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       1                 :            : // Copyright (c) 2018-2022 The Bitcoin Core developers
       2                 :            : // Distributed under the MIT software license, see the accompanying
       3                 :            : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       4                 :            : 
       5                 :            : #ifndef BITCOIN_UTIL_SPANPARSING_H
       6                 :            : #define BITCOIN_UTIL_SPANPARSING_H
       7                 :            : 
       8                 :            : #include <span.h>
       9                 :            : 
      10                 :            : #include <string>
      11                 :            : #include <string_view>
      12                 :            : #include <vector>
      13                 :            : 
      14                 :            : namespace spanparsing {
      15                 :            : 
      16                 :            : /** Parse a constant.
      17                 :            :  *
      18                 :            :  * If sp's initial part matches str, sp is updated to skip that part, and true is returned.
      19                 :            :  * Otherwise sp is unmodified and false is returned.
      20                 :            :  */
      21                 :            : bool Const(const std::string& str, Span<const char>& sp);
      22                 :            : 
      23                 :            : /** Parse a function call.
      24                 :            :  *
      25                 :            :  * If sp's initial part matches str + "(", and sp ends with ")", sp is updated to be the
      26                 :            :  * section between the braces, and true is returned. Otherwise sp is unmodified and false
      27                 :            :  * is returned.
      28                 :            :  */
      29                 :            : bool Func(const std::string& str, Span<const char>& sp);
      30                 :            : 
      31                 :            : /** Extract the expression that sp begins with.
      32                 :            :  *
      33                 :            :  * This function will return the initial part of sp, up to (but not including) the first
      34                 :            :  * comma or closing brace, skipping ones that are surrounded by braces. So for example,
      35                 :            :  * for "foo(bar(1),2),3" the initial part "foo(bar(1),2)" will be returned. sp will be
      36                 :            :  * updated to skip the initial part that is returned.
      37                 :            :  */
      38                 :            : Span<const char> Expr(Span<const char>& sp);
      39                 :            : 
      40                 :            : /** Split a string on any char found in separators, returning a vector.
      41                 :            :  *
      42                 :            :  * If sep does not occur in sp, a singleton with the entirety of sp is returned.
      43                 :            :  *
      44                 :            :  * Note that this function does not care about braces, so splitting
      45                 :            :  * "foo(bar(1),2),3) on ',' will return {"foo(bar(1)", "2)", "3)"}.
      46                 :            :  */
      47                 :            : template <typename T = Span<const char>>
      48                 :          8 : std::vector<T> Split(const Span<const char>& sp, std::string_view separators)
      49                 :            : {
      50                 :          8 :     std::vector<T> ret;
      51                 :          8 :     auto it = sp.begin();
      52                 :          8 :     auto start = it;
      53         [ +  + ]:         52 :     while (it != sp.end()) {
      54         [ +  - ]:         44 :         if (separators.find(*it) != std::string::npos) {
      55         [ #  # ]:          0 :             ret.emplace_back(start, it);
      56                 :          0 :             start = it + 1;
      57                 :          0 :         }
      58                 :         44 :         ++it;
      59                 :            :     }
      60         [ +  - ]:          8 :     ret.emplace_back(start, it);
      61                 :          8 :     return ret;
      62         [ +  - ]:          8 : }
      63                 :            : 
      64                 :            : /** Split a string on every instance of sep, returning a vector.
      65                 :            :  *
      66                 :            :  * If sep does not occur in sp, a singleton with the entirety of sp is returned.
      67                 :            :  *
      68                 :            :  * Note that this function does not care about braces, so splitting
      69                 :            :  * "foo(bar(1),2),3) on ',' will return {"foo(bar(1)", "2)", "3)"}.
      70                 :            :  */
      71                 :            : template <typename T = Span<const char>>
      72                 :          8 : std::vector<T> Split(const Span<const char>& sp, char sep)
      73                 :            : {
      74                 :          8 :     return Split<T>(sp, std::string_view{&sep, 1});
      75                 :            : }
      76                 :            : 
      77                 :            : } // namespace spanparsing
      78                 :            : 
      79                 :            : #endif // BITCOIN_UTIL_SPANPARSING_H