kopia lustrzana https://github.com/micropython/micropython
commit
7bf724da21
78
py/gc.c
78
py/gc.c
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@ -326,20 +326,72 @@ machine_uint_t gc_nbytes(void *ptr_in) {
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return 0;
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}
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void *gc_realloc(void *ptr, machine_uint_t n_bytes) {
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machine_uint_t n_existing = gc_nbytes(ptr);
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if (n_bytes <= n_existing) {
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return ptr;
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} else {
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// TODO check if we can grow inplace
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void *ptr2 = gc_alloc(n_bytes);
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if (ptr2 == NULL) {
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return ptr2;
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}
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memcpy(ptr2, ptr, n_existing);
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gc_free(ptr);
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return ptr2;
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void *gc_realloc(void *ptr_in, machine_uint_t n_bytes) {
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void *ptr_out = NULL;
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machine_uint_t block =0;
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machine_uint_t ptr = (machine_uint_t)ptr_in;
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if (ptr_in == NULL) {
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return gc_alloc(n_bytes);
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}
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if (VERIFY_PTR(ptr) /* verify pointer */
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&& (block = BLOCK_FROM_PTR(ptr)) /* get first block */
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&& ATB_GET_KIND(block) == AT_HEAD) { /* make sure it's a HEAD block */
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byte block_type;
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machine_uint_t n_free = 0;
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machine_uint_t n_blocks = 1; /* counting HEAD block */
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/* get the number of consecutive tail blocks and
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the number of free blocks after last tail block */
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do {
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block_type = ATB_GET_KIND(block + n_blocks + n_free);
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switch (block_type) {
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case AT_FREE: n_free++; break;
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case AT_TAIL: n_blocks++; break;
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default: break;
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}
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/* stop as soon as we find enough blocks for n_bytes */
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} while (block_type != AT_HEAD && (n_bytes > (n_blocks * BYTES_PER_BLOCK)));
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/* number of allocated bytes */
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machine_uint_t n_existing = n_blocks * BYTES_PER_BLOCK;
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/* check if realloc'ing to a smaller size */
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if (n_bytes <= n_existing) {
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ptr_out = ptr_in;
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/* TODO should free remaining tail blocks ? */
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machine_uint_t last_block = block + n_blocks;
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while (ATB_GET_KIND(last_block) == AT_TAIL) {
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ATB_ANY_TO_FREE(last_block);
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last_block++;
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}
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/* check if we can expand in place */
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} else if (n_bytes <= (n_existing + (n_free * BYTES_PER_BLOCK))) {
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/* number of blocks needed to expand +1 if there's a remainder */
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machine_uint_t n_diff = ( n_bytes - n_existing)/BYTES_PER_BLOCK+
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((n_bytes - n_existing)%BYTES_PER_BLOCK!=0);
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DEBUG_printf("gc_realloc: expanding " UINT_FMT " blocks (" UINT_FMT " bytes) to " UINT_FMT " blocks (" UINT_FMT " bytes)\n",
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n_existing/BYTES_PER_BLOCK, n_existing, n_existing/BYTES_PER_BLOCK+n_diff, n_existing + n_diff*BYTES_PER_BLOCK);
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/* mark rest of blocks as used tail */
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for (machine_uint_t bl = block+n_blocks; bl < (block+n_blocks+n_diff); bl++) {
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ATB_FREE_TO_TAIL(bl);
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}
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ptr_out = ptr_in;
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/* try to find a new contiguous chain */
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} else if ((ptr_out = gc_alloc(n_bytes)) != NULL) {
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printf("gc_realloc: allocated new block \n");
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memcpy(ptr_out, ptr_in, n_existing);
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gc_free(ptr_in);
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}
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}
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return ptr_out;
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}
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void gc_dump_info() {
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