From c8bae7493d2f2910b57f13ded012e86bdcfb0532 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 16:47:53 +0200 Subject: Adding upstream version 1:2.39.2. Signed-off-by: Daniel Baumann --- mem-pool.c | 178 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 178 insertions(+) create mode 100644 mem-pool.c (limited to 'mem-pool.c') diff --git a/mem-pool.c b/mem-pool.c new file mode 100644 index 0000000..599d8e8 --- /dev/null +++ b/mem-pool.c @@ -0,0 +1,178 @@ +/* + * Memory Pool implementation logic. + */ + +#include "cache.h" +#include "mem-pool.h" + +#define BLOCK_GROWTH_SIZE (1024 * 1024 - sizeof(struct mp_block)) + +/* + * The inner union is an approximation for C11's max_align_t, and the + * struct + offsetof computes _Alignof. This can all just be replaced + * with _Alignof(max_align_t) if/when C11 is part of the baseline. + * Note that _Alignof(X) need not be the same as sizeof(X); it's only + * required to be a (possibly trivial) factor. They are the same for + * most architectures, but m68k for example has only 2-byte alignment + * for its 4-byte and 8-byte types, so using sizeof would waste space. + * + * Add more types to the union if the current set is insufficient. + */ +struct git_max_alignment { + char unalign; + union { + uintmax_t max_align_uintmax; + void *max_align_pointer; + } aligned; +}; +#define GIT_MAX_ALIGNMENT offsetof(struct git_max_alignment, aligned) + +/* + * Allocate a new mp_block and insert it after the block specified in + * `insert_after`. If `insert_after` is NULL, then insert block at the + * head of the linked list. + */ +static struct mp_block *mem_pool_alloc_block(struct mem_pool *pool, + size_t block_alloc, + struct mp_block *insert_after) +{ + struct mp_block *p; + + pool->pool_alloc += sizeof(struct mp_block) + block_alloc; + p = xmalloc(st_add(sizeof(struct mp_block), block_alloc)); + + p->next_free = (char *)p->space; + p->end = p->next_free + block_alloc; + + if (insert_after) { + p->next_block = insert_after->next_block; + insert_after->next_block = p; + } else { + p->next_block = pool->mp_block; + pool->mp_block = p; + } + + return p; +} + +void mem_pool_init(struct mem_pool *pool, size_t initial_size) +{ + memset(pool, 0, sizeof(*pool)); + pool->block_alloc = BLOCK_GROWTH_SIZE; + + if (initial_size > 0) + mem_pool_alloc_block(pool, initial_size, NULL); +} + +void mem_pool_discard(struct mem_pool *pool, int invalidate_memory) +{ + struct mp_block *block, *block_to_free; + + block = pool->mp_block; + while (block) + { + block_to_free = block; + block = block->next_block; + + if (invalidate_memory) + memset(block_to_free->space, 0xDD, ((char *)block_to_free->end) - ((char *)block_to_free->space)); + + free(block_to_free); + } + + pool->mp_block = NULL; + pool->pool_alloc = 0; +} + +void *mem_pool_alloc(struct mem_pool *pool, size_t len) +{ + struct mp_block *p = NULL; + void *r; + + /* round up to a 'GIT_MAX_ALIGNMENT' alignment */ + if (len & (GIT_MAX_ALIGNMENT - 1)) + len += GIT_MAX_ALIGNMENT - (len & (GIT_MAX_ALIGNMENT - 1)); + + if (pool->mp_block && + pool->mp_block->end - pool->mp_block->next_free >= len) + p = pool->mp_block; + + if (!p) { + if (len >= (pool->block_alloc / 2)) + return mem_pool_alloc_block(pool, len, pool->mp_block); + + p = mem_pool_alloc_block(pool, pool->block_alloc, NULL); + } + + r = p->next_free; + p->next_free += len; + return r; +} + +void *mem_pool_calloc(struct mem_pool *pool, size_t count, size_t size) +{ + size_t len = st_mult(count, size); + void *r = mem_pool_alloc(pool, len); + memset(r, 0, len); + return r; +} + +char *mem_pool_strdup(struct mem_pool *pool, const char *str) +{ + size_t len = strlen(str) + 1; + char *ret = mem_pool_alloc(pool, len); + + return memcpy(ret, str, len); +} + +char *mem_pool_strndup(struct mem_pool *pool, const char *str, size_t len) +{ + char *p = memchr(str, '\0', len); + size_t actual_len = (p ? p - str : len); + char *ret = mem_pool_alloc(pool, actual_len+1); + + ret[actual_len] = '\0'; + return memcpy(ret, str, actual_len); +} + +int mem_pool_contains(struct mem_pool *pool, void *mem) +{ + struct mp_block *p; + + /* Check if memory is allocated in a block */ + for (p = pool->mp_block; p; p = p->next_block) + if ((mem >= ((void *)p->space)) && + (mem < ((void *)p->end))) + return 1; + + return 0; +} + +void mem_pool_combine(struct mem_pool *dst, struct mem_pool *src) +{ + struct mp_block *p; + + /* Append the blocks from src to dst */ + if (dst->mp_block && src->mp_block) { + /* + * src and dst have blocks, append + * blocks from src to dst. + */ + p = dst->mp_block; + while (p->next_block) + p = p->next_block; + + p->next_block = src->mp_block; + } else if (src->mp_block) { + /* + * src has blocks, dst is empty. + */ + dst->mp_block = src->mp_block; + } else { + /* src is empty, nothing to do. */ + } + + dst->pool_alloc += src->pool_alloc; + src->pool_alloc = 0; + src->mp_block = NULL; +} -- cgit v1.2.3