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kc3-lang/harfbuzz/src/hb-serialize.hh
Behdad Esfahbod
- src/hb-serialize.hh
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/* * Copyright © 2007,2008,2009,2010 Red Hat, Inc. * Copyright © 2012,2018 Google, Inc. * Copyright © 2019 Facebook, Inc. * * This is part of HarfBuzz, a text shaping library. * * Permission is hereby granted, without written agreement and without * license or royalty fees, to use, copy, modify, and distribute this * software and its documentation for any purpose, provided that the * above copyright notice and the following two paragraphs appear in * all copies of this software. * * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH * DAMAGE. * * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. * * Red Hat Author(s): Behdad Esfahbod * Google Author(s): Behdad Esfahbod * Facebook Author(s): Behdad Esfahbod */ #ifndef HB_SERIALIZE_HH #define HB_SERIALIZE_HH #include "hb.hh" #include "hb-blob.hh" #include "hb-map.hh" #include "hb-pool.hh" /* * Serialize */ struct hb_serialize_context_t { typedef unsigned objidx_t; enum whence_t { Head, /* Relative to the current object head (default). */ Tail, /* Relative to the current object tail after packed. */ Absolute /* Absolute: from the start of the serialize buffer. */ }; struct object_t { void fini () { links.fini (); } bool operator == (const object_t &o) const { return (tail - head == o.tail - o.head) && (links.length == o.links.length) && 0 == hb_memcmp (head, o.head, tail - head) && links.as_bytes () == o.links.as_bytes (); } uint32_t hash () const { return hb_bytes_t (head, tail - head).hash () ^ links.as_bytes ().hash (); } struct link_t { bool is_wide: 1; bool is_signed: 1; unsigned whence: 2; unsigned position: 28; unsigned bias; objidx_t objidx; }; char *head; char *tail; hb_vector_t<link_t> links; object_t *next; }; struct snapshot_t { char *head; char *tail; object_t *current; // Just for sanity check unsigned num_links; }; snapshot_t snapshot () { return snapshot_t { head, tail, current, current->links.length }; } hb_serialize_context_t (void *start_, unsigned int size) : start ((char *) start_), end (start + size), current (nullptr) { reset (); } ~hb_serialize_context_t () { fini (); } void fini () { for (object_t *_ : ++hb_iter (packed)) _->fini (); packed.fini (); this->packed_map.fini (); while (current) { auto *_ = current; current = current->next; _->fini (); } object_pool.fini (); } bool in_error () const { return !this->successful; } void reset () { this->successful = true; this->ran_out_of_room = false; this->head = this->start; this->tail = this->end; this->debug_depth = 0; fini (); this->packed.push (nullptr); } bool check_success (bool success) { return this->successful && (success || (err_other_error (), false)); } template <typename T1, typename T2> bool check_equal (T1 &&v1, T2 &&v2) { return check_success ((long long) v1 == (long long) v2); } template <typename T1, typename T2> bool check_assign (T1 &v1, T2 &&v2) { return check_equal (v1 = v2, v2); } template <typename T> bool propagate_error (T &&obj) { return check_success (!hb_deref (obj).in_error ()); } template <typename T1, typename... Ts> bool propagate_error (T1 &&o1, Ts&&... os) { return propagate_error (hb_forward<T1> (o1)) && propagate_error (hb_forward<Ts> (os)...); } /* To be called around main operation. */ template <typename Type> Type *start_serialize () { DEBUG_MSG_LEVEL (SERIALIZE, this->start, 0, +1, "start [%p..%p] (%lu bytes)", this->start, this->end, (unsigned long) (this->end - this->start)); assert (!current); return push<Type> (); } void end_serialize () { DEBUG_MSG_LEVEL (SERIALIZE, this->start, 0, -1, "end [%p..%p] serialized %u bytes; %s", this->start, this->end, (unsigned) (this->head - this->start), this->successful ? "successful" : "UNSUCCESSFUL"); propagate_error (packed, packed_map); if (unlikely (!current)) return; assert (!current->next); /* Only "pack" if there exist other objects... Otherwise, don't bother. * Saves a move. */ if (packed.length <= 1) return; pop_pack (false); resolve_links (); } template <typename Type = void> Type *push () { object_t *obj = object_pool.alloc (); if (unlikely (!obj)) check_success (false); else { obj->head = head; obj->tail = tail; obj->next = current; current = obj; } return start_embed<Type> (); } void pop_discard () { object_t *obj = current; if (unlikely (!obj)) return; current = current->next; revert (obj->head, obj->tail); obj->fini (); object_pool.free (obj); } /* Set share to false when an object is unlikely sharable with others * so not worth an attempt, or a contiguous table is serialized as * multiple consecutive objects in the reverse order so can't be shared. */ objidx_t pop_pack (bool share=true) { object_t *obj = current; if (unlikely (!obj)) return 0; current = current->next; obj->tail = head; obj->next = nullptr; unsigned len = obj->tail - obj->head; head = obj->head; /* Rewind head. */ if (!len) { assert (!obj->links.length); return 0; } objidx_t objidx; if (share) { objidx = packed_map.get (obj); if (objidx) { obj->fini (); return objidx; } } tail -= len; memmove (tail, obj->head, len); obj->head = tail; obj->tail = tail + len; packed.push (obj); if (unlikely (packed.in_error ())) return 0; objidx = packed.length - 1; if (share) packed_map.set (obj, objidx); return objidx; } void revert (snapshot_t snap) { assert (snap.current == current); current->links.shrink (snap.num_links); revert (snap.head, snap.tail); } void revert (char *snap_head, char *snap_tail) { assert (snap_head <= head); assert (tail <= snap_tail); head = snap_head; tail = snap_tail; discard_stale_objects (); } void discard_stale_objects () { while (packed.length > 1 && packed.tail ()->head < tail) { packed_map.del (packed.tail ()); assert (!packed.tail ()->next); packed.tail ()->fini (); packed.pop (); } if (packed.length > 1) assert (packed.tail ()->head == tail); } template <typename T> void add_link (T &ofs, objidx_t objidx, whence_t whence = Head, unsigned bias = 0) { static_assert (sizeof (T) == 2 || sizeof (T) == 4, ""); if (!objidx) return; assert (current); assert (current->head <= (const char *) &ofs); auto& link = *current->links.push (); link.is_wide = sizeof (T) == 4; link.is_signed = hb_is_signed (hb_unwrap_type (T)); link.whence = (unsigned) whence; link.position = (const char *) &ofs - current->head; link.bias = bias; link.objidx = objidx; } unsigned to_bias (const void *base) const { if (!base) return 0; assert (current); assert (current->head <= (const char *) base); return (const char *) base - current->head; } void resolve_links () { if (unlikely (in_error ())) return; assert (!current); assert (packed.length > 1); for (const object_t* parent : ++hb_iter (packed)) for (const object_t::link_t &link : parent->links) { const object_t* child = packed[link.objidx]; if (unlikely (!child)) { err_other_error(); return; } unsigned offset = 0; switch ((whence_t) link.whence) { case Head: offset = child->head - parent->head; break; case Tail: offset = child->head - parent->tail; break; case Absolute: offset = (head - start) + (child->head - tail); break; } assert (offset >= link.bias); offset -= link.bias; if (link.is_signed) { if (link.is_wide) assign_offset<int32_t> (parent, link, offset); else assign_offset<int16_t> (parent, link, offset); } else { if (link.is_wide) assign_offset<uint32_t> (parent, link, offset); else assign_offset<uint16_t> (parent, link, offset); } } } unsigned int length () const { return this->head - current->head; } void align (unsigned int alignment) { unsigned int l = length () % alignment; if (l) allocate_size<void> (alignment - l); } template <typename Type = void> Type *start_embed (const Type *obj HB_UNUSED = nullptr) const { return reinterpret_cast<Type *> (this->head); } template <typename Type> Type *start_embed (const Type &obj) const { return start_embed (hb_addressof (obj)); } /* Following two functions exist to allow setting breakpoint on. */ void err_ran_out_of_room () { this->ran_out_of_room = true; } void err_other_error () { this->successful = false; } template <typename Type> Type *allocate_size (unsigned int size) { if (unlikely (!this->successful)) return nullptr; if (this->tail - this->head < ptrdiff_t (size)) { err_ran_out_of_room (); this->successful = false; return nullptr; } memset (this->head, 0, size); char *ret = this->head; this->head += size; return reinterpret_cast<Type *> (ret); } template <typename Type> Type *allocate_min () { return this->allocate_size<Type> (Type::min_size); } template <typename Type> Type *embed (const Type *obj) { unsigned int size = obj->get_size (); Type *ret = this->allocate_size<Type> (size); if (unlikely (!ret)) return nullptr; memcpy (ret, obj, size); return ret; } template <typename Type> Type *embed (const Type &obj) { return embed (hb_addressof (obj)); } template <typename Type, typename ...Ts> auto _copy (const Type &src, hb_priority<1>, Ts&&... ds) HB_RETURN (Type *, src.copy (this, hb_forward<Ts> (ds)...)) template <typename Type> auto _copy (const Type &src, hb_priority<0>) -> decltype (&(hb_declval<Type> () = src)) { Type *ret = this->allocate_size<Type> (sizeof (Type)); if (unlikely (!ret)) return nullptr; *ret = src; return ret; } /* Like embed, but active: calls obj.operator=() or obj.copy() to transfer data * instead of memcpy(). */ template <typename Type, typename ...Ts> Type *copy (const Type &src, Ts&&... ds) { return _copy (src, hb_prioritize, hb_forward<Ts> (ds)...); } template <typename Type, typename ...Ts> Type *copy (const Type *src, Ts&&... ds) { return copy (*src, hb_forward<Ts> (ds)...); } template<typename Iterator, hb_requires (hb_is_iterator (Iterator)), typename ...Ts> void copy_all (Iterator it, Ts&&... ds) { for (decltype (*it) _ : it) copy (_, hb_forward<Ts> (ds)...); } template <typename Type> hb_serialize_context_t& operator << (const Type &obj) & { embed (obj); return *this; } template <typename Type> Type *extend_size (Type *obj, unsigned int size) { assert (this->start <= (char *) obj); assert ((char *) obj <= this->head); assert ((char *) obj + size >= this->head); if (unlikely (!this->allocate_size<Type> (((char *) obj) + size - this->head))) return nullptr; return reinterpret_cast<Type *> (obj); } template <typename Type> Type *extend_size (Type &obj, unsigned int size) { return extend_size (hb_addressof (obj), size); } template <typename Type> Type *extend_min (Type *obj) { return extend_size (obj, obj->min_size); } template <typename Type> Type *extend_min (Type &obj) { return extend_min (hb_addressof (obj)); } template <typename Type, typename ...Ts> Type *extend (Type *obj, Ts&&... ds) { return extend_size (obj, obj->get_size (hb_forward<Ts> (ds)...)); } template <typename Type, typename ...Ts> Type *extend (Type &obj, Ts&&... ds) { return extend (hb_addressof (obj), hb_forward<Ts> (ds)...); } /* Output routines. */ hb_bytes_t copy_bytes () const { assert (this->successful); /* Copy both items from head side and tail side... */ unsigned int len = (this->head - this->start) + (this->end - this->tail); char *p = (char *) malloc (len); if (unlikely (!p)) return hb_bytes_t (); memcpy (p, this->start, this->head - this->start); memcpy (p + (this->head - this->start), this->tail, this->end - this->tail); return hb_bytes_t (p, len); } template <typename Type> Type *copy () const { return reinterpret_cast<Type *> ((char *) copy_bytes ().arrayZ); } hb_blob_t *copy_blob () const { hb_bytes_t b = copy_bytes (); return hb_blob_create (b.arrayZ, b.length, HB_MEMORY_MODE_WRITABLE, (char *) b.arrayZ, free); } private: template <typename T> void assign_offset (const object_t* parent, const object_t::link_t &link, unsigned offset) { auto &off = * ((BEInt<T, sizeof (T)> *) (parent->head + link.position)); assert (0 == off); check_assign (off, offset); } public: /* TODO Make private. */ char *start, *head, *tail, *end; unsigned int debug_depth; bool successful; bool ran_out_of_room; private: /* Object memory pool. */ hb_pool_t<object_t> object_pool; /* Stack of currently under construction objects. */ object_t *current; /* Stack of packed objects. Object 0 is always nil object. */ hb_vector_t<object_t *> packed; /* Map view of packed objects. */ hb_hashmap_t<const object_t *, objidx_t, nullptr, 0> packed_map; }; #endif /* HB_SERIALIZE_HH */