allwpilib/src/nt_persistent.cpp

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2015. All Rights Reserved.                             */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#include "ntcore.h"

#include <cstdio>

#include "llvm/StringExtras.h"
#include "nt_base64.h"
#include "nt_storage.h"

using namespace NtImpl;

static void
write_string(FILE *f, llvm::StringRef str)
{
    fputc('"', f);
    for (unsigned int i = 0, e = str.size(); i != e; ++i)
    {
        unsigned char c = str[i];

        switch (c)
        {
        case '\\': fputs("\\\\", f); break;
        case '\t': fputs("\\t", f); break;
        case '\n': fputs("\\n", f); break;
        case '"': fputs("\\\"", f); break;
        default:
            if (std::isprint(c))
            {
                fputc(c, f);
                break;
            }

            // Write out the escaped representation.
            fputs("\\x", f);
            fputc(llvm::hexdigit((c >> 4 & 0xF)), f);
            fputc(llvm::hexdigit((c >> 0) & 0xF), f);
        }
    }
    fputc('"', f);
}

const char *
NT_SavePersistent(const char *filename)
{
    FILE *f = fopen(filename, "wt");
    if (!f)
        return "could not open file";

    fputs("[NetworkTables Storage 3.0]\n", f);

    Storage &storage = Storage::GetInstance();
    for (Storage::EntriesMap::const_iterator i = storage.entries.begin(),
         end = storage.entries.end(); i != end; ++i)
    {
        const StorageEntry &entry = i->getValue();
        // only write persistent-flagged values
        if ((entry.flags & NT_PERSISTENT) == 0)
            continue;

        // type
        const NT_Value &v = entry.value;
        switch (v.type)
        {
        case NT_BOOLEAN:        fputs("boolean ", f); break;
        case NT_DOUBLE:         fputs("double ", f); break;
        case NT_STRING:         fputs("string ", f); break;
        case NT_RAW:            fputs("raw ", f); break;
        case NT_BOOLEAN_ARRAY:  fputs("array boolean ", f); break;
        case NT_DOUBLE_ARRAY:   fputs("array double ", f); break;
        case NT_STRING_ARRAY:   fputs("array string ", f); break;
        default:
            continue;
        }

        // name
        write_string(f, i->getKey());

        // =
        fputc('=', f);

        // value
        switch (v.type)
        {
        case NT_BOOLEAN:
            fputs(v.data.v_boolean ? "true" : "false", f);
            break;
        case NT_DOUBLE:
            fprintf(f, "%g", v.data.v_double);
            break;
        case NT_STRING:
            write_string(f, make_StringRef(v.data.v_string));
            break;
        case NT_RAW:
        {
            char *buf = new char[base64encode_len(v.data.v_raw.len)];
            base64encode(buf,
                    reinterpret_cast<const unsigned char*>(v.data.v_raw.str),
                    v.data.v_raw.len);
            fputs(buf, f);
            delete[] buf;
            break;
        }
        case NT_BOOLEAN_ARRAY:
            for (size_t i=0; i<v.data.arr_boolean.size; ++i)
            {
                fputs(v.data.arr_boolean.arr[i] ? "true" : "false", f);
                if (i != (v.data.arr_boolean.size - 1))
                    fputc(',', f);
            }
            break;
        case NT_DOUBLE_ARRAY:
            for (size_t i=0; i<v.data.arr_double.size; ++i)
            {
                fprintf(f, "%g", v.data.arr_double.arr[i]);
                if (i != (v.data.arr_double.size - 1))
                    fputc(',', f);
            }
            break;
        case NT_STRING_ARRAY:
            for (size_t i=0; i<v.data.arr_double.size; ++i)
            {
                write_string(f, make_StringRef(v.data.arr_string.arr[i]));
                if (i != (v.data.arr_double.size - 1))
                    fputc(',', f);
            }
            break;
        default:
            break;
        }

        // eol
        fputc('\n', f);
    }

    fclose(f);
    return 0;
}

const char *
NT_LoadPersistent(const char *filename)
{
    FILE *f = fopen(filename, "rt");
    if (!f)
        return "could not open file";

    fclose(f);
    return 0;
}