iu9-ca-web-chat/src/http_server/new_york_transit_line/parser.cpp

#include "core.h"
#include "alotalot.h"
#include <vector>
#include <assert.h>

namespace nytl {
    size_t first_nw_char(const std::string& str) {
        size_t i = 0;
        for (; i < str.size(); i++)
            if (!isSPACE(str[i]))
                break;
        return i;
    }

    bool is_space_only(const std::string& str) {
        return first_nw_char(str) == str.size();
    }

    void rstrip(std::string& str) {
        while (!str.empty() && isSPACE(str.back()))
            str.resize(str.size() - 1);
    }

    std::string clement_lstrip(const std::string& str) {
        size_t gone = 0;
        size_t n = str.size();
        for (size_t i = 0; i < n; i++) {
            if (str[i] == '\n') {
                gone = i + 1;
            } else if (!isSPACE(str[i])) {
                return str.substr(gone);
            }
        }
        return "";
    }

    int peep(ParsingContext &ctx) {
        if (ctx.text.size() <= ctx.pos)
            return EOFVAL;
        return ctx.text[ctx.pos];
    }

    void advance(ParsingContext& ctx) {
        if (ctx.text[ctx.pos] == '\n') {
            ctx.line++;
            ctx.column = 0;
        } else {
            ctx.column++;
        }
        ctx.pos++;
    }

    void skip(ParsingContext& ctx) {
        ASSERT(ctx.pos < ctx.text.size(), "Unexpected EOF");
        advance(ctx);
    }

    void skip(ParsingContext& ctx, char ch) {
        ASSERT(ctx.pos < ctx.text.size(), "Unexpected EOF");
        ASSERT(ctx.text[ctx.pos] == ch, "Unexpected character");
        advance(ctx);
    }

    void skipWhitespace(ParsingContext &ctx) {
        while (peep(ctx) > 0 && isSPACE((char)peep(ctx)))
            skip(ctx);
    }

    std::vector<std::string> splitIntoLines(const std::string &str) {
        std::vector<std::string> result = {""};
        for (char ch: str) {
            if (ch == '\n')
                result.emplace_back();
            else
                result.back() += ch;
        }
        return result;
    }

    std::string concatenateLines(const std::vector<std::string>& lines) {
        std::string result;
        size_t n = lines.size();
        for (size_t i = 0; i < n; i++) {
            if (i)
                result += '\n';
            result += lines[i];
        }
        return result;
    }

    void one_part_update_min_start_wsp_non_empty(const std::string& str, bool is_first, size_t& min) {
        std::vector<std::string> lines = splitIntoLines(str);
        size_t L = lines.size();
        for (size_t i = is_first ? 0 : 1; i < L; i++) {
            size_t first_nw = first_nw_char(lines[i]);
            if (first_nw < lines[i].size())
                min = std::min(min, first_nw);
        }
    }

    std::string one_part_cut_excess_tab(const std::string& str, bool is_first, size_t cut) {
        std::vector<std::string> lines = splitIntoLines(str);
        size_t L = lines.size();
        for (size_t i = is_first ? 0 : 1; i < L; i++) {
            if (!is_space_only(lines[i]))
                lines[i] = lines[i].substr(cut);
        }
        return concatenateLines(lines);
    }

    void parse_bare_file(const std::string& filename, const std::string& content,
                             global_elem_set_t& result)
    {
        ASSERT(result.count(filename) == 0, "Repeated element " + filename);
        std::string P = clement_lstrip(content);
        rstrip(P);
        size_t cut = 9999999999999;
        one_part_update_min_start_wsp_non_empty(P, true, cut);
        P = one_part_cut_excess_tab(P, true, cut);
        Element& el = result[filename];
        el.parts = {ElementPart{element_part_types::code}};
        el.parts[0].when_code.lines = mv(P);
    }

    void parse_special_file(const std::string& filename, const std::string& content,
        std::map<std::string, Element>& result)
    {
        // THROW("Don't know how to parse it yet");
    }
}