mirrors
/
OpenRCT2
mirror of https://github.com/OpenRCT2/OpenRCT2.git
2
0
Fork 0
Code Issues Projects Releases Wiki Activity

Added encode functions. Missing check sum calc for end of chunk

This commit is contained in:
Duncan Frost 2014-10-03 20:07:21 +01:00
parent 2ea8d9e4b2
commit 45f9f585f1
1 changed files with 73 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

78
src/sawyercoding.c
View File

@ -28,6 +28,8 @@ static int decode_chunk_rle(uint8* src_buffer, uint8* dst_buffer, int length);
static int decode_chunk_repeat(char *buffer, int length);
static void decode_chunk_rotate(char *buffer, int length);
int encode_chunk_rle(char *src_buffer, char *dst_buffer, int length);
void encode_chunk_rotate(char *buffer, int length);
/**
*
* rct2: 0x00676FD2
@ -195,22 +197,88 @@ static void decode_chunk_rotate(char *buffer, int length)
*
*/
int sawyercoding_write_chunk(FILE *file, uint8* buffer, sawyercoding_chunk_header chunkHeader){
uint8* dst_buffer;
switch (chunkHeader.encoding){
case CHUNK_ENCODING_NONE:
fwrite(&chunkHeader, sizeof(sawyercoding_chunk_header), 1, file);
fwrite(buffer, 1, chunkHeader.length, file);
break;
case CHUNK_ENCODING_RLE:
//chunkHeader.length = decode_chunk_rle(src_buffer, buffer, chunkHeader.length);
dst_buffer = malloc(0x600000);
chunkHeader.length = encode_chunk_rle(buffer, dst_buffer, chunkHeader.length);
fwrite(&chunkHeader, sizeof(sawyercoding_chunk_header), 1, file);
fwrite(dst_buffer, 1, chunkHeader.length, file);
free(dst_buffer);
break;
case CHUNK_ENCODING_RLECOMPRESSED:
//chunkHeader.length = decode_chunk_rle(src_buffer, buffer, chunkHeader.length);
//chunkHeader.length = decode_chunk_repeat(buffer, chunkHeader.length);
break;
case CHUNK_ENCODING_ROTATE:
//memcpy(buffer, src_buffer, chunkHeader.length);
//decode_chunk_rotate(buffer, chunkHeader.length);
encode_chunk_rotate(buffer, chunkHeader.length);
fwrite(&chunkHeader, sizeof(sawyercoding_chunk_header), 1, file);
fwrite(buffer, 1, chunkHeader.length, file);
break;
}
}
return chunkHeader.length;
}
/**
* Ensure dst_buffer is bigger than src_buffer then resize afterwards
* returns length of dst_buffer
*/
int encode_chunk_rle(char *src_buffer, char *dst_buffer, int length)
{
char* src = src_buffer;
char* dst = dst_buffer;
char* end_src = src + length;
uint8 count = 0;
char* src_norm_start = src;
while (src < end_src - 1){
if ((count && *src == src[1]) || count > 126){
*dst++ = count;
for (; count != 0; --count){
*dst++ = *src_norm_start++;
}
}
if (*src == src[1]){
for (; (count < 127) && ((src + count) < end_src); count++){
if (*src != src[count]) break;
}
*dst++ = 257 - count;
*dst++ = *src;
src += count;
src_norm_start = src;
count = 0;
}
else{
count++;
src++;
}
}
if (src == end_src - 1)count++;
if (count){
*dst++ = count;
for (; count != 0; --count){
*dst++ = *src_norm_start++;
}
}
return dst - dst_buffer;
}
/**
*
*
*/
void encode_chunk_rotate(char *buffer, int length)
{
int i, code = 1;
for (i = 0; i < length; i++) {
buffer[i] = rol8(buffer[i], code);
code = (code + 2) % 8;
}
}