THUAI6/CAPI/cpp/grpc/include/upb/internal/table.h

/*
 * Copyright (c) 2009-2021, Google LLC
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of Google LLC nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 */

/*
 * upb_table
 *
 * This header is INTERNAL-ONLY!  Its interfaces are not public or stable!
 * This file defines very fast int->upb_value (inttable) and string->upb_value
 * (strtable) hash tables.
 *
 * The table uses chained scatter with Brent's variation (inspired by the Lua
 * implementation of hash tables).  The hash function for strings is Austin
 * Appleby's "MurmurHash."
 *
 * The inttable uses uintptr_t as its key, which guarantees it can be used to
 * store pointers or integers of at least 32 bits (upb isn't really useful on
 * systems where sizeof(void*) < 4).
 *
 * The table must be homogeneous (all values of the same type).  In debug
 * mode, we check this on insert and lookup.
 */

#ifndef UPB_INTERNAL_TABLE_H_
#define UPB_INTERNAL_TABLE_H_

#include <stdint.h>
#include <string.h>

#include "upb/upb.h"

// Must be last.
#include "upb/port_def.inc"

#ifdef __cplusplus
extern "C"
{
#endif

    /* upb_value ******************************************************************/

    typedef struct
    {
        uint64_t val;
    } upb_value;

    /* Variant that works with a length-delimited rather than NULL-delimited string,
     * as supported by strtable. */
    char* upb_strdup2(const char* s, size_t len, upb_Arena* a);

    UPB_INLINE void _upb_value_setval(upb_value* v, uint64_t val)
    {
        v->val = val;
    }

/* For each value ctype, define the following set of functions:
 *
 * // Get/set an int32 from a upb_value.
 * int32_t upb_value_getint32(upb_value val);
 * void upb_value_setint32(upb_value *val, int32_t cval);
 *
 * // Construct a new upb_value from an int32.
 * upb_value upb_value_int32(int32_t val); */
#define FUNCS(name, membername, type_t, converter, proto_type)       \
    UPB_INLINE void upb_value_set##name(upb_value* val, type_t cval) \
    {                                                                \
        val->val = (converter)cval;                                  \
    }                                                                \
    UPB_INLINE upb_value upb_value_##name(type_t val)                \
    {                                                                \
        upb_value ret;                                               \
        upb_value_set##name(&ret, val);                              \
        return ret;                                                  \
    }                                                                \
    UPB_INLINE type_t upb_value_get##name(upb_value val)             \
    {                                                                \
        return (type_t)(converter)val.val;                           \
    }

    FUNCS(int32, int32, int32_t, int32_t, UPB_CTYPE_INT32)
    FUNCS(int64, int64, int64_t, int64_t, UPB_CTYPE_INT64)
    FUNCS(uint32, uint32, uint32_t, uint32_t, UPB_CTYPE_UINT32)
    FUNCS(uint64, uint64, uint64_t, uint64_t, UPB_CTYPE_UINT64)
    FUNCS(bool, _bool, bool, bool, UPB_CTYPE_BOOL)
    FUNCS(cstr, cstr, char*, uintptr_t, UPB_CTYPE_CSTR)
    FUNCS(ptr, ptr, void*, uintptr_t, UPB_CTYPE_PTR)
    FUNCS(constptr, constptr, const void*, uintptr_t, UPB_CTYPE_CONSTPTR)

#undef FUNCS

    UPB_INLINE void upb_value_setfloat(upb_value* val, float cval)
    {
        memcpy(&val->val, &cval, sizeof(cval));
    }

    UPB_INLINE void upb_value_setdouble(upb_value* val, double cval)
    {
        memcpy(&val->val, &cval, sizeof(cval));
    }

    UPB_INLINE upb_value upb_value_float(float cval)
    {
        upb_value ret;
        upb_value_setfloat(&ret, cval);
        return ret;
    }

    UPB_INLINE upb_value upb_value_double(double cval)
    {
        upb_value ret;
        upb_value_setdouble(&ret, cval);
        return ret;
    }

#undef SET_TYPE

    /* upb_tabkey *****************************************************************/

    /* Either:
     *   1. an actual integer key, or
     *   2. a pointer to a string prefixed by its uint32_t length, owned by us.
     *
     * ...depending on whether this is a string table or an int table.  We would
     * make this a union of those two types, but C89 doesn't support statically
     * initializing a non-first union member. */
    typedef uintptr_t upb_tabkey;

    UPB_INLINE char* upb_tabstr(upb_tabkey key, uint32_t* len)
    {
        char* mem = (char*)key;
        if (len)
            memcpy(len, mem, sizeof(*len));
        return mem + sizeof(*len);
    }

    UPB_INLINE upb_StringView upb_tabstrview(upb_tabkey key)
    {
        upb_StringView ret;
        uint32_t len;
        ret.data = upb_tabstr(key, &len);
        ret.size = len;
        return ret;
    }

    /* upb_tabval *****************************************************************/

    typedef struct upb_tabval
    {
        uint64_t val;
    } upb_tabval;

#define UPB_TABVALUE_EMPTY_INIT \
    {                           \
        -1                      \
    }

    /* upb_table ******************************************************************/

    typedef struct _upb_tabent
    {
        upb_tabkey key;
        upb_tabval val;

        /* Internal chaining.  This is const so we can create static initializers for
         * tables.  We cast away const sometimes, but *only* when the containing
         * upb_table is known to be non-const.  This requires a bit of care, but
         * the subtlety is confined to table.c. */
        const struct _upb_tabent* next;
    } upb_tabent;

    typedef struct
    {
        size_t count;       /* Number of entries in the hash part. */
        uint32_t mask;      /* Mask to turn hash value -> bucket. */
        uint32_t max_count; /* Max count before we hit our load limit. */
        uint8_t size_lg2;   /* Size of the hashtable part is 2^size_lg2 entries. */
        upb_tabent* entries;
    } upb_table;

    typedef struct
    {
        upb_table t;
    } upb_strtable;

    typedef struct
    {
        upb_table t;             /* For entries that don't fit in the array part. */
        const upb_tabval* array; /* Array part of the table. See const note above. */
        size_t array_size;       /* Array part size. */
        size_t array_count;      /* Array part number of elements. */
    } upb_inttable;

    UPB_INLINE size_t upb_table_size(const upb_table* t)
    {
        if (t->size_lg2 == 0)
            return 0;
        else
            return 1 << t->size_lg2;
    }

    /* Internal-only functions, in .h file only out of necessity. */
    UPB_INLINE bool upb_tabent_isempty(const upb_tabent* e)
    {
        return e->key == 0;
    }

    /* Initialize and uninitialize a table, respectively.  If memory allocation
     * failed, false is returned that the table is uninitialized. */
    bool upb_inttable_init(upb_inttable* table, upb_Arena* a);
    bool upb_strtable_init(upb_strtable* table, size_t expected_size, upb_Arena* a);

    /* Returns the number of values in the table. */
    size_t upb_inttable_count(const upb_inttable* t);
    UPB_INLINE size_t upb_strtable_count(const upb_strtable* t)
    {
        return t->t.count;
    }

    void upb_strtable_clear(upb_strtable* t);

    /* Inserts the given key into the hashtable with the given value.  The key must
     * not already exist in the hash table.  For strtables, the key is not required
     * to be NULL-terminated, and the table will make an internal copy of the key.
     * Inttables must not insert a value of UINTPTR_MAX.
     *
     * If a table resize was required but memory allocation failed, false is
     * returned and the table is unchanged. */
    bool upb_inttable_insert(upb_inttable* t, uintptr_t key, upb_value val, upb_Arena* a);
    bool upb_strtable_insert(upb_strtable* t, const char* key, size_t len, upb_value val, upb_Arena* a);

    /* Looks up key in this table, returning "true" if the key was found.
     * If v is non-NULL, copies the value for this key into *v. */
    bool upb_inttable_lookup(const upb_inttable* t, uintptr_t key, upb_value* v);
    bool upb_strtable_lookup2(const upb_strtable* t, const char* key, size_t len, upb_value* v);

    /* For NULL-terminated strings. */
    UPB_INLINE bool upb_strtable_lookup(const upb_strtable* t, const char* key, upb_value* v)
    {
        return upb_strtable_lookup2(t, key, strlen(key), v);
    }

    /* Removes an item from the table.  Returns true if the remove was successful,
     * and stores the removed item in *val if non-NULL. */
    bool upb_inttable_remove(upb_inttable* t, uintptr_t key, upb_value* val);
    bool upb_strtable_remove2(upb_strtable* t, const char* key, size_t len, upb_value* val);

    UPB_INLINE bool upb_strtable_remove(upb_strtable* t, const char* key, upb_value* v)
    {
        return upb_strtable_remove2(t, key, strlen(key), v);
    }

    /* Updates an existing entry in an inttable.  If the entry does not exist,
     * returns false and does nothing.  Unlike insert/remove, this does not
     * invalidate iterators. */
    bool upb_inttable_replace(upb_inttable* t, uintptr_t key, upb_value val);

    /* Optimizes the table for the current set of entries, for both memory use and
     * lookup time.  Client should call this after all entries have been inserted;
     * inserting more entries is legal, but will likely require a table resize. */
    void upb_inttable_compact(upb_inttable* t, upb_Arena* a);

    /* Exposed for testing only. */
    bool upb_strtable_resize(upb_strtable* t, size_t size_lg2, upb_Arena* a);

    /* Iterators ******************************************************************/

    /* Iteration over inttable.
     *
     *   intptr_t iter = UPB_INTTABLE_BEGIN;
     *   uintptr_t key;
     *   upb_value val;
     *   while (upb_inttable_next2(t, &key, &val, &iter)) {
     *      // ...
     *   }
     */

#define UPB_INTTABLE_BEGIN -1

    bool upb_inttable_next2(const upb_inttable* t, uintptr_t* key, upb_value* val, intptr_t* iter);
    void upb_inttable_removeiter(upb_inttable* t, intptr_t* iter);

    /* Iteration over strtable.
     *
     *   intptr_t iter = UPB_INTTABLE_BEGIN;
     *   upb_StringView key;
     *   upb_value val;
     *   while (upb_strtable_next2(t, &key, &val, &iter)) {
     *      // ...
     *   }
     */

#define UPB_STRTABLE_BEGIN -1

    bool upb_strtable_next2(const upb_strtable* t, upb_StringView* key, upb_value* val, intptr_t* iter);
    void upb_strtable_removeiter(upb_strtable* t, intptr_t* iter);

    /* DEPRECATED iterators, slated for removal.
     *
     * Iterators for int and string tables.  We are subject to some kind of unusual
     * design constraints:
     *
     * For high-level languages:
     *  - we must be able to guarantee that we don't crash or corrupt memory even if
     *    the program accesses an invalidated iterator.
     *
     * For C++11 range-based for:
     *  - iterators must be copyable
     *  - iterators must be comparable
     *  - it must be possible to construct an "end" value.
     *
     * Iteration order is undefined.
     *
     * Modifying the table invalidates iterators.  upb_{str,int}table_done() is
     * guaranteed to work even on an invalidated iterator, as long as the table it
     * is iterating over has not been freed.  Calling next() or accessing data from
     * an invalidated iterator yields unspecified elements from the table, but it is
     * guaranteed not to crash and to return real table elements (except when done()
     * is true). */

    /* upb_strtable_iter **********************************************************/

    /*   upb_strtable_iter i;
     *   upb_strtable_begin(&i, t);
     *   for(; !upb_strtable_done(&i); upb_strtable_next(&i)) {
     *     const char *key = upb_strtable_iter_key(&i);
     *     const upb_value val = upb_strtable_iter_value(&i);
     *     // ...
     *   }
     */

    typedef struct
    {
        const upb_strtable* t;
        size_t index;
    } upb_strtable_iter;

    void upb_strtable_begin(upb_strtable_iter* i, const upb_strtable* t);
    void upb_strtable_next(upb_strtable_iter* i);
    bool upb_strtable_done(const upb_strtable_iter* i);
    upb_StringView upb_strtable_iter_key(const upb_strtable_iter* i);
    upb_value upb_strtable_iter_value(const upb_strtable_iter* i);
    void upb_strtable_iter_setdone(upb_strtable_iter* i);
    bool upb_strtable_iter_isequal(const upb_strtable_iter* i1, const upb_strtable_iter* i2);

    /* upb_inttable_iter **********************************************************/

    /*   upb_inttable_iter i;
     *   upb_inttable_begin(&i, t);
     *   for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
     *     uintptr_t key = upb_inttable_iter_key(&i);
     *     upb_value val = upb_inttable_iter_value(&i);
     *     // ...
     *   }
     */

    typedef struct
    {
        const upb_inttable* t;
        size_t index;
        bool array_part;
    } upb_inttable_iter;

    UPB_INLINE const upb_tabent* str_tabent(const upb_strtable_iter* i)
    {
        return &i->t->t.entries[i->index];
    }

    void upb_inttable_begin(upb_inttable_iter* i, const upb_inttable* t);
    void upb_inttable_next(upb_inttable_iter* i);
    bool upb_inttable_done(const upb_inttable_iter* i);
    uintptr_t upb_inttable_iter_key(const upb_inttable_iter* i);
    upb_value upb_inttable_iter_value(const upb_inttable_iter* i);
    void upb_inttable_iter_setdone(upb_inttable_iter* i);
    bool upb_inttable_iter_isequal(const upb_inttable_iter* i1, const upb_inttable_iter* i2);

    uint32_t _upb_Hash(const void* p, size_t n, uint64_t seed);

#ifdef __cplusplus
} /* extern "C" */
#endif

#include "upb/port_undef.inc"

#endif /* UPB_INTERNAL_TABLE_H_ */