项目中需要设计一个远程设备升级程序，程序优化时想在数字显示升级进度的同时用类似wget的进度条的形式显示升级进度，于是写了一个简单的数字+进度条显示升级进度的程序，以下为程序的核心部分，以达到抛砖引玉的效果。

/* The progress bar like this:

xx% [=======> ]

*/

int dlbytes_size = 1 + MAX (size_grouped_len, 11);

int progress_size = bp->width - (4 + 2 + dlbytes_size + 8 + 14);

/* The difference between the number of bytes used,

and the number of columns used. */

int bytes_cols_diff = 0;

if (progress_size < 5)

progress_size = 0;

/* "xx% " */

if (bp->total_length > 0)

{

int percentage = 100.0 * size / bp->total_length;

assert (percentage <= 100);

if (percentage < 100)

sprintf (p, "%2d%% ", percentage);

else

strcpy (p, "100%");

p += 4;

}

else

APPEND_LITERAL (" ");

/* The progress bar: "[====> ]" or "[++==> ]". */

if (progress_size && bp->total_length > 0)

{

/* Size of the initial portion. */

int insz = (double)bp->initial_length / bp->total_length * progress_size;

/* Size of the downloaded portion. */

int dlsz = (double)size / bp->total_length * progress_size;

char *begin;

int i;

assert (dlsz <= progress_size);

assert (insz <= dlsz);

*p++ = '[';

begin = p;

/* Print the initial portion of the download with '+' chars, the

rest with '=' and one '>'. */

for (i = 0; i < insz; i++)

*p++ = '+';

dlsz -= insz;

if (dlsz > 0)

{

for (i = 0; i < dlsz - 1; i++)

*p++ = '=';

*p++ = '>';

}

while (p - begin < progress_size)

*p++ = ' ';

*p++ = ']';

}

else if (progress_size)

{

/* If we can't draw a real progress bar, then at least show

*something* to the user. */

int ind = bp->tick % (progress_size * 2 - 6);

int i, pos;

/* Make the star move in two directions. */

if (ind < progress_size - 2)

pos = ind + 1;

else

pos = progress_size - (ind - progress_size + 5);

*p++ = '[';

for (i = 0; i < progress_size; i++)

{

if (i == pos - 1) *p++ = '';

else

*p++ = ' ';

}

*p++ = ']';

++bp->tick;

}