#pragma once

// ----------------------------------------------------------------------------
// dynamic array

typedef struct BufHdr
{
    vlong len;
    vlong cap;
    byte  buf[];
} BufHdr;

#define bufhdr(b)        ((BufHdr*)((uint8*)(b)-offsetof(BufHdr, buf)))
#define buflen(b)        ((b) ? (bufhdr(b)->len) : 0)
#define bufcap(b)        ((b) ? (bufhdr(b)->cap) : 0)
#define bufend(b)        ((b) + buflen(b))
#define bufsize(b)       ((b) ? (buflen(b) * sizeof((b)[0])) : 0)

#define buffree(b)       ((b) ? (free(bufhdr(b)), (b) = nil) : 0)
#define buffit(b, n)     ((n) <= bufcap(b) ? 0 : ((b) = ·bufgrow((b), (n), sizeof(*(b)))))

#define bufpush(b, ...)  (buffit((b), 1 + buflen(b)), (b)[bufhdr(b)->len++] = (__VA_ARGS__))
#define bufaddn(b, n)    (buffit(b, buflen(b)+n), bufhdr(b)->len += n, b+bufhdr(b)->len-n)

#define bufpop(b)         ((b)[--bufhdr(b)->len])
#define bufdel(b, i)      bufdeln((b), (i), 1)
#define bufdeln(b, i, n)  (memmove((b)+(i), (b)+(i)+(n), sizeof(*(b))*(bufhdr(b)->len-(n)-(i)), bufhdr(b)->len -= (n))
#define bufdelswap(b, i)  ((b)[i] = bufend(b)[-1], bufhdr(b)->len-=1)

void* ·bufgrow(void*, vlong, vlong);

// -----------------------------------------------------------------------------
// memory allocation

/* allocator interface */
typedef struct mem·Allocator {
    void *(*alloc)(void *heap, uint n, ulong size);
    void  (*free)(void *heap, void *ptr);
} mem·Allocator;

extern mem·Allocator sys·Memory;

typedef struct mem·Reallocator {
    void *(*alloc)(void *iface, uint n, ulong size);
    void *(*realloc)(void *iface, void *ptr, uint n, ulong size);
    void  (*free)(void *iface, void *ptr);
} mem·Reallocator;

extern mem·Reallocator sys·FullMemory;

/* simple memory arena */
typedef struct mem·Arena mem·Arena;

mem·Arena *mem·makearena(mem·Allocator from, void*);
void      *mem·arenaalloc(mem·Arena *A, uint n, ulong size); 
void       mem·freearena(mem·Arena *A);

extern mem·Allocator mem·ArenaAllocator;

/* mem functions */
int   mem·move(void *dst, void *src, uintptr size);
void *mem·findc(void *dst, uintptr len, int c);
int   mem·set(void *dst, int val, uintptr size);
int   mem·set64(void *dst, uint64 val, uintptr size);