extmod/modre.c - lite/micropython - Linaro Git Browser

 /*
  * This file is part of the MicroPython project, http://micropython.org/
  *
  * The MIT License (MIT)
  *
  * Copyright (c) 2014 Paul Sokolovsky
  *
  * 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.
  */

 #include <stdio.h>
 #include <assert.h>
 #include <string.h>

 #include "py/runtime.h"
 #include "py/binary.h"
 #include "py/objstr.h"
 #include "py/cstack.h"

 #if MICROPY_PY_BUILTINS_STR_UNICODE
 #include "py/unicode.h"
 #endif

 #if MICROPY_PY_RE

 #define re1_5_stack_chk() mp_cstack_check()

 #include "lib/re1.5/re1.5.h"

 #define FLAG_DEBUG 0x1000

 typedef struct _mp_obj_re_t {
     mp_obj_base_t base;
     ByteProg re;
 } mp_obj_re_t;

 typedef struct _mp_obj_match_t {
     mp_obj_base_t base;
     int num_matches;
     mp_obj_t str;
     const char *caps[0];
 } mp_obj_match_t;

 static mp_obj_t mod_re_compile(size_t n_args, const mp_obj_t *args);
 #if !MICROPY_ENABLE_DYNRUNTIME
 static const mp_obj_type_t re_type;
 #endif

 static void match_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_match_t *self = MP_OBJ_TO_PTR(self_in);
     mp_printf(print, "<match num=%d>", self->num_matches);
 }

 static mp_obj_t match_group(mp_obj_t self_in, mp_obj_t no_in) {
     mp_obj_match_t *self = MP_OBJ_TO_PTR(self_in);
     mp_int_t no = mp_obj_get_int(no_in);
     if (no < 0 || no >= self->num_matches) {
         mp_raise_type_arg(&mp_type_IndexError, no_in);
     }

     const char *start = self->caps[no * 2];
     if (start == NULL) {
         // no match for this group
         return mp_const_none;
     }
     return mp_obj_new_str_of_type(mp_obj_get_type(self->str),
         (const byte *)start, self->caps[no * 2 + 1] - start);
 }
 MP_DEFINE_CONST_FUN_OBJ_2(match_group_obj, match_group);

 #if MICROPY_PY_RE_MATCH_GROUPS

 static mp_obj_t match_groups(mp_obj_t self_in) {
     mp_obj_match_t *self = MP_OBJ_TO_PTR(self_in);
     if (self->num_matches <= 1) {
         return mp_const_empty_tuple;
     }
     mp_obj_tuple_t *groups = MP_OBJ_TO_PTR(mp_obj_new_tuple(self->num_matches - 1, NULL));
     for (int i = 1; i < self->num_matches; ++i) {
         groups->items[i - 1] = match_group(self_in, MP_OBJ_NEW_SMALL_INT(i));
     }
     return MP_OBJ_FROM_PTR(groups);
 }
 MP_DEFINE_CONST_FUN_OBJ_1(match_groups_obj, match_groups);

 #endif

 #if MICROPY_PY_RE_MATCH_SPAN_START_END

 static void match_span_helper(size_t n_args, const mp_obj_t *args, mp_obj_t span[2]) {
     mp_obj_match_t *self = MP_OBJ_TO_PTR(args[0]);

     mp_int_t no = 0;
     if (n_args == 2) {
         no = mp_obj_get_int(args[1]);
         if (no < 0 || no >= self->num_matches) {
             mp_raise_type_arg(&mp_type_IndexError, args[1]);
         }
     }

     mp_int_t s = -1;
     mp_int_t e = -1;
     const char *start = self->caps[no * 2];
     if (start != NULL) {
         // have a match for this group
         const char *begin = mp_obj_str_get_str(self->str);
         s = start - begin;
         e = self->caps[no * 2 + 1] - begin;
     }

     #if MICROPY_PY_BUILTINS_STR_UNICODE
     if (mp_obj_get_type(self->str) == &mp_type_str) {
         const byte *begin = (const byte *)mp_obj_str_get_str(self->str);
         if (s != -1) {
             s = utf8_ptr_to_index(begin, begin + s);
         }
         if (e != -1) {
             e = utf8_ptr_to_index(begin, begin + e);
         }
     }
     #endif

     span[0] = mp_obj_new_int(s);
     span[1] = mp_obj_new_int(e);
 }

 static mp_obj_t match_span(size_t n_args, const mp_obj_t *args) {
     mp_obj_t span[2];
     match_span_helper(n_args, args, span);
     return mp_obj_new_tuple(2, span);
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(match_span_obj, 1, 2, match_span);

 static mp_obj_t match_start(size_t n_args, const mp_obj_t *args) {
     mp_obj_t span[2];
     match_span_helper(n_args, args, span);
     return span[0];
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(match_start_obj, 1, 2, match_start);

 static mp_obj_t match_end(size_t n_args, const mp_obj_t *args) {
     mp_obj_t span[2];
     match_span_helper(n_args, args, span);
     return span[1];
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(match_end_obj, 1, 2, match_end);

 #endif

 #if !MICROPY_ENABLE_DYNRUNTIME
 static const mp_rom_map_elem_t match_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_group), MP_ROM_PTR(&match_group_obj) },
     #if MICROPY_PY_RE_MATCH_GROUPS
     { MP_ROM_QSTR(MP_QSTR_groups), MP_ROM_PTR(&match_groups_obj) },
     #endif
     #if MICROPY_PY_RE_MATCH_SPAN_START_END
     { MP_ROM_QSTR(MP_QSTR_span), MP_ROM_PTR(&match_span_obj) },
     { MP_ROM_QSTR(MP_QSTR_start), MP_ROM_PTR(&match_start_obj) },
     { MP_ROM_QSTR(MP_QSTR_end), MP_ROM_PTR(&match_end_obj) },
     #endif
 };

 static MP_DEFINE_CONST_DICT(match_locals_dict, match_locals_dict_table);

 static MP_DEFINE_CONST_OBJ_TYPE(
     match_type,
     MP_QSTR_match,
     MP_TYPE_FLAG_NONE,
     print, match_print,
     locals_dict, &match_locals_dict
     );
 #endif

 static void re_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_re_t *self = MP_OBJ_TO_PTR(self_in);
     mp_printf(print, "<re %p>", self);
 }

 // Note: this function can't be named re_exec because it may clash with system headers, eg on FreeBSD
 static mp_obj_t re_exec_helper(bool is_anchored, uint n_args, const mp_obj_t *args) {
     (void)n_args;
     mp_obj_re_t *self;
     if (mp_obj_is_type(args[0], (mp_obj_type_t *)&re_type)) {
         self = MP_OBJ_TO_PTR(args[0]);
     } else {
         self = MP_OBJ_TO_PTR(mod_re_compile(1, args));
     }
     Subject subj;
     size_t len;
     subj.begin_line = subj.begin = mp_obj_str_get_data(args[1], &len);
     subj.end = subj.begin + len;
     int caps_num = (self->re.sub + 1) * 2;
     mp_obj_match_t *match = m_new_obj_var(mp_obj_match_t, caps, char *, caps_num);
     // cast is a workaround for a bug in msvc: it treats const char** as a const pointer instead of a pointer to pointer to const char
     memset((char *)match->caps, 0, caps_num * sizeof(char *));
     int res = re1_5_recursiveloopprog(&self->re, &subj, match->caps, caps_num, is_anchored);
     if (res == 0) {
         m_del_var(mp_obj_match_t, caps, char *, caps_num, match);
         return mp_const_none;
     }

     match->base.type = (mp_obj_type_t *)&match_type;
     match->num_matches = caps_num / 2; // caps_num counts start and end pointers
     match->str = args[1];
     return MP_OBJ_FROM_PTR(match);
 }

 static mp_obj_t re_match(size_t n_args, const mp_obj_t *args) {
     return re_exec_helper(true, n_args, args);
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(re_match_obj, 2, 4, re_match);

 static mp_obj_t re_search(size_t n_args, const mp_obj_t *args) {
     return re_exec_helper(false, n_args, args);
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(re_search_obj, 2, 4, re_search);

 static mp_obj_t re_split(size_t n_args, const mp_obj_t *args) {
     mp_obj_re_t *self = MP_OBJ_TO_PTR(args[0]);
     Subject subj;
     size_t len;
     const mp_obj_type_t *str_type = mp_obj_get_type(args[1]);
     subj.begin_line = subj.begin = mp_obj_str_get_data(args[1], &len);
     subj.end = subj.begin + len;
     int caps_num = (self->re.sub + 1) * 2;

     int maxsplit = 0;
     if (n_args > 2) {
         maxsplit = mp_obj_get_int(args[2]);
     }

     mp_obj_t retval = mp_obj_new_list(0, NULL);
     const char **caps = mp_local_alloc(caps_num * sizeof(char *));
     while (true) {
         // cast is a workaround for a bug in msvc: it treats const char** as a const pointer instead of a pointer to pointer to const char
         memset((char **)caps, 0, caps_num * sizeof(char *));
         int res = re1_5_recursiveloopprog(&self->re, &subj, caps, caps_num, false);

         // if we didn't have a match, or had an empty match, it's time to stop
         if (!res || caps[0] == caps[1]) {
             break;
         }

         mp_obj_t s = mp_obj_new_str_of_type(str_type, (const byte *)subj.begin, caps[0] - subj.begin);
         mp_obj_list_append(retval, s);
         if (self->re.sub > 0) {
             mp_raise_NotImplementedError(MP_ERROR_TEXT("splitting with sub-captures"));
         }
         subj.begin = caps[1];
         if (maxsplit > 0 && --maxsplit == 0) {
             break;
         }
     }
     // cast is a workaround for a bug in msvc (see above)
     mp_local_free((char **)caps);

     mp_obj_t s = mp_obj_new_str_of_type(str_type, (const byte *)subj.begin, subj.end - subj.begin);
     mp_obj_list_append(retval, s);
     return retval;
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(re_split_obj, 2, 3, re_split);

 #if MICROPY_PY_RE_SUB

 static mp_obj_t re_sub_helper(size_t n_args, const mp_obj_t *args) {
     mp_obj_re_t *self;
     if (mp_obj_is_type(args[0], (mp_obj_type_t *)&re_type)) {
         self = MP_OBJ_TO_PTR(args[0]);
     } else {
         self = MP_OBJ_TO_PTR(mod_re_compile(1, args));
     }
     mp_obj_t replace = args[1];
     mp_obj_t where = args[2];
     mp_int_t count = 0;
     if (n_args > 3) {
         count = mp_obj_get_int(args[3]);
         // Note: flags are currently ignored
     }

     size_t where_len;
     const char *where_str = mp_obj_str_get_data(where, &where_len);
     Subject subj;
     subj.begin_line = subj.begin = where_str;
     subj.end = subj.begin + where_len;
     int caps_num = (self->re.sub + 1) * 2;

     vstr_t vstr_return;
     vstr_return.buf = NULL; // We'll init the vstr after the first match
     mp_obj_match_t *match = mp_local_alloc(sizeof(mp_obj_match_t) + caps_num * sizeof(char *));
     match->base.type = (mp_obj_type_t *)&match_type;
     match->num_matches = caps_num / 2; // caps_num counts start and end pointers
     match->str = where;

     for (;;) {
         // cast is a workaround for a bug in msvc: it treats const char** as a const pointer instead of a pointer to pointer to const char
         memset((char *)match->caps, 0, caps_num * sizeof(char *));
         int res = re1_5_recursiveloopprog(&self->re, &subj, match->caps, caps_num, false);

         // If we didn't have a match, or had an empty match, it's time to stop
         if (!res || match->caps[0] == match->caps[1]) {
             break;
         }

         // Initialise the vstr if it's not already
         if (vstr_return.buf == NULL) {
             vstr_init(&vstr_return, match->caps[0] - subj.begin);
         }

         // Add pre-match string
         vstr_add_strn(&vstr_return, subj.begin, match->caps[0] - subj.begin);

         // Get replacement string
         const char *repl = mp_obj_str_get_str((mp_obj_is_callable(replace) ? mp_call_function_1(replace, MP_OBJ_FROM_PTR(match)) : replace));

         // Append replacement string to result, substituting any regex groups
         while (*repl != '\0') {
             if (*repl == '\\') {
                 ++repl;
                 bool is_g_format = false;
                 if (*repl == 'g' && repl[1] == '<') {
                     // Group specified with syntax "\g<number>"
                     repl += 2;
                     is_g_format = true;
                 }

                 if ('0' <= *repl && *repl <= '9') {
                     // Group specified with syntax "\g<number>" or "\number"
                     unsigned int match_no = 0;
                     do {
                         match_no = match_no * 10 + (*repl++ - '0');
                     } while ('0' <= *repl && *repl <= '9');
                     if (is_g_format && *repl == '>') {
                         ++repl;
                     }

                     if (match_no >= (unsigned int)match->num_matches) {
                         mp_raise_type_arg(&mp_type_IndexError, MP_OBJ_NEW_SMALL_INT(match_no));
                     }

                     const char *start_match = match->caps[match_no * 2];
                     if (start_match != NULL) {
                         // Add the substring matched by group
                         const char *end_match = match->caps[match_no * 2 + 1];
                         vstr_add_strn(&vstr_return, start_match, end_match - start_match);
                     }
                 } else if (*repl == '\\') {
                     // Add the \ character
                     vstr_add_byte(&vstr_return, *repl++);
                 }
             } else {
                 // Just add the current byte from the replacement string
                 vstr_add_byte(&vstr_return, *repl++);
             }
         }

         // Move start pointer to end of last match
         subj.begin = match->caps[1];

         // Stop substitutions if count was given and gets to 0
         if (count > 0 && --count == 0) {
             break;
         }
     }

     mp_local_free(match);

     if (vstr_return.buf == NULL) {
         // Optimisation for case of no substitutions
         return where;
     }

     // Add post-match string
     vstr_add_strn(&vstr_return, subj.begin, subj.end - subj.begin);

     if (mp_obj_get_type(where) == &mp_type_str) {
         return mp_obj_new_str_from_utf8_vstr(&vstr_return);
     } else {
         return mp_obj_new_bytes_from_vstr(&vstr_return);
     }
 }

 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(re_sub_obj, 3, 5, re_sub_helper);

 #endif

 #if !MICROPY_ENABLE_DYNRUNTIME
 static const mp_rom_map_elem_t re_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_match), MP_ROM_PTR(&re_match_obj) },
     { MP_ROM_QSTR(MP_QSTR_search), MP_ROM_PTR(&re_search_obj) },
     { MP_ROM_QSTR(MP_QSTR_split), MP_ROM_PTR(&re_split_obj) },
     #if MICROPY_PY_RE_SUB
     { MP_ROM_QSTR(MP_QSTR_sub), MP_ROM_PTR(&re_sub_obj) },
     #endif
 };

 static MP_DEFINE_CONST_DICT(re_locals_dict, re_locals_dict_table);

 static MP_DEFINE_CONST_OBJ_TYPE(
     re_type,
     MP_QSTR_re,
     MP_TYPE_FLAG_NONE,
     print, re_print,
     locals_dict, &re_locals_dict
     );
 #endif

 static mp_obj_t mod_re_compile(size_t n_args, const mp_obj_t *args) {
     (void)n_args;
     const char *re_str = mp_obj_str_get_str(args[0]);
     int size = re1_5_sizecode(re_str);
     if (size == -1) {
         #if MICROPY_ERROR_REPORTING >= MICROPY_ERROR_REPORTING_NORMAL
         mp_raise_ValueError(MP_ERROR_TEXT("regex too complex"));
         #endif
         goto error;
     }
     mp_obj_re_t *o = mp_obj_malloc_var(mp_obj_re_t, re.insts, char, size, (mp_obj_type_t *)&re_type);
     #if MICROPY_PY_RE_DEBUG
     int flags = 0;
     if (n_args > 1) {
         flags = mp_obj_get_int(args[1]);
     }
     #endif
     int error = re1_5_compilecode(&o->re, re_str);
     if (error != 0) {
     error:
         mp_raise_ValueError(MP_ERROR_TEXT("error in regex"));
     }
     #if MICROPY_PY_RE_DEBUG
     if (flags & FLAG_DEBUG) {
         re1_5_dumpcode(&o->re);
     }
     #endif
     return MP_OBJ_FROM_PTR(o);
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_re_compile_obj, 1, 2, mod_re_compile);

 #if !MICROPY_ENABLE_DYNRUNTIME
 static const mp_rom_map_elem_t mp_module_re_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_re) },
     { MP_ROM_QSTR(MP_QSTR_compile), MP_ROM_PTR(&mod_re_compile_obj) },
     { MP_ROM_QSTR(MP_QSTR_match), MP_ROM_PTR(&re_match_obj) },
     { MP_ROM_QSTR(MP_QSTR_search), MP_ROM_PTR(&re_search_obj) },
     #if MICROPY_PY_RE_SUB
     { MP_ROM_QSTR(MP_QSTR_sub), MP_ROM_PTR(&re_sub_obj) },
     #endif
     #if MICROPY_PY_RE_DEBUG
     { MP_ROM_QSTR(MP_QSTR_DEBUG), MP_ROM_INT(FLAG_DEBUG) },
     #endif
 };

 static MP_DEFINE_CONST_DICT(mp_module_re_globals, mp_module_re_globals_table);

 const mp_obj_module_t mp_module_re = {
     .base = { &mp_type_module },
     .globals = (mp_obj_dict_t *)&mp_module_re_globals,
 };

 MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_re, mp_module_re);
 #endif

 // Source files #include'd here to make sure they're compiled in
 // only if module is enabled by config setting.

 #define re1_5_fatal(x) assert(!x)

 #include "lib/re1.5/compilecode.c"
 #include "lib/re1.5/recursiveloop.c"
 #include "lib/re1.5/charclass.c"

 #if MICROPY_PY_RE_DEBUG
 // Make sure the output print statements go to the same output as other Python output.
 #define printf(...) mp_printf(&mp_plat_print, __VA_ARGS__)
 #include "lib/re1.5/dumpcode.c"
 #undef printf
 #endif

 #endif // MICROPY_PY_RE
	/*
	* This file is part of the MicroPython project, http://micropython.org/
	*
	* The MIT License (MIT)
	*
	* Copyright (c) 2014 Paul Sokolovsky
	*
	* 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.
	*/

	#include <stdio.h>
	#include <assert.h>
	#include <string.h>

	#include "py/runtime.h"
	#include "py/binary.h"
	#include "py/objstr.h"
	#include "py/cstack.h"

	#if MICROPY_PY_BUILTINS_STR_UNICODE
	#include "py/unicode.h"
	#endif

	#if MICROPY_PY_RE

	#define re1_5_stack_chk() mp_cstack_check()

	#include "lib/re1.5/re1.5.h"

	#define FLAG_DEBUG 0x1000

	typedef struct _mp_obj_re_t {
	mp_obj_base_t base;
	ByteProg re;
	} mp_obj_re_t;

	typedef struct _mp_obj_match_t {
	mp_obj_base_t base;
	int num_matches;
	mp_obj_t str;
	const char *caps[0];
	} mp_obj_match_t;

	static mp_obj_t mod_re_compile(size_t n_args, const mp_obj_t *args);
	#if !MICROPY_ENABLE_DYNRUNTIME
	static const mp_obj_type_t re_type;
	#endif

	static void match_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
	(void)kind;
	mp_obj_match_t *self = MP_OBJ_TO_PTR(self_in);
	mp_printf(print, "<match num=%d>", self->num_matches);
	}

	static mp_obj_t match_group(mp_obj_t self_in, mp_obj_t no_in) {
	mp_obj_match_t *self = MP_OBJ_TO_PTR(self_in);
	mp_int_t no = mp_obj_get_int(no_in);
	if (no < 0 \|\| no >= self->num_matches) {
	mp_raise_type_arg(&mp_type_IndexError, no_in);
	}

	const char start = self->caps[no 2];
	if (start == NULL) {
	// no match for this group
	return mp_const_none;
	}
	return mp_obj_new_str_of_type(mp_obj_get_type(self->str),
	(const byte )start, self->caps[no 2 + 1] - start);
	}
	MP_DEFINE_CONST_FUN_OBJ_2(match_group_obj, match_group);

	#if MICROPY_PY_RE_MATCH_GROUPS

	static mp_obj_t match_groups(mp_obj_t self_in) {
	mp_obj_match_t *self = MP_OBJ_TO_PTR(self_in);
	if (self->num_matches <= 1) {
	return mp_const_empty_tuple;
	}
	mp_obj_tuple_t *groups = MP_OBJ_TO_PTR(mp_obj_new_tuple(self->num_matches - 1, NULL));
	for (int i = 1; i < self->num_matches; ++i) {
	groups->items[i - 1] = match_group(self_in, MP_OBJ_NEW_SMALL_INT(i));
	}
	return MP_OBJ_FROM_PTR(groups);
	}
	MP_DEFINE_CONST_FUN_OBJ_1(match_groups_obj, match_groups);

	#endif

	#if MICROPY_PY_RE_MATCH_SPAN_START_END

	static void match_span_helper(size_t n_args, const mp_obj_t *args, mp_obj_t span[2]) {
	mp_obj_match_t *self = MP_OBJ_TO_PTR(args[0]);

	mp_int_t no = 0;
	if (n_args == 2) {
	no = mp_obj_get_int(args[1]);
	if (no < 0 \|\| no >= self->num_matches) {
	mp_raise_type_arg(&mp_type_IndexError, args[1]);
	}
	}

	mp_int_t s = -1;
	mp_int_t e = -1;
	const char start = self->caps[no 2];
	if (start != NULL) {
	// have a match for this group
	const char *begin = mp_obj_str_get_str(self->str);
	s = start - begin;
	e = self->caps[no * 2 + 1] - begin;
	}

	#if MICROPY_PY_BUILTINS_STR_UNICODE
	if (mp_obj_get_type(self->str) == &mp_type_str) {
	const byte begin = (const byte )mp_obj_str_get_str(self->str);
	if (s != -1) {
	s = utf8_ptr_to_index(begin, begin + s);
	}
	if (e != -1) {
	e = utf8_ptr_to_index(begin, begin + e);
	}
	}
	#endif

	span[0] = mp_obj_new_int(s);
	span[1] = mp_obj_new_int(e);
	}

	static mp_obj_t match_span(size_t n_args, const mp_obj_t *args) {
	mp_obj_t span[2];
	match_span_helper(n_args, args, span);
	return mp_obj_new_tuple(2, span);
	}
	MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(match_span_obj, 1, 2, match_span);

	static mp_obj_t match_start(size_t n_args, const mp_obj_t *args) {
	mp_obj_t span[2];
	match_span_helper(n_args, args, span);
	return span[0];
	}
	MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(match_start_obj, 1, 2, match_start);

	static mp_obj_t match_end(size_t n_args, const mp_obj_t *args) {
	mp_obj_t span[2];
	match_span_helper(n_args, args, span);
	return span[1];
	}
	MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(match_end_obj, 1, 2, match_end);

	#endif

	#if !MICROPY_ENABLE_DYNRUNTIME
	static const mp_rom_map_elem_t match_locals_dict_table[] = {
	{ MP_ROM_QSTR(MP_QSTR_group), MP_ROM_PTR(&match_group_obj) },
	#if MICROPY_PY_RE_MATCH_GROUPS
	{ MP_ROM_QSTR(MP_QSTR_groups), MP_ROM_PTR(&match_groups_obj) },
	#endif
	#if MICROPY_PY_RE_MATCH_SPAN_START_END
	{ MP_ROM_QSTR(MP_QSTR_span), MP_ROM_PTR(&match_span_obj) },
	{ MP_ROM_QSTR(MP_QSTR_start), MP_ROM_PTR(&match_start_obj) },
	{ MP_ROM_QSTR(MP_QSTR_end), MP_ROM_PTR(&match_end_obj) },
	#endif
	};

	static MP_DEFINE_CONST_DICT(match_locals_dict, match_locals_dict_table);

	static MP_DEFINE_CONST_OBJ_TYPE(
	match_type,
	MP_QSTR_match,
	MP_TYPE_FLAG_NONE,
	print, match_print,
	locals_dict, &match_locals_dict
	);
	#endif

	static void re_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
	(void)kind;
	mp_obj_re_t *self = MP_OBJ_TO_PTR(self_in);
	mp_printf(print, "<re %p>", self);
	}

	// Note: this function can't be named re_exec because it may clash with system headers, eg on FreeBSD
	static mp_obj_t re_exec_helper(bool is_anchored, uint n_args, const mp_obj_t *args) {
	(void)n_args;
	mp_obj_re_t *self;
	if (mp_obj_is_type(args[0], (mp_obj_type_t *)&re_type)) {
	self = MP_OBJ_TO_PTR(args[0]);
	} else {
	self = MP_OBJ_TO_PTR(mod_re_compile(1, args));
	}
	Subject subj;
	size_t len;
	subj.begin_line = subj.begin = mp_obj_str_get_data(args[1], &len);
	subj.end = subj.begin + len;
	int caps_num = (self->re.sub + 1) * 2;
	mp_obj_match_t match = m_new_obj_var(mp_obj_match_t, caps, char , caps_num);
	// cast is a workaround for a bug in msvc: it treats const char** as a const pointer instead of a pointer to pointer to const char
	memset((char )match->caps, 0, caps_num sizeof(char *));
	int res = re1_5_recursiveloopprog(&self->re, &subj, match->caps, caps_num, is_anchored);
	if (res == 0) {
	m_del_var(mp_obj_match_t, caps, char *, caps_num, match);
	return mp_const_none;
	}

	match->base.type = (mp_obj_type_t *)&match_type;
	match->num_matches = caps_num / 2; // caps_num counts start and end pointers
	match->str = args[1];
	return MP_OBJ_FROM_PTR(match);
	}

	static mp_obj_t re_match(size_t n_args, const mp_obj_t *args) {
	return re_exec_helper(true, n_args, args);
	}
	MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(re_match_obj, 2, 4, re_match);

	static mp_obj_t re_search(size_t n_args, const mp_obj_t *args) {
	return re_exec_helper(false, n_args, args);
	}
	MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(re_search_obj, 2, 4, re_search);

	static mp_obj_t re_split(size_t n_args, const mp_obj_t *args) {
	mp_obj_re_t *self = MP_OBJ_TO_PTR(args[0]);
	Subject subj;
	size_t len;
	const mp_obj_type_t *str_type = mp_obj_get_type(args[1]);
	subj.begin_line = subj.begin = mp_obj_str_get_data(args[1], &len);
	subj.end = subj.begin + len;
	int caps_num = (self->re.sub + 1) * 2;

	int maxsplit = 0;
	if (n_args > 2) {
	maxsplit = mp_obj_get_int(args[2]);
	}

	mp_obj_t retval = mp_obj_new_list(0, NULL);
	const char *caps = mp_local_alloc(caps_num sizeof(char *));
	while (true) {
	// cast is a workaround for a bug in msvc: it treats const char** as a const pointer instead of a pointer to pointer to const char
	memset((char *)caps, 0, caps_num sizeof(char *));
	int res = re1_5_recursiveloopprog(&self->re, &subj, caps, caps_num, false);

	// if we didn't have a match, or had an empty match, it's time to stop
	if (!res \|\| caps[0] == caps[1]) {
	break;
	}

	mp_obj_t s = mp_obj_new_str_of_type(str_type, (const byte *)subj.begin, caps[0] - subj.begin);
	mp_obj_list_append(retval, s);
	if (self->re.sub > 0) {
	mp_raise_NotImplementedError(MP_ERROR_TEXT("splitting with sub-captures"));
	}
	subj.begin = caps[1];
	if (maxsplit > 0 && --maxsplit == 0) {
	break;
	}
	}
	// cast is a workaround for a bug in msvc (see above)
	mp_local_free((char **)caps);

	mp_obj_t s = mp_obj_new_str_of_type(str_type, (const byte *)subj.begin, subj.end - subj.begin);
	mp_obj_list_append(retval, s);
	return retval;
	}
	MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(re_split_obj, 2, 3, re_split);

	#if MICROPY_PY_RE_SUB

	static mp_obj_t re_sub_helper(size_t n_args, const mp_obj_t *args) {
	mp_obj_re_t *self;
	if (mp_obj_is_type(args[0], (mp_obj_type_t *)&re_type)) {
	self = MP_OBJ_TO_PTR(args[0]);
	} else {
	self = MP_OBJ_TO_PTR(mod_re_compile(1, args));
	}
	mp_obj_t replace = args[1];
	mp_obj_t where = args[2];
	mp_int_t count = 0;
	if (n_args > 3) {
	count = mp_obj_get_int(args[3]);
	// Note: flags are currently ignored
	}

	size_t where_len;
	const char *where_str = mp_obj_str_get_data(where, &where_len);
	Subject subj;
	subj.begin_line = subj.begin = where_str;
	subj.end = subj.begin + where_len;
	int caps_num = (self->re.sub + 1) * 2;

	vstr_t vstr_return;
	vstr_return.buf = NULL; // We'll init the vstr after the first match
	mp_obj_match_t match = mp_local_alloc(sizeof(mp_obj_match_t) + caps_num sizeof(char *));
	match->base.type = (mp_obj_type_t *)&match_type;
	match->num_matches = caps_num / 2; // caps_num counts start and end pointers
	match->str = where;

	for (;;) {
	// cast is a workaround for a bug in msvc: it treats const char** as a const pointer instead of a pointer to pointer to const char
	memset((char )match->caps, 0, caps_num sizeof(char *));
	int res = re1_5_recursiveloopprog(&self->re, &subj, match->caps, caps_num, false);

	// If we didn't have a match, or had an empty match, it's time to stop
	if (!res \|\| match->caps[0] == match->caps[1]) {
	break;
	}

	// Initialise the vstr if it's not already
	if (vstr_return.buf == NULL) {
	vstr_init(&vstr_return, match->caps[0] - subj.begin);
	}

	// Add pre-match string
	vstr_add_strn(&vstr_return, subj.begin, match->caps[0] - subj.begin);

	// Get replacement string
	const char *repl = mp_obj_str_get_str((mp_obj_is_callable(replace) ? mp_call_function_1(replace, MP_OBJ_FROM_PTR(match)) : replace));

	// Append replacement string to result, substituting any regex groups
	while (*repl != '\0') {
	if (*repl == '\\') {
	++repl;
	bool is_g_format = false;
	if (*repl == 'g' && repl[1] == '<') {
	// Group specified with syntax "\g<number>"
	repl += 2;
	is_g_format = true;
	}

	if ('0' <= repl && repl <= '9') {
	// Group specified with syntax "\g<number>" or "\number"
	unsigned int match_no = 0;
	do {
	match_no = match_no * 10 + (*repl++ - '0');
	} while ('0' <= repl && repl <= '9');
	if (is_g_format && *repl == '>') {
	++repl;
	}

	if (match_no >= (unsigned int)match->num_matches) {
	mp_raise_type_arg(&mp_type_IndexError, MP_OBJ_NEW_SMALL_INT(match_no));
	}

	const char start_match = match->caps[match_no 2];
	if (start_match != NULL) {
	// Add the substring matched by group
	const char end_match = match->caps[match_no 2 + 1];
	vstr_add_strn(&vstr_return, start_match, end_match - start_match);
	}
	} else if (*repl == '\\') {
	// Add the \ character
	vstr_add_byte(&vstr_return, *repl++);
	}
	} else {
	// Just add the current byte from the replacement string
	vstr_add_byte(&vstr_return, *repl++);
	}
	}

	// Move start pointer to end of last match
	subj.begin = match->caps[1];

	// Stop substitutions if count was given and gets to 0
	if (count > 0 && --count == 0) {
	break;
	}
	}

	mp_local_free(match);

	if (vstr_return.buf == NULL) {
	// Optimisation for case of no substitutions
	return where;
	}

	// Add post-match string
	vstr_add_strn(&vstr_return, subj.begin, subj.end - subj.begin);

	if (mp_obj_get_type(where) == &mp_type_str) {
	return mp_obj_new_str_from_utf8_vstr(&vstr_return);
	} else {
	return mp_obj_new_bytes_from_vstr(&vstr_return);
	}
	}

	MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(re_sub_obj, 3, 5, re_sub_helper);

	#endif

	#if !MICROPY_ENABLE_DYNRUNTIME
	static const mp_rom_map_elem_t re_locals_dict_table[] = {
	{ MP_ROM_QSTR(MP_QSTR_match), MP_ROM_PTR(&re_match_obj) },
	{ MP_ROM_QSTR(MP_QSTR_search), MP_ROM_PTR(&re_search_obj) },
	{ MP_ROM_QSTR(MP_QSTR_split), MP_ROM_PTR(&re_split_obj) },
	#if MICROPY_PY_RE_SUB
	{ MP_ROM_QSTR(MP_QSTR_sub), MP_ROM_PTR(&re_sub_obj) },
	#endif
	};

	static MP_DEFINE_CONST_DICT(re_locals_dict, re_locals_dict_table);

	static MP_DEFINE_CONST_OBJ_TYPE(
	re_type,
	MP_QSTR_re,
	MP_TYPE_FLAG_NONE,
	print, re_print,
	locals_dict, &re_locals_dict
	);
	#endif

	static mp_obj_t mod_re_compile(size_t n_args, const mp_obj_t *args) {
	(void)n_args;
	const char *re_str = mp_obj_str_get_str(args[0]);
	int size = re1_5_sizecode(re_str);
	if (size == -1) {
	#if MICROPY_ERROR_REPORTING >= MICROPY_ERROR_REPORTING_NORMAL
	mp_raise_ValueError(MP_ERROR_TEXT("regex too complex"));
	#endif
	goto error;
	}
	mp_obj_re_t o = mp_obj_malloc_var(mp_obj_re_t, re.insts, char, size, (mp_obj_type_t )&re_type);
	#if MICROPY_PY_RE_DEBUG
	int flags = 0;
	if (n_args > 1) {
	flags = mp_obj_get_int(args[1]);
	}
	#endif
	int error = re1_5_compilecode(&o->re, re_str);
	if (error != 0) {
	error:
	mp_raise_ValueError(MP_ERROR_TEXT("error in regex"));
	}
	#if MICROPY_PY_RE_DEBUG
	if (flags & FLAG_DEBUG) {
	re1_5_dumpcode(&o->re);
	}
	#endif
	return MP_OBJ_FROM_PTR(o);
	}
	MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_re_compile_obj, 1, 2, mod_re_compile);

	#if !MICROPY_ENABLE_DYNRUNTIME
	static const mp_rom_map_elem_t mp_module_re_globals_table[] = {
	{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_re) },
	{ MP_ROM_QSTR(MP_QSTR_compile), MP_ROM_PTR(&mod_re_compile_obj) },
	{ MP_ROM_QSTR(MP_QSTR_match), MP_ROM_PTR(&re_match_obj) },
	{ MP_ROM_QSTR(MP_QSTR_search), MP_ROM_PTR(&re_search_obj) },
	#if MICROPY_PY_RE_SUB
	{ MP_ROM_QSTR(MP_QSTR_sub), MP_ROM_PTR(&re_sub_obj) },
	#endif
	#if MICROPY_PY_RE_DEBUG
	{ MP_ROM_QSTR(MP_QSTR_DEBUG), MP_ROM_INT(FLAG_DEBUG) },
	#endif
	};

	static MP_DEFINE_CONST_DICT(mp_module_re_globals, mp_module_re_globals_table);

	const mp_obj_module_t mp_module_re = {
	.base = { &mp_type_module },
	.globals = (mp_obj_dict_t *)&mp_module_re_globals,
	};

	MP_REGISTER_EXTENSIBLE_MODULE(MP_QSTR_re, mp_module_re);
	#endif

	// Source files #include'd here to make sure they're compiled in
	// only if module is enabled by config setting.

	#define re1_5_fatal(x) assert(!x)

	#include "lib/re1.5/compilecode.c"
	#include "lib/re1.5/recursiveloop.c"
	#include "lib/re1.5/charclass.c"

	#if MICROPY_PY_RE_DEBUG
	// Make sure the output print statements go to the same output as other Python output.
	#define printf(...) mp_printf(&mp_plat_print, __VA_ARGS__)
	#include "lib/re1.5/dumpcode.c"
	#undef printf
	#endif

	#endif // MICROPY_PY_RE