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

/* Only for the sleep, the progress bar code itself is standard C */
#include <unistd.h>

typedef enum
{
    false=0,
    true=!false
} bool;

typedef struct
{
    /* Start delimiter (e.g. [ )*/
    char StartDelimiter;
    /* End Delimiter (e.g. ] )*/
    char EndDelimiter;
    /* Central block (e.g. = )*/
    char Block;
    /* Last blocks, rotated at each refresh (typical value: - | / - \ | / ) */
    char LastBlocks[10];
    /* Used positions of LastBlocks */
    size_t LastBlocksSize;
    /* LastBlocks index to be used next time */
    size_t LastBlockIndex;
    /* Width of the progress bar (in characters) */
    unsigned int Width;
    /* Maximum value of the progress bar */
    double Max;
    /* True if we have to print also the percentage of the operation */
    bool PrintPercentage;
    /* True if the bar must be redrawn;
       note that this must be just set to false before the first call, the function then will change it by itself.  */
    bool Update;
} ProgressBarSettings;

/* Prints/updates the progress bar */
void PrintProgressBar(double Pos, ProgressBarSettings * Settings);
/* Inits the settings of the progress bar to the default values */
void DefaultProgressBar(ProgressBarSettings * Settings);

int main()
{
    int i;
    /* Init the bar settings */
    ProgressBarSettings pbs;
    DefaultProgressBar(&pbs);
    pbs.Max=400;
    pbs.Width=60;
    printf("Progress: ");
    /* Show the empty bar */
    PrintProgressBar(0,&pbs);
    for(i=0;i<=pbs.Max;i++)
    {
        /* Wait 25 msec */
        usleep(25000);
        /* Update the progress bar */
        PrintProgressBar(i,&pbs);
    }
    puts(" Done");
    return 0;
}

/* Inits the settings of the progress bar to the default values */
void DefaultProgressBar(ProgressBarSettings * Settings)
{
    const char * defaultLastBlocks="-\\|/-\\|/";
    Settings->StartDelimiter='[';
    Settings->EndDelimiter=']';
    Settings->Block='=';
    strncpy(Settings->LastBlocks, defaultLastBlocks, sizeof(Settings->LastBlocks));
    Settings->LastBlocksSize=strlen(defaultLastBlocks);
    if(Settings->LastBlocksSize>sizeof(Settings->LastBlocks))
        Settings->LastBlocksSize=sizeof(Settings->LastBlocks);
    Settings->LastBlockIndex=0;
    Settings->PrintPercentage=true;
    Settings->Update=false;
    Settings->Max=100;
    Settings->Width=40;
}

/* Prints/updates the progress bar */
void PrintProgressBar(double Pos, ProgressBarSettings * Settings)
{
    /* Blocks to print */
    unsigned int printBlocks=(unsigned int)(Settings->Width*Pos/Settings->Max);
    /* Counter */
    unsigned int counter;
    /* If we are updating an existing bar...*/
    if(Settings->Update)
    {
        /* ... we get back to its first character to rewrite it... */
        for(counter=Settings->Width+2+(Settings->PrintPercentage?5:0);counter;counter--)
            putchar('\b');
    }
    else
        Settings->Update=true; /* next time we'll be updating it */
    /* Print the first delimiter */
    putchar(Settings->StartDelimiter);
    /* Reset the counter */
    counter=Settings->Width;
    /* Print all the blocks except the last; in the meantime, we decrement the counter, so in the end we'll have
       the number of spaces to fill the bar */ 
    for(;printBlocks>1;printBlocks--,counter--)
        putchar(Settings->Block);
    /* Print the last block; if the operation ended, use the normal block, otherwise the one for the last block */
    putchar((Settings->Max==Pos)?Settings->Block:Settings->LastBlocks[Settings->LastBlockIndex]);
    /* At the next update we'll use the next last block */
    Settings->LastBlockIndex=(Settings->LastBlockIndex+1)%Settings->LastBlocksSize;
    /* Another block was printed, decrement the counter */ 
    counter--;
    /* Fill the rest of the bar with spaces */
    for(;counter;counter--)
        putchar(' ');
    /* Print the end delimiter */
    putchar(Settings->EndDelimiter);
    /* If asked, print also the percentage */
    if(Settings->PrintPercentage)
        printf(" %3d%%",(int)(100*Pos/Settings->Max));
    /* Flush the output buffer */
    fflush(stdout);
};