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[mono.git] / mcs / class / System / System.Text.RegularExpressions / arch.cs

//
// assembly:    System
// namespace:   System.Text.RegularExpressions
// file:        arch.cs
//
// author:      Dan Lewis (dlewis@gmx.co.uk)
//              (c) 2002

//
// 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 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.
//

using System;
using System.Collections;

namespace System.Text.RegularExpressions {

        enum OpCode : ushort {
                False           = 0,    // always fails
                True,                   // always succeeds

                // matching

                Position,               // zero-width position assertion
                String,                 // match string literal
                Reference,              // back reference

                // character matching

                Character,              // match character exactly
                Category,               // match character from category
                NotCategory,            // match character _not_ from category
                Range,                  // match character from range
                Set,                    // match character from set
                In,                     // match character from group of tests

                // capturing

                Open,                   // open group
                Close,                  // close group
                Balance,                // balance groups
                BalanceStart,           //track balance group length

                // control flow

                IfDefined,              // conditional on capture
                Sub,                    // non-backtracking subexpression
                Test,                   // non-backtracking lookahead/behind
                Branch,                 // alternative expression
                Jump,                   // unconditional goto
                Repeat,                 // new repeat context
                Until,                  // repeat subexpression within context
                FastRepeat,             // repeat simple subexpression
                Anchor,                 // anchoring expression

                // miscellaneous
                
                Info                    // pattern information
        }

        [Flags]
        enum OpFlags : ushort {
                None            = 0x000,
                Negate          = 0x100,        // succeed on mismatch
                IgnoreCase      = 0x200,        // case insensitive matching
                RightToLeft     = 0x400,        // right-to-left matching
                Lazy            = 0x800         // minimizing repeat
        }

        enum Position : ushort {
                Any,                    // anywhere
                Start,                  // start of string                      \A
                StartOfString,          // start of string                      \A
                StartOfLine,            // start of line                        ^
                StartOfScan,            // start of scan                        \G
                End,                    // end or before newline at end         \Z
                EndOfString,            // end of string                        \z
                EndOfLine,              // end of line                          $
                Boundary,               // word boundary                        \b
                NonBoundary             // not word boundary                    \B
        };
        
        // see category.cs for Category enum

        interface IMachine {
                Match Scan (Regex regex, string text, int start, int end);
                string [] Split (Regex regex, string input, int count, int startat);
                string Replace (Regex regex, string input, string replacement, int count, int startat);
                string Result (string replacement, Match match);
        }

        interface IMachineFactory {
                IMachine NewInstance ();
                IDictionary Mapping { get; set; }
                int GroupCount { get; }
                int Gap { get; set; } // Index of first group whose number differs from its index, or 1+GroupCount
                string [] NamesMapping { get; set; }
        }

        // Anchor SKIP OFFSET
        //
        // Flags:       [RightToLeft] ??
        // SKIP:        relative address of tail expression
        // OFFSET:      offset of anchor from start of pattern
        //
        // Usage:
        //
        //      Anchor :1 OFFSET
        //              <expr>
        //              True
        // 1:   <tail>
        //
        // Notes:
        //
        // In practice, the anchoring expression is only going to be
        // Position (StartOfString, StartOfLine, StartOfScan) or String.
        // This is because the optimizer looks for position anchors at the
        // start of the expression, and if that fails it looks for the
        // longest substring. If an expression has neither a position
        // anchor or a longest substring anchor, then the anchoring expression
        // is left empty. Since an empty expression will anchor at any
        // position in any string, the entire input string will be scanned.

        // String LEN STR...
        //
        // Flags:       [RightToLeft, IgnoreCase]
        // LEN:         length of string
        // STR:         string characters

        // Branch SKIP
        //
        // SKIP:        relative address of next branch
        //
        //      Branch :1
        //              <alt expr 1>
        //              Jump :4
        // 1:   Branch :2
        //              <alt expr 2>
        //              Jump :4
        // 2:   Branch :3
        //              <alt expr 3>
        //              Jump :4
        // 3:   False
        // 4:   <tail>

        // Repeat SKIP MIN MAX
        //
        // Flags:       [Lazy]
        // SKIP:        relative address of Until instruction
        // MIN:         minimum iterations (2 slots)
        // MAX:         maximum iterations (2 slots, 0x7fffffff is infinity)
        //
        //      Repeat :1 MIN MAX
        //              <expr>
        //              Until
        // 1:   <tail>

        // FastRepeat SKIP MIN MAX
        //
        // Flags:       [Lazy]
        // SKIP:        relative address of tail expression
        // MIN:         minimum iterations (2 slots)
        // MAX:         maximum iterations (2 slots, 0x7fffffff is infinity)
        //
        //      FastRepeat :1 MIN MAX
        //              <expr>
        //              True
        // 1:   <tail>
        //
        // Notes:
        //
        // The subexpression of a FastRepeat construct must not contain any
        // complex operators. These include: Open, Close, Balance, Repeat,
        // FastRepeat, Sub, Test. In addition, the subexpression must have
        // been determined to have a fixed width.
        
        // Sub SKIP
        //
        // SKIP:        relative address of tail expression
        //
        //      Sub :1
        //              <expr>
        // 1:   <tail>
        //
        // Notes:
        //
        // The Sub operator invokes an independent subexpression. This means
        // that the subexpression will match only once and so will not
        // participate in any backtracking.

        // Test TSKIP FSKIP
        //
        // TSKIP:       relative address of true expression
        // FSKIP:       relative address of false expression
        //
        // Usage:       (?(?=test)true|false)
        //
        //      Test :1 :2
        //              <test expr>
        // 1:           <true expr>
        //              Jump
        // 2:           <false epxr>
        //      <tail>
        //
        // Usage:       (?(?=test)true)
        //
        //      Test :1 :2
        //              <test expr>
        // 1:           <true expr>
        // 2:   <tail>
        //
        // Usage:       (?=test)
        //
        //      Test :1 :2
        //              <test expr>
        // 1:           <true expr>
        //              Jump 3:
        // 2:           False
        // 3:           <tail>
        //
        // Notes:
        //
        // For negative lookaheads, just swap the values of TSKIP and
        // FSKIP. For lookbehinds, the test expression must be compiled
        // in reverse. The test expression is always executed as an
        // independent subexpression, so its behaviour is non-backtracking
        // (like a Sub clause.)

        // IfDefined SKIP GID
        //
        // SKIP:        relative address of else expression
        // GID:         number of group to check
        //
        // Usage:       (?(gid)true)
        //
        //      IfDefined :1
        //              <true expr>
        // 1:   <tail>
        //
        // Usage:       (?(gid)true|false)
        //
        //      IfDefined :1
        //              <true expr>
        //              Jump :2
        // 1:           <false expr>
        // 2:   <tail>

        // Jump SKIP
        //
        // SKIP:        relative address of target expression
        //
        //      Jump :1
        //      ...
        // :1   <target expr>

        // Character CHAR
        //
        // Flags:       [Negate, IgnoreCase, RightToLeft]
        // CHAR:        exact character to match

        // Category CAT
        //
        // Flags:       [Negate, RightToLeft]
        // CAT:         category to match (see Category enum)

        // Range LO HI
        //
        // Flags:       [Negate, IgnoreCase, RightToLeft]
        // LO:          lowest character in range
        // HI:          higest character in range

        // Set LO LEN SET...
        //
        // Flags:       [Negate, IgnoreCase, RightToLeft]
        // LO:          lowest character in set
        // LEN:         number of words in set
        // SET:         bit array representing characters in set
        //
        // Notes:
        //
        // Each word in the set represents 16 characters, so the first word
        // defines membership for characters LO to LO + 15, the second for
        // LO + 16 to LO + 31, and so on up to LO + (LEN * 16 - 1). It is
        // up to the compiler to provide a compact representation for sparse
        // unicode sets. The simple way is to use Set 0 4096. Other methods
        // involve paritioning the set and placing the components into an
        // In block.

        // In SKIP
        //
        // SKIP:        relative address of tail expression
        //
        // Usage:       [expr]
        //
        //      In :1
        //              <expr>
        //              True
        // :1   <tail>
        //
        // Usage:       [^expr]
        //
        //      In :1
        //              <expr>
        //              False
        // :1   <tail>
        //
        // Notes:
        //
        // The In instruction consumes a single character, using the flags
        // of the first instruction in the subexpression to determine its
        // IgnoreCase and RightToLeft properties. The subexpression is then
        // applied to the single character as a disjunction. If any instruction
        // in the subexpression succeeds, the entire In construct succeeds
        // and matching continues with the tail.

        // Position POS
        //
        // POS:         position to match (see Position enum)

        // Open GID
        //
        // GID:         number of group to open

        // Close GID
        //
        // GID:         number of group to close
        
        // Balance GID BAL
        //
        // GID:         number of capturing group (0 if none)
        // BAL:         number of group to undefine

        // Info GROUPS MIN MAX
        //
        // GROUPS:      number of capturing groups (2 slots)
        // MIN:         minimum width of pattern (2 slots)
        // MAX:         maximum width of pattern (2 slots, 0x7fffffff means undefined)

        // False

        // True

        // Reference GID
        //
        // Flags:       [IgnoreCase, RightToLeft]
        // GID:         number of group to reference
}