godot/drivers/nrex/nrex.cpp
2015-07-24 13:25:04 +01:00

910 lines
22 KiB
C++

// NREX: Node RegEx
//
// Copyright (c) 2015, Zher Huei Lee
// All rights reserved.
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software. If you use this software
// in a product, an acknowledgment in the product documentation would
// be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and must not
// be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source
// distribution.
//
#include "nrex.hpp"
#ifdef NREX_UNICODE
#include <wctype.h>
#include <wchar.h>
#define NREX_ISALPHANUM iswalnum
#define NREX_STRLEN wcslen
#else
#include <ctype.h>
#include <string.h>
#define NREX_ISALPHANUM isalnum
#define NREX_STRLEN strlen
#endif
#ifdef NREX_THROW_ERROR
#define NREX_COMPILE_ERROR(M) throw nrex_compile_error(M)
#else
#define NREX_COMPILE_ERROR(M) reset(); return false
#endif
#ifndef NREX_NEW
#define NREX_NEW(X) new X
#define NREX_NEW_ARRAY(X, N) new X[N]
#define NREX_DELETE(X) delete X
#define NREX_DELETE_ARRAY(X) delete[] X
#endif
template<typename T>
class nrex_array
{
private:
T* _data;
unsigned int _reserved;
unsigned int _size;
public:
nrex_array()
: _data(NREX_NEW_ARRAY(T, 2))
, _reserved(2)
, _size(0)
{
}
~nrex_array()
{
NREX_DELETE_ARRAY(_data);
}
unsigned int size() const
{
return _size;
}
void reserve(unsigned int size)
{
T* old = _data;
_data = NREX_NEW_ARRAY(T, size);
_reserved = size;
for (unsigned int i = 0; i < _size; ++i)
{
_data[i] = old[i];
}
NREX_DELETE_ARRAY(old);
}
void push(T item)
{
if (_size == _reserved)
{
reserve(_reserved * 2);
}
_data[_size] = item;
_size++;
}
T& top()
{
return _data[_size - 1];
}
const T& operator[] (unsigned int i) const
{
return _data[i];
}
void pop()
{
if (_size > 0)
{
--_size;
}
}
};
static nrex_char nrex_unescape(nrex_char repr)
{
switch (repr)
{
case '^': return '^';
case '$': return '$';
case '(': return '(';
case ')': return ')';
case '\\': return '\\';
case '.': return '.';
case '+': return '+';
case '*': return '*';
case '?': return '?';
case '-': return '-';
case 'a': return '\a';
case 'e': return '\e';
case 'f': return '\f';
case 'n': return '\n';
case 'r': return '\r';
case 't': return '\t';
case 'v': return '\v';
}
return 0;
}
struct nrex_search
{
public:
const nrex_char* str;
nrex_result* captures;
int end;
bool complete;
nrex_char at(int pos)
{
return str[pos];
}
nrex_search(const nrex_char* str, nrex_result* captures)
: str(str)
, captures(captures)
, end(0)
{
}
};
struct nrex_node
{
nrex_node* next;
nrex_node* previous;
nrex_node* parent;
bool quantifiable;
nrex_node(bool quantify = false)
: next(NULL)
, previous(NULL)
, parent(NULL)
, quantifiable(quantify)
{
}
virtual ~nrex_node()
{
if (next)
{
NREX_DELETE(next);
}
}
virtual int test(nrex_search* s, int pos) const
{
return next ? next->test(s, pos) : -1;
}
virtual int test_parent(nrex_search* s, int pos) const
{
if (next)
{
pos = next->test(s, pos);
}
if (parent && pos >= 0)
{
pos = parent->test_parent(s, pos);
}
if (pos >= 0)
{
s->complete = true;
}
return pos;
}
};
struct nrex_node_group : public nrex_node
{
int capturing;
bool negate;
nrex_array<nrex_node*> childset;
nrex_node* back;
nrex_node_group(int capturing)
: nrex_node(true)
, capturing(capturing)
, negate(false)
, back(NULL)
{
}
virtual ~nrex_node_group()
{
for (unsigned int i = 0; i < childset.size(); ++i)
{
NREX_DELETE(childset[i]);
}
}
int test(nrex_search* s, int pos) const
{
if (capturing >= 0)
{
s->captures[capturing].start = pos;
}
for (unsigned int i = 0; i < childset.size(); ++i)
{
s->complete = false;
int res = childset[i]->test(s, pos);
if (s->complete)
{
return res;
}
if (negate)
{
if (res < 0)
{
res = pos + 1;
}
else
{
return -1;
}
}
if (res >= 0)
{
if (capturing >= 0)
{
s->captures[capturing].length = res - pos;
}
return next ? next->test(s, res) : res;
}
}
return -1;
}
virtual int test_parent(nrex_search* s, int pos) const
{
if (capturing >= 0)
{
s->captures[capturing].length = pos - s->captures[capturing].start;
}
return nrex_node::test_parent(s, pos);
}
void add_childset()
{
back = NULL;
}
void add_child(nrex_node* node)
{
node->parent = this;
node->previous = back;
if (back)
{
back->next = node;
}
else
{
childset.push(node);
}
back = node;
}
nrex_node* swap_back(nrex_node* node)
{
if (!back)
{
add_child(node);
return NULL;
}
nrex_node* old = back;
if (!old->previous)
{
childset.pop();
}
back = old->previous;
add_child(node);
return old;
}
};
struct nrex_node_char : public nrex_node
{
nrex_char ch;
nrex_node_char(nrex_char c)
: nrex_node(true)
, ch(c)
{
}
int test(nrex_search* s, int pos) const
{
if (s->end == pos || s->at(pos) != ch)
{
return -1;
}
return next ? next->test(s, pos + 1) : pos + 1;
}
};
struct nrex_node_range : public nrex_node
{
nrex_char start;
nrex_char end;
nrex_node_range(nrex_char s, nrex_char e)
: nrex_node(true)
, start(s)
, end(e)
{
}
int test(nrex_search* s, int pos) const
{
if (s->end == pos)
{
return -1;
}
nrex_char c = s->at(pos);
if (c < start || end < c)
{
return -1;
}
return next ? next->test(s, pos + 1) : pos + 1;
}
};
static bool nrex_is_whitespace(nrex_char repr)
{
switch (repr)
{
case ' ':
case '\t':
case '\r':
case '\n':
case '\f':
return true;
}
return false;
}
static bool nrex_is_shorthand(nrex_char repr)
{
switch (repr)
{
case 'W':
case 'w':
case 'D':
case 'd':
case 'S':
case 's':
return true;
}
return false;
}
struct nrex_node_shorthand : public nrex_node
{
nrex_char repr;
nrex_node_shorthand(nrex_char c)
: nrex_node(true)
, repr(c)
{
}
int test(nrex_search* s, int pos) const
{
if (s->end == pos)
{
return -1;
}
bool found = false;
bool invert = false;
nrex_char c = s->at(pos);
switch (repr)
{
case '.':
found = true;
break;
case 'W':
invert = true;
case 'w':
if (c == '_' || NREX_ISALPHANUM(c))
{
found = true;
}
break;
case 'D':
invert = true;
case 'd':
if ('0' <= c && c <= '9')
{
found = true;
}
break;
case 'S':
invert = true;
case 's':
if (nrex_is_whitespace(c))
{
found = true;
}
break;
}
if (found == invert)
{
return -1;
}
return next ? next->test(s, pos + 1) : pos + 1;
}
};
static bool nrex_is_quantifier(nrex_char repr)
{
switch (repr)
{
case '?':
case '*':
case '+':
case '{':
return true;
}
return false;
}
struct nrex_node_quantifier : public nrex_node
{
int min;
int max;
bool greedy;
nrex_node* child;
nrex_node_quantifier()
: nrex_node()
, min(0)
, max(0)
, greedy(true)
, child(NULL)
{
}
virtual ~nrex_node_quantifier()
{
if (child)
{
NREX_DELETE(child);
}
}
int test(nrex_search* s, int pos) const
{
nrex_array<int> backtrack;
backtrack.push(pos);
while (backtrack.top() <= s->end)
{
if (max >= 1 && backtrack.size() > (unsigned int)max)
{
break;
}
if (!greedy && (unsigned int)min < backtrack.size())
{
int res = backtrack.top();
if (next)
{
res = next->test(s, res);
}
if (s->complete)
{
return res;
}
if (res >= 0 && parent->test_parent(s, res) >= 0)
{
return res;
}
}
int res = child->test(s, backtrack.top());
if (s->complete)
{
return res;
}
if (res < 0 || res == backtrack.top())
{
break;
}
backtrack.push(res);
}
while (greedy && (unsigned int) min < backtrack.size())
{
int res = backtrack.top();
if (next)
{
res = next->test(s, res);
}
if (res >= 0 && parent->test_parent(s, res) >= 0)
{
return res;
}
if (s->complete)
{
return res;
}
backtrack.pop();
}
return -1;
}
};
struct nrex_node_anchor : public nrex_node
{
bool end;
nrex_node_anchor(bool end)
: nrex_node()
, end(end)
{
}
int test(nrex_search* s, int pos) const
{
if (!end && pos != 0)
{
return -1;
}
else if (end && pos != s->end)
{
return -1;
}
return next ? next->test(s, pos) : pos;
}
};
struct nrex_node_backreference : public nrex_node
{
int ref;
nrex_node_backreference(int ref)
: nrex_node(true)
, ref(ref)
{
}
int test(nrex_search* s, int pos) const
{
nrex_result& r = s->captures[ref];
for (int i = 0; i < r.length; ++i)
{
if (pos + i >= s->end)
{
return -1;
}
if (s->at(r.start + i) != s->at(pos + i))
{
return -1;
}
}
return next ? next->test(s, pos + r.length) : pos + r.length;
}
};
nrex::nrex()
: _capturing(0)
, _root(NULL)
{
}
nrex::~nrex()
{
if (_root)
{
NREX_DELETE(_root);
}
}
bool nrex::valid() const
{
return (_root != NULL);
}
void nrex::reset()
{
_capturing = 0;
if (_root)
{
NREX_DELETE(_root);
}
_root = NULL;
}
int nrex::capture_size() const
{
return _capturing + 1;
}
bool nrex::compile(const nrex_char* pattern)
{
reset();
nrex_node_group* root = NREX_NEW(nrex_node_group(_capturing));
nrex_array<nrex_node_group*> stack;
stack.push(root);
_root = root;
for (const nrex_char* c = pattern; c[0] != '\0'; ++c)
{
if (c[0] == '(')
{
if (c[1] == '?')
{
if (c[2] == ':')
{
c = &c[2];
nrex_node_group* group = NREX_NEW(nrex_node_group(-1));
stack.top()->add_child(group);
stack.push(group);
}
else
{
NREX_COMPILE_ERROR("unrecognised qualifier for parenthesis");
}
}
else if (_capturing < 99)
{
nrex_node_group* group = NREX_NEW(nrex_node_group(++_capturing));
stack.top()->add_child(group);
stack.push(group);
}
else
{
nrex_node_group* group = NREX_NEW(nrex_node_group(-1));
stack.top()->add_child(group);
stack.push(group);
}
}
else if (c[0] == ')')
{
if (stack.size() > 1)
{
stack.pop();
}
else
{
NREX_COMPILE_ERROR("unexpected ')'");
}
}
else if (c[0] == '[')
{
nrex_node_group* group = NREX_NEW(nrex_node_group(-1));
stack.top()->add_child(group);
if (c[1] == '^')
{
group->negate = true;
++c;
}
while (true)
{
group->add_childset();
++c;
if (c[0] == '\0')
{
NREX_COMPILE_ERROR("unclosed character class '[]'");
}
if (c[0] == ']')
{
break;
}
else if (c[0] == '\\')
{
nrex_char unescaped = nrex_unescape(c[1]);
if (unescaped)
{
group->add_child(NREX_NEW(nrex_node_char(unescaped)));
++c;
}
else if (nrex_is_shorthand(c[1]))
{
group->add_child(NREX_NEW(nrex_node_shorthand(c[1])));
++c;
}
else
{
NREX_COMPILE_ERROR("escape token not recognised");
}
}
else
{
if (c[1] == '-' && c[2] != '\0')
{
bool range = false;
if ('A' <= c[0] && c[0] <= 'Z' && 'A' <= c[2] && c[2] <= 'Z')
{
range = true;
}
if ('a' <= c[0] && c[0] <= 'z' && 'a' <= c[2] && c[2] <= 'z')
{
range = true;
}
if ('0' <= c[0] && c[0] <= '9' && '0' <= c[2] && c[2] <= '9')
{
range = true;
}
if (range)
{
group->add_child(NREX_NEW(nrex_node_range(c[0], c[2])));
c = &c[2];
continue;
}
}
group->add_child(NREX_NEW(nrex_node_char(c[0])));
}
}
}
else if (nrex_is_quantifier(c[0]))
{
nrex_node_quantifier* quant = NREX_NEW(nrex_node_quantifier);
quant->child = stack.top()->swap_back(quant);
if (quant->child == NULL || !quant->child->quantifiable)
{
NREX_COMPILE_ERROR("element not quantifiable");
}
quant->child->previous = NULL;
quant->child->next = NULL;
quant->child->parent = quant;
if (c[0] == '?')
{
quant->min = 0;
quant->max = 1;
}
else if (c[0] == '+')
{
quant->min = 1;
quant->max = -1;
}
else if (c[0] == '*')
{
quant->min = 0;
quant->max = -1;
}
else if (c[0] == '{')
{
bool max_set = false;
quant->min = 0;
quant->max = -1;
while (true)
{
++c;
if (c[0] == '\0')
{
NREX_COMPILE_ERROR("unclosed range quantifier '{}'");
}
else if (c[0] == '}')
{
break;
}
else if (c[0] == ',')
{
max_set = true;
continue;
}
else if (c[0] < '0' || '9' < c[0])
{
NREX_COMPILE_ERROR("expected numeric digits, ',' or '}'");
}
if (max_set)
{
if (quant->max < 0)
{
quant->max = int(c[0] - '0');
}
else
{
quant->max = quant->max * 10 + int(c[0] - '0');
}
}
else
{
quant->min = quant->min * 10 + int(c[0] - '0');
}
}
if (!max_set)
{
quant->max = quant->min;
}
}
if (c[1] == '?')
{
quant->greedy = false;
++c;
}
}
else if (c[0] == '|')
{
stack.top()->add_childset();
}
else if (c[0] == '^' || c[0] == '$')
{
stack.top()->add_child(NREX_NEW(nrex_node_anchor((c[0] == '$'))));
}
else if (c[0] == '.')
{
stack.top()->add_child(NREX_NEW(nrex_node_shorthand('.')));
}
else if (c[0] == '\\')
{
nrex_char unescaped = nrex_unescape(c[1]);
if (unescaped)
{
stack.top()->add_child(NREX_NEW(nrex_node_char(unescaped)));
++c;
}
else if (nrex_is_shorthand(c[1]))
{
stack.top()->add_child(NREX_NEW(nrex_node_shorthand(c[1])));
++c;
}
else if ('1' <= c[1] && c[1] <= '9')
{
int ref = 0;
if ('0' <= c[2] && c[2] <= '9')
{
ref = int(c[1] - '0') * 10 + int(c[2] - '0');
c = &c[2];
}
else
{
ref = int(c[1] - '0');
++c;
}
if (ref > _capturing)
{
NREX_COMPILE_ERROR("backreference to non-existent capture");
}
stack.top()->add_child(NREX_NEW(nrex_node_backreference(ref)));
}
else
{
NREX_COMPILE_ERROR("escape token not recognised");
}
}
else
{
stack.top()->add_child(NREX_NEW(nrex_node_char(c[0])));
}
}
return true;
}
bool nrex::match(const nrex_char* str, nrex_result* captures, int offset, int end) const
{
nrex_search s(str, captures);
if (end >= offset)
{
s.end = end;
}
else
{
s.end = NREX_STRLEN(str);
}
for (int i = offset; i < s.end; ++i)
{
for (int c = 0; c <= _capturing; ++c)
{
captures[c].start = 0;
captures[c].length = 0;
}
if (_root->test(&s, i) >= 0)
{
return true;
}
}
return false;
}