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Little optimization to the bmp loader loop (unfortunately almost no

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effect as the open() takes the longest time).


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8436 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Miika Pekkarinen 2006-01-24 08:12:36 +00:00
parent ef4241a2ee
commit 465982b2af
1 changed files with 8 additions and 17 deletions
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25
apps/recorder/bmp.c
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@ -80,14 +80,6 @@ static long readlong(long *value) {
#endif
/* Function to get a pixel from a line. (Tomas: maybe a better way?) */
int getpix(int px, unsigned char *bmpbuf) {
int a = (px / 8);
int b = (7 - (px % 8));
return (bmpbuf[a] & (1 << b)) != 0;
}
/******************************************************************************
* read_bmp_file()
@ -172,6 +164,9 @@ int read_bmp_file(char* filename,
/* loop to read rows and put them to buffer */
for (row = 0; row < bitmap_height; row++) {
int bitsel = 1 << ((bitmap_height - row - 1) % 8);
int bytesel = bitmap_width * ((bitmap_height - row - 1) / 8);
/* read one row */
ret = read(fd, bmpbuf, PaddedWidth);
if (ret != PaddedWidth) {
@ -183,14 +178,11 @@ int read_bmp_file(char* filename,
/* loop though the pixels in this line. */
for (col = 0; col < bitmap_width; col++) {
ret = getpix(col, bmpbuf);
if (ret == 1) {
bitmap[bitmap_width * ((bitmap_height - row - 1) / 8) + col]
&= ~ 1 << ((bitmap_height - row - 1) % 8);
} else {
bitmap[bitmap_width * ((bitmap_height - row - 1) / 8) + col]
|= 1 << ((bitmap_height - row - 1) % 8);
}
ret = (bmpbuf[col/8] & (1 << (7 - (col % 8)))) != 0;
if (ret == 1)
bitmap[bytesel + col] &= ~bitsel;
else
bitmap[bytesel + col] |= bitsel;
}
}
@ -201,5 +193,4 @@ int read_bmp_file(char* filename,
*get_height = bitmap_height;
return (PaddedHeight * bitmap_width); /* return the used buffer size. */
}