{ Copyright 2000-2005 The Apache Software Foundation or its licensors, as
 * applicable.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 }

{
 * @file apr_tables.h
 * @brief APR Table library
 }

{
 * @defgroup apr_tables Table and Array Functions
 * @ingroup APR
 * Tables are used to store entirely opaque structures
 * for applications, while Arrays are usually used to
 * deal with string lists.
 }

{ the table abstract data type }
type
  apr_table_t = record end;
  Papr_table_t = ^apr_table_t;

{ An opaque array type }
  apr_array_header_t = record
    { The pool the array is allocated out of }
    pool: Papr_pool_t;
    { The amount of memory allocated for each element of the array }
    elt_size: Integer;
    { The number of active elements in the array }
    nelts: Integer;
    { The number of elements allocated in the array }
    nalloc: Integer;
    { The elements in the array }
    elts: PChar;
  end;
  Papr_array_header_t = ^apr_array_header_t;
  PPapr_array_header_t = ^Papr_array_header_t;

{
 * The (opaque) structure for string-content tables.
 }

{ The type for each entry in a string-content table }
  apr_table_entry_t = record
    { The key for the current table entry }
    key: PChar;          { maybe NULL in future;
                         * check when iterating thru table_elts
                         }
    { The value for the current table entry }
    val: PChar;

    { A checksum for the key, for use by the apr_table internals }
    key_checksum: apr_uint32_t;
  end;

{
 * Get the elements from a table
 * @param t The table
 * @return An array containing the contents of the table
 }
function apr_table_elts(const t: Papr_table_t): Papr_array_header_t;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_elts' + LibSuff4;

{
 * Determine if the table is empty
 * @param t The table to check
 * @return True if empty, False otherwise
 }
function apr_is_empty_table(const t: Papr_table_t): Integer;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_is_empty_table' + LibSuff4;

{
 * Determine if the array is empty
 * @param a The array to check
 * @return True if empty, False otherwise
 }
function apr_is_empty_array(const a: Papr_array_header_t): Integer;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_is_empty_array' + LibSuff4;

{
 * Create an array
 * @param p The pool to allocate the memory out of
 * @param nelts the number of elements in the initial array
 * @param elt_size The size of each element in the array.
 * @return The new array
 }
function apr_array_make(p: Papr_pool_t;
 nelts, elt_size: Integer): Papr_array_header_t;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_array_make' + LibSuff12;

{
 * Add a new element to an array (as a first-in, last-out stack)
 * @param arr The array to add an element to.
 * @return Location for the new element in the array.
 * @remark If there are no free spots in the array, then this function will
 *         allocate new space for the new element.
 }
function apr_array_push(arr: Papr_array_header_t): Pointer;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_array_push' + LibSuff4;

{
 * Remove an element from an array (as a first-in, last-out stack)
 * @param arr The array to remove an element from.
 * @return Location of the element in the array.
 * @remark If there are no elements in the array, NULL is returned.
 }
function apr_array_pop(arr: Papr_array_header_t): Pointer;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_array_pop' + LibSuff4;

{
 * Concatenate two arrays together
 * @param dst The destination array, and the one to go first in the combined
 *            array
 * @param src The source array to add to the destination array
 }
procedure apr_array_cat(dst: Papr_array_header_t;
 const src: Papr_array_header_t);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_array_cat' + LibSuff8;

{
 * Copy the entire array
 * @param p The pool to allocate the copy of the array out of
 * @param arr The array to copy
 * @return An exact copy of the array passed in
 * @remark The alternate apr_array_copy_hdr copies only the header, and arranges
 *         for the elements to be copied if (and only if) the code subsequently
 *         does a push or arraycat.
 }
function apr_array_copy(p: Papr_pool_t;
 const arr: Papr_array_header_t): Papr_array_header_t;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_array_copy' + LibSuff8;

{
 * Copy the headers of the array, and arrange for the elements to be copied if
 * and only if the code subsequently does a push or arraycat.
 * @param p The pool to allocate the copy of the array out of
 * @param arr The array to copy
 * @return An exact copy of the array passed in
 * @remark The alternate apr_array_copy copies the *entire* array.
 }
function apr_array_copy_hdr(p: Papr_pool_t;
 const arr: Papr_array_header_t): Papr_array_header_t;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_array_copy_hdr' + LibSuff8;

{
 * Append one array to the end of another, creating a new array in the process.
 * @param p The pool to allocate the new array out of
 * @param first The array to put first in the new array.
 * @param second The array to put second in the new array.
 * @return A new array containing the data from the two arrays passed in.
}
function apr_array_append(p: Papr_pool_t;
 const first, second: Papr_array_header_t): Papr_array_header_t;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_array_append' + LibSuff12;

{
 * Generates a new string from the apr_pool_t containing the concatenated
 * sequence of substrings referenced as elements within the array.  The string
 * will be empty if all substrings are empty or null, or if there are no
 * elements in the array.  If sep is non-NUL, it will be inserted between
 * elements as a separator.
 * @param p The pool to allocate the string out of
 * @param arr The array to generate the string from
 * @param sep The separator to use
 * @return A string containing all of the data in the array.
 }
function apr_array_pstrcat(p: Papr_pool_t;
 const arr: Papr_array_header_t; sep: Char): PChar;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_array_pstrcat' + LibSuff12;

{
 * Make a new table
 * @param p The pool to allocate the pool out of
 * @param nelts The number of elements in the initial table.
 * @return The new table.
 * @warning This table can only store text data
 }
function apr_table_make(p: Papr_pool_t; nelts: Integer): Papr_table_t;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_make' + LibSuff8;

{
 * Create a new table and copy another table into it
 * @param p The pool to allocate the new table out of
 * @param t The table to copy
 * @return A copy of the table passed in
 }
function apr_table_copy(p: Papr_pool_t; const t: Papr_table_t): Papr_table_t;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_copy' + LibSuff8;

{
 * Delete all of the elements from a table
 * @param t The table to clear
 }
procedure apr_table_clear(t: Papr_table_t);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_clear' + LibSuff4;

{
 * Get the value associated with a given key from the table.  After this call,
 * The data is still in the table
 * @param t The table to search for the key
 * @param key The key to search for
 * @return The value associated with the key, or NULL if the key does not exist.
 }
function apr_table_get(t: Papr_table_t; key: PChar): PChar;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_get' + LibSuff8;

{
 * Add a key/value pair to a table, if another element already exists with the
 * same key, this will over-write the old data.
 * @param t The table to add the data to.
 * @param key The key fo use
 * @param val The value to add
 * @remark When adding data, this function makes a copy of both the key and the
 *         value.
 }
procedure apr_table_set(t: Papr_table_t; const key, val: PChar);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_set' + LibSuff12;

{
 * Add a key/value pair to a table, if another element already exists with the
 * same key, this will over-write the old data.
 * @param t The table to add the data to.
 * @param key The key to use
 * @param val The value to add
 * @warning When adding data, this function does not make a copy of the key or
 *          the value, so care should be taken to ensure that the values will
 *          not change after they have been added..
 }
procedure apr_table_setn(t: Papr_table_t; const key, val: PChar);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_setn' + LibSuff12;

{
 * Remove data from the table
 * @param t The table to remove data from
 * @param key The key of the data being removed
 }
procedure apr_table_unset(t: Papr_table_t; const key: PChar);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_unset' + LibSuff8;

{
 * Add data to a table by merging the value with data that has already been
 * stored
 * @param t The table to search for the data
 * @param key The key to merge data for
 * @param val The data to add
 * @remark If the key is not found, then this function acts like apr_table_add
 }
procedure apr_table_merge(t: Papr_table_t; const key, val: PChar);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_merge' + LibSuff12;

{
 * Add data to a table by merging the value with data that has already been
 * stored
 * @param t The table to search for the data
 * @param key The key to merge data for
 * @param val The data to add
 * @remark If the key is not found, then this function acts like apr_table_addn
 }
procedure apr_table_mergen(t: Papr_table_t; const key, val: PChar);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_mergen' + LibSuff12;

{
 * Add data to a table, regardless of whether there is another element with the
 * same key.
 * @param t The table to add to
 * @param key The key to use
 * @param val The value to add.
 * @remark When adding data, this function makes a copy of both the key and the
 *         value.
 }
procedure apr_table_add(t: Papr_table_t; const key, val: PChar);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_add' + LibSuff12;

{
 * Add data to a table, regardless of whether there is another element with the
 * same key.
 * @param t The table to add to
 * @param key The key to use
 * @param val The value to add.
 * @remark When adding data, this function does not make a copy of the key or the
 *         value, so care should be taken to ensure that the values will not
 *         change after they have been added..
 }
procedure apr_table_addn(t: Papr_table_t; const key, val: PChar);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_addn' + LibSuff12;

{
 * Merge two tables into one new table
 * @param p The pool to use for the new table
 * @param overlay The first table to put in the new table
 * @param base The table to add at the end of the new table
 * @return A new table containing all of the data from the two passed in
 }
function apr_table_overlay(t: Papr_table_t;
 const overlay, base: Papr_table_t): Papr_table_t;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_overlay' + LibSuff12;

{
 * Declaration prototype for the iterator callback function of apr_table_do()
 * and apr_table_vdo().
 * @param rec The data passed as the first argument to apr_table_[v]do()
 * @param key The key from this iteration of the table
 * @param value The value from this iteration of the table
 * @remark Iteration continues while this callback function returns non-zero.
 * To export the callback function for apr_table_[v]do() it must be declared
 * in the _NONSTD convention.
 }
type
  apr_table_do_callback_fn_t = function (rec: Pointer;
   const key, value: PChar): Integer;
   
  Papr_table_do_callback_fn_t = ^apr_table_do_callback_fn_t;

{
 * Iterate over a table running the provided function once for every
 * element in the table.  If there is data passed in as a vararg, then the
 * function is only run on those elements whose key matches something in
 * the vararg.  If the vararg is NULL, then every element is run through the
 * function.  Iteration continues while the function returns non-zero.
 * @param comp The function to run
 * @param rec The data to pass as the first argument to the function
 * @param t The table to iterate over
 * @param ... The vararg.  If this is NULL, then all elements in the table are
 *            run through the function, otherwise only those whose key matches
 *            are run.
 * @return FALSE if one of the comp() iterations returned zero; TRUE if all
 *            iterations returned non-zero
 * @see apr_table_do_callback_fn_t
 }
{APR_DECLARE_NONSTD(int) apr_table_do(apr_table_do_callback_fn_t *comp,
                                     void *rec, const apr_table_t *t, ...);
}
{
 * Iterate over a table running the provided function once for every
 * element in the table.  If there is data passed in as a vararg, then the
 * function is only run on those element's whose key matches something in
 * the vararg.  If the vararg is NULL, then every element is run through the
 * function.  Iteration continues while the function returns non-zero.
 * @param comp The function to run
 * @param rec The data to pass as the first argument to the function
 * @param t The table to iterate over
 * @param vp The vararg table.  If this is NULL, then all elements in the
 *                table are run through the function, otherwise only those
 *                whose key matches are run.
 * @return FALSE if one of the comp() iterations returned zero; TRUE if all
 *            iterations returned non-zero
 * @see apr_table_do_callback_fn_t
 }
function apr_table_vdo(comp: Papr_table_do_callback_fn_t;
 rec: Pointer; const t: Papr_table_t; vp: va_list): Integer;
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_vdo' + LibSuff16;

const
  { flag for overlap to use apr_table_setn }
  APR_OVERLAP_TABLES_SET = 0;
  { flag for overlap to use apr_table_mergen }
  APR_OVERLAP_TABLES_MERGE = 1;

{
 * For each element in table b, either use setn or mergen to add the data
 * to table a.  Which method is used is determined by the flags passed in.
 * @param a The table to add the data to.
 * @param b The table to iterate over, adding its data to table a
 * @param flags How to add the table to table a.  One of:
 *          APR_OVERLAP_TABLES_SET        Use apr_table_setn
 *          APR_OVERLAP_TABLES_MERGE      Use apr_table_mergen
 * @remark  This function is highly optimized, and uses less memory and CPU cycles
 *          than a function that just loops through table b calling other functions.
 }
{
 *<PRE>
 * Conceptually, apr_table_overlap does this:
 *
 *  apr_array_header_t *barr = apr_table_elts(b);
 *  apr_table_entry_t *belt = (apr_table_entry_t *)barr->elts;
 *  int i;
 *
 *  for (i = 0; i < barr->nelts; ++i) (
 *      if (flags & APR_OVERLAP_TABLES_MERGE) (
 *          apr_table_mergen(a, belt[i].key, belt[i].val);
 *      )
 *      else (
 *          apr_table_setn(a, belt[i].key, belt[i].val);
 *      )
 *  )
 *
 *  Except that it is more efficient (less space and cpu-time) especially
 *  when b has many elements.
 *
 *  Notice the assumptions on the keys and values in b -- they must be
 *  in an ancestor of a's pool.  In practice b and a are usually from
 *  the same pool.
 * </PRE>
 }
procedure apr_table_overlap(a: Papr_table_t;
 const b: Papr_table_t; flags: cuint);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_overlap' + LibSuff12;

{
 * Eliminate redundant entries in a table by either overwriting
 * or merging duplicates
 *
 * @param t Table.
 * @param flags APR_OVERLAP_TABLES_MERGE to merge, or
 *              APR_OVERLAP_TABLES_SET to overwrite
 }
procedure apr_table_compress(t: Papr_table_t; flags: cuint);
 {$IFDEF WINDOWS} stdcall; {$ELSE} cdecl; {$ENDIF}
 external LibAPR name LibNamePrefix + 'apr_table_compress' + LibSuff8;