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/*

 * Copyright © 2008 Intel Corporation

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice (including the next

 * paragraph) shall be included in all copies or substantial portions of the

 * Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 */

#include "main/imports.h"

#include "symbol_table.h"

#include "hash_table.h"

struct symbol {

    /**

     * Link to the next symbol in the table with the same name

     *

     * The linked list of symbols with the same name is ordered by scope

     * from inner-most to outer-most.

     */

    struct symbol *next_with_same_name;

    /**

     * Link to the next symbol in the table with the same scope

     *

     * The linked list of symbols with the same scope is unordered.  Symbols

     * in this list my have unique names.

     */

    struct symbol *next_with_same_scope;

    /**

     * Header information for the list of symbols with the same name.

     */

    struct symbol_header *hdr;

    /**

     * Name space of the symbol

     *

     * Name space are arbitrary user assigned integers.  No two symbols can

     * exist in the same name space at the same scope level.

     */

    int name_space;

    /** Scope depth where this symbol was defined. */

    unsigned depth;

    /**

     * Arbitrary user supplied data.

     */

    void *data;

};

/**

 */

struct symbol_header {

    /** Linkage in list of all headers in a given symbol table. */

    struct symbol_header *next;

    /** Symbol name. */

    char *name;

    /** Linked list of symbols with the same name. */

    struct symbol *symbols;

};

/**

 * Element of the scope stack.

 */

struct scope_level {

    /** Link to next (inner) scope level. */

    struct scope_level *next;

    /** Linked list of symbols with the same scope. */

    struct symbol *symbols;

};

/**

 *

 */

struct _mesa_symbol_table {

    /** Hash table containing all symbols in the symbol table. */

    struct hash_table *ht;

    /** Top of scope stack. */

    struct scope_level *current_scope;

    /** List of all symbol headers in the table. */

    struct symbol_header *hdr;

    /** Current scope depth. */

    unsigned depth;

};

static void

check_symbol_table(struct _mesa_symbol_table *table)

{

#if !defined(NDEBUG)

    struct scope_level *scope;

    for (scope = table->current_scope; scope != NULL; scope = scope->next) {

        struct symbol *sym;

        for (sym = scope->symbols

             ; sym != NULL

             ; sym = sym->next_with_same_name) {

            const struct symbol_header *const hdr = sym->hdr;

            struct symbol *sym2;

            for (sym2 = hdr->symbols

                 ; sym2 != NULL

                 ; sym2 = sym2->next_with_same_name) {

                assert(sym2->hdr == hdr);

            }

        }

    }

#else

    (void) table;

#endif /* !defined(NDEBUG) */

}

void

_mesa_symbol_table_pop_scope(struct _mesa_symbol_table *table)

{

    struct scope_level *const scope = table->current_scope;

    struct symbol *sym = scope->symbols;

    table->current_scope = scope->next;

    table->depth--;

    free(scope);

    while (sym != NULL) {

        struct symbol *const next = sym->next_with_same_scope;

        struct symbol_header *const hdr = sym->hdr;

        assert(hdr->symbols == sym);

        hdr->symbols = sym->next_with_same_name;

        free(sym);

        sym = next;

    }

    check_symbol_table(table);

}

void

_mesa_symbol_table_push_scope(struct _mesa_symbol_table *table)

{

    struct scope_level *const scope = calloc(1, sizeof(*scope));

    if (scope == NULL) {

       _mesa_error_no_memory(__func__);

       return;

    }

    scope->next = table->current_scope;

    table->current_scope = scope;

    table->depth++;

}

static struct symbol_header *

find_symbol(struct _mesa_symbol_table *table, const char *name)

{

    return (struct symbol_header *) hash_table_find(table->ht, name);

}

/**

 * Determine the scope "distance" of a symbol from the current scope

 *

 * \return

 * A non-negative number for the number of scopes between the current scope

 * and the scope where a symbol was defined.  A value of zero means the current

 * scope.  A negative number if the symbol does not exist.

 */

int

_mesa_symbol_table_symbol_scope(struct _mesa_symbol_table *table,

				int name_space, const char *name)

{

    struct symbol_header *const hdr = find_symbol(table, name);

    struct symbol *sym;

    if (hdr != NULL) {

       for (sym = hdr->symbols; sym != NULL; sym = sym->next_with_same_name) {

	  assert(sym->hdr == hdr);

	  if ((name_space == -1) || (sym->name_space == name_space)) {

	     assert(sym->depth <= table->depth);

	     return sym->depth - table->depth;

	  }

       }

    }

    return -1;

}

void *

_mesa_symbol_table_find_symbol(struct _mesa_symbol_table *table,

                               int name_space, const char *name)

{

    struct symbol_header *const hdr = find_symbol(table, name);

    if (hdr != NULL) {

        struct symbol *sym;

        for (sym = hdr->symbols; sym != NULL; sym = sym->next_with_same_name) {

            assert(sym->hdr == hdr);

            if ((name_space == -1) || (sym->name_space == name_space)) {

                return sym->data;

            }

        }

    }

    return NULL;

}

int

_mesa_symbol_table_add_symbol(struct _mesa_symbol_table *table,

                              int name_space, const char *name,

                              void *declaration)

{

    struct symbol_header *hdr;

    struct symbol *sym;

    check_symbol_table(table);

    hdr = find_symbol(table, name);

    check_symbol_table(table);

    if (hdr == NULL) {

       hdr = calloc(1, sizeof(*hdr));

       if (hdr == NULL) {

          _mesa_error_no_memory(__func__);

          return -1;

       }

       hdr->name = strdup(name);

       if (hdr->name == NULL) {

          free(hdr);

          _mesa_error_no_memory(__func__);

          return -1;

       }

       hash_table_insert(table->ht, hdr, hdr->name);

       hdr->next = table->hdr;

       table->hdr = hdr;

    }

    check_symbol_table(table);

    /* If the symbol already exists in this namespace at this scope, it cannot

     * be added to the table.

     */

    for (sym = hdr->symbols

	 ; (sym != NULL) && (sym->name_space != name_space)

	 ; sym = sym->next_with_same_name) {

       /* empty */

    }

    if (sym && (sym->depth == table->depth))

       return -1;

    sym = calloc(1, sizeof(*sym));

    if (sym == NULL) {

       _mesa_error_no_memory(__func__);

       return -1;

    }

    sym->next_with_same_name = hdr->symbols;

    sym->next_with_same_scope = table->current_scope->symbols;

    sym->hdr = hdr;

    sym->name_space = name_space;

    sym->data = declaration;

    sym->depth = table->depth;

    assert(sym->hdr == hdr);

    hdr->symbols = sym;

    table->current_scope->symbols = sym;

    check_symbol_table(table);

    return 0;

}

int

_mesa_symbol_table_add_global_symbol(struct _mesa_symbol_table *table,

				     int name_space, const char *name,

				     void *declaration)

{

    struct symbol_header *hdr;

    struct symbol *sym;

    struct symbol *curr;

    struct scope_level *top_scope;

    check_symbol_table(table);

    hdr = find_symbol(table, name);

    check_symbol_table(table);

    if (hdr == NULL) {

        hdr = calloc(1, sizeof(*hdr));

        if (hdr == NULL) {

           _mesa_error_no_memory(__func__);

           return -1;

        }

        hdr->name = strdup(name);

        hash_table_insert(table->ht, hdr, hdr->name);

        hdr->next = table->hdr;

        table->hdr = hdr;

    }

    check_symbol_table(table);

    /* If the symbol already exists in this namespace at this scope, it cannot

     * be added to the table.

     */

    for (sym = hdr->symbols

	 ; (sym != NULL) && (sym->name_space != name_space)

	 ; sym = sym->next_with_same_name) {

       /* empty */

    }

    if (sym && sym->depth == 0)

       return -1;

    /* Find the top-level scope */

    for (top_scope = table->current_scope

	 ; top_scope->next != NULL

	 ; top_scope = top_scope->next) {

       /* empty */

    }

    sym = calloc(1, sizeof(*sym));

    if (sym == NULL) {

       _mesa_error_no_memory(__func__);

       return -1;

    }

    sym->next_with_same_scope = top_scope->symbols;

    sym->hdr = hdr;

    sym->name_space = name_space;

    sym->data = declaration;

    assert(sym->hdr == hdr);

    /* Since next_with_same_name is ordered by scope, we need to append the

     * new symbol to the _end_ of the list.

     */

    if (hdr->symbols == NULL) {

       hdr->symbols = sym;

    } else {

       for (curr = hdr->symbols

	    ; curr->next_with_same_name != NULL

	    ; curr = curr->next_with_same_name) {

	  /* empty */

       }

       curr->next_with_same_name = sym;

    }

    top_scope->symbols = sym;

    check_symbol_table(table);

    return 0;

}

struct _mesa_symbol_table *

_mesa_symbol_table_ctor(void)

{

    struct _mesa_symbol_table *table = calloc(1, sizeof(*table));

    if (table != NULL) {

       table->ht = hash_table_ctor(32, hash_table_string_hash,

				   hash_table_string_compare);

       _mesa_symbol_table_push_scope(table);

    }

    return table;

}

void

_mesa_symbol_table_dtor(struct _mesa_symbol_table *table)

{

   struct symbol_header *hdr;

   struct symbol_header *next;

   while (table->current_scope != NULL) {

      _mesa_symbol_table_pop_scope(table);

   }

   for (hdr = table->hdr; hdr != NULL; hdr = next) {

       next = hdr->next;

       free(hdr->name);

       free(hdr);

   }

   hash_table_dtor(table->ht);

   free(table);

}