/*
* Copyright (C) 2009 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <string.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include "expr.h"
// Functions should:
//
// - return a malloc()'d string
// - if Evaluate() on any argument returns NULL, return NULL.
int BooleanString(const char* s) {
return s[0] != '\0';
}
char* Evaluate(void* cookie, Expr* expr) {
return expr->fn(expr->name, cookie, expr->argc, expr->argv);
}
char* ConcatFn(const char* name, void* cookie, int argc, Expr* argv[]) {
if (argc == 0) {
return strdup("");
}
char** strings = malloc(argc * sizeof(char*));
int i;
for (i = 0; i < argc; ++i) {
strings[i] = NULL;
}
char* result = NULL;
int length = 0;
for (i = 0; i < argc; ++i) {
strings[i] = Evaluate(cookie, argv[i]);
if (strings[i] == NULL) {
goto done;
}
length += strlen(strings[i]);
}
result = malloc(length+1);
int p = 0;
for (i = 0; i < argc; ++i) {
strcpy(result+p, strings[i]);
p += strlen(strings[i]);
}
result[p] = '\0';
done:
for (i = 0; i < argc; ++i) {
free(strings[i]);
}
return result;
}
char* IfElseFn(const char* name, void* cookie, int argc, Expr* argv[]) {
if (argc != 2 && argc != 3) {
return NULL;
}
char* cond = Evaluate(cookie, argv[0]);
if (cond == NULL) {
return NULL;
}
if (BooleanString(cond) == true) {
free(cond);
return Evaluate(cookie, argv[1]);
} else {
if (argc == 3) {
free(cond);
return Evaluate(cookie, argv[2]);
} else {
return cond;
}
}
}
char* AbortFn(const char* name, void* cookie, int argc, Expr* argv[]) {
return NULL;
}
char* AssertFn(const char* name, void* cookie, int argc, Expr* argv[]) {
int i;
for (i = 0; i < argc; ++i) {
char* v = Evaluate(cookie, argv[i]);
if (v == NULL) {
return NULL;
}
int b = BooleanString(v);
free(v);
if (!b) {
return NULL;
}
}
return strdup("");
}
char* PrintFn(const char* name, void* cookie, int argc, Expr* argv[]) {
int i;
for (i = 0; i < argc; ++i) {
char* v = Evaluate(cookie, argv[i]);
if (v == NULL) {
return NULL;
}
fputs(v, stdout);
free(v);
}
return strdup("");
}
char* LogicalAndFn(const char* name, void* cookie,
int argc, Expr* argv[]) {
char* left = Evaluate(cookie, argv[0]);
if (left == NULL) return NULL;
if (BooleanString(left) == true) {
free(left);
return Evaluate(cookie, argv[1]);
} else {
return left;
}
}
char* LogicalOrFn(const char* name, void* cookie,
int argc, Expr* argv[]) {
char* left = Evaluate(cookie, argv[0]);
if (left == NULL) return NULL;
if (BooleanString(left) == false) {
free(left);
return Evaluate(cookie, argv[1]);
} else {
return left;
}
}
char* LogicalNotFn(const char* name, void* cookie,
int argc, Expr* argv[]) {
char* val = Evaluate(cookie, argv[0]);
if (val == NULL) return NULL;
bool bv = BooleanString(val);
free(val);
if (bv) {
return strdup("");
} else {
return strdup("t");
}
}
char* SubstringFn(const char* name, void* cookie,
int argc, Expr* argv[]) {
char* needle = Evaluate(cookie, argv[0]);
if (needle == NULL) return NULL;
char* haystack = Evaluate(cookie, argv[1]);
if (haystack == NULL) {
free(needle);
return NULL;
}
char* result = strdup(strstr(haystack, needle) ? "t" : "");
free(needle);
free(haystack);
return result;
}
char* EqualityFn(const char* name, void* cookie, int argc, Expr* argv[]) {
char* left = Evaluate(cookie, argv[0]);
if (left == NULL) return NULL;
char* right = Evaluate(cookie, argv[1]);
if (right == NULL) {
free(left);
return NULL;
}
char* result = strdup(strcmp(left, right) == 0 ? "t" : "");
free(left);
free(right);
return result;
}
char* InequalityFn(const char* name, void* cookie, int argc, Expr* argv[]) {
char* left = Evaluate(cookie, argv[0]);
if (left == NULL) return NULL;
char* right = Evaluate(cookie, argv[1]);
if (right == NULL) {
free(left);
return NULL;
}
char* result = strdup(strcmp(left, right) != 0 ? "t" : "");
free(left);
free(right);
return result;
}
char* SequenceFn(const char* name, void* cookie, int argc, Expr* argv[]) {
char* left = Evaluate(cookie, argv[0]);
if (left == NULL) return NULL;
free(left);
return Evaluate(cookie, argv[1]);
}
char* Literal(const char* name, void* cookie, int argc, Expr* argv[]) {
return strdup(name);
}
Expr* Build(Function fn, int count, ...) {
va_list v;
va_start(v, count);
Expr* e = malloc(sizeof(Expr));
e->fn = fn;
e->name = "(operator)";
e->argc = count;
e->argv = malloc(count * sizeof(Expr*));
int i;
for (i = 0; i < count; ++i) {
e->argv[i] = va_arg(v, Expr*);
}
va_end(v);
return e;
}
static int fn_entries = 0;
static int fn_size = 0;
NamedFunction* fn_table = NULL;
void RegisterFunction(const char* name, Function fn) {
if (fn_entries <= fn_size) {
fn_size = fn_size*2 + 1;
fn_table = realloc(fn_table, fn_size * sizeof(NamedFunction));
}
fn_table[fn_entries].name = name;
fn_table[fn_entries].fn = fn;
++fn_entries;
}
static int fn_entry_compare(const void* a, const void* b) {
const char* na = ((const NamedFunction*)a)->name;
const char* nb = ((const NamedFunction*)b)->name;
return strcmp(na, nb);
}
void FinishRegistration() {
qsort(fn_table, fn_entries, sizeof(NamedFunction), fn_entry_compare);
}
Function FindFunction(const char* name) {
NamedFunction key;
key.name = name;
NamedFunction* nf = bsearch(&key, fn_table, fn_entries, sizeof(NamedFunction),
fn_entry_compare);
if (nf == NULL) {
return NULL;
}
return nf->fn;
}
void RegisterBuiltins() {
RegisterFunction("ifelse", IfElseFn);
RegisterFunction("abort", AbortFn);
RegisterFunction("assert", AssertFn);
RegisterFunction("concat", ConcatFn);
RegisterFunction("is_substring", SubstringFn);
RegisterFunction("print", PrintFn);
}
