPrev = c;
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c = pRe->xNextChar(&in);
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pThis = pNext;
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pNext = &aStateSet[iSwap];
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iSwap = 1 - iSwap;
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pNext->nState = 0;
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for(i=0; i<pThis->nState; i++){
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int x = pThis->aState[i];
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switch( pRe->aOp[x] ){
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case RE_OP_MATCH: {
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if( pRe->aArg[x]==c ) re_add_state(pNext, x+1);
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break;
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}
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case RE_OP_ANY: {
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re_add_state(pNext, x+1);
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break;
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}
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case RE_OP_WORD: {
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if( re_word_char(c) ) re_add_state(pNext, x+1);
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break;
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}
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case RE_OP_NOTWORD: {
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if( !re_word_char(c) ) re_add_state(pNext, x+1);
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break;
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}
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case RE_OP_DIGIT: {
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if( re_digit_char(c) ) re_add_state(pNext, x+1);
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break;
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}
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case RE_OP_NOTDIGIT: {
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if( !re_digit_char(c) ) re_add_state(pNext, x+1);
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break;
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}
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case RE_OP_SPACE: {
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if( re_space_char(c) ) re_add_state(pNext, x+1);
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break;
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}
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case RE_OP_NOTSPACE: {
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if( !re_space_char(c) ) re_add_state(pNext, x+1);
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break;
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}
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case RE_OP_BOUNDARY: {
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if( re_word_char(c)!=re_word_char(cPrev) ) re_add_state(pThis, x+1);
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break;
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}
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case RE_OP_ANYSTAR: {
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re_add_state(pNext, x);
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re_add_state(pThis, x+1);
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break;
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}
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case RE_OP_FORK: {
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re_add_state(pThis, x+pRe->aArg[x]);
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re_add_state(pThis, x+1);
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break;
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}
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case RE_OP_GOTO: {
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re_add_state(pThis, x+pRe->aArg[x]);
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break;
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}
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case RE_OP_ACCEPT: {
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rc = 1;
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goto re_match_end;
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}
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case RE_OP_CC_INC:
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case RE_OP_CC_EXC: {
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int j = 1;
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int n = pRe->aArg[x];
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int hit = 0;
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for(j=1; j>0 && j<n; j++){
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if( pRe->aOp[x+j]==RE_OP_CC_VALUE ){
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if( pRe->aArg[x+j]==c ){
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hit = 1;
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j = -1;
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}
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}else{
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if( pRe->aArg[x+j]<=c && pRe->aArg[x+j+1]>=c ){
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hit = 1;
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j = -1;
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}else{
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j++;
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}
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}
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}
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if( pRe->aOp[x]==RE_OP_CC_EXC ) hit = !hit;
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if( hit ) re_add_state(pNext, x+n);
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break;
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}
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}
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}
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}
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for(i=0; i<pNext->nState; i++){
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if( pRe->aOp[pNext->aState[i]]==RE_OP_ACCEPT ){ rc = 1; break; }
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}
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re_match_end:
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sqlite3_free(pToFree);
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return rc;
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}
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/* Resize the opcode and argument arrays for an RE under construction.
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*/
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static int re_resize(ReCompiled *p, int N){
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char *aOp;
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int *aArg;
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aOp = sqlite3_realloc(p->aOp, N*sizeof(p->aOp[0]));
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if( aOp==0 ) return 1;
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p->aOp = aOp;
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aArg = sqlite3_realloc(p->aArg, N*sizeof(p->aArg[0]));
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if( aArg==0 ) return 1;
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p->aArg = aArg;
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p->nAlloc = N;
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return 0;
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}
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/* Insert a new opcode and argument into an RE under construction. The
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** insertion point is just prior to existing opcode iBefore.
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*/
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static int re_insert(ReCompiled *p, int iBefore, int op, int arg){
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int i;
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if( p->nAlloc<=p->nState && re_resize(p, p->nAlloc*2) ) return 0;
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for(i=p->nState; i>iBefore; i--){
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p->aOp[i] = p->aOp[i-1];
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p->aArg[i] = p->aArg[i-1];
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}
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p->nState++;
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p->aOp[iBefore] = op;
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p->aArg[iBefore] = arg;
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return iBefore;
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}
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/* Append a new opcode and argument to the end of the RE under construction.
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*/
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static int re_append(ReCompiled *p, int op, int arg){
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return re_insert(p, p->nState, op, arg);
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}
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/* Make a copy of N opcodes starting at iStart onto the end of the RE
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** under construction.
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*/
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static void re_copy(ReCompiled *p, int iStart, int N){
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if( p->nState+N>=p->nAlloc && re_resize(p, p->nAlloc*2+N) ) return;
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memcpy(&p->aOp[p->nState], &p->aOp[iStart], N*sizeof(p->aOp[0]));
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memcpy(&p->aArg[p->nState], &p->aArg[iStart], N*sizeof(p->aArg[0]));
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p->nState += N;
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}
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/* Return true if c is a hexadecimal digit character: [0-9a-fA-F]
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** If c is a hex digit, also set *pV = (*pV)*16 + valueof(c). If
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** c is not a hex digit *pV is unchanged.
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*/
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static int re_hex(int c, int *pV){
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if( c>='0' && c<='9' ){
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c -= '0';
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}else if( c>='a' && c<='f' ){
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c -= 'a' - 10;
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}else if( c>='A' && c<='F' ){
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c -= 'A' - 10;
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}else{
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return 0;
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}
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*pV = (*pV)*16 + (c & 0xff);
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return 1;
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}
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/* A backslash character has been seen, read the next character and
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** return its interpretation.
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*/
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static unsigned re_esc_char(ReCompiled *p){
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static const char zEsc[] = "afnrtv\\()*.+?[$^{|}]";
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static const char zTrans[] = "\a\f\n\r\t\v";
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int i, v = 0;
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char c;
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if( p->sIn.i>=p->sIn.mx ) return 0;
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c = p->sIn.z[p->sIn.i];
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if( c=='u' && p->sIn.i+4<p->sIn.mx ){
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const unsigned char *zIn = p->sIn.z + p->sIn.i;
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if( re_hex(zIn[1],&v)
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&& re_hex(zIn[2],&v)
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&& re_hex(zIn[3],&v)
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&& re_hex(zIn[4],&v)
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){
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p->sIn.i += 5;
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return v;
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}
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}
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if( c=='x' && p->sIn.i+2<p->sIn.mx ){
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const unsigned char *zIn = p->sIn.z + p->sIn.i;
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if( re_hex(zIn[1],&v)
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&& re_hex(zIn[2],&v)
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){
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p->sIn.i += 3;
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return v;
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}
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}
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for(i=0; zEsc[i] && zEsc[i]!=c; i++){}
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if( zEsc[i] ){
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if( i<6 ) c = zTrans[i];
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p->sIn.i++;
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}else{
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p->zErr = "unknown \\ escape";
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}
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return c;
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}
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/* Forward declaration */
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static const char *re_subcompile_string(ReCompiled*);
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/* Peek at the next byte of input */
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static unsigned char rePeek(ReCompiled *p){
|
|
return p->sIn.i<p->sIn.mx ? p->sIn.z[p->sIn.i] : 0;
|
|
}
|
|
|
|
/* Compile RE text into a sequence of opcodes. Continue up to the
|
|
** first unmatched ")" character, then return. If an error is found,
|
|
** return a pointer to the error message string.
|
|
*/
|
|
static const char *re_subcompile_re(ReCompiled *p){
|
|
const char *zErr;
|
|
int iStart, iEnd, iGoto;
|
|
iStart = p->nState;
|
|
zErr = re_subcompile_string(p);
|
|
if( zErr ) return zErr;
|
|
while( rePeek(p)=='|' ){
|
|
iEnd = p->nState;
|
|
re_insert(p, iStart, RE_OP_FORK, iEnd + 2 - iStart);
|
|
iGoto = re_append(p, RE_OP_GOTO, 0);
|
|
p->sIn.i++;
|
|
zErr = re_subcompile_string(p);
|
|
if( zErr ) return zErr;
|
|
p->aArg[iGoto] = p->nState - iGoto;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Compile an element of regular expression text (anything that can be
|
|
** an operand to the "|" operator). Return NULL on success or a pointer
|
|
** to the error message if there is a problem.
|
|
*/
|
|
static const char *re_subcompile_string(ReCompiled *p){
|
|
int iPrev = -1;
|
|
int iStart;
|
|
unsigned c;
|
|
const char *zErr;
|
|
while( (c = p->xNextChar(&p->sIn))!=0 ){
|
|
iStart = p->nState;
|
|
switch( c ){
|
|
case '|':
|
|
case '$':
|
|
case ')': {
|
|
p->sIn.i--;
|
|
return 0;
|
|
}
|
|
case '(': {
|
|
zErr = re_subcompile_re(p);
|
|
if( zErr ) return zErr;
|
|
if( rePeek(p)!=')' ) return "unmatched '('";
|
|
p->sIn.i++;
|
|
break;
|
|
}
|
|
case '.': {
|
|
if( rePeek(p)=='*' ){
|
|
re_append(p, RE_OP_ANYSTAR, 0);
|
|
p->sIn.i++;
|
|
}else{
|
|
re_append(p, RE_OP_ANY, 0);
|
|
}
|
|
break;
|
|
}
|
|
case '*': {
|
|
if( iPrev<0 ) return "'*' without operand";
|
|
re_insert(p, iPrev, RE_OP_GOTO, p->nState - iPrev + 1);
|
|
re_append(p, RE_OP_FORK, iPrev - p->nState + 1);
|
|
break;
|
|
}
|
|
case '+': {
|
|
if( iPrev<0 ) return "'+' without operand";
|
|
re_append(p, RE_OP_FORK, iPrev - p->nState);
|
|
break;
|
|
}
|
|
case '?': {
|
|
if( iPrev<0 ) return "'?' without operand";
|
|
re_insert(p, iPrev, RE_OP_FORK, p->nState - iPrev+1);
|
|
break;
|
|
}
|
|
case '{': {
|
|
int m = 0, n = 0;
|
|
int sz, j;
|
|
if( iPrev<0 ) return "'{m,n}' without operand";
|
|
while( (c=rePeek(p))>='0' && c<='9' ){ m = m*10 + c - '0'; p->sIn.i++; }
|
|
n = m;
|
|
if( c==',' ){
|
|
p->sIn.i++;
|
|
n = 0;
|
|
while( (c=rePeek(p))>='0' && c<='9' ){ n = n*10 + c-'0'; p->sIn.i++; }
|
|
}
|
|
if( c!='}' ) return "unmatched '{'";
|
|
if( n>0 && n<m ) return "n less than m in '{m,n}'";
|
|
p->sIn.i++;
|
|
sz = p->nState - iPrev;
|
|
if( m==0 ){
|
|
if( n==0 ) return "both m and n are zero in '{m,n}'";
|
|
re_insert(p, iPrev, RE_OP_FORK, sz+1);
|
|
n--;
|
|
}else{
|
|
for(j=1; j<m; j++) re_copy(p, iPrev, sz);
|
|
}
|
|
for(j=m; j<n; j++){
|
|
re_append(p, RE_OP_FORK, sz+1);
|
|
re_copy(p, iPrev, sz);
|
|
}
|
|
if( n==0 && m>0 ){
|
|
re_append(p, RE_OP_FORK, -sz);
|
|
}
|
|
break;
|
|
}
|
|
case '[': {
|
|
int iFirst = p->nState;
|
|
if( rePeek(p)=='^' ){
|
|
re_append(p, RE_OP_CC_EXC, 0);
|
|
p->sIn.i++;
|
|
}else{
|
|
re_append(p, RE_OP_CC_INC, 0);
|
|
}
|
|
while( (c = p->xNextChar(&p->sIn))!=0 ){
|
|
if( c=='[' && rePeek(p)==':' ){
|
|
return "POSIX character classes not supported";
|
|
}
|
|
if( c=='\\' ) c = re_esc_char(p);
|
|
if( rePeek(p)=='-' ){
|
|
re_append(p, RE_OP_CC_RANGE, c);
|
|
p->sIn.i++;
|
|
c = p->xNextChar(&p->sIn);
|
|
if( c=='\\' ) c = re_esc_char(p);
|
|
re_append(p, RE_OP_CC_RANGE, c);
|
|
}else{
|
|
re_append(p, RE_OP_CC_VALUE, c);
|
|
}
|
|
if( rePeek(p)==']' ){ p->sIn.i++; break; }
|
|
}
|
|
if( c==0 ) return "unclosed '['";
|
|
p->aArg[iFirst] = p->nState - iFirst;
|
|
break;
|
|
}
|
|
case '\\': {
|
|
int specialOp = 0;
|
|
switch( rePeek(p) ){
|
|
case 'b': specialOp = RE_OP_BOUNDARY; break;
|
|
case 'd': specialOp = RE_OP_DIGIT; break;
|
|
case 'D': specialOp = RE_OP_NOTDIGIT; break;
|
|
case 's': specialOp = RE_OP_SPACE; break;
|
|
case 'S': specialOp = RE_OP_NOTSPACE; break;
|
|
case 'w': specialOp = RE_OP_WORD; break;
|
|
case 'W': specialOp = RE_OP_NOTWORD; break;
|
|
}
|
|
if( specialOp ){
|
|
p->sIn.i++;
|
|
re_append(p, specialOp, 0);
|
|
}else{
|
|
c = re_esc_char(p);
|
|
re_append(p, RE_OP_MATCH, c);
|
|
}
|
|
break;
|
|
}
|
|
default: {
|
|
re_append(p, RE_OP_MATCH, c);
|
|
break;
|
|
}
|
|
}
|
|
iPrev = iStart;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Free and reclaim all the memory used by a previously compiled
|
|
** regular expression. Applications should invoke this routine once
|
|
** for every call to re_compile() to avoid memory leaks.
|
|
*/
|
|
void re_free(ReCompiled *pRe){
|
|
if( pRe ){
|
|
sqlite3_free(pRe->aOp);
|
|
sqlite3_free(pRe->aArg);
|
|
sqlite3_free(pRe);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Compile a textual regular expression in zIn[] into a compiled regular
|
|
** expression suitable for us by re_match() and return a pointer to the
|
|
** compiled regular expression in *ppRe. Return NULL on success or an
|
|
** error message if something goes wrong.
|
|
*/
|
|
const char *re_compile(ReCompiled **ppRe, const char *zIn, int noCase){
|
|
ReCompiled *pRe;
|
|
const char *zErr;
|
|
int i, j;
|
|
|
|
*ppRe = 0;
|
|
pRe = sqlite3_malloc( sizeof(*pRe) );
|
|
if( pRe==0 ){
|
|
return "out of memory";
|
|
}
|
|
memset(pRe, 0, sizeof(*pRe));
|
|
pRe->xNextChar = noCase ? re_next_char_nocase : re_next_char;
|
|
if( re_resize(pRe, 30) ){
|
|
re_free(pRe);
|
|
return "out of memory";
|
|
}
|
|
if( zIn[0]=='^' ){
|
|
zIn++;
|
|
}else{
|
|
re_append(pRe, RE_OP_ANYSTAR, 0);
|
|
}
|
|
pRe->sIn.z = (unsigned char*)zIn;
|
|
pRe->sIn.i = 0;
|
|
pRe->sIn.mx = (int)strlen(zIn);
|
|
zErr = re_subcompile_re(pRe);
|
|
if( zErr ){
|
|
re_free(pRe);
|
|
return zErr;
|
|
}
|
|
if( rePeek(pRe)=='$' && pRe->sIn.i+1>=pRe->sIn.mx ){
|
|
re_append(pRe, RE_OP_MATCH, RE_EOF);
|
|
re_append(pRe, RE_OP_ACCEPT, 0);
|
|
*ppRe = pRe;
|
|
}else if( pRe->sIn.i>=pRe->sIn.mx ){
|
|
re_append(pRe, RE_OP_ACCEPT, 0);
|
|
*ppRe = pRe;
|
|
}else{
|
|
re_free(pRe);
|
|
return "unrecognized character";
|
|
}
|
|
|
|
/* The following is a performance optimization. If the regex begins with
|
|
** ".*" (if the input regex lacks an initial "^") and afterwards there are
|
|
** one or more matching characters, enter those matching characters into
|
|
** zInit[]. The re_match() routine can then search ahead in the input
|
|
** string looking for the initial match without having to run the whole
|
|
** regex engine over the string. Do not worry able trying to match
|
|
** unicode characters beyond plane 0 - those are very rare and this is
|
|
** just an optimization. */
|
|
if( pRe->aOp[0]==RE_OP_ANYSTAR ){
|
|
for(j=0, i=1; j<sizeof(pRe->zInit)-2 && pRe->aOp[i]==RE_OP_MATCH; i++){
|
|
unsigned x = pRe->aArg[i];
|
|
if( x<=127 ){
|
|
pRe->zInit[j++] = x;
|
|
}else if( x<=0xfff ){
|
|
pRe->zInit[j++] = 0xc0 | (x>>6);
|
|
pRe->zInit[j++] = 0x80 | (x&0x3f);
|
|
}else if( x<=0xffff ){
|
|
pRe->zInit[j++] = 0xd0 | (x>>12);
|
|
pRe->zInit[j++] = 0x80 | ((x>>6)&0x3f);
|
|
pRe->zInit[j++] = 0x80 | (x&0x3f);
|
|
}else{
|
|
break;
|
|
}
|
|
}
|
|
if( j>0 && pRe->zInit[j-1]==0 ) j--;
|
|
pRe->nInit = j;
|
|
}
|
|
return pRe->zErr;
|
|
}
|
|
|
|
/*
|
|
** Implementation of the regexp() SQL function. This function implements
|
|
** the build-in REGEXP operator. The first argument to the function is the
|
|
** pattern and the second argument is the string. So, the SQL statements:
|
|
**
|
|
** A REGEXP B
|
|
**
|
|
** is implemented as regexp(B,A).
|
|
*/
|
|
static void re_sql_func(
|
|
sqlite3_context *context,
|
|
int argc,
|
|
sqlite3_value **argv
|
|
){
|
|
ReCompiled *pRe; /* Compiled regular expression */
|
|
const char *zPattern; /* The regular expression */
|
|
const unsigned char *zStr;/* String being searched */
|
|
const char *zErr; /* Compile error message */
|
|
int setAux = 0; /* True to invoke sqlite3_set_auxdata() */
|
|
|
|
pRe = sqlite3_get_auxdata(context, 0);
|
|
if( pRe==0 ){
|
|
zPattern = (const char*)sqlite3_value_text(argv[0]);
|
|
if( zPattern==0 ) return;
|
|
zErr = re_compile(&pRe, zPattern, 0);
|
|
if( zErr ){
|
|
re_free(pRe);
|
|
sqlite3_result_error(context, zErr, -1);
|
|
return;
|
|
}
|
|
if( pRe==0 ){
|
|
sqlite3_result_error_nomem(context);
|
|
return;
|
|
}
|
|
setAux = 1;
|
|
}
|
|
zStr = (const unsigned char*)sqlite3_value_text(argv[1]);
|
|
if( zStr!=0 ){
|
|
sqlite3_result_int(context, re_match(pRe, zStr, -1));
|
|
}
|
|
if( setAux ){
|
|
sqlite3_set_auxdata(context, 0, pRe, (void(*)(void*))re_free);
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Invoke this routine to register the regexp() function with the
|
|
** SQLite database connection.
|
|
*/
|
|
#ifdef _WIN32
|
|
__declspec(dllexport)
|
|
#endif
|
|
int sqlite3_regexp_init(
|
|
sqlite3 *db,
|
|
char **pzErrMsg,
|
|
const sqlite3_api_routines *pApi
|
|
){
|
|
int rc = SQLITE_OK;
|
|
SQLITE_EXTENSION_INIT2(pApi);
|
|
rc = sqlite3_create_function(db, "regexp", 2, SQLITE_UTF8, 0,
|
|
re_sql_func, 0, 0);
|
|
return rc;
|
|
}
|