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February 16, 2022 23:17
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A simple array/buffer datastructure
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| #include <stdlib.h> | |
| #include <stdint.h> | |
| #include <assert.h> | |
| // Dynamic Array: | |
| // A stretchy buffer datastructure and a macro interface for both the buffers and static arrays. | |
| // Structure idea by Sean Barrett: | |
| // https://github.com/nothings/stb/blob/master/deprecated/stretchy_buffer.h | |
| typedef struct BufHdr BufHdr; | |
| typedef struct ArrHdr ArrHdr; | |
| struct BufHdr { | |
| size_t len; | |
| size_t cap; | |
| size_t size; | |
| char buf[]; | |
| }; | |
| struct ArrHdr { | |
| size_t len; | |
| size_t cap; | |
| char buf[]; | |
| }; | |
| struct BufHdr* bhdr (const void* buf) { | |
| BufHdr* hdr = (BufHdr*)((char*)buf - offsetof(BufHdr, buf)); | |
| if (hdr->len == hdr->cap) { | |
| hdr->cap <<= 1; | |
| realloc(hdr, offsetof(BufHdr, buf) + hdr->size * hdr->cap); | |
| } | |
| return hdr; | |
| } | |
| void* buf_init (size_t size) { | |
| size_t cap = 8; | |
| BufHdr* hdr = malloc(offsetof(BufHdr, buf) + size * cap); | |
| hdr->len = 0; | |
| hdr->cap = cap; | |
| hdr->size = size; | |
| return hdr->buf; | |
| } | |
| void buf_free (const void* buf) { | |
| free(bhdr(buf)); | |
| buf = 0; | |
| } | |
| // Buffer interface | |
| #define bdel(b) buf_free(b) | |
| #define bset(s) buf_init(s) | |
| #define bcap(b) bhdr(b)->cap | |
| #define blen(b) bhdr(b)->len | |
| #define bput(b, ...) b[bhdr(b)->len++] = (__VA_ARGS__) | |
| #define bclr(b) bhdr(b)->len = 0 | |
| // Array interface | |
| #define ahdr(a) ((ArrHdr*)((char*)a - offsetof(ArrHdr, buf))) | |
| #define aset(a, s) (char[(sizeof(*a)*s)+offsetof(ArrHdr, buf)]){0}; ahdr(a)->len = 0; ahdr(a)->cap = s | |
| #define acap(a) ahdr(a)->cap | |
| #define alen(a) ahdr(a)->len | |
| #define aput(a, ...) a[ahdr(a)->len++] = (__VA_ARGS__) | |
| #define aclr(a) ahdr(a)->len = 0 | |
| // Example | |
| #if 0 | |
| int main (int argc, char** argv) { | |
| // Buffer | |
| { | |
| int* b = bset(sizeof(int)); | |
| for (int i = 0; i < 10; i++) { | |
| bput(b, i); | |
| } | |
| for (int i = 0; i < blen(b); i++) { | |
| assert(b[i] == i); | |
| } | |
| bclr(b); | |
| assert(blen(b) == 0); | |
| bdel(b); | |
| } | |
| // Array | |
| { | |
| int* a = (int*)aset(a, 8); | |
| for (int i = 0; i < acap(a); i++) { | |
| aput(a, i); | |
| } | |
| for (int i = 0; i < acap(a); i++) { | |
| assert(a[i] == i); | |
| } | |
| assert(alen(a) == acap(a)); | |
| aclr(a); | |
| assert(alen(a) == 0); | |
| } | |
| return 0; | |
| } | |
| #endif |
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