summaryrefslogtreecommitdiff
path: root/ext/misc/regexp.c
diff options
context:
space:
mode:
Diffstat (limited to 'ext/misc/regexp.c')
-rw-r--r--ext/misc/regexp.c756
1 files changed, 756 insertions, 0 deletions
diff --git a/ext/misc/regexp.c b/ext/misc/regexp.c
new file mode 100644
index 0000000..16fa7d0
--- /dev/null
+++ b/ext/misc/regexp.c
@@ -0,0 +1,756 @@
+/*
+** 2012-11-13
+**
+** The author disclaims copyright to this source code. In place of
+** a legal notice, here is a blessing:
+**
+** May you do good and not evil.
+** May you find forgiveness for yourself and forgive others.
+** May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+** The code in this file implements a compact but reasonably
+** efficient regular-expression matcher for posix extended regular
+** expressions against UTF8 text.
+**
+** This file is an SQLite extension. It registers a single function
+** named "regexp(A,B)" where A is the regular expression and B is the
+** string to be matched. By registering this function, SQLite will also
+** then implement the "B regexp A" operator. Note that with the function
+** the regular expression comes first, but with the operator it comes
+** second.
+**
+** The following regular expression syntax is supported:
+**
+** X* zero or more occurrences of X
+** X+ one or more occurrences of X
+** X? zero or one occurrences of X
+** X{p,q} between p and q occurrences of X
+** (X) match X
+** X|Y X or Y
+** ^X X occurring at the beginning of the string
+** X$ X occurring at the end of the string
+** . Match any single character
+** \c Character c where c is one of \{}()[]|*+?.
+** \c C-language escapes for c in afnrtv. ex: \t or \n
+** \uXXXX Where XXXX is exactly 4 hex digits, unicode value XXXX
+** \xXX Where XX is exactly 2 hex digits, unicode value XX
+** [abc] Any single character from the set abc
+** [^abc] Any single character not in the set abc
+** [a-z] Any single character in the range a-z
+** [^a-z] Any single character not in the range a-z
+** \b Word boundary
+** \w Word character. [A-Za-z0-9_]
+** \W Non-word character
+** \d Digit
+** \D Non-digit
+** \s Whitespace character
+** \S Non-whitespace character
+**
+** A nondeterministic finite automaton (NFA) is used for matching, so the
+** performance is bounded by O(N*M) where N is the size of the regular
+** expression and M is the size of the input string. The matcher never
+** exhibits exponential behavior. Note that the X{p,q} operator expands
+** to p copies of X following by q-p copies of X? and that the size of the
+** regular expression in the O(N*M) performance bound is computed after
+** this expansion.
+*/
+#include <string.h>
+#include <stdlib.h>
+#include "sqlite3ext.h"
+SQLITE_EXTENSION_INIT1
+
+/*
+** The following #defines change the names of some functions implemented in
+** this file to prevent name collisions with C-library functions of the
+** same name.
+*/
+#define re_match sqlite3re_match
+#define re_compile sqlite3re_compile
+#define re_free sqlite3re_free
+
+/* The end-of-input character */
+#define RE_EOF 0 /* End of input */
+
+/* The NFA is implemented as sequence of opcodes taken from the following
+** set. Each opcode has a single integer argument.
+*/
+#define RE_OP_MATCH 1 /* Match the one character in the argument */
+#define RE_OP_ANY 2 /* Match any one character. (Implements ".") */
+#define RE_OP_ANYSTAR 3 /* Special optimized version of .* */
+#define RE_OP_FORK 4 /* Continue to both next and opcode at iArg */
+#define RE_OP_GOTO 5 /* Jump to opcode at iArg */
+#define RE_OP_ACCEPT 6 /* Halt and indicate a successful match */
+#define RE_OP_CC_INC 7 /* Beginning of a [...] character class */
+#define RE_OP_CC_EXC 8 /* Beginning of a [^...] character class */
+#define RE_OP_CC_VALUE 9 /* Single value in a character class */
+#define RE_OP_CC_RANGE 10 /* Range of values in a character class */
+#define RE_OP_WORD 11 /* Perl word character [A-Za-z0-9_] */
+#define RE_OP_NOTWORD 12 /* Not a perl word character */
+#define RE_OP_DIGIT 13 /* digit: [0-9] */
+#define RE_OP_NOTDIGIT 14 /* Not a digit */
+#define RE_OP_SPACE 15 /* space: [ \t\n\r\v\f] */
+#define RE_OP_NOTSPACE 16 /* Not a digit */
+#define RE_OP_BOUNDARY 17 /* Boundary between word and non-word */
+
+/* Each opcode is a "state" in the NFA */
+typedef unsigned short ReStateNumber;
+
+/* Because this is an NFA and not a DFA, multiple states can be active at
+** once. An instance of the following object records all active states in
+** the NFA. The implementation is optimized for the common case where the
+** number of actives states is small.
+*/
+typedef struct ReStateSet {
+ unsigned nState; /* Number of current states */
+ ReStateNumber *aState; /* Current states */
+} ReStateSet;
+
+/* An input string read one character at a time.
+*/
+typedef struct ReInput ReInput;
+struct ReInput {
+ const unsigned char *z; /* All text */
+ int i; /* Next byte to read */
+ int mx; /* EOF when i>=mx */
+};
+
+/* A compiled NFA (or an NFA that is in the process of being compiled) is
+** an instance of the following object.
+*/
+typedef struct ReCompiled ReCompiled;
+struct ReCompiled {
+ ReInput sIn; /* Regular expression text */
+ const char *zErr; /* Error message to return */
+ char *aOp; /* Operators for the virtual machine */
+ int *aArg; /* Arguments to each operator */
+ unsigned (*xNextChar)(ReInput*); /* Next character function */
+ unsigned char zInit[12]; /* Initial text to match */
+ int nInit; /* Number of characters in zInit */
+ unsigned nState; /* Number of entries in aOp[] and aArg[] */
+ unsigned nAlloc; /* Slots allocated for aOp[] and aArg[] */
+};
+
+/* Add a state to the given state set if it is not already there */
+static void re_add_state(ReStateSet *pSet, int newState){
+ unsigned i;
+ for(i=0; i<pSet->nState; i++) if( pSet->aState[i]==newState ) return;
+ pSet->aState[pSet->nState++] = newState;
+}
+
+/* Extract the next unicode character from *pzIn and return it. Advance
+** *pzIn to the first byte past the end of the character returned. To
+** be clear: this routine converts utf8 to unicode. This routine is
+** optimized for the common case where the next character is a single byte.
+*/
+static unsigned re_next_char(ReInput *p){
+ unsigned c;
+ if( p->i>=p->mx ) return 0;
+ c = p->z[p->i++];
+ if( c>=0x80 ){
+ if( (c&0xe0)==0xc0 && p->i<p->mx && (p->z[p->i]&0xc0)==0x80 ){
+ c = (c&0x1f)<<6 | (p->z[p->i++]&0x3f);
+ if( c<0x80 ) c = 0xfffd;
+ }else if( (c&0xf0)==0xe0 && p->i+1<p->mx && (p->z[p->i]&0xc0)==0x80
+ && (p->z[p->i+1]&0xc0)==0x80 ){
+ c = (c&0x0f)<<12 | ((p->z[p->i]&0x3f)<<6) | (p->z[p->i+1]&0x3f);
+ p->i += 2;
+ if( c<=0x3ff || (c>=0xd800 && c<=0xdfff) ) c = 0xfffd;
+ }else if( (c&0xf8)==0xf0 && p->i+3<p->mx && (p->z[p->i]&0xc0)==0x80
+ && (p->z[p->i+1]&0xc0)==0x80 && (p->z[p->i+2]&0xc0)==0x80 ){
+ c = (c&0x07)<<18 | ((p->z[p->i]&0x3f)<<12) | ((p->z[p->i+1]&0x3f)<<6)
+ | (p->z[p->i+2]&0x3f);
+ p->i += 3;
+ if( c<=0xffff || c>0x10ffff ) c = 0xfffd;
+ }else{
+ c = 0xfffd;
+ }
+ }
+ return c;
+}
+static unsigned re_next_char_nocase(ReInput *p){
+ unsigned c = re_next_char(p);
+ if( c>='A' && c<='Z' ) c += 'a' - 'A';
+ return c;
+}
+
+/* Return true if c is a perl "word" character: [A-Za-z0-9_] */
+static int re_word_char(int c){
+ return (c>='0' && c<='9') || (c>='a' && c<='z')
+ || (c>='A' && c<='Z') || c=='_';
+}
+
+/* Return true if c is a "digit" character: [0-9] */
+static int re_digit_char(int c){
+ return (c>='0' && c<='9');
+}
+
+/* Return true if c is a perl "space" character: [ \t\r\n\v\f] */
+static int re_space_char(int c){
+ return c==' ' || c=='\t' || c=='\n' || c=='\r' || c=='\v' || c=='\f';
+}
+
+/* Run a compiled regular expression on the zero-terminated input
+** string zIn[]. Return true on a match and false if there is no match.
+*/
+static int re_match(ReCompiled *pRe, const unsigned char *zIn, int nIn){
+ ReStateSet aStateSet[2], *pThis, *pNext;
+ ReStateNumber aSpace[100];
+ ReStateNumber *pToFree;
+ unsigned int i = 0;
+ unsigned int iSwap = 0;
+ int c = RE_EOF+1;
+ int cPrev = 0;
+ int rc = 0;
+ ReInput in;
+
+ in.z = zIn;
+ in.i = 0;
+ in.mx = nIn>=0 ? nIn : (int)strlen((char const*)zIn);
+
+ /* Look for the initial prefix match, if there is one. */
+ if( pRe->nInit ){
+ unsigned char x = pRe->zInit[0];
+ while( in.i+pRe->nInit<=in.mx
+ && (zIn[in.i]!=x ||
+ strncmp((const char*)zIn+in.i, (const char*)pRe->zInit, pRe->nInit)!=0)
+ ){
+ in.i++;
+ }
+ if( in.i+pRe->nInit>in.mx ) return 0;
+ }
+
+ if( pRe->nState<=(sizeof(aSpace)/(sizeof(aSpace[0])*2)) ){
+ pToFree = 0;
+ aStateSet[0].aState = aSpace;
+ }else{
+ pToFree = sqlite3_malloc( sizeof(ReStateNumber)*2*pRe->nState );
+ if( pToFree==0 ) return -1;
+ aStateSet[0].aState = pToFree;
+ }
+ aStateSet[1].aState = &aStateSet[0].aState[pRe->nState];
+ pNext = &aStateSet[1];
+ pNext->nState = 0;
+ re_add_state(pNext, 0);
+ while( c!=RE_EOF && pNext->nState>0 ){
+ cPrev = c;
+ c = pRe->xNextChar(&in);
+ pThis = pNext;
+ pNext = &aStateSet[iSwap];
+ iSwap = 1 - iSwap;
+ pNext->nState = 0;
+ for(i=0; i<pThis->nState; i++){
+ int x = pThis->aState[i];
+ switch( pRe->aOp[x] ){
+ case RE_OP_MATCH: {
+ if( pRe->aArg[x]==c ) re_add_state(pNext, x+1);
+ break;
+ }
+ case RE_OP_ANY: {
+ re_add_state(pNext, x+1);
+ break;
+ }
+ case RE_OP_WORD: {
+ if( re_word_char(c) ) re_add_state(pNext, x+1);
+ break;
+ }
+ case RE_OP_NOTWORD: {
+ if( !re_word_char(c) ) re_add_state(pNext, x+1);
+ break;
+ }
+ case RE_OP_DIGIT: {
+ if( re_digit_char(c) ) re_add_state(pNext, x+1);
+ break;
+ }
+ case RE_OP_NOTDIGIT: {
+ if( !re_digit_char(c) ) re_add_state(pNext, x+1);
+ break;
+ }
+ case RE_OP_SPACE: {
+ if( re_space_char(c) ) re_add_state(pNext, x+1);
+ break;
+ }
+ case RE_OP_NOTSPACE: {
+ if( !re_space_char(c) ) re_add_state(pNext, x+1);
+ break;
+ }
+ case RE_OP_BOUNDARY: {
+ if( re_word_char(c)!=re_word_char(cPrev) ) re_add_state(pThis, x+1);
+ break;
+ }
+ case RE_OP_ANYSTAR: {
+ re_add_state(pNext, x);
+ re_add_state(pThis, x+1);
+ break;
+ }
+ case RE_OP_FORK: {
+ re_add_state(pThis, x+pRe->aArg[x]);
+ re_add_state(pThis, x+1);
+ break;
+ }
+ case RE_OP_GOTO: {
+ re_add_state(pThis, x+pRe->aArg[x]);
+ break;
+ }
+ case RE_OP_ACCEPT: {
+ rc = 1;
+ goto re_match_end;
+ }
+ case RE_OP_CC_INC:
+ case RE_OP_CC_EXC: {
+ int j = 1;
+ int n = pRe->aArg[x];
+ int hit = 0;
+ for(j=1; j>0 && j<n; j++){
+ if( pRe->aOp[x+j]==RE_OP_CC_VALUE ){
+ if( pRe->aArg[x+j]==c ){
+ hit = 1;
+ j = -1;
+ }
+ }else{
+ if( pRe->aArg[x+j]<=c && pRe->aArg[x+j+1]>=c ){
+ hit = 1;
+ j = -1;
+ }else{
+ j++;
+ }
+ }
+ }
+ if( pRe->aOp[x]==RE_OP_CC_EXC ) hit = !hit;
+ if( hit ) re_add_state(pNext, x+n);
+ break;
+ }
+ }
+ }
+ }
+ for(i=0; i<pNext->nState; i++){
+ if( pRe->aOp[pNext->aState[i]]==RE_OP_ACCEPT ){ rc = 1; break; }
+ }
+re_match_end:
+ sqlite3_free(pToFree);
+ return rc;
+}
+
+/* Resize the opcode and argument arrays for an RE under construction.
+*/
+static int re_resize(ReCompiled *p, int N){
+ char *aOp;
+ int *aArg;
+ aOp = sqlite3_realloc(p->aOp, N*sizeof(p->aOp[0]));
+ if( aOp==0 ) return 1;
+ p->aOp = aOp;
+ aArg = sqlite3_realloc(p->aArg, N*sizeof(p->aArg[0]));
+ if( aArg==0 ) return 1;
+ p->aArg = aArg;
+ p->nAlloc = N;
+ return 0;
+}
+
+/* Insert a new opcode and argument into an RE under construction. The
+** insertion point is just prior to existing opcode iBefore.
+*/
+static int re_insert(ReCompiled *p, int iBefore, int op, int arg){
+ int i;
+ if( p->nAlloc<=p->nState && re_resize(p, p->nAlloc*2) ) return 0;
+ for(i=p->nState; i>iBefore; i--){
+ p->aOp[i] = p->aOp[i-1];
+ p->aArg[i] = p->aArg[i-1];
+ }
+ p->nState++;
+ p->aOp[iBefore] = op;
+ p->aArg[iBefore] = arg;
+ return iBefore;
+}
+
+/* Append a new opcode and argument to the end of the RE under construction.
+*/
+static int re_append(ReCompiled *p, int op, int arg){
+ return re_insert(p, p->nState, op, arg);
+}
+
+/* Make a copy of N opcodes starting at iStart onto the end of the RE
+** under construction.
+*/
+static void re_copy(ReCompiled *p, int iStart, int N){
+ if( p->nState+N>=p->nAlloc && re_resize(p, p->nAlloc*2+N) ) return;
+ memcpy(&p->aOp[p->nState], &p->aOp[iStart], N*sizeof(p->aOp[0]));
+ memcpy(&p->aArg[p->nState], &p->aArg[iStart], N*sizeof(p->aArg[0]));
+ p->nState += N;
+}
+
+/* Return true if c is a hexadecimal digit character: [0-9a-fA-F]
+** If c is a hex digit, also set *pV = (*pV)*16 + valueof(c). If
+** c is not a hex digit *pV is unchanged.
+*/
+static int re_hex(int c, int *pV){
+ if( c>='0' && c<='9' ){
+ c -= '0';
+ }else if( c>='a' && c<='f' ){
+ c -= 'a' - 10;
+ }else if( c>='A' && c<='F' ){
+ c -= 'A' - 10;
+ }else{
+ return 0;
+ }
+ *pV = (*pV)*16 + (c & 0xff);
+ return 1;
+}
+
+/* A backslash character has been seen, read the next character and
+** return its interpretation.
+*/
+static unsigned re_esc_char(ReCompiled *p){
+ static const char zEsc[] = "afnrtv\\()*.+?[$^{|}]";
+ static const char zTrans[] = "\a\f\n\r\t\v";
+ int i, v = 0;
+ char c;
+ if( p->sIn.i>=p->sIn.mx ) return 0;
+ c = p->sIn.z[p->sIn.i];
+ if( c=='u' && p->sIn.i+4<p->sIn.mx ){
+ const unsigned char *zIn = p->sIn.z + p->sIn.i;
+ if( re_hex(zIn[1],&v)
+ && re_hex(zIn[2],&v)
+ && re_hex(zIn[3],&v)
+ && re_hex(zIn[4],&v)
+ ){
+ p->sIn.i += 5;
+ return v;
+ }
+ }
+ if( c=='x' && p->sIn.i+2<p->sIn.mx ){
+ const unsigned char *zIn = p->sIn.z + p->sIn.i;
+ if( re_hex(zIn[1],&v)
+ && re_hex(zIn[2],&v)
+ ){
+ p->sIn.i += 3;
+ return v;
+ }
+ }
+ for(i=0; zEsc[i] && zEsc[i]!=c; i++){}
+ if( zEsc[i] ){
+ if( i<6 ) c = zTrans[i];
+ p->sIn.i++;
+ }else{
+ p->zErr = "unknown \\ escape";
+ }
+ return c;
+}
+
+/* Forward declaration */
+static const char *re_subcompile_string(ReCompiled*);
+
+/* Peek at the next byte of input */
+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 */
+
+ 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;
+ }
+ sqlite3_set_auxdata(context, 0, pRe, (void(*)(void*))re_free);
+ }
+ zStr = (const unsigned char*)sqlite3_value_text(argv[1]);
+ if( zStr!=0 ){
+ sqlite3_result_int(context, re_match(pRe, zStr, -1));
+ }
+}
+
+/*
+** 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;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-08 17:08:41 +0000