📄 irom_decodegifimage_arm.c
字号:
///////////////////////////////////////////////////////////////////////////////
//
// decode_image.c
//
// DESCRIPTION
// Define function for LZW decoding.
//
//
///////////////////////////////////////////////////////////////////////////////
/*
Include declarations.
*/
#include "OPUS_typedef.h"
#include "irom_gifheader.h"
#include "irom_gifdefine.h"
#include "irom_gifclassify.h"
#include "irom_gifimage.h"
#define EROM_TARGET
// inline functions
// generic bistream read function
__inline unsigned int myReadBlob
(
Image *image,
const unsigned int length,
unsigned char **data
)
{
unsigned int count;
count = Min(length, image->blob->length - image->blob->offset);
if(count != 0)
{
*data = image->blob->data + image->blob->offset;
image->blob->offset += count;
}
return(count);
}
// read a byte from bitstream
__inline int myReadBlobByte
(
Image *image
)
{
unsigned int count;
unsigned char *tp;
unsigned char **p;
p = &tp;
count = myReadBlob(image, 1, p);
if (count == 0)
{
return(0);
}
return(*tp);
}
// read a block from bitstream
__inline unsigned int myReadBlobBlock
(
Image *image,
unsigned char **data
)
{
unsigned char *tp;
unsigned char **p;
unsigned int count;
p = &tp;
count = myReadBlob(image, 1, p);
if (count == 0)
{
return(0);
}
return(myReadBlob(image, *tp, data));
}
/////////////////////////////////////////////////////////////////////////////
// NAME
// DecodeGIFImage
//
// DESCRIPTION
// uncompresses an image via GIF-coding
//
// INPUTS
// image - the address of a structure of type Image
// opacity - The colormap index associated with the transparent color
// func - callback function to determine if we need to continue
//
// OUTPUTS
// none
//
// RETURN VALUE
// returns True if all the pixels are uncompressed without error,
// otherwise False.
//
/////////////////////////////////////////////////////////////////////////////
unsigned int DecodeGIFImage
(
Image *image,
const long opacity,
OP_BOOLEAN func(OP_UINT16 x, OP_UINT16 y)
)
{
#define MaxStackSize 4096
#define NullCode (-1)
int bits;
int code_size;
int offset;
int pass;
long available;
long code_mask;
long end_of_information;
long in_code;
long old_code;
long y;
register long code;
register long clear;
register long columns;
register long x;
register unsigned int *map;
register unsigned int *q;
register unsigned char *c;
register unsigned long datum;
register unsigned int count;
register short *prefix;
unsigned char data_size;
unsigned char first;
unsigned char *tp;
unsigned char **pp;
unsigned char *pixel_stack;
register unsigned char *top_stack;
register unsigned char *suffix;
#ifndef EROM_TARGET
IROM_CODE_CHECK_FEATURE_LOCK(FEATURE_LOCK_CHECK_MP3_JPEG);
#endif //EROM_TARGET
pp = &tp;
map = (unsigned int*)image->colormap;
columns = image->columns;
#ifndef EROM_TARGET
IROM_CODE_CHECK_FEATURE_LOCK(FEATURE_LOCK_CHECK_MP3_JPEG);
#endif //EROM_TARGET
/*
Allocate decoder tables.
*/
prefix = (short *) image->getmemory(MaxStackSize*sizeof(short));
suffix = (unsigned char *) image->getmemory(MaxStackSize);
pixel_stack = (unsigned char *) image->getmemory(MaxStackSize+1);
#ifndef EROM_TARGET
IROM_CODE_CHECK_FEATURE_LOCK(FEATURE_LOCK_CHECK_MP3_JPEG);
#endif //EROM_TARGET
if ((prefix == (short *) OP_NULL) || (suffix == (unsigned char *) OP_NULL) ||
(pixel_stack == (unsigned char *) OP_NULL))
{
if(pixel_stack != OP_NULL)
{
image->freememory(pixel_stack);
}
if(suffix != OP_NULL)
{
image->freememory(suffix);
}
if(prefix != OP_NULL)
{
image->freememory(prefix);
}
return OP_FALSE;
}
#ifndef EROM_TARGET
IROM_CODE_CHECK_FEATURE_LOCK(FEATURE_LOCK_CHECK_MP3_JPEG);
#endif //EROM_TARGET
/*
Initialize GIF data stream decoder.
*/
data_size = myReadBlobByte(image);
if (data_size > 8)
{
image->freememory(pixel_stack);
image->freememory(suffix);
image->freememory(prefix);
return OP_FALSE;
}
#ifndef EROM_TARGET
IROM_CODE_CHECK_FEATURE_LOCK(FEATURE_LOCK_CHECK_MP3_JPEG);
#endif //EROM_TARGET
clear = 1 << data_size;
end_of_information = clear+1;
available = clear+2;
old_code = NullCode;
code_size = data_size+1;
code_mask = (1 << code_size)-1;
#ifndef EROM_TARGET
IROM_CODE_CHECK_FEATURE_LOCK(FEATURE_LOCK_CHECK_MP3_JPEG);
#endif //EROM_TARGET
for (code=0; code < clear; code++)
{
prefix[code] = 0;
suffix[code] = (unsigned char) code;
}
#ifndef EROM_TARGET
IROM_CODE_CHECK_FEATURE_LOCK(FEATURE_LOCK_CHECK_MP3_JPEG);
#endif //EROM_TARGET
/*
Decode GIF pixel stream.
*/
datum = 0;
bits = 0;
c = 0;
count = 0;
first = 0;
offset = 0;
pass = 0;
top_stack = pixel_stack;
#ifndef EROM_TARGET
IROM_CODE_CHECK_FEATURE_LOCK(FEATURE_LOCK_CHECK_MP3_JPEG);
#endif //EROM_TARGET
for (y=0; y < (long) image->rows; y++)
{
// check if we need to continue
if(func != OP_NULL)
{
if(!func(x, y))
{
break;
}
}
if(image->pixeldata == OP_NULL)
{
q = OP_NULL;
}
q = (unsigned int*)(image->pixeldata + image->columns * offset);
if (q == (unsigned int *) OP_NULL)
{
break;
}
for (x=0; x < columns; )
{
if (top_stack == pixel_stack)
{
if (bits < code_size)
{
/*
Load bytes until there is enough bits for a code.
*/
if (count == 0)
{
/*
Read a new data block.
*/
count = myReadBlobBlock(image,pp);
c = *pp;
if (count == 0)
{
break;
}
}
datum += (unsigned long) (*c++) << bits;
bits += 8;
count--;
if(count != 0)
{
datum += (unsigned long) (*c++) << bits;
bits += 8;
count--;
}
else
{
continue;
}
}
/*
Get the next code.
*/
code = (long) (datum & code_mask);
datum >>= code_size;
bits -= code_size;
/*
Interpret the code
*/
if ((code > available) || (code == end_of_information))
{
break;
}
if (code == clear)
{
/*
Reset decoder.
*/
code_size = data_size+1;
code_mask = (1 << code_size)-1;
available = clear+2;
old_code = NullCode;
continue;
}
if (old_code == NullCode)
{
*top_stack++ = suffix[code];
old_code = code;
first = (unsigned char) code;
continue;
}
in_code = code;
if (code >= available)
{
*top_stack++ = first;
code = old_code;
}
while (code >= clear)
{
*top_stack++ = suffix[code];
code = prefix[code];
}
first = suffix[code];
/*
Add a new string to the string table,
*/
if (available >= MaxStackSize)
{
break;
}
*top_stack++ = first;
prefix[available] = (short) old_code;
suffix[available] = first;
available++;
if (((available & code_mask) == 0) && (available < MaxStackSize))
{
code_size++;
code_mask += available;
}
old_code = in_code;
}
/*
Pop a pixel off the pixel stack.
*/
top_stack--;
*q = map[*top_stack];
*q = (*q & 0x00ffffffL) |
((unsigned int)(*top_stack == opacity ? TransparentOpacity : OpaqueOpacity)) << 24;
x++;
q++;
}
if (image->interlace == NoInterlace)
{
offset++;
}
else
{
switch (pass)
{
case 0:
default:
{
offset += 8;
if (offset >= (long) image->rows)
{
pass++;
offset = 4;
}
break;
}
case 1:
{
offset += 8;
if (offset >= (long) image->rows)
{
pass++;
offset = 2;
}
break;
}
case 2:
{
offset += 4;
if (offset >= (long) image->rows)
{
pass++;
offset = 1;
}
break;
}
case 3:
{
offset += 2;
break;
}
}
}
if (x < (long) image->columns)
{
break;
}
}
#ifndef EROM_TARGET
IROM_CODE_CHECK_FEATURE_LOCK(FEATURE_LOCK_CHECK_MP3_JPEG);
#endif //EROM_TARGET
image->freememory(pixel_stack);
image->freememory(suffix);
image->freememory(prefix);
#ifndef EROM_TARGET
IROM_CODE_CHECK_FEATURE_LOCK(FEATURE_LOCK_CHECK_MP3_JPEG);
#endif //EROM_TARGET
if (y < (long) image->rows)
{
return OP_FALSE;
}
return(OP_TRUE);
}
/////////////////////////////////////////////////////////////////////////////
// NAME
// skip_decoding_datablock
//
// DESCRIPTION
// uncompresses an image via GIF-coding
//
// INPUTS
// image - the address of a structure of type Image
// opacity - The colormap index associated with the transparent color
// func - callback function to determine if we need to continue
//
// OUTPUTS
// none
//
// RETURN VALUE
// returns True if all the pixels are uncompressed without error,
// otherwise False.
//
/////////////////////////////////////////////////////////////////////////////
unsigned int skip_decoding_datablock
(
Image *image
)
{
unsigned char data_size;
unsigned char *tp;
unsigned char **pp;
unsigned int count;
pp = &tp;
/*
Initialize GIF data stream decoder.
*/
data_size = myReadBlobByte(image);
if (data_size > 8)
{
return OP_FALSE;
}
/*
Read a new data block.
*/
for ( ; ; )
{
count = myReadBlobBlock(image,pp);
if (count == 0)
{
image->blob->offset -= 1;
break;
}
}
return(OP_TRUE);
}
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -