Initial implementation

.gitignore

@@ -0,0 +1 @@
+a.out

vec.c

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+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+
+typedef struct vec {
+  size_t len;
+  int    capacity;
+  size_t element_size;
+  void*  ptr;
+} vec;
+
+vec vecMalloc(size_t element_size) {
+  vec new;
+  new.len = 0;
+  new.capacity = 32;
+  new.element_size = element_size;
+  new.ptr = calloc(new.capacity, element_size);
+  if (new.ptr == NULL) new.capacity = -1;
+  return new;
+}
+
+#define vecNew(type) vecMalloc(sizeof(type))
+
+void vecFree(vec* v) {
+  if (v->capacity < 0) return;
+  v->capacity = -1;
+  v->len = 0;
+  free(v->ptr);
+}
+
+// Returns 0 on success
+int vecResize(vec* v, int newcap) {
+  void* newptr = calloc(newcap, v->element_size);
+  if (newptr == NULL) return 1;
+
+  memcpy(newptr, v->ptr, v->len * v->element_size);
+
+  void *oldptr = v->ptr;
+  v->ptr = newptr;
+  v->capacity = newcap;
+  free(oldptr);
+
+  return 0;
+}
+
+// returns 0 on success
+int vecPush(vec* v, void* item) {
+  if (v->capacity < v->len) return 1;
+
+  if (v->len + 1 >= v->capacity) {
+    if (vecResize(v, v->capacity * 2)) return 1;
+  }
+
+  memcpy(v->ptr + (v->element_size * v->len), item, v->element_size);
+  v->len += 1;
+  
+  return 0;
+}
+
+// returns NULL on failure
+void* vecAt(vec* v, size_t index) {
+  if (index >= v->len) return NULL;
+  return v->ptr + (index * v->element_size);
+}
+
+// NOTE: returns 1 on success, 0 on failure. For use with loops.
+int vecAtPtr(vec* v, size_t index, void** ptr) {
+  if(index >= v->len) return 0;
+  *ptr = v->ptr + (index * v->element_size);
+  return 1;
+}
+#define vecIter(v, type) for(struct{int i; type* item;} iter = {0, NULL}; vecAtPtr(&v, iter.i, (void**)&iter.item); ++iter.i)
+
+int main(int argc, char *argv[]) {
+  printf("Hello World!\n");
+  char* str = "HI";
+
+  vec v = vecNew(char);
+  
+  if(vecPush(&v, str)) {
+    printf("Error pushing %c\n", *str);
+  } else {
+    printf("Pushed %c\n", *str);
+  };
+  
+  printf(vecPush(&v, str+1) ? "Error pushing %c\n" : "Pushed %c\n", *(str+1));
+
+  printf("vec len: %d\n", v.len);
+
+  printf("Iter fn\n");
+  vecIter(v, char) {
+    printf("%d: %c\n", iter.i, *iter.item);
+  }
+
+  printf("For loop\n");
+  for(size_t i = 0; i < v.len; i++) {
+    char* item = (char*)vecAt(&v, i);
+    printf("%d: %c\n", i, *item);
+  }
+  return EXIT_SUCCESS;
+}