#include <stdio.h>

#include <malloc.h>

#include "libiconv/iconv.h"

#ifdef _DEBUG

#pragma comment(lib, "libiconv/libiconvd.lib")

#else

#pragma comment(lib, "libiconv/libiconv.lib")

#endif

#define BUFFER_SIZE 10 * 1024 * 1024

int main()

{

    const char *toCode = "GBK", *fromCode = "UTF-8";

    iconv_t conversionDescriptor = iconv_open(toCode, fromCode);

    if ((iconv_t)- == conversionDescriptor)

    {

        if (errno == EINVAL)

            printf("Not supported from %s to %s.\n", fromCode, toCode);

        else

            printf("Unknown error.\n");

    }

    else

    {

        const char *filename = "text_utf-8.txt";

        FILE *inputFile = fopen(filename, "r");

        if (inputFile)

        {

            filename = "text_gbk.txt";

            FILE *outputFile = fopen(filename, "w");

            if (outputFile)

            {

                char *sourceBuffer = (char *)malloc(sizeof(char) * BUFFER_SIZE);

                const char *sourcePtr = sourceBuffer;

                size_t destinationBufferSize = BUFFER_SIZE * , availableSpaceOfDestinationBuffer = destinationBufferSize;

                char *destinationBuffer = (char *)malloc(sizeof(char) * destinationBufferSize), *destinationPtr = destinationBuffer;

                size_t numberOfCharactersRead = fread(sourceBuffer, sizeof(char), BUFFER_SIZE, inputFile);

                iconv(conversionDescriptor, &sourcePtr, &numberOfCharactersRead, &destinationPtr, &availableSpaceOfDestinationBuffer);

                size_t characterCount = destinationBufferSize - availableSpaceOfDestinationBuffer;

                destinationBuffer[characterCount] = '\0';

                printf(destinationBuffer);

                fwrite(destinationBuffer, sizeof(char), characterCount, outputFile);

                free(sourceBuffer);

                free(destinationBuffer);

                fclose(outputFile);

            }

            else

                printf("Cannot open file: %s.\n", filename);

            fclose(inputFile);

        }

        else

            printf("Cannot open file: %s.\n", filename);

        iconv_close(conversionDescriptor);

    }

    system("pause");

    return ;

}