m/grafX2
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

move PackBits packing code to packbits.c

Browse Source 
new functions :
- PackBits_pack_init()
- PackBits_pack_add()
- PackBits_pack_flush()
This commit is contained in:
Thomas Bernard
2020-01-01 23:17:41 +01:00
parent e656139f93
commit 0dcee6acc3
5 changed files with 188 additions and 120 deletions
Download Patch File Download Diff File Expand all files Collapse all files

113
src/packbits.c
View File

@@ -28,6 +28,7 @@
#include <stdio.h>
#include <string.h>
#include "struct.h"
#include "io.h"
#include "gfx2log.h"
#include "packbits.h"
@@ -67,3 +68,115 @@ int PackBits_unpack_from_file(FILE * f, byte * dest, unsigned int count)
}
return PACKBITS_UNPACK_OK;
}
void PackBits_pack_init(T_PackBits_data * data, FILE * f)
{
memset(data, 0, sizeof(T_PackBits_data));
data->f = f;
}
int PackBits_pack_add(T_PackBits_data * data, byte b)
{
switch (data->list_size)
{
case 0 : // First color
data->list[0] = b;
data->list_size = 1;
break;
case 1 : // second color
data->repetition_mode = (data->list[0] == b);
data->list[1] = b;
data->list_size = 2;
break;
default: // next colors
if (data->list[data->list_size - 1] == b) // repeat detected
{
if ( !data->repetition_mode && data->list_size >= 127)
{
// diff mode with 126 bytes then 2 identical bytes
data->list_size--;
if (PackBits_pack_flush(data) < 0)
return -1;
data->list[0] = b;
data->list[1] = b;
data->list_size = 2;
data->repetition_mode = 1;
}
else if ((data->repetition_mode) || (data->list[data->list_size - 2] != b))
{
// same mode is kept
if (data->list_size == 128)
{
if (PackBits_pack_flush(data) < 0)
return -1;
}
data->list[data->list_size++] = b;
}
else
{
// diff mode and 3 identical bytes
data->list_size -= 2;
if (PackBits_pack_flush(data) < 0)
return -1;
data->list[0] = b;
data->list[1] = b;
data->list[2] = b;
data->list_size = 3;
data->repetition_mode = 1;
}
}
else // the color is different from the previous one
{
if (!data->repetition_mode) // keep mode
{
if (data->list_size == 128)
{
if (PackBits_pack_flush(data) < 0)
return -1;
}
data->list[data->list_size++] = b;
}
else // change mode
{
if (PackBits_pack_flush(data) < 0)
return -1;
data->list[data->list_size++] = b;
}
}
}
return 0; // OK
}
int PackBits_pack_flush(T_PackBits_data * data)
{
if (data->list_size > 0)
{
if (data->list_size > 128)
{
GFX2_Log(GFX2_ERROR, "PackBits_pack_flush() list_size=%d !\n", data->list_size);
}
if (data->repetition_mode)
{
if (data->f != NULL)
{
if (!Write_byte(data->f, 257 - data->list_size) ||
!Write_byte(data->f, data->list[0]))
return -1;
}
data->output_count += 2;
}
else
{
if (data->f != NULL)
{
if (!Write_byte(data->f, data->list_size - 1) ||
!Write_bytes(data->f, data->list, data->list_size))
return -1;
}
data->output_count += 1 + data->list_size;
}
data->list_size = 0;
data->repetition_mode = 0;
}
return data->output_count;
}