Add a C++ example: simple grep

examples/cheap_grep.cpp

@@ -0,0 +1,88 @@
+#include <iostream>
+#include <cstdint>
+#include <fstream>
+#include <iomanip>
+#include "../lite_string.h"
+
+/**
+ * @brief A simple emulation of the grep command.
+ *
+ * This function reads the input stream line by line and prints the lines that contain the specified pattern.
+ *
+ * @param pattern The pattern to search for.
+ * @param input The input stream to read from.
+ * @param ignoreCase Whether to ignore the case of the characters.
+ * @return 0 if the pattern is found, 1 otherwise.
+ */
+int cheap_grep(const lite_string *pattern, std::istream &input, bool ignoreCase) {
+    char line[4096];
+    int ret = 1;
+
+    lite_string *s = string_new();
+    lite_string *patternCopy = string_new();
+    lite_string *lineCopy = string_new();
+
+    string_copy(pattern, patternCopy);
+    if (ignoreCase) string_to_lower(patternCopy);
+
+
+    while (input.getline(line, sizeof line)) {
+        string_append_cstr(s, line);
+        string_copy(s, lineCopy);
+
+        if (ignoreCase) string_to_lower(lineCopy);
+
+        if (string_find_substr(lineCopy, patternCopy) != SIZE_MAX) {
+            ret = 0;
+            std::cout << line << '\n';
+        }
+
+        string_clear(s);
+    }
+    // The strings must be freed after use.
+    string_free(s);
+    string_free(patternCopy);
+    string_free(lineCopy);
+
+    return ret;
+}
+
+int main(int argc, char *argv[]) {
+    if (argc < 3) {
+        std::cerr << "Usage: " << argv[0] << " [-i] <pattern> <filename>\n";
+        return 1;
+    }
+
+    bool ignoreCase = false;
+    int argIndex = 1;
+    lite_string *firstArg = string_new_cstr(argv[1]);
+
+    if (argc > 3 && string_compare_cstr(firstArg, "-i")) {
+        ignoreCase = true;
+        argIndex = 2;
+    }
+
+    lite_string *pattern = string_new_cstr(argv[argIndex]);
+    lite_string *filename = string_new_cstr(argv[argIndex + 1]);
+    int ret = 0;
+
+    // If the filename is "-", read from stdin.
+    if (string_compare_cstr(filename, "-")) {
+        ret = cheap_grep(pattern, std::cin, ignoreCase);
+    } else {
+        std::ifstream file(string_cstr(filename));
+        if (!file.is_open()) {
+            std::cerr << "Error: Unable to open file: " << std::quoted(string_cstr(filename)) << std::endl;
+            ret = 1;
+            goto CLEANUP;
+        }
+        ret = cheap_grep(pattern, file, ignoreCase);
+    }
+
+    CLEANUP: // Free the strings to release the memory.
+    string_free(firstArg);
+    string_free(pattern);
+    string_free(filename);
+
+    return ret;
+}