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Expr filtering: function to free tokens.

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antirez 2025-02-17 20:03:52 +01:00
parent c6bd5d3542
commit 9e4413d1e3
1 changed files with 20 additions and 15 deletions
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35
expr.c
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@ -114,6 +114,11 @@ struct {
#define EXPR_OP_SPECIALCHARS "+-*%/!()<>=|&"
/* ================================ Expr token ============================== */
void exprFreeToken(exprtoken *t) {
free(t);
}
/* ============================== Stack handling ============================ */
#include <stdlib.h>
@ -163,7 +168,7 @@ exprtoken *exprStackPeek(exprstack *stack) {
* assumed to be heap allocated. The passed pointer itself is not freed. */
void exprStackFree(exprstack *stack) {
for (int j = 0; j < stack->numitems; j++)
free(stack->items[j]);
exprFreeToken(stack->items[j]);
free(stack->items);
}
@ -188,11 +193,11 @@ void exprParseOperatorOrSelector(exprstate *es) {
{
es->p++;
}
size_t matchlen = es->p - start;
int matchlen = es->p - start;
/* If this is not a selector for an attribute to retrive, then
* it must be one of the valid operators. */
size_t bestlen = 0;
int bestlen = 0;
if (es->current.token_type == EXPR_TOKEN_OP) {
int j;
for (j = 0; ExprOptable[j].opname != NULL; j++) {
@ -279,7 +284,7 @@ void exprFree(exprstate *es) {
/* Split the provided expression into a stack of tokens. Returns
* 0 on success, 1 on error. */
int exprTokenize(exprstate *es, char *expr, int *errpos) {
int exprTokenize(exprstate *es, int *errpos) {
/* Main parsing loop. */
while(1) {
exprConsumeSpaces(es);
@ -332,7 +337,7 @@ int exprTokenize(exprstate *es, char *expr, int *errpos) {
token->offset = es->p - es->expr; /* To report errors gracefully. */
if (!exprStackPush(&es->tokens, token)) {
free(token);
exprFreeToken(token);
return 1; // OOM.
}
if (es->current.token_type == EXPR_TOKEN_EOF) break;
@ -376,8 +381,8 @@ int exprProcessOperator(exprstate *es, exprtoken *op, int *stack_items, int *err
}
if (top_op->opcode == EXPR_OP_OPAREN) {
free(top_op); // Free the opening parenthesis token.
free(op); // Free the closing parenthesis token.
exprFreeToken(top_op); // Free the opening parenthesis token.
exprFreeToken(op); // Free the closing parenthesis token.
return 0;
}
@ -444,15 +449,15 @@ exprstate *exprCompile(char *expr, int *errpos) {
exprStackInit(&es->program);
/* Tokenization. */
if (exprTokenize(es, expr, errpos)) {
if (exprTokenize(es, errpos)) {
exprFree(es);
return NULL;
}
/* Compile the expression into a sequence of operations. */
int stack_items = 0; // Track # of items that would be on the stack
// during execution. This way we can detect arity
// issues at compile time.
// during execution. This way we can detect arity
// issues at compile time.
/* Process each token. */
for (int i = 0; i < es->tokens.numitems; i++) {
@ -473,7 +478,7 @@ exprstate *exprCompile(char *expr, int *errpos) {
}
*value_token = *token; // Copy the token.
if (!exprStackPush(&es->program, value_token)) {
free(value_token);
exprFreeToken(value_token);
if (errpos) *errpos = token->offset;
exprFree(es);
return NULL;
@ -505,7 +510,7 @@ exprstate *exprCompile(char *expr, int *errpos) {
exprtoken *op = exprStackPop(&es->ops_stack);
if (op->opcode == EXPR_OP_OPAREN) {
if (errpos) *errpos = op->offset;
free(op);
exprFreeToken(op);
exprFree(es);
return NULL;
}
@ -513,13 +518,13 @@ exprstate *exprCompile(char *expr, int *errpos) {
int arity = exprGetOpArity(op->opcode);
if (stack_items < arity) {
if (errpos) *errpos = op->offset;
free(op);
exprFreeToken(op);
exprFree(es);
return NULL;
}
if (!exprStackPush(&es->program, op)) {
free(op);
exprFreeToken(op);
if (errpos) *errpos = op->offset;
exprFree(es);
return NULL;
@ -584,7 +589,7 @@ void exprPrintStack(exprstack *stack, const char *name) {
}
int main(int argc, char **argv) {
char *testexpr = "(5*2)-3 and 'foo'";
char *testexpr = "(5+2)*3 and 'foo'";
if (argc >= 2) testexpr = argv[1];
printf("Compiling expression: %s\n", testexpr);