agrego practicas

c/arena/main.c

@@ -0,0 +1,90 @@
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct{
+    unsigned char *buffer;
+    size_t size;
+    size_t offset;
+}Arena;
+
+Arena arena_create(size_t);
+void* arena_alloc(Arena *, size_t);
+void arena_destroy(Arena *);
+
+int main(void){
+    Arena  arena =  arena_create(13);
+    int *ptrInt1 = (int*)arena_alloc(&arena, sizeof(int));
+    int *ptrInt2 = (int*)arena_alloc(&arena, sizeof(int));
+    float *ptrFloat1 = (float*)arena_alloc(&arena, sizeof(float));
+    char *ptrChar1 = (char*)arena_alloc(&arena, sizeof(char));
+
+    int need = sizeof(int)*2 + sizeof(float) + sizeof(char);
+
+    printf("sizeof int: %d\n", (int)sizeof(int));
+    printf("sizeof float: %d\n", (int)sizeof(float));
+    printf("sizeof char: %d\n", (int)sizeof(char));
+
+    printf("Necesitamos: %d\n", need);
+
+    if(ptrInt1 != NULL){
+        *ptrInt1 = 18;
+        printf("Primer entero: %d\n", *ptrInt1);
+    }
+    if(ptrInt2 != NULL){
+        *ptrInt2 = 27;
+        printf("Segundo entero: %d\n", *ptrInt2);
+    }
+    if(ptrFloat1 != NULL){
+        *ptrFloat1 = 3.1415f;
+        printf("Primer flotante: %f\n", *ptrFloat1);
+    }
+    if(ptrChar1 != NULL){
+        *ptrChar1 = 'L';
+        printf("Primer char: %c\n", *ptrChar1);
+    }
+
+    arena_destroy(&arena);
+
+    return 0;
+}
+
+Arena arena_create( size_t bytes){
+    Arena new_arena = {
+        .buffer = NULL,
+        .size = bytes,
+        .offset = 0
+    };
+
+    new_arena.buffer = (unsigned char *)malloc(bytes);
+
+    if(new_arena.buffer == NULL){
+        perror("Error asignando memoria");
+        exit(1);
+    }
+
+    return new_arena;
+
+}
+void* arena_alloc(Arena *ref_arena, size_t bytes){
+
+    if(ref_arena->buffer == NULL){
+        return NULL;
+    }
+
+    if(ref_arena->offset + bytes > ref_arena->size){
+        perror("Memoria llena\n");
+        return NULL;
+    }
+    void* ptr_ref = ref_arena->buffer + ref_arena->offset;
+    ref_arena->offset += bytes;
+    return ptr_ref;
+}
+
+void arena_destroy(Arena *ref_arena){
+    if(ref_arena->buffer != NULL){
+        free(ref_arena->buffer);
+        ref_arena->buffer = NULL;
+    }
+}
+