zigzag.c

C代码完成jpeg编码和解码

#include "dct.h" 

extern short block[BLOCK_SIZE];

void zigzag(void)
{
	int i;
	short zig[BLOCK_SIZE];

	zig[0] = block[0];
	zig[1] = block[1];
	zig[2] = block[8];
	zig[3] = block[16];
	zig[4] = block[9];
	zig[5] = block[2];
	zig[6] = block[3];
	zig[7] = block[10];
	zig[8] = block[17];
	zig[9] = block[24];
	zig[10] = block[32];
	zig[11] = block[25];
	zig[12] = block[18];
	zig[13] = block[11];
	zig[14] = block[4];
	zig[15] = block[5];
	zig[16] = block[12];
	zig[17] = block[19];
	zig[18] = block[26];
	zig[19] = block[33];
	zig[20] = block[40];
	zig[21] = block[48];
	zig[22] = block[41];
	zig[23] = block[34];
	zig[24] = block[27];
	zig[25] = block[20];
	zig[26] = block[13];
	zig[27] = block[6];
	zig[28] = block[7];
	zig[29] = block[14];
	zig[30] = block[21];
	zig[31] = block[28];
	zig[32] = block[35];
	zig[33] = block[42];
	zig[34] = block[49];
	zig[35] = block[56];
	zig[36] = block[57];
	zig[37] = block[50];
	zig[38] = block[43];
	zig[39] = block[36];
	zig[40] = block[29];
	zig[41] = block[22];
	zig[42] = block[15];
	zig[43] = block[23];
	zig[44] = block[30];
	zig[45] = block[37];
	zig[46] = block[44];
	zig[47] = block[51];
	zig[48] = block[58];
	zig[49] = block[59];
	zig[50] = block[52];
	zig[51] = block[45];
	zig[52] = block[38];
	zig[53] = block[31];
	zig[54] = block[39];
	zig[55] = block[46];
	zig[56] = block[53];
	zig[57] = block[60];
	zig[58] = block[61];
	zig[59] = block[54];
	zig[60] = block[47];
	zig[61] = block[55];
	zig[62] = block[62];
	zig[63] = block[63];

	for(i=0;i<64;i++)
	{
		block[i] = zig[i];
	}
}