jpeg.h

整理的JPEG解码器

#define M_SOF0  0xc0
#define M_DHT   0xc4
#define M_EOI   0xd9
#define M_SOS   0xda
#define M_DQT   0xdb
#define M_DRI   0xdd
#define M_APP0  0xe0

static int Zig_Zag[8][8]={{0,1,5,6,14,15,27,28},
						  {2,4,7,13,16,26,29,42},
						  {3,8,12,17,25,30,41,43},
						  {9,11,18,24,37,40,44,53},
						  {10,19,23,32,39,45,52,54},
						  {20,22,33,38,46,51,55,60},
						  {21,34,37,47,50,56,59,61},
						  {35,36,48,49,57,58,62,63}
						 };

#define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */
#define W2 2676 /* 2048*sqrt(2)*cos(2*pi/16) */
#define W3 2408 /* 2048*sqrt(2)*cos(3*pi/16) */
#define W5 1609 /* 2048*sqrt(2)*cos(5*pi/16) */
#define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */
#define W7 565  /* 2048*sqrt(2)*cos(7*pi/16) */