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Enhance the ext/misc/regexp.c code so that when it is compiled with

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SQLITE_DEBUG, a new function named regexp_bytecode() is available that
prints out the compiled NFA as human-readable text, for debugging purposes.

FossilOrigin-Name: cb5c08978fe8f074e6ae16953575213709e98b8bbae4359e0d2e6de67a7ea9e5
This commit is contained in:
drh
2022-07-18 11:44:16 +00:00
parent b496eef690
commit 67a0bf383f
3 changed files with 102 additions and 9 deletions
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95
ext/misc/regexp.c
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@@ -94,6 +94,31 @@ SQLITE_EXTENSION_INIT1
#define RE_OP_NOTSPACE 16 /* Not a digit */
#define RE_OP_BOUNDARY 17 /* Boundary between word and non-word */
#if defined(SQLITE_DEBUG)
/* Opcode names used for symbolic debugging */
static const char *ReOpName[] = {
"EOF",
"MATCH",
"ANY",
"ANYSTAR",
"FORK",
"GOTO",
"ACCEPT",
"CC_INC",
"CC_EXC",
"CC_VALUE",
"CC_RANGE",
"WORD",
"NOTWORD",
"DIGIT",
"NOTDIGIT",
"SPACE",
"NOTSPACE",
"BOUNDARY",
};
#endif /* SQLITE_DEBUG */
/* Each opcode is a "state" in the NFA */
typedef unsigned short ReStateNumber;
@@ -127,7 +152,7 @@ struct ReCompiled {
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 */
int nInit; /* Number of bytes in zInit */
unsigned nState; /* Number of entries in aOp[] and aArg[] */
unsigned nAlloc; /* Slots allocated for aOp[] and aArg[] */
};
@@ -745,6 +770,67 @@ static void re_sql_func(
}
}
#if defined(SQLITE_DEBUG)
/*
** This function is used for testing and debugging only. It is only available
** if the SQLITE_DEBUG compile-time option is used.
**
** Compile a regular expression and then convert the compiled expression into
** text and return that text.
*/
static void re_bytecode_func(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const char *zPattern;
const char *zErr;
ReCompiled *pRe;
sqlite3_str *pStr;
int i;
int n;
char *z;
zPattern = (const char*)sqlite3_value_text(argv[0]);
if( zPattern==0 ) return;
zErr = re_compile(&pRe, zPattern, sqlite3_user_data(context)!=0);
if( zErr ){
re_free(pRe);
sqlite3_result_error(context, zErr, -1);
return;
}
if( pRe==0 ){
sqlite3_result_error_nomem(context);
return;
}
pStr = sqlite3_str_new(0);
if( pStr==0 ) goto re_bytecode_func_err;
if( pRe->nInit>0 ){
sqlite3_str_appendf(pStr, "INIT ");
for(i=0; i<pRe->nInit; i++){
sqlite3_str_appendf(pStr, "%02x", pRe->zInit[i]);
}
sqlite3_str_appendf(pStr, "\n");
}
for(i=0; i<pRe->nState; i++){
sqlite3_str_appendf(pStr, "%-8s %4d\n",
ReOpName[(unsigned char)pRe->aOp[i]], pRe->aArg[i]);
}
n = sqlite3_str_length(pStr);
z = sqlite3_str_finish(pStr);
if( n==0 ){
sqlite3_free(z);
}else{
sqlite3_result_text(context, z, n-1, sqlite3_free);
}
re_bytecode_func_err:
re_free(pRe);
}
#endif /* SQLITE_DEBUG */
/*
** Invoke this routine to register the regexp() function with the
** SQLite database connection.
@@ -769,6 +855,13 @@ int sqlite3_regexp_init(
rc = sqlite3_create_function(db, "regexpi", 2,
SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
(void*)db, re_sql_func, 0, 0);
#if defined(SQLITE_DEBUG)
if( rc==SQLITE_OK ){
rc = sqlite3_create_function(db, "regexp_bytecode", 1,
SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
0, re_bytecode_func, 0, 0);
}
#endif /* SQLITE_DEBUG */
}
return rc;
}