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Added SDL_crc32()

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This commit is contained in:
Sam Lantinga
2020-11-16 15:00:15 -08:00
parent 3d48fc05c3
commit 71e32f5e1b
11 changed files with 83 additions and 50 deletions
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25
src/joystick/android/SDL_sysjoystick.c
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@@ -70,28 +70,6 @@ static SDL_joylist_item *SDL_joylist_tail = NULL;
static int numjoysticks = 0;
/* Public domain CRC implementation adapted from:
http://home.thep.lu.se/~bjorn/crc/crc32_simple.c
*/
static Uint32 crc32_for_byte(Uint32 r)
{
int i;
for(i = 0; i < 8; ++i) {
r = (r & 1? 0: (Uint32)0xEDB88320L) ^ r >> 1;
}
return r ^ (Uint32)0xFF000000L;
}
static Uint32 crc32(const void *data, size_t count)
{
Uint32 crc = 0;
int i;
for(i = 0; i < count; ++i) {
crc = crc32_for_byte((Uint8)crc ^ ((const Uint8*)data)[i]) ^ crc >> 8;
}
return crc;
}
/* Function to convert Android keyCodes into SDL ones.
* This code manipulation is done to get a sequential list of codes.
* FIXME: This is only suited for the case where we use a fixed number of buttons determined by ANDROID_MAX_NBUTTONS
@@ -391,7 +369,8 @@ Android_AddJoystick(int device_id, const char *name, const char *desc, int vendo
*guid16++ = SDL_SwapLE16(product_id);
*guid16++ = 0;
} else {
Uint32 crc = crc32(desc, SDL_strlen(desc));
Uint32 crc = 0;
SDL_crc32(crc, desc, SDL_strlen(desc));
SDL_memcpy(guid16, desc, SDL_min(2*sizeof(*guid16), SDL_strlen(desc)));
guid16 += 2;
*(Uint32 *)guid16 = SDL_SwapLE32(crc);