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v/vlib/regex/regex_util.v

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/*
regex 1.0 alpha
Copyright (c) 2019-2021 Dario Deledda. All rights reserved.
Use of this source code is governed by an MIT license
that can be found in the LICENSE file.
*/
module regex
import strings
/******************************************************************************
*
* Inits
*
******************************************************************************/
// regex create a regex object from the query string, retunr RE object and errors as re_err, err_pos
pub fn regex_base(pattern string) (RE, int, int) {
// init regex
mut re := RE{}
re.prog = []Token{len: pattern.len + 1} // max program length, can not be longer then the pattern
re.cc = []CharClass{len: pattern.len} // can not be more char class the the length of the pattern
re.group_csave_flag = false // enable continuos group saving
re.group_max_nested = 128 // set max 128 group nested
re.group_max = pattern.len >> 1 // we can't have more groups than the half of the pattern legth
re.group_stack = []int{len: re.group_max, init: -1}
re.group_data = []int{len: re.group_max, init: -1}
re_err, err_pos := re.impl_compile(pattern)
return re, re_err, err_pos
}
/******************************************************************************
*
* Utilities
*
******************************************************************************/
// get_group_bounds_by_name get a group boundaries by its name
pub fn (re RE) get_group_bounds_by_name(group_name string) (int, int) {
if group_name in re.group_map {
tmp_index := re.group_map[group_name] - 1
start := re.groups[tmp_index * 2]
end := re.groups[tmp_index * 2 + 1]
return start, end
}
return -1, -1
}
// get_group_by_name get a group boundaries by its name
pub fn (re RE) get_group_by_name(in_txt string, group_name string) string {
if group_name in re.group_map {
tmp_index := re.group_map[group_name] - 1
start := re.groups[tmp_index * 2]
end := re.groups[tmp_index * 2 + 1]
if start >= 0 && end > start {
return in_txt[start..end]
}
}
return ''
}
// get_group_by_id get a group string by its id
pub fn (re RE) get_group_by_id(in_txt string, group_id int) string {
if group_id < (re.groups.len >> 1) {
index := group_id << 1
start := re.groups[index]
end := re.groups[index + 1]
if start >= 0 && end > start {
return in_txt[start..end]
}
}
return ''
}
// get_group_by_id get a group boundaries by its id
pub fn (re RE) get_group_bounds_by_id(group_id int) (int, int) {
if group_id < re.group_count {
index := group_id << 1
return re.groups[index], re.groups[index + 1]
}
return -1, -1
}
pub struct Re_group {
pub:
start int = -1
end int = -1
}
// get_group_list return a list of Re_group for the found groups
pub fn (re RE) get_group_list() []Re_group {
mut res := []Re_group{len: re.groups.len >> 1}
mut gi := 0
// println("len: ${re.groups.len} groups: ${re.groups}")
for gi < re.groups.len {
if re.groups[gi] >= 0 {
txt_st := re.groups[gi]
txt_en := re.groups[gi + 1]
// println("#${gi/2} start: ${re.groups[gi]} end: ${re.groups[gi + 1]} ")
if txt_st >= 0 && txt_en > txt_st {
tmp := Re_group{
start: re.groups[gi]
end: re.groups[gi + 1]
}
// println(tmp)
res[gi >> 1] = tmp
} else {
res[gi >> 1] = Re_group{}
}
}
gi += 2
}
return res
}
/******************************************************************************
*
* Matchers
*
******************************************************************************/
// match_string Match the pattern with the in_txt string
[direct_array_access]
pub fn (mut re RE) match_string(in_txt string) (int, int) {
start, mut end := re.match_base(in_txt.str, in_txt.len + 1)
if end > in_txt.len {
end = in_txt.len
}
if start >= 0 && end > start {
if (re.flag & f_ms) != 0 && start > 0 {
return no_match_found, 0
}
if (re.flag & f_me) != 0 && end < in_txt.len {
if in_txt[end] in new_line_list {
return start, end
}
return no_match_found, 0
}
return start, end
}
return start, end
}
/******************************************************************************
*
* Finders
*
******************************************************************************/
/*
// find internal implementation HERE for reference do not remove!!
[direct_array_access]
fn (mut re RE) find_imp(in_txt string) (int,int) {
old_flag := re.flag
re.flag |= f_src // enable search mode
start, mut end := re.match_base(in_txt.str, in_txt.len + 1)
//print("Find [$start,$end] '${in_txt[start..end]}'")
if end > in_txt.len {
end = in_txt.len
}
re.flag = old_flag
if start >= 0 && end > start {
return start, end
}
return no_match_found, 0
}
*/
// find try to find the first match in the input string
[direct_array_access]
pub fn (mut re RE) find(in_txt string) (int, int) {
// old_flag := re.flag
// re.flag |= f_src // enable search mode
mut i := 0
for i < in_txt.len {
mut s := -1
mut e := -1
unsafe {
// tmp_str := tos(in_txt.str + i, in_txt.len - i)
// println("Check: [$tmp_str]")
s, e = re.match_base(in_txt.str + i, in_txt.len - i + 1)
if s >= 0 && e > s {
// println("find match in: ${i+s},${i+e} [${in_txt[i+s..i+e]}]")
// re.flag = old_flag
return i + s, i + e
}
i++
}
}
// re.flag = old_flag
return -1, -1
}
// find try to find the first match in the input string strarting from start index
[direct_array_access]
pub fn (mut re RE) find_from(in_txt string, start int) (int, int) {
old_flag := re.flag
re.flag |= f_src // enable search mode
mut i := start
if i < 0 {
return -1, -1
}
for i < in_txt.len {
//--- speed references ---
mut s := -1
mut e := -1
unsafe {
tmp_str := tos(in_txt.str + i, in_txt.len - i)
s, e = re.match_string(tmp_str)
}
//------------------------
// s,e = re.find_imp(in_txt[i..])
//------------------------
if s >= 0 && e > s {
// println("find match in: ${i+s},${i+e} [${in_txt[i+s..i+e]}]")
re.flag = old_flag
return i + s, i + e
} else {
i++
}
}
re.flag = old_flag
return -1, -1
}
// find_all find all the non overlapping occurrences of the match pattern
[direct_array_access]
pub fn (mut re RE) find_all(in_txt string) []int {
// old_flag := re.flag
// re.flag |= f_src // enable search mode
mut i := 0
mut res := []int{}
for i < in_txt.len {
mut s := -1
mut e := -1
unsafe {
// tmp_str := in_txt[i..]
// tmp_str := tos(in_txt.str + i, in_txt.len - i)
// println("Check: [$tmp_str]")
s, e = re.match_base(in_txt.str + i, in_txt.len + 1 - i)
if s >= 0 && e > s {
res << i + s
res << i + e
i += e
continue
}
}
i++
}
// re.flag = old_flag
return res
}
// find_all_str find all the non overlapping occurrences of the match pattern, return a string list
[direct_array_access]
pub fn (mut re RE) find_all_str(in_txt string) []string {
// old_flag := re.flag
// re.flag |= f_src // enable search mode
mut i := 0
mut res := []string{}
for i < in_txt.len {
mut s := -1
mut e := -1
unsafe {
// tmp_str := in_txt[i..]
// tmp_str := tos(in_txt.str + i, in_txt.len - i)
// println("Check: [$tmp_str]")
s, e = re.match_base(in_txt.str + i, in_txt.len + 1 - i)
if s >= 0 && e > s {
tmp_str := tos(in_txt.str + i, in_txt.len - i)
// println("Found: $s:$e [${tmp_str[s..e]}]")
res << tmp_str[..e]
i += e
continue
}
}
i++
}
// re.flag = old_flag
return res
}
/******************************************************************************
*
* Replacers
*
******************************************************************************/
// replace_simple return a string where the matches are replaced with the replace string
pub fn (mut re RE) replace_simple(in_txt string, repl string) string {
pos := re.find_all(in_txt)
if pos.len > 0 {
mut res := ''
mut i := 0
mut s1 := 0
mut e1 := in_txt.len
for i < pos.len {
e1 = pos[i]
res += in_txt[s1..e1] + repl
s1 = pos[i + 1]
i += 2
}
res += in_txt[s1..]
return res
}
return in_txt
}
// type of function used for custom replace
// in_txt source text
// start index of the start of the match in in_txt
// end index of the end of the match in in_txt
// the match is in in_txt[start..end]
pub type FnReplace = fn (re RE, in_txt string, start int, end int) string
// replace_by_fn return a string where the matches are replaced with the string from the repl_fn callback function
pub fn (mut re RE) replace_by_fn(in_txt string, repl_fn FnReplace) string {
mut i := 0
mut res := strings.new_builder(in_txt.len)
mut last_end := 0
for i < in_txt.len {
// println("Find Start. $i [${in_txt[i..]}]")
s, e := re.find_from(in_txt, i)
// println("Find End.")
if s >= 0 && e > s {
// println("find match in: ${s},${e} [${in_txt[s..e]}]")
if last_end < s {
res.write_string(in_txt[last_end..s])
}
for g_i in 0 .. re.group_count {
re.groups[g_i << 1] += i
re.groups[(g_i << 1) + 1] += i
}
repl := repl_fn(re, in_txt, s, e)
// println("repl res: $repl")
res.write_string(repl)
// res.write_string("[[${in_txt[s..e]}]]")
last_end = e
i = e
} else {
break
// i++
}
// println(i)
}
if last_end >= 0 && last_end < in_txt.len {
res.write_string(in_txt[last_end..])
}
return res.str()
}
fn (re RE) parsed_replace_string(in_txt string, repl string) string {
str_lst := repl.split('\\')
mut res := str_lst[0]
mut i := 1
for i < str_lst.len {
tmp := str_lst[i]
// println("tmp: ${tmp}")
if tmp.len > 0 && tmp[0] >= `0` && tmp[0] <= `9` {
group_id := int(tmp[0] - `0`)
group := re.get_group_by_id(in_txt, group_id)
// println("group: $group_id [$group]")
res += '$group${tmp[1..]}'
} else {
res += '\\' + tmp
}
i++
}
return res
}
// replace return a string where the matches are replaced with the repl_str string,
// this function support use groups in the replace string
pub fn (mut re RE) replace(in_txt string, repl_str string) string {
mut i := 0
mut res := strings.new_builder(in_txt.len)
mut last_end := 0
for i < in_txt.len {
// println("Find Start. $i [${in_txt[i..]}]")
s, e := re.find_from(in_txt, i)
// println("Find End.")
if s >= 0 && e > s {
// println("find match in: ${s},${e} [${in_txt[s..e]}]")
if last_end < s {
res.write_string(in_txt[last_end..s])
}
for g_i in 0 .. re.group_count {
re.groups[g_i << 1] += i
re.groups[(g_i << 1) + 1] += i
}
// repl := repl_fn(re, in_txt, s, e)
repl := re.parsed_replace_string(in_txt, repl_str)
// println("repl res: $repl")
res.write_string(repl)
// res.write_string("[[${in_txt[s..e]}]]")
last_end = e
i = e
} else {
break
// i++
}
// println(i)
}
if last_end >= 0 && last_end < in_txt.len {
res.write_string(in_txt[last_end..])
}
return res.str()
}