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/* common bit magic */
static inline void
printbits(FILE *f, int code, int nbits)
{
int n, b;
for (n = nbits - 1; n >= 0; n--)
{
b = (code >> n) & 1;
fprintf(f, "%c", b ? '1' : '0');
}
}
static inline int
getbit(const unsigned char *buf, int x)
{
return ( buf[x >> 3] >> ( 7 - (x & 7) ) ) & 1;
}
static inline void
printline(FILE *f, unsigned char *line, int w)
{
int i;
for (i = 0; i < w; i++)
fprintf(f, "%c", getbit(line, i) ? '#' : '.');
fprintf(f, "\n");
}
static inline int
getrun(const unsigned char *line, int x, int w, int c)
{
int z;
int b;
if (x < 0)
x = 0;
z = x;
while (z < w)
{
b = getbit(line, z);
if (c != b)
break;
z ++;
}
return z - x;
}
static inline int
findchanging(const unsigned char *line, int x, int w)
{
int a, b;
if (line == 0)
return w;
if (x == -1)
{
a = 0;
x = 0;
}
else
{
a = getbit(line, x);
x++;
}
while (x < w)
{
b = getbit(line, x);
if (a != b)
break;
x++;
}
return x;
}
static inline int
findchangingcolor(const unsigned char *line, int x, int w, int color)
{
if (line == 0)
return w;
x = findchanging(line, x, w);
if (x < w && getbit(line, x) != color)
x = findchanging(line, x, w);
return x;
}
static const unsigned char lm[8] =
{ 0xFF, 0x7F, 0x3F, 0x1F, 0x0F, 0x07, 0x03, 0x01 };
static const unsigned char rm[8] =
{ 0x00, 0x80, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC, 0xFE };
static inline void
setbits(unsigned char *line, int x0, int x1)
{
int a0, a1, b0, b1, a;
a0 = x0 >> 3;
a1 = x1 >> 3;
b0 = x0 & 7;
b1 = x1 & 7;
if (a0 == a1)
{
if (b1)
line[a0] |= lm[b0] & rm[b1];
}
else
{
line[a0] |= lm[b0];
for (a = a0 + 1; a < a1; a++)
line[a] = 0xFF;
if (b1)
line[a1] |= rm[b1];
}
}
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