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Posted to docs-cvs@perl.apache.org by st...@apache.org on 2001/10/02 16:59:18 UTC

cvs commit: modperl-docs/src/api/mod_perl-2.0/APR Table.pod

stas        01/10/02 07:59:18

  Added:       src/api/mod_perl-2.0/APR Table.pod
  Log:
  - starting APR/Table.pod
  - documenting APR::Table methods
  
  Revision  Changes    Path
  1.1                  modperl-docs/src/api/mod_perl-2.0/APR/Table.pod
  
  Index: Table.pod
  ===================================================================
  =head1 NAME
  
  C<APR::Table> -- A Perl API for manipulating paque string-content table
  
  =head1 SYNOPSIS
  
    use APR::Table;
    
    $table = make($pool, $nelts);
    $table_copy = $table->copy($pool);
    
    $table->clear();
    
    $table->set($key => $val);
    $table->unset($key);
    $table->add($key, $val);
    
    $val = $table->get($key);
    @val = $table->get($key);
    
    $table->merge($key => $val);
    overlap($table_a, $table_b, $flags);
    $new_table = overlay($table_base, $table_overlay, $pool);
  
  =head1 DESCRIPTION
  
  C<APR::Table> allows its users to manipulate opaque string-content
  tables. The table is somewhat similar to the Perl hash, but allows
  multiply values for the same key.  An access to the records stored in
  the table always requires a key.
  
  The key-value pairs are stored in the order they are added.
  
  The keys are case-insensitive.
  
  However as of the current implementation if more than value for the
  same key is requested, the whole table it lineary searched, which is
  very inefficient unless the table is very small.
  
  C<APR::Table> provides a L<TIE Interface>.
  
  See I<apr/include/apr_tables.h> in ASF's I<apr> project for low level
  details.
  
  =head1 API
  
  The variables used in the API definition have the following
  I<"types">:
  
  =over
  
  =item * APR::Table
  
  C<$table_*>
  
  =item * APR::Pool
  
  C<$pool>
  
  =item * scalars: unsigned integers only (SVIV) (as C expects them)
  
  C<$nelts>, C<$flags>
  
  =item * scalars: (numerical (SVIV/SVNV) and strings (SVPV))
  
  C<$key>, C<$val>
  
  =back
  
  Function arguments (if any) and return values are shown in the
  function's synopsis.
  
  =over
  
  =item * make()
  
    $table = make($pool, $nelts);
  
  Make a new table.
  
  param C<$pool>: The pool to allocate the pool out of.
  
  param C<$nelts>: The number of elements in the initial table.
  
  return: a new table.
  
  warning: This table can only store text data
  
  =item * copy()
  
    $table_copy = $table->copy($pool);
  
  Create a new table and copy another table into it
  
  param C<$pool>: The pool to allocate the new table out of
  
  param C<$table>: The table to copy
  
  return: A copy of the table passed in
  
  =item * clear()
  
    $table->clear();
  
  Delete all of the elements from a table.
  
  param C<$table>: A copy of the table passed in
  
  =item * set();
  
    $table->set($key => $val);
  
  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 C<$table>: The table to add the data to.
  
  param C<$key>: The key fo use.
  
  param C<$val>: The value to add.
  
  =item * add()
  
    $table->add($key, $val);
  
  Add data to a table, regardless of whether there is another element
  with the same key.
  
  param C<$table>: The table to add to
  
  param C<$key>: The key to use
  
  param C<$val>: The value to add.
  
  =item * do()
  
    META: ???
  
  =item * get()
  
    $val = $table->get($key);
    @val = $table->get($key);
  
  Get the value(s) associated with a given key.
  
  After this call, the data is still in the table.
  
  param C<$table>: The table to search for the key
  
  param C<$key>: The key to search for
  
  return: In the scalar context the first matching value returned. (The
  oldest in the table, if there is more than one value.) In the list
  context the whole table is traversed and all matching values are
  returned. If nothing matches I<undef> is returned.
  
  =item * unset();
  
    $table->unset($key);
  
  Remove data from the table
  
  param C<$table>: The table to remove data from
  
  param C<$key>: The key of the data being removed
  
  
  =item * merge()
  
    $table->merge($key => $val);
  
  Add data to a table by merging the value with data that has already
  been stored
  
  param C<$table>: The table to search for the data
  
  param C<$key>: The key to merge data for
  
  param C<$val>: The data to add
  
  remark: If the key is not found, then this function acts like add()
  
  =item * overlap()
  
    overlap($table_a, $table_b, $flags);
  
  For each key/value pair in C<$table_b>, add the data to
  C<$table_a>. The definition of C<$flags> explains how C<$flags> define
  the overlapping method.
  
  param C<$table_a>: The table to add the data to.
  
  param C<$table_b>: The table to iterate over, adding its data to
  C<%table_a>.
  
  param C<$flags>: How to add the C<$table_b> to C<$table_a>.
  
  When C<$flags> == C<APR_OVERLAP_TABLES_SET>, if another element
  already exists with the same key, this will over-write the old data.
  
  When C<$flags> == C<APR_OVERLAP_TABLES_MERGE>, the key/value pair from
  C<$table_b> is added, regardless of whether there is another element
  with the same key in C<$table_a>.
  
  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.
  
  =item * overlay()
  
    $new_table = overlay($table_base, $table_overlay, $pool);
  
  Merge two tables into one new table. The resulting table may have more
  than one value for the same key.
  
  param C<$pool>: The pool to use for the new table
  
  param C<$table_overlay>: The first table to put in the new table
  
  param C<$table_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
  
  =back
  
  =head2 TIE Interface
  
  APR::Table sports TIE interface, so you can work with the C<$table>
  object as a hash.
  
  META: complete
  
  
  =cut
  
  
  
  

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