cvs.zerfleddert.de Git - rigol/blame_incremental

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Commit	Line	Data
	1	#include <string.h>
	2	#include <stdint.h>
	3	#include <arpa/inet.h>
	4	#include <zlib.h>
	5	#include <stdio.h>
	6	#include <stdlib.h>
	7
	8	#include "png.h"
	9
	10	/* Table of CRCs of all 8-bit messages. */
	11	static unsigned long crc_table[256];
	12
	13	/* Flag: has the table been computed? Initially false. */
	14	static int crc_table_computed = 0;
	15
	16	/* Make the table for a fast CRC. */
	17	static void make_crc_table(void)
	18	{
	19	unsigned long c;
	20	int n, k;
	21
	22	for (n = 0; n < 256; n++) {
	23	c = (unsigned long) n;
	24	for (k = 0; k < 8; k++) {
	25	if (c & 1)
	26	c = 0xedb88320L ^ (c >> 1);
	27	else
	28	c = c >> 1;
	29	}
	30	crc_table[n] = c;
	31	}
	32	crc_table_computed = 1;
	33	}
	34
	35	/* Update a running CRC with the bytes buf[0..len-1]--the CRC
	36	should be initialized to all 1's, and the transmitted value
	37	is the 1's complement of the final running CRC (see the
	38	crc() routine below). */
	39
	40	static unsigned long update_crc(unsigned long crc, unsigned char *buf,
	41	int len)
	42	{
	43	unsigned long c = crc;
	44	int n;
	45
	46	if (!crc_table_computed)
	47	make_crc_table();
	48	for (n = 0; n < len; n++) {
	49	c = crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
	50	}
	51	return c;
	52	}
	53
	54	/* Return the CRC of the bytes buf[0..len-1]. */
	55	static unsigned long crc(unsigned char *buf, int len)
	56	{
	57	return update_crc(0xffffffffL, buf, len) ^ 0xffffffffL;
	58	}
	59
	60	unsigned char lcd2png(unsigned char lcd, int *len)
	61	{
	62	unsigned char screen_conv[3202343];
	63	unsigned char lut[256][3];
	64	unsigned char *image;
	65	unsigned char *outpos;
	66	static const unsigned char png[] = {137, 80, 78, 71, 13, 10, 26, 10};
	67	static unsigned char ihdr[] = {'I', 'H', 'D', 'R',
	68	0x00, 0x00, 0x01, 0x40, /* 320 - Width */
	69	0x00, 0x00, 0x00, 0xea, /* 234 - Height */
	70	0x08, /* Bit depth */
	71	0x02, /* RGB Truecolor, Colour type */
	72	0x00, /* Deflate, Compression method */
	73	0x00, /* None, Filter method */
	74	0x00 /* No interlace, Interlace method */
	75	};
	76	static unsigned char idat[] = {'I', 'D', 'A', 'T'};
	77	static unsigned char iend[] = {'I', 'E', 'N', 'D'};
	78	uint32_t l;
	79	int i;
	80	int toalloc = 0;
	81	z_stream strm;
	82
	83	for(i = 0; i < 256; i++) {
	84	lut[i][0] = ((i >> 6) * 0x55);
	85	lut[i][1] = ((((i >> 3) & 7) * 0x49) >> 1);
	86	lut[i][2] = (((i & 7) * 0x49) >> 1);
	87	}
	88
	89	for(i = 0; i < sizeof(screen_conv); i += 3) {
	90	screen_conv[i] = lut[lcd[i/3]][0];
	91	screen_conv[i+1] = lut[lcd[i/3]][1];
	92	screen_conv[i+2] = lut[lcd[i/3]][2];
	93	}
	94
	95	strm.zalloc = Z_NULL;
	96	strm.zfree = Z_NULL;
	97	strm.opaque = Z_NULL;
	98	if (deflateInit(&strm, 9) != Z_OK) {
	99	perror("deflateInit");
	100	exit(EXIT_FAILURE);
	101	}
	102
	103
	104	image = malloc(3202342); /* TODO: FIXME! */
	105	outpos = image;
	106	memcpy(outpos, png, sizeof(png));
	107	outpos += sizeof(png);
	108
	109	l = htonl(sizeof(ihdr) - 4); /* "IHDR" is not counted */
	110	memcpy(outpos, &l, sizeof(l));
	111	outpos += sizeof(l);
	112	memcpy(outpos, ihdr, sizeof(ihdr));
	113	outpos += sizeof(ihdr);
	114	l = crc(ihdr, sizeof(ihdr));
	115	memcpy(outpos, &l, sizeof(l));
	116	outpos += sizeof(l);
	117
	118	l = htonl(sizeof(iend) - 4); /* "IEND" is not counted */
	119	memcpy(outpos, &l, sizeof(l));
	120	outpos += sizeof(l);
	121	memcpy(outpos, iend, sizeof(iend));
	122	outpos += sizeof(iend);
	123	l = crc(iend, sizeof(iend));
	124	memcpy(outpos, &l, sizeof(l));
	125	outpos += sizeof(l);
	126
	127	*len = (int)(outpos - image);
	128	return image;
	129	}