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-rw-r--r--jpg/jpg.c948
1 files changed, 948 insertions, 0 deletions
diff --git a/jpg/jpg.c b/jpg/jpg.c
new file mode 100644
index 0000000..c4a9bac
--- /dev/null
+++ b/jpg/jpg.c
@@ -0,0 +1,948 @@
+#include "jpg.h"
+
+#define ERR_NO_SOI 1
+#define ERR_NOT_8BIT 2
+#define ERR_HEIGHT_MISMATCH 3
+#define ERR_WIDTH_MISMATCH 4
+#define ERR_BAD_WIDTH_OR_HEIGHT 5
+#define ERR_TOO_MANY_COMPPS 6
+#define ERR_ILLEGAL_HV 7
+#define ERR_QUANT_TABLE_SELECTOR 8
+#define ERR_NOT_YCBCR_221111 9
+#define ERR_UNKNOWN_CID_IN_SCAN 10
+#define ERR_NOT_SEQUENTIAL_DCT 11
+#define ERR_WRONG_MARKER 12
+#define ERR_NO_EOI 13
+#define ERR_BAD_TABLES 14
+#define ERR_DEPTH_MISMATCH 15
+
+#define ISHIFT 11
+
+#define IFIX(a) ((int)((a) * (1 << ISHIFT) + .5))
+#define IMULT(a, b) (((a) * (b)) >> ISHIFT)
+#define ITOINT(a) ((a) >> ISHIFT)
+
+#ifndef __P
+# define __P(x) x
+#endif
+
+/* special markers */
+#define M_BADHUFF -1
+#define M_EOF 0x80
+
+struct in {
+ unsigned int bits;
+ int left;
+ int marker;
+ void *data;
+};
+
+/*********************************/
+struct dec_hufftbl;
+struct enc_hufftbl;
+
+union hufftblp {
+ struct dec_hufftbl *dhuff;
+ struct enc_hufftbl *ehuff;
+};
+
+struct scan {
+ int dc; /* old dc value */
+
+ union hufftblp hudc;
+ union hufftblp huac;
+ int next; /* when to switch to next scan */
+
+ int cid; /* component id */
+ int hv; /* horiz/vert, copied from comp */
+ int tq; /* quant tbl, copied from comp */
+};
+
+/*********************************/
+
+#define DECBITS 8 /* seems to be the optimum */
+
+struct dec_hufftbl {
+ int maxcode[17];
+ int valptr[16];
+ unsigned char vals[256];
+ unsigned int llvals[1 << DECBITS];
+};
+
+struct jpeg_decdata {
+ int dcts[6 * 64 + 16];
+ int out[64 * 6];
+ int dquant[3][64];
+};
+
+static void decode_mcus __P((struct in *, int *, int, struct scan *, int *));
+static void dec_makehuff __P((struct dec_hufftbl *, int *, unsigned char *));
+
+static void setinput __P((struct in *));
+/*********************************/
+
+#undef PREC
+#define PREC int
+
+static void idctqtab __P((unsigned char *, PREC *));
+static void idct __P((int *, int *, PREC *, PREC, int));
+static void scaleidctqtab __P((PREC *, PREC));
+
+/*********************************/
+
+static void initcol __P((PREC[][64]));
+
+static void col221111(int *out, unsigned char *pic, int width, int bits);
+static unsigned char tmp_img[16*16*4]; /* 16 x 16, 32 bit color */
+
+/*********************************/
+
+#define M_SOI 0xd8
+#define M_APP0 0xe0
+#define M_DQT 0xdb
+#define M_SOF0 0xc0
+#define M_DHT 0xc4
+#define M_DRI 0xdd
+#define M_SOS 0xda
+#define M_RST0 0xd0
+#define M_EOI 0xd9
+#define M_COM 0xfe
+
+static unsigned char *datap;
+static struct jpeg_decdata decdata;
+
+static void memset(void *p, int c, int n)
+{
+ unsigned char *x = p;
+
+ while(n--) *x++ = c;
+}
+
+
+static int getbyte(void)
+{
+ return *datap++;
+}
+
+static int getword(void)
+{
+ int c1, c2;
+ c1 = *datap;
+ c2 = datap[1];
+ datap += 2;
+ return c1 << 8 | c2;
+}
+
+struct comp {
+ int cid;
+ int hv;
+ int tq;
+};
+
+#define MAXCOMP 4
+struct jpginfo {
+ int nc; /* number of components */
+ int ns; /* number of scans */
+ int dri; /* restart interval */
+};
+
+static struct jpginfo info;
+static struct comp comps[MAXCOMP];
+
+static struct scan dscans[MAXCOMP];
+
+static unsigned char quant[4][64];
+
+static struct dec_hufftbl dhuff[4];
+
+#define dec_huffdc (dhuff + 0)
+#define dec_huffac (dhuff + 2)
+
+static struct in in;
+
+static int readtables(int till)
+{
+ int m, l, i, j, lq, pq, tq;
+ int tc, th, tt;
+
+ for (;;) {
+ if (getbyte() != 0xff)
+ return -1;
+ if ((m = getbyte()) == till)
+ break;
+
+ switch (m) {
+ case 0xc2:
+ return 0;
+
+ case M_DQT:
+ lq = getword();
+ while (lq > 2) {
+ pq = getbyte();
+ tq = pq & 15;
+ if (tq > 3)
+ return -1;
+ pq >>= 4;
+ if (pq != 0)
+ return -1;
+ for (i = 0; i < 64; i++)
+ quant[tq][i] = getbyte();
+ lq -= 64 + 1;
+ }
+ break;
+
+ case M_DHT:
+ l = getword();
+ while (l > 2) {
+ int hufflen[16], k;
+ unsigned char huffvals[256];
+
+ tc = getbyte();
+ th = tc & 15;
+ tc >>= 4;
+ tt = tc * 2 + th;
+ if (tc > 1 || th > 1)
+ return -1;
+ for (i = 0; i < 16; i++)
+ hufflen[i] = getbyte();
+ l -= 1 + 16;
+ k = 0;
+ for (i = 0; i < 16; i++) {
+ for (j = 0; j < hufflen[i]; j++)
+ huffvals[k++] = getbyte();
+ l -= hufflen[i];
+ }
+ dec_makehuff(dhuff + tt, hufflen,
+ huffvals);
+ }
+ break;
+
+ case M_DRI:
+ l = getword();
+ info.dri = getword();
+ break;
+
+ default:
+ l = getword();
+ while (l-- > 2)
+ getbyte();
+ break;
+ }
+ }
+ return 0;
+}
+
+static void dec_initscans(void)
+{
+ int i;
+
+ for (i = 0; i < info.ns; i++)
+ dscans[i].dc = 0;
+}
+
+int jpeg_decode(unsigned char *buf, unsigned char *pic, int x0, int x1, int y0, int y1, int color_bits)
+{
+ int i, j, m, tac, tdc;
+ int mcusx, mcusy, mx, my;
+ int max[6];
+ int width, height;
+ int mx0, mx1, my0, my1;
+
+ datap = buf;
+ if (getbyte() != 0xff)
+ return ERR_NO_SOI;
+ if (getbyte() != M_SOI)
+ return ERR_NO_SOI;
+ if (readtables(M_SOF0))
+ return ERR_BAD_TABLES;
+ if(info.dri) return ERR_WRONG_MARKER;
+
+ getword();
+ i = getbyte();
+ if (i != 8)
+ return ERR_NOT_8BIT;
+
+ height = getword();
+ width = getword();
+
+ info.nc = getbyte();
+ if (info.nc > MAXCOMP)
+ return ERR_TOO_MANY_COMPPS;
+ for (i = 0; i < info.nc; i++) {
+ int h, v;
+ comps[i].cid = getbyte();
+ comps[i].hv = getbyte();
+ v = comps[i].hv & 15;
+ h = comps[i].hv >> 4;
+ comps[i].tq = getbyte();
+ if (h > 3 || v > 3)
+ return ERR_ILLEGAL_HV;
+ if (comps[i].tq > 3)
+ return ERR_QUANT_TABLE_SELECTOR;
+ }
+ if (readtables(M_SOS))
+ return ERR_BAD_TABLES;
+ getword();
+ info.ns = getbyte();
+ if (info.ns != 3)
+ return ERR_NOT_YCBCR_221111;
+ for (i = 0; i < 3; i++) {
+ dscans[i].cid = getbyte();
+ tdc = getbyte();
+ tac = tdc & 15;
+ tdc >>= 4;
+ if (tdc > 1 || tac > 1)
+ return ERR_QUANT_TABLE_SELECTOR;
+ for (j = 0; j < info.nc; j++)
+ if (comps[j].cid == dscans[i].cid)
+ break;
+ if (j == info.nc)
+ return ERR_UNKNOWN_CID_IN_SCAN;
+ dscans[i].hv = comps[j].hv;
+ dscans[i].tq = comps[j].tq;
+ dscans[i].hudc.dhuff = dec_huffdc + tdc;
+ dscans[i].huac.dhuff = dec_huffac + tac;
+ }
+
+ i = getbyte();
+ j = getbyte();
+ m = getbyte();
+
+ if (i != 0 || j != 63 || m != 0)
+ return ERR_NOT_SEQUENTIAL_DCT;
+
+ if (dscans[0].cid != 1 || dscans[1].cid != 2 || dscans[2].cid != 3)
+ return ERR_NOT_YCBCR_221111;
+
+ if (dscans[0].hv != 0x22 || dscans[1].hv != 0x11 || dscans[2].hv != 0x11)
+ return ERR_NOT_YCBCR_221111;
+
+ mcusx = (width + 15) >> 4;
+ mcusy = (height + 15) >> 4;
+
+ mx0 = x0 >> 4;
+ my0 = y0 >> 4;
+
+ /* inclusive! */
+ mx1 = ((x1 + 15) >> 4) - 1;
+ my1 = ((y1 + 15) >> 4) - 1;
+
+ if(my1 < mcusy) mcusy = my1 + 1;
+
+ idctqtab(quant[dscans[0].tq], decdata.dquant[0]);
+ idctqtab(quant[dscans[1].tq], decdata.dquant[1]);
+ idctqtab(quant[dscans[2].tq], decdata.dquant[2]);
+ initcol(decdata.dquant);
+ setinput(&in);
+
+ dec_initscans();
+
+ dscans[0].next = 6 - 4;
+ dscans[1].next = 6 - 4 - 1;
+ dscans[2].next = 6 - 4 - 1 - 1; /* 411 encoding */
+ for (my = 0; my < mcusy; my++) {
+ for (mx = 0; mx < mcusx; mx++) {
+ decode_mcus(&in, decdata.dcts, 6, dscans, max);
+
+ if(
+ my >= my0 && my <= my1 &&
+ mx >= mx0 && mx <= mx1
+ ) {
+ int i0, i1, j0, j1, yofs;
+
+ idct(decdata.dcts, decdata.out, decdata.dquant[0], IFIX(128.5), max[0]);
+ idct(decdata.dcts + 64, decdata.out + 64, decdata.dquant[0], IFIX(128.5), max[1]);
+ idct(decdata.dcts + 128, decdata.out + 128, decdata.dquant[0], IFIX(128.5), max[2]);
+ idct(decdata.dcts + 192, decdata.out + 192, decdata.dquant[0], IFIX(128.5), max[3]);
+ idct(decdata.dcts + 256, decdata.out + 256, decdata.dquant[1], IFIX(0.5), max[4]);
+ idct(decdata.dcts + 320, decdata.out + 320, decdata.dquant[2], IFIX(0.5), max[5]);
+
+ // color_bits * 2: actually 16 * (color_bits / 8)
+ col221111(decdata.out, tmp_img, color_bits * 2, color_bits);
+
+ j0 = my == my0 ? y0 - 16 * my : 0;
+ j1 = my == my1 ? y1 - 16 * my : 16;
+ for(j = j0; j < j1; j++) {
+ yofs = (16 * my - y0 + j) * (x1 - x0);
+ i0 = mx == mx0 ? x0 - 16 * mx : 0;
+ i1 = mx == mx1 ? x1 - 16 * mx : 16;
+
+ switch(color_bits) {
+ case 8:
+ for(i = i0; i < i1; i++) {
+ *((unsigned char *) pic + 16 * mx - x0 + i + yofs) =
+ *((unsigned char *) tmp_img + 16 * j + i);
+ }
+ break;
+
+ case 16:
+ for(i = i0; i < i1; i++) {
+ *((unsigned short *) pic + 16 * mx - x0 + i + yofs) =
+ *((unsigned short *) tmp_img + 16 * j + i);
+ }
+ break;
+
+ case 32:
+ for(i = i0; i < i1; i++) {
+ *((unsigned *) pic + 16 * mx - x0 + i + yofs) =
+ *((unsigned *) tmp_img + 16 * j + i);
+ }
+ break;
+ }
+ }
+ }
+ }
+ }
+
+ return 0;
+}
+
+/****************************************************************/
+/************** huffman decoder ***************/
+/****************************************************************/
+
+static int fillbits __P((struct in *, int, unsigned int));
+static int dec_rec2
+__P((struct in *, struct dec_hufftbl *, int *, int, int));
+
+static void setinput(in)
+struct in *in;
+{
+ in->left = 0;
+ in->bits = 0;
+ in->marker = 0;
+}
+
+static int fillbits(in, le, bi)
+struct in *in;
+int le;
+unsigned int bi;
+{
+ int b, m;
+
+ if (in->marker) {
+ if (le <= 16)
+ in->bits = bi << 16, le += 16;
+ return le;
+ }
+ while (le <= 24) {
+ b = getbyte();
+ if (b == 0xff && (m = getbyte()) != 0) {
+ in->marker = m;
+ if (le <= 16)
+ bi = bi << 16, le += 16;
+ break;
+ }
+ bi = bi << 8 | b;
+ le += 8;
+ }
+ in->bits = bi; /* tmp... 2 return values needed */
+ return le;
+}
+
+#define LEBI_DCL int le, bi
+#define LEBI_GET(in) (le = in->left, bi = in->bits)
+#define LEBI_PUT(in) (in->left = le, in->bits = bi)
+
+#define GETBITS(in, n) ( \
+ (le < (n) ? le = fillbits(in, le, bi), bi = in->bits : 0), \
+ (le -= (n)), \
+ bi >> le & ((1 << (n)) - 1) \
+)
+
+#define UNGETBITS(in, n) ( \
+ le += (n) \
+)
+
+
+static int dec_rec2(in, hu, runp, c, i)
+struct in *in;
+struct dec_hufftbl *hu;
+int *runp;
+int c, i;
+{
+ LEBI_DCL;
+
+ LEBI_GET(in);
+ if (i) {
+ UNGETBITS(in, i & 127);
+ *runp = i >> 8 & 15;
+ i >>= 16;
+ } else {
+ for (i = DECBITS; (c = ((c << 1) | GETBITS(in, 1))) >= (hu->maxcode[i]); i++);
+ if (i >= 16) {
+ in->marker = M_BADHUFF;
+ return 0;
+ }
+ i = hu->vals[hu->valptr[i] + c - hu->maxcode[i - 1] * 2];
+ *runp = i >> 4;
+ i &= 15;
+ }
+ if (i == 0) { /* sigh, 0xf0 is 11 bit */
+ LEBI_PUT(in);
+ return 0;
+ }
+ /* receive part */
+ c = GETBITS(in, i);
+ if (c < (1 << (i - 1)))
+ c += (-1 << i) + 1;
+ LEBI_PUT(in);
+ return c;
+}
+
+#define DEC_REC(in, hu, r, i) ( \
+ r = GETBITS(in, DECBITS), \
+ i = hu->llvals[r], \
+ i & 128 ? \
+ ( \
+ UNGETBITS(in, i & 127), \
+ r = i >> 8 & 15, \
+ i >> 16 \
+ ) \
+ : \
+ ( \
+ LEBI_PUT(in), \
+ i = dec_rec2(in, hu, &r, r, i), \
+ LEBI_GET(in), \
+ i \
+ ) \
+)
+
+static void decode_mcus(in, dct, n, sc, maxp)
+struct in *in;
+int *dct;
+int n;
+struct scan *sc;
+int *maxp;
+{
+ struct dec_hufftbl *hu;
+ int i, r, t;
+ LEBI_DCL;
+
+ memset(dct, 0, n * 64 * sizeof(*dct));
+ LEBI_GET(in);
+ while (n-- > 0) {
+ hu = sc->hudc.dhuff;
+ *dct++ = (sc->dc += DEC_REC(in, hu, r, t));
+
+ hu = sc->huac.dhuff;
+ i = 63;
+ while (i > 0) {
+ t = DEC_REC(in, hu, r, t);
+ if (t == 0 && r == 0) {
+ dct += i;
+ break;
+ }
+ dct += r;
+ *dct++ = t;
+ i -= r + 1;
+ }
+ *maxp++ = 64 - i;
+ if (n == sc->next)
+ sc++;
+ }
+ LEBI_PUT(in);
+}
+
+static void dec_makehuff(hu, hufflen, huffvals)
+struct dec_hufftbl *hu;
+int *hufflen;
+unsigned char *huffvals;
+{
+ int code, k, i, j, d, x, c, v;
+ for (i = 0; i < (1 << DECBITS); i++)
+ hu->llvals[i] = 0;
+
+/*
+ * llvals layout:
+ *
+ * value v already known, run r, backup u bits:
+ * vvvvvvvvvvvvvvvv 0000 rrrr 1 uuuuuuu
+ * value unknown, size b bits, run r, backup u bits:
+ * 000000000000bbbb 0000 rrrr 0 uuuuuuu
+ * value and size unknown:
+ * 0000000000000000 0000 0000 0 0000000
+ */
+ code = 0;
+ k = 0;
+ for (i = 0; i < 16; i++, code <<= 1) { /* sizes */
+ hu->valptr[i] = k;
+ for (j = 0; j < hufflen[i]; j++) {
+ hu->vals[k] = *huffvals++;
+ if (i < DECBITS) {
+ c = code << (DECBITS - 1 - i);
+ v = hu->vals[k] & 0x0f; /* size */
+ for (d = 1 << (DECBITS - 1 - i); --d >= 0;) {
+ if (v + i < DECBITS) { /* both fit in table */
+ x = d >> (DECBITS - 1 - v -
+ i);
+ if (v && x < (1 << (v - 1)))
+ x += (-1 << v) + 1;
+ x = x << 16 | (hu-> vals[k] & 0xf0) << 4 |
+ (DECBITS - (i + 1 + v)) | 128;
+ } else
+ x = v << 16 | (hu-> vals[k] & 0xf0) << 4 |
+ (DECBITS - (i + 1));
+ hu->llvals[c | d] = x;
+ }
+ }
+ code++;
+ k++;
+ }
+ hu->maxcode[i] = code;
+ }
+ hu->maxcode[16] = 0x20000; /* always terminate decode */
+}
+
+/****************************************************************/
+/************** idct ***************/
+/****************************************************************/
+
+#define ONE ((PREC)IFIX(1.))
+#define S2 ((PREC)IFIX(0.382683432))
+#define C2 ((PREC)IFIX(0.923879532))
+#define C4 ((PREC)IFIX(0.707106781))
+
+#define S22 ((PREC)IFIX(2 * 0.382683432))
+#define C22 ((PREC)IFIX(2 * 0.923879532))
+#define IC4 ((PREC)IFIX(1 / 0.707106781))
+
+#define C3IC1 ((PREC)IFIX(0.847759065)) /* c3/c1 */
+#define C5IC1 ((PREC)IFIX(0.566454497)) /* c5/c1 */
+#define C7IC1 ((PREC)IFIX(0.198912367)) /* c7/c1 */
+
+#define XPP(a,b) (t = a + b, b = a - b, a = t)
+#define XMP(a,b) (t = a - b, b = a + b, a = t)
+#define XPM(a,b) (t = a + b, b = b - a, a = t)
+
+#define ROT(a,b,s,c) ( t = IMULT(a + b, s), \
+ a = IMULT(a, c - s) + t, \
+ b = IMULT(b, c + s) - t)
+
+#define IDCT \
+( \
+ XPP(t0, t1), \
+ XMP(t2, t3), \
+ t2 = IMULT(t2, IC4) - t3, \
+ XPP(t0, t3), \
+ XPP(t1, t2), \
+ XMP(t4, t7), \
+ XPP(t5, t6), \
+ XMP(t5, t7), \
+ t5 = IMULT(t5, IC4), \
+ ROT(t4, t6, S22, C22),\
+ t6 -= t7, \
+ t5 -= t6, \
+ t4 -= t5, \
+ XPP(t0, t7), \
+ XPP(t1, t6), \
+ XPP(t2, t5), \
+ XPP(t3, t4) \
+)
+
+static unsigned char zig2[64] = {
+ 0, 2, 3, 9, 10, 20, 21, 35,
+ 14, 16, 25, 31, 39, 46, 50, 57,
+ 5, 7, 12, 18, 23, 33, 37, 48,
+ 27, 29, 41, 44, 52, 55, 59, 62,
+ 15, 26, 30, 40, 45, 51, 56, 58,
+ 1, 4, 8, 11, 19, 22, 34, 36,
+ 28, 42, 43, 53, 54, 60, 61, 63,
+ 6, 13, 17, 24, 32, 38, 47, 49
+};
+
+void idct(in, out, quant, off, max)
+int *in;
+int *out;
+PREC *quant;
+PREC off;
+int max;
+{
+ PREC t0, t1, t2, t3, t4, t5, t6, t7, t;
+ PREC tmp[64], *tmpp;
+ int i, j;
+ unsigned char *zig2p;
+
+ t0 = off;
+ if (max == 1) {
+ t0 += in[0] * quant[0];
+ for (i = 0; i < 64; i++)
+ out[i] = ITOINT(t0);
+ return;
+ }
+ zig2p = zig2;
+ tmpp = tmp;
+ for (i = 0; i < 8; i++) {
+ j = *zig2p++;
+ t0 += in[j] * quant[j];
+ j = *zig2p++;
+ t5 = in[j] * quant[j];
+ j = *zig2p++;
+ t2 = in[j] * quant[j];
+ j = *zig2p++;
+ t7 = in[j] * quant[j];
+ j = *zig2p++;
+ t1 = in[j] * quant[j];
+ j = *zig2p++;
+ t4 = in[j] * quant[j];
+ j = *zig2p++;
+ t3 = in[j] * quant[j];
+ j = *zig2p++;
+ t6 = in[j] * quant[j];
+ IDCT;
+ tmpp[0 * 8] = t0;
+ tmpp[1 * 8] = t1;
+ tmpp[2 * 8] = t2;
+ tmpp[3 * 8] = t3;
+ tmpp[4 * 8] = t4;
+ tmpp[5 * 8] = t5;
+ tmpp[6 * 8] = t6;
+ tmpp[7 * 8] = t7;
+ tmpp++;
+ t0 = 0;
+ }
+ for (i = 0; i < 8; i++) {
+ t0 = tmp[8 * i + 0];
+ t1 = tmp[8 * i + 1];
+ t2 = tmp[8 * i + 2];
+ t3 = tmp[8 * i + 3];
+ t4 = tmp[8 * i + 4];
+ t5 = tmp[8 * i + 5];
+ t6 = tmp[8 * i + 6];
+ t7 = tmp[8 * i + 7];
+ IDCT;
+ out[8 * i + 0] = ITOINT(t0);
+ out[8 * i + 1] = ITOINT(t1);
+ out[8 * i + 2] = ITOINT(t2);
+ out[8 * i + 3] = ITOINT(t3);
+ out[8 * i + 4] = ITOINT(t4);
+ out[8 * i + 5] = ITOINT(t5);
+ out[8 * i + 6] = ITOINT(t6);
+ out[8 * i + 7] = ITOINT(t7);
+ }
+}
+
+static unsigned char zig[64] = {
+ 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, 31, 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
+};
+
+static PREC aaidct[8] = {
+ IFIX(0.3535533906), IFIX(0.4903926402),
+ IFIX(0.4619397663), IFIX(0.4157348062),
+ IFIX(0.3535533906), IFIX(0.2777851165),
+ IFIX(0.1913417162), IFIX(0.0975451610)
+};
+
+
+static void idctqtab(qin, qout)
+unsigned char *qin;
+PREC *qout;
+{
+ int i, j;
+
+ for (i = 0; i < 8; i++)
+ for (j = 0; j < 8; j++)
+ qout[zig[i * 8 + j]] = qin[zig[i * 8 + j]] *
+ IMULT(aaidct[i], aaidct[j]);
+}
+
+static void scaleidctqtab(q, sc)
+PREC *q;
+PREC sc;
+{
+ int i;
+
+ for (i = 0; i < 64; i++)
+ q[i] = IMULT(q[i], sc);
+}
+
+/****************************************************************/
+/************** color decoder ***************/
+/****************************************************************/
+
+/*
+ * YCbCr Color transformation:
+ *
+ * y:0..255 Cb:-128..127 Cr:-128..127
+ *
+ * R = Y + 1.40200 * Cr
+ * G = Y - 0.34414 * Cb - 0.71414 * Cr
+ * B = Y + 1.77200 * Cb
+ *
+ * =>
+ * Cr *= 1.40200;
+ * Cb *= 1.77200;
+ * Cg = 0.19421 * Cb + .50937 * Cr;
+ * R = Y + Cr;
+ * G = Y - Cg;
+ * B = Y + Cb;
+ *
+ * =>
+ * Cg = (50 * Cb + 130 * Cr + 128) >> 8;
+ */
+
+static void initcol(q)
+PREC q[][64];
+{
+ scaleidctqtab(q[1], IFIX(1.77200));
+ scaleidctqtab(q[2], IFIX(1.40200));
+}
+
+/* This is optimized for the stupid sun SUNWspro compiler. */
+#define STORECLAMP(a,x) \
+( \
+ (a) = (x), \
+ (unsigned int)(x) >= 256 ? \
+ ((a) = (x) < 0 ? 0 : 255) \
+ : \
+ 0 \
+)
+
+#define CLAMP(x) ((unsigned int)(x) >= 256 ? ((x) < 0 ? 0 : 255) : (x))
+
+#define CBCRCG(xin) \
+( \
+ cb = outc[0 + xin], \
+ cr = outc[64 + xin], \
+ cg = (50 * cb + 130 * cr + 128) >> 8 \
+)
+
+#define PIC(yin, xin, p, xout) \
+( \
+ y = outy[(yin) * 8 + xin], \
+ STORECLAMP(p[(xout) * 4 + 0], y + cb), \
+ STORECLAMP(p[(xout) * 4 + 1], y - cg), \
+ STORECLAMP(p[(xout) * 4 + 2], y + cr) \
+)
+
+#define PIC221111x(xin, xin_4, xin_3) \
+( \
+ CBCRCG(xin), \
+ PIC(xin_4 + 0, xin_3 + 0, pic0, xin * 2 + 0), \
+ PIC(xin_4 + 0, xin_3 + 1, pic0, xin * 2 + 1), \
+ PIC(xin_4 + 1, xin_3 + 0, pic1, xin * 2 + 0), \
+ PIC(xin_4 + 1, xin_3 + 1, pic1, xin * 2 + 1) \
+)
+
+#define PIC_16(yin, xin, p, xout, add) \
+( \
+ y = outy[(yin) * 8 + xin], \
+ *(unsigned short *) (p + (xout) * 2) = store_16(CLAMP(y + cr), CLAMP(y - cg), CLAMP(y + cb), add) \
+)
+
+#define PIC221111_16x(xin, xin_4, xin_3) \
+( \
+ CBCRCG(xin), \
+ PIC_16(xin_4 + 0, xin_3 + 0, pic0, xin * 2 + 0, 3 * 0x55), \
+ PIC_16(xin_4 + 0, xin_3 + 1, pic0, xin * 2 + 1, 0 * 0x55), \
+ PIC_16(xin_4 + 1, xin_3 + 0, pic1, xin * 2 + 0, 1 * 0x55), \
+ PIC_16(xin_4 + 1, xin_3 + 1, pic1, xin * 2 + 1, 2 * 0x55) \
+)
+
+#define PIC_8(yin, xin, p, xout, add) \
+( \
+ y = outy[(yin) * 8 + xin], \
+ p[(xout)] = store_8(CLAMP(y + cr), CLAMP(y - cg), CLAMP(y + cb), add) \
+)
+
+#define PIC221111_8x(xin, xin_4, xin_3) \
+( \
+ CBCRCG(xin), \
+ PIC_8(xin_4 + 0, xin_3 + 0, pic0, xin * 2 + 0, 3 * 0x55), \
+ PIC_8(xin_4 + 0, xin_3 + 1, pic0, xin * 2 + 1, 0 * 0x55), \
+ PIC_8(xin_4 + 1, xin_3 + 0, pic1, xin * 2 + 0, 1 * 0x55), \
+ PIC_8(xin_4 + 1, xin_3 + 1, pic1, xin * 2 + 1, 2 * 0x55) \
+)
+
+
+static unsigned store_16(unsigned r, unsigned g, unsigned b, unsigned add)
+{
+ unsigned rgb;
+
+ rgb = (((r << 5) - r + add) >> 8) << 11;
+ rgb += (((g << 6) - g + add) >> 8) << 5;
+ rgb += ((b << 5) - b + add) >> 8;
+
+ return rgb;
+}
+
+static unsigned store_8(unsigned r, unsigned g, unsigned b, unsigned add)
+{
+ unsigned rgb;
+
+#if 0
+ r = ((r << 2) - r + add) >> 8;
+ g = ((g << 3) - g + add) >> 8;
+ b = ((b << 3) - b + add) >> 8;
+
+ rgb = (r << 6) + (g << 3) + b;
+#endif
+
+ rgb = (((r << 2) - r + add) >> 8) << 6;
+ rgb += (((g << 3) - g + add) >> 8) << 3;
+ rgb += ((b << 3) - b + add) >> 8;
+
+ return rgb;
+}
+
+static void col221111(int *out, unsigned char *pic, int width, int bits)
+{
+ int i, j, k, k_4, k_3;
+ unsigned char *pic0, *pic1;
+ int *outy, *outc;
+ int cr, cg, cb, y;
+
+ pic0 = pic;
+ pic1 = pic + width;
+ outy = out;
+ outc = out + 64 * 4;
+ for(i = 2; i > 0; i--) {
+ for(j = 4; j > 0; j--) {
+ for(k = 0; k < 8; k++) {
+ k_4 = (k >> 2) << 3;
+ k_3 = (k & 3) << 1;
+ switch(bits) {
+ case 8:
+ PIC221111_8x(k, k_4, k_3);
+ break;
+ case 16:
+ PIC221111_16x(k, k_4, k_3);
+ break;
+ case 32:
+ PIC221111x(k, k_4, k_3);
+ break;
+ }
+ }
+ outc += 8;
+ outy += 16;
+ pic0 += 2 * width;
+ pic1 += 2 * width;
+ }
+ outy += 64 * 2 - 16 * 4;
+ }
+}
+
+
+/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
+unsigned jpeg_get_size(unsigned char *buf)
+{
+ unsigned u;
+
+ datap = buf;
+ getbyte(); getbyte();
+ if(readtables(M_SOF0)) return 0;
+ getword(); getbyte();
+
+ u = getword() << 16;
+ u += getword();
+
+ return u;
+}
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-25 05:06:09 +0000