/* Copyright (c) 2017 - 2021 LiteSpeed Technologies Inc. See LICENSE. */ /* * Tiny receive history. It is used in IETF mini connection, where we want * to use as little memory as possible. This data structure is an array of * packet ranges. Each packet range is six bytes. This is possible because * initial packets must not be wider than four bytes. * * Another limitation of this history is that it never shrinks. (Although * technically is is possible to implement. */ #ifndef LSQUIC_TRECHIST #define LSQUIC_TRECHIST 1 struct lsquic_packno_range; /* This value could be as large as 32, which is how many bits wide * trechist_mask_t is. The other limit on the number of ranges is * UCHAR_MAX, which is how many different values can fit into te_next. */ #define TRECHIST_MAX_RANGES 16 struct trechist_elem { uint32_t te_low; unsigned char te_count; unsigned char te_next; /* 0 means no next element */ }; #define TE_HIGH(te_) ((te_)->te_low + (te_)->te_count - 1) #define TRECHIST_SIZE (TRECHIST_MAX_RANGES * sizeof(struct trechist_elem)) /* There are two parts to this: the array of trechist_elem's and the bitmask * that tracks which elements are used. The smallest range must always be at * offset zero. */ typedef uint32_t trechist_mask_t; int lsquic_trechist_insert (trechist_mask_t *, struct trechist_elem *, uint32_t); struct trechist_iter { struct lsquic_packno_range range; const struct trechist_elem *elems; trechist_mask_t mask; unsigned char next; }; void lsquic_trechist_iter (struct trechist_iter *iter, trechist_mask_t mask, const struct trechist_elem *); /* Don't modify history while iterating */ const struct lsquic_packno_range * lsquic_trechist_first (void *iter); const struct lsquic_packno_range * lsquic_trechist_next (void *iter); int lsquic_trechist_copy_ranges (trechist_mask_t *mask /* This gets overwritten */, struct trechist_elem *elems, void *src_rechist, const struct lsquic_packno_range * (*first) (void *), const struct lsquic_packno_range * (*next) (void *)); int lsquic_trechist_contains (trechist_mask_t mask, const struct trechist_elem *elems, uint32_t packno); uint32_t lsquic_trechist_max (trechist_mask_t mask, const struct trechist_elem *elems); #endif