Functions for Loading/Saving RFC4180 CSV

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

std::string& string_replace (std::string& str, const std::string& from, const std::string& to)
{
    std::string::size_type pos = 0;
    while (pos = str.find(from, pos), pos != std::string::npos) {
        str.replace(pos, from.length(), to);
        pos += to.length();
    }
    return str;
}

std::string csv_escape(const std::string &token)
{
    std::string res(token);
    bool needsQuote = false;
    if (res.find("\"", 0) != std::string::npos) {
        needsQuote = true;
        string_replace(res, "\"", "\"\"");
    }
    if (res.find(",", 0) != std::string::npos ||
        res.find("\n", 0) != std::string::npos) {
        needsQuote = true;
    }
    if (needsQuote) {
        res.insert(0, "\"");
        res.append("\"");
    }
    return res;
}


std::string csv_unescape(const std::string &token)
{
    std::string res(token);
    if (res.length() >= 2 && res[0] == '\"' && res[res.length() - 1] == '\"') {
        res.erase(res.length() - 1, 1);
        res.erase(0, 1);
    }
    string_replace(res, "\"\"", "\"");
    return res;
}

std::vector<std::string> csv_split(const std::string &str, bool *valid = NULL)
{
    std::vector<std::string> res;

    if (valid != NULL) {
        *valid = true;
    }

    std::string::size_type start = 0;
    std::string::size_type current = 0;
    std::string::size_type found;
    bool insideQuote = false;
    while ((found = str.find_first_of(",\"", current)) != std::string::npos) {
        char c = str[found];
        if (c == '\"') {
            if (insideQuote) {
                if (str[found + 1] == '\"') {
                    found++; // skip the next quote
                }
                else {
                    if (valid != NULL && str[found + 1] != ',' && str[found + 1] != '\0' && str[found + 1] != '\r' && str[found + 1] != '\n') {
                        *valid = false;
                    }
                    insideQuote = false;
                }
            }
            else {
                if (valid != NULL && found > 0 && str[found - 1] != ',' && str[found - 1] != '\r' && str[found - 1] != '\n') {
                    *valid = false;
                }
                insideQuote = true;
            }
        }
        else if (c == ',') {
            if (!insideQuote) {
                res.push_back(std::string(str, start, found - start));
                start = found + 1;
            }
        }
        current = found + 1;
    }
    res.push_back(std::string(str, start, str.size() - start));

    if (valid != NULL && insideQuote) {
        *valid = false;
    }

    for (int i = 0; i < res.size(); i++) {
        res[i] = csv_unescape(res[i]);
    }
    return res;
}

std::string csv_join(std::vector<std::string> &v)
{
    std::string res;

    std::vector<std::string>::iterator iter = v.begin();
    bool first = true;
    while(iter != v.end())
    {
        if (first) {
            first = false;
        }
        else {
            res.append(",");
        }

        res.append(csv_escape(*iter));
        iter++;
    }
    return res;
}

bool ParseCSV(const char *filename)
{
    FILE *fs = fopen(filename, "r");
    char linebuf[1024];

    // note: this function do not support fields containing line breaks
    while (fgets(linebuf, 1024, fs) != NULL)
    {
        linebuf[strlen(linebuf) - 1] = '\0';

        bool valid = true;
        std::vector<std::string> param = csv_split(std::string(linebuf), &valid);

        printf("{ ");
        for (int i = 0; i < param.size(); i++)
        {
            if (i)
                printf(", ");
            printf("[%d]=%s", i, param[i].c_str());
        }
        printf(" }");
        if (!valid) {
            printf(" // illegal?");
        }
        printf("\n");
    }
    fclose(fs);
    return true;
}

int main(int argc, char *argv[])
{
    if (argc < 2) {
        fprintf(stderr, "error: no filename\n");
        return 1;
    }
    printf("return %s;\n", ParseCSV(argv[1]) ? "true" : "false");

    //FILE *fs = fopen("saved.csv", "w");
    //if (!fs) return 0;
    //bool enabled = true;
    //std::string code("7E00BE:99+7E00BF:99");
    //std::string name("Money MAX");
    //std::vector<std::string> v;
    //v.push_back(enabled ? "enabled" : "disabled");
    //v.push_back(code);
    //v.push_back(name);
    //fprintf(fs, "%s\n", csv_join(v).c_str());
    //fclose(fs);

    return 0;
}