winsz

byte_header.c

@@ -0,0 +1,94 @@
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/*
+ * Pack header data into a byte.
+ * 3 bits are used for type (2^3 = 8 different types)
+ * 5 bits are used for length (2^5 = 32 max length, unit is up to you)
+ */
+
+typedef enum {
+    Ok = 0,
+    OversizedType,
+    OversizedLen,
+} Result;
+
+#define TYPE_LEN (4)
+#define LEN      (4)
+
+Result msg_create_header(uint8_t type, uint8_t len, uint8_t *out);
+void   msg_parse_header(uint8_t header, uint8_t *type_out, uint8_t *len_out);
+
+int main(void) {
+    assert(TYPE_LEN + LEN <= 8);
+    uint8_t maxlen = (1 << LEN) - 1;
+    uint8_t maxtype = (1 << TYPE_LEN) - 1;
+
+    {
+        uint8_t hdr;
+        Result  res = msg_create_header(3, 8, &hdr);
+
+        if (res == OversizedType)
+            printf("The type is out of range");
+        if (res == OversizedLen)
+            printf("The length is out of range");
+
+        printf("Header: 0x%02X\n", hdr);
+        printf("Error: %d\n", res);
+
+        uint8_t plen, ptype;
+        msg_parse_header(hdr, &ptype, &plen);
+        printf("Type: %d\n", ptype);
+        printf("Len: %d\n", plen);
+    }
+    {
+        printf("Max len: %d\n", maxlen);
+        printf("Max type: %d\n", maxtype);
+
+        uint8_t hdr;
+        Result  res = msg_create_header(maxtype, maxlen, &hdr);
+        assert(res == Ok);
+
+        uint8_t plen, ptype;
+        msg_parse_header(hdr, &ptype, &plen);
+        printf("plen: %d\n", plen);
+        printf("ptype: %d\n", ptype);
+        assert(ptype == maxtype);
+        assert(plen == maxlen);
+    }
+    {
+        for (int i = 0; i < 1000; i++) {
+            uint8_t len = arc4random() % maxlen;
+            uint8_t type = arc4random() % maxtype;
+            uint8_t hdr;
+            Result  res = msg_create_header(type, len, &hdr);
+            assert(res == Ok);
+
+            uint8_t plen, ptype;
+            msg_parse_header(hdr, &ptype, &plen);
+            assert(ptype == type);
+            assert(plen == len);
+        }
+    }
+
+    return 0;
+}
+
+Result msg_create_header(uint8_t type, uint8_t len, uint8_t *out) {
+    if (type > (1 << TYPE_LEN) - 1)
+        return OversizedType;
+
+    if (len > (1 << LEN) - 1)
+        return OversizedLen;
+
+    *out = (type << LEN) | (len & (0xFF >> TYPE_LEN));
+
+    return Ok;
+}
+
+void msg_parse_header(uint8_t header, uint8_t *type_out, uint8_t *len_out) {
+    *type_out = (header >> LEN) & ((1 << LEN) - 1);
+    *len_out = header & (0xFF >> TYPE_LEN);
+}

config_ini/Makefile

@@ -0,0 +1,14 @@
+CC = gcc
+CFLAGS = -Wall -O2
+
+TARGET = main.elf
+SRC = main.c conf.c
+
+#LDFLAGS =
+
+$(TARGET): $(SRC)
+	@echo CC $@
+	@$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+
+clean:
+	rm -f $(TARGET)

config_ini/conf.c

@@ -0,0 +1,80 @@
+#include "conf.h"
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MAX_LINE 256
+#define MAX_VAL  128
+
+/* Trim leading/trailing whitespace */
+static char *trim(char *str) {
+    char *end;
+
+    while (isspace((unsigned char)*str)) str++;
+    if (*str == 0)
+        return str; // only spaces
+
+    end = str + strnlen(str, MAX_VAL) - 1;
+
+    while (end > str && isspace((unsigned char)*end)) end--;
+    end[1] = '\0';
+    return str;
+}
+
+/* Load INI-style config */
+Config *config_load(const char *filename) {
+    FILE *f = fopen(filename, "r");
+    if (!f)
+        return NULL;
+
+    Config *cfg = calloc(1, sizeof(Config));
+    char    line[MAX_LINE];
+
+    while (fgets(line, sizeof(line), f)) {
+        char *s = trim(line);
+
+        // Skip empty or comment lines
+        if (*s == '\0' || *s == '#' || *s == ';')
+            continue;
+
+        char *eq = strchr(s, '=');
+        if (!eq)
+            continue; // invalid line, skip
+
+        *eq = '\0';
+        char *key = trim(s);
+        char *val = trim(eq + 1);
+
+        ConfigEntry *entry = malloc(sizeof(ConfigEntry));
+        entry->key = strndup(key, MAX_VAL);
+        entry->value = strndup(val, MAX_VAL);
+        entry->next = cfg->head;
+        cfg->head = entry;
+    }
+
+    fclose(f);
+    return cfg;
+}
+
+/* Get value for a key */
+const char *config_get(Config *cfg, const char *key) {
+    for (ConfigEntry *e = cfg->head; e; e = e->next) {
+        if (strncmp(e->key, key, MAX_VAL) == 0)
+            return e->value;
+    }
+    return NULL;
+}
+
+/* Free the config struct */
+void config_free(Config *cfg) {
+    ConfigEntry *e = cfg->head;
+    while (e) {
+        ConfigEntry *next = e->next;
+        free(e->key);
+        free(e->value);
+        free(e);
+        e = next;
+    }
+    free(cfg);
+}

config_ini/conf.h

@@ -0,0 +1,13 @@
+typedef struct ConfigEntry {
+    char               *key;
+    char               *value;
+    struct ConfigEntry *next;
+} ConfigEntry;
+
+typedef struct {
+    ConfigEntry *head;
+} Config;
+
+Config     *config_load(const char *filename);
+const char *config_get(Config *cfg, const char *key);
+void        config_free(Config *cfg);

config_ini/config.ini

@@ -0,0 +1,6 @@
+# Example INI file
+username = testuser
+password = secret123
+
+; comments work too
+timeout = 30

config_ini/config_broken.ini

@@ -0,0 +1,7 @@
+# Example INI file
+username = testuser ; inline
+password = secret123 # Comment
+
+; comments work too
+[aa]
+timeout = 30

config_ini/main.c

@@ -0,0 +1,20 @@
+#include "conf.h"
+#include <stdio.h>
+
+// Example usage
+int main(void) {
+    Config *cfg = config_load("config.ini");
+    if (!cfg) {
+        fprintf(stderr, "Failed to load config.ini\n");
+        return 1;
+    }
+
+    const char *user = config_get(cfg, "username");
+    const char *pass = config_get(cfg, "password");
+
+    printf("Username: %s\n", user ? user : "(not set)");
+    printf("Password: %s\n", pass ? pass : "(not set)");
+
+    config_free(cfg);
+    return 0;
+}

winsz.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+int main(void) {
+    struct winsize w;
+
+    if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &w) == -1) {
+        perror("ioctl");
+        return 1;
+    }
+
+    printf("Rows (height): %d\n", w.ws_row);
+    printf("Cols (width):  %d\n", w.ws_col);
+
+    return 0;
+}