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-rw-r--r--apps/plugins/jpeg/jpeg_decoder.c1540
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diff --git a/apps/plugins/jpeg/jpeg_decoder.c b/apps/plugins/jpeg/jpeg_decoder.c
new file mode 100644
index 0000000000..ffd71a1320
--- /dev/null
+++ b/apps/plugins/jpeg/jpeg_decoder.c
@@ -0,0 +1,1540 @@
+/***************************************************************************
+* __________ __ ___.
+* Open \______ \ ____ ____ | | _\_ |__ _______ ___
+* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
+* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
+* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
+* \/ \/ \/ \/ \/
+* $Id$
+*
+* JPEG image viewer
+* (This is a real mess if it has to be coded in one single C file)
+*
+* File scrolling addition (C) 2005 Alexander Spyridakis
+* Copyright (C) 2004 Jörg Hohensohn aka [IDC]Dragon
+* Heavily borrowed from the IJG implementation (C) Thomas G. Lane
+* Small & fast downscaling IDCT (C) 2002 by Guido Vollbeding JPEGclub.org
+*
+* This program is free software; you can redistribute it and/or
+* modify it under the terms of the GNU General Public License
+* as published by the Free Software Foundation; either version 2
+* of the License, or (at your option) any later version.
+*
+* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+* KIND, either express or implied.
+*
+****************************************************************************/
+
+#include "plugin.h"
+
+#include "jpeg_decoder.h"
+
+extern const struct plugin_api* rb;
+
+/* for portability of below JPEG code */
+#define MEMSET(p,v,c) rb->memset(p,v,c)
+#define MEMCPY(d,s,c) rb->memcpy(d,s,c)
+#define INLINE static inline
+#define ENDIAN_SWAP16(n) n /* only for poor little endian machines */
+
+/**************** begin JPEG code ********************/
+
+INLINE unsigned range_limit(int value)
+{
+#if CONFIG_CPU == SH7034
+ unsigned tmp;
+ asm ( /* Note: Uses knowledge that only low byte of result is used */
+ "mov #-128,%[t] \n"
+ "sub %[t],%[v] \n" /* value -= -128; equals value += 128; */
+ "extu.b %[v],%[t] \n"
+ "cmp/eq %[v],%[t] \n" /* low byte == whole number ? */
+ "bt 1f \n" /* yes: no overflow */
+ "cmp/pz %[v] \n" /* overflow: positive? */
+ "subc %[v],%[v] \n" /* %[r] now either 0 or 0xffffffff */
+ "1: \n"
+ : /* outputs */
+ [v]"+r"(value),
+ [t]"=&r"(tmp)
+ );
+ return value;
+#elif defined(CPU_COLDFIRE)
+ asm ( /* Note: Uses knowledge that only the low byte of the result is used */
+ "add.l #128,%[v] \n" /* value += 128; */
+ "cmp.l #255,%[v] \n" /* overflow? */
+ "bls.b 1f \n" /* no: return value */
+ "spl.b %[v] \n" /* yes: set low byte to appropriate boundary */
+ "1: \n"
+ : /* outputs */
+ [v]"+d"(value)
+ );
+ return value;
+#elif defined(CPU_ARM)
+ asm ( /* Note: Uses knowledge that only the low byte of the result is used */
+ "add %[v], %[v], #128 \n" /* value += 128 */
+ "cmp %[v], #255 \n" /* out of range 0..255? */
+ "mvnhi %[v], %[v], asr #31 \n" /* yes: set all bits to ~(sign_bit) */
+ : /* outputs */
+ [v]"+r"(value)
+ );
+ return value;
+#else
+ value += 128;
+
+ if ((unsigned)value <= 255)
+ return value;
+
+ if (value < 0)
+ return 0;
+
+ return 255;
+#endif
+}
+
+/* IDCT implementation */
+
+
+#define CONST_BITS 13
+#define PASS1_BITS 2
+
+
+/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus
+* causing a lot of useless floating-point operations at run time.
+* To get around this we use the following pre-calculated constants.
+* If you change CONST_BITS you may want to add appropriate values.
+* (With a reasonable C compiler, you can just rely on the FIX() macro...)
+*/
+#define FIX_0_298631336 2446 /* FIX(0.298631336) */
+#define FIX_0_390180644 3196 /* FIX(0.390180644) */
+#define FIX_0_541196100 4433 /* FIX(0.541196100) */
+#define FIX_0_765366865 6270 /* FIX(0.765366865) */
+#define FIX_0_899976223 7373 /* FIX(0.899976223) */
+#define FIX_1_175875602 9633 /* FIX(1.175875602) */
+#define FIX_1_501321110 12299 /* FIX(1.501321110) */
+#define FIX_1_847759065 15137 /* FIX(1.847759065) */
+#define FIX_1_961570560 16069 /* FIX(1.961570560) */
+#define FIX_2_053119869 16819 /* FIX(2.053119869) */
+#define FIX_2_562915447 20995 /* FIX(2.562915447) */
+#define FIX_3_072711026 25172 /* FIX(3.072711026) */
+
+
+
+/* Multiply an long variable by an long constant to yield an long result.
+* For 8-bit samples with the recommended scaling, all the variable
+* and constant values involved are no more than 16 bits wide, so a
+* 16x16->32 bit multiply can be used instead of a full 32x32 multiply.
+* For 12-bit samples, a full 32-bit multiplication will be needed.
+*/
+#define MULTIPLY16(var,const) (((short) (var)) * ((short) (const)))
+
+
+/* Dequantize a coefficient by multiplying it by the multiplier-table
+* entry; produce an int result. In this module, both inputs and result
+* are 16 bits or less, so either int or short multiply will work.
+*/
+/* #define DEQUANTIZE(coef,quantval) (((int) (coef)) * (quantval)) */
+#define DEQUANTIZE MULTIPLY16
+
+/* Descale and correctly round an int value that's scaled by N bits.
+* We assume RIGHT_SHIFT rounds towards minus infinity, so adding
+* the fudge factor is correct for either sign of X.
+*/
+#define DESCALE(x,n) (((x) + (1l << ((n)-1))) >> (n))
+
+
+
+/*
+* Perform dequantization and inverse DCT on one block of coefficients,
+* producing a reduced-size 1x1 output block.
+*/
+void idct1x1(unsigned char* p_byte, int* inptr, int* quantptr, int skip_line)
+{
+ (void)skip_line; /* unused */
+ *p_byte = range_limit(inptr[0] * quantptr[0] >> 3);
+}
+
+
+
+/*
+* Perform dequantization and inverse DCT on one block of coefficients,
+* producing a reduced-size 2x2 output block.
+*/
+void idct2x2(unsigned char* p_byte, int* inptr, int* quantptr, int skip_line)
+{
+ int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5;
+ unsigned char* outptr;
+
+ /* Pass 1: process columns from input, store into work array. */
+
+ /* Column 0 */
+ tmp4 = DEQUANTIZE(inptr[8*0], quantptr[8*0]);
+ tmp5 = DEQUANTIZE(inptr[8*1], quantptr[8*1]);
+
+ tmp0 = tmp4 + tmp5;
+ tmp2 = tmp4 - tmp5;
+
+ /* Column 1 */
+ tmp4 = DEQUANTIZE(inptr[8*0+1], quantptr[8*0+1]);
+ tmp5 = DEQUANTIZE(inptr[8*1+1], quantptr[8*1+1]);
+
+ tmp1 = tmp4 + tmp5;
+ tmp3 = tmp4 - tmp5;
+
+ /* Pass 2: process 2 rows, store into output array. */
+
+ /* Row 0 */
+ outptr = p_byte;
+
+ outptr[0] = range_limit((int) DESCALE(tmp0 + tmp1, 3));
+ outptr[1] = range_limit((int) DESCALE(tmp0 - tmp1, 3));
+
+ /* Row 1 */
+ outptr = p_byte + skip_line;
+
+ outptr[0] = range_limit((int) DESCALE(tmp2 + tmp3, 3));
+ outptr[1] = range_limit((int) DESCALE(tmp2 - tmp3, 3));
+}
+
+
+
+/*
+* Perform dequantization and inverse DCT on one block of coefficients,
+* producing a reduced-size 4x4 output block.
+*/
+void idct4x4(unsigned char* p_byte, int* inptr, int* quantptr, int skip_line)
+{
+ int tmp0, tmp2, tmp10, tmp12;
+ int z1, z2, z3;
+ int * wsptr;
+ unsigned char* outptr;
+ int ctr;
+ int workspace[4*4]; /* buffers data between passes */
+
+ /* Pass 1: process columns from input, store into work array. */
+
+ wsptr = workspace;
+ for (ctr = 0; ctr < 4; ctr++, inptr++, quantptr++, wsptr++)
+ {
+ /* Even part */
+
+ tmp0 = DEQUANTIZE(inptr[8*0], quantptr[8*0]);
+ tmp2 = DEQUANTIZE(inptr[8*2], quantptr[8*2]);
+
+ tmp10 = (tmp0 + tmp2) << PASS1_BITS;
+ tmp12 = (tmp0 - tmp2) << PASS1_BITS;
+
+ /* Odd part */
+ /* Same rotation as in the even part of the 8x8 LL&M IDCT */
+
+ z2 = DEQUANTIZE(inptr[8*1], quantptr[8*1]);
+ z3 = DEQUANTIZE(inptr[8*3], quantptr[8*3]);
+
+ z1 = MULTIPLY16(z2 + z3, FIX_0_541196100);
+ tmp0 = DESCALE(z1 + MULTIPLY16(z3, - FIX_1_847759065), CONST_BITS-PASS1_BITS);
+ tmp2 = DESCALE(z1 + MULTIPLY16(z2, FIX_0_765366865), CONST_BITS-PASS1_BITS);
+
+ /* Final output stage */
+
+ wsptr[4*0] = (int) (tmp10 + tmp2);
+ wsptr[4*3] = (int) (tmp10 - tmp2);
+ wsptr[4*1] = (int) (tmp12 + tmp0);
+ wsptr[4*2] = (int) (tmp12 - tmp0);
+ }
+
+ /* Pass 2: process 4 rows from work array, store into output array. */
+
+ wsptr = workspace;
+ for (ctr = 0; ctr < 4; ctr++)
+ {
+ outptr = p_byte + (ctr*skip_line);
+ /* Even part */
+
+ tmp0 = (int) wsptr[0];
+ tmp2 = (int) wsptr[2];
+
+ tmp10 = (tmp0 + tmp2) << CONST_BITS;
+ tmp12 = (tmp0 - tmp2) << CONST_BITS;
+
+ /* Odd part */
+ /* Same rotation as in the even part of the 8x8 LL&M IDCT */
+
+ z2 = (int) wsptr[1];
+ z3 = (int) wsptr[3];
+
+ z1 = MULTIPLY16(z2 + z3, FIX_0_541196100);
+ tmp0 = z1 + MULTIPLY16(z3, - FIX_1_847759065);
+ tmp2 = z1 + MULTIPLY16(z2, FIX_0_765366865);
+
+ /* Final output stage */
+
+ outptr[0] = range_limit((int) DESCALE(tmp10 + tmp2,
+ CONST_BITS+PASS1_BITS+3));
+ outptr[3] = range_limit((int) DESCALE(tmp10 - tmp2,
+ CONST_BITS+PASS1_BITS+3));
+ outptr[1] = range_limit((int) DESCALE(tmp12 + tmp0,
+ CONST_BITS+PASS1_BITS+3));
+ outptr[2] = range_limit((int) DESCALE(tmp12 - tmp0,
+ CONST_BITS+PASS1_BITS+3));
+
+ wsptr += 4; /* advance pointer to next row */
+ }
+}
+
+
+
+/*
+* Perform dequantization and inverse DCT on one block of coefficients.
+*/
+void idct8x8(unsigned char* p_byte, int* inptr, int* quantptr, int skip_line)
+{
+ long tmp0, tmp1, tmp2, tmp3;
+ long tmp10, tmp11, tmp12, tmp13;
+ long z1, z2, z3, z4, z5;
+ int * wsptr;
+ unsigned char* outptr;
+ int ctr;
+ int workspace[64]; /* buffers data between passes */
+
+ /* Pass 1: process columns from input, store into work array. */
+ /* Note results are scaled up by sqrt(8) compared to a true IDCT; */
+ /* furthermore, we scale the results by 2**PASS1_BITS. */
+
+ wsptr = workspace;
+ for (ctr = 8; ctr > 0; ctr--)
+ {
+ /* Due to quantization, we will usually find that many of the input
+ * coefficients are zero, especially the AC terms. We can exploit this
+ * by short-circuiting the IDCT calculation for any column in which all
+ * the AC terms are zero. In that case each output is equal to the
+ * DC coefficient (with scale factor as needed).
+ * With typical images and quantization tables, half or more of the
+ * column DCT calculations can be simplified this way.
+ */
+
+ if ((inptr[8*1] | inptr[8*2] | inptr[8*3]
+ | inptr[8*4] | inptr[8*5] | inptr[8*6] | inptr[8*7]) == 0)
+ {
+ /* AC terms all zero */
+ int dcval = DEQUANTIZE(inptr[8*0], quantptr[8*0]) << PASS1_BITS;
+
+ wsptr[8*0] = wsptr[8*1] = wsptr[8*2] = wsptr[8*3] = wsptr[8*4]
+ = wsptr[8*5] = wsptr[8*6] = wsptr[8*7] = dcval;
+ inptr++; /* advance pointers to next column */
+ quantptr++;
+ wsptr++;
+ continue;
+ }
+
+ /* Even part: reverse the even part of the forward DCT. */
+ /* The rotator is sqrt(2)*c(-6). */
+
+ z2 = DEQUANTIZE(inptr[8*2], quantptr[8*2]);
+ z3 = DEQUANTIZE(inptr[8*6], quantptr[8*6]);
+
+ z1 = MULTIPLY16(z2 + z3, FIX_0_541196100);
+ tmp2 = z1 + MULTIPLY16(z3, - FIX_1_847759065);
+ tmp3 = z1 + MULTIPLY16(z2, FIX_0_765366865);
+
+ z2 = DEQUANTIZE(inptr[8*0], quantptr[8*0]);
+ z3 = DEQUANTIZE(inptr[8*4], quantptr[8*4]);
+
+ tmp0 = (z2 + z3) << CONST_BITS;
+ tmp1 = (z2 - z3) << CONST_BITS;
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ /* Odd part per figure 8; the matrix is unitary and hence its
+ transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively. */
+
+ tmp0 = DEQUANTIZE(inptr[8*7], quantptr[8*7]);
+ tmp1 = DEQUANTIZE(inptr[8*5], quantptr[8*5]);
+ tmp2 = DEQUANTIZE(inptr[8*3], quantptr[8*3]);
+ tmp3 = DEQUANTIZE(inptr[8*1], quantptr[8*1]);
+
+ z1 = tmp0 + tmp3;
+ z2 = tmp1 + tmp2;
+ z3 = tmp0 + tmp2;
+ z4 = tmp1 + tmp3;
+ z5 = MULTIPLY16(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */
+
+ tmp0 = MULTIPLY16(tmp0, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
+ tmp1 = MULTIPLY16(tmp1, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
+ tmp2 = MULTIPLY16(tmp2, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
+ tmp3 = MULTIPLY16(tmp3, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
+ z1 = MULTIPLY16(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
+ z2 = MULTIPLY16(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
+ z3 = MULTIPLY16(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
+ z4 = MULTIPLY16(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+
+ /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+ wsptr[8*0] = (int) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
+ wsptr[8*7] = (int) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
+ wsptr[8*1] = (int) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
+ wsptr[8*6] = (int) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
+ wsptr[8*2] = (int) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
+ wsptr[8*5] = (int) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
+ wsptr[8*3] = (int) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
+ wsptr[8*4] = (int) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
+
+ inptr++; /* advance pointers to next column */
+ quantptr++;
+ wsptr++;
+ }
+
+ /* Pass 2: process rows from work array, store into output array. */
+ /* Note that we must descale the results by a factor of 8 == 2**3, */
+ /* and also undo the PASS1_BITS scaling. */
+
+ wsptr = workspace;
+ for (ctr = 0; ctr < 8; ctr++)
+ {
+ outptr = p_byte + (ctr*skip_line);
+ /* Rows of zeroes can be exploited in the same way as we did with columns.
+ * However, the column calculation has created many nonzero AC terms, so
+ * the simplification applies less often (typically 5% to 10% of the time).
+ * On machines with very fast multiplication, it's possible that the
+ * test takes more time than it's worth. In that case this section
+ * may be commented out.
+ */
+
+#ifndef NO_ZERO_ROW_TEST
+ if ((wsptr[1] | wsptr[2] | wsptr[3]
+ | wsptr[4] | wsptr[5] | wsptr[6] | wsptr[7]) == 0)
+ {
+ /* AC terms all zero */
+ unsigned char dcval = range_limit((int) DESCALE((long) wsptr[0],
+ PASS1_BITS+3));
+
+ outptr[0] = dcval;
+ outptr[1] = dcval;
+ outptr[2] = dcval;
+ outptr[3] = dcval;
+ outptr[4] = dcval;
+ outptr[5] = dcval;
+ outptr[6] = dcval;
+ outptr[7] = dcval;
+
+ wsptr += 8; /* advance pointer to next row */
+ continue;
+ }
+#endif
+
+ /* Even part: reverse the even part of the forward DCT. */
+ /* The rotator is sqrt(2)*c(-6). */
+
+ z2 = (long) wsptr[2];
+ z3 = (long) wsptr[6];
+
+ z1 = MULTIPLY16(z2 + z3, FIX_0_541196100);
+ tmp2 = z1 + MULTIPLY16(z3, - FIX_1_847759065);
+ tmp3 = z1 + MULTIPLY16(z2, FIX_0_765366865);
+
+ tmp0 = ((long) wsptr[0] + (long) wsptr[4]) << CONST_BITS;
+ tmp1 = ((long) wsptr[0] - (long) wsptr[4]) << CONST_BITS;
+
+ tmp10 = tmp0 + tmp3;
+ tmp13 = tmp0 - tmp3;
+ tmp11 = tmp1 + tmp2;
+ tmp12 = tmp1 - tmp2;
+
+ /* Odd part per figure 8; the matrix is unitary and hence its
+ * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively. */
+
+ tmp0 = (long) wsptr[7];
+ tmp1 = (long) wsptr[5];
+ tmp2 = (long) wsptr[3];
+ tmp3 = (long) wsptr[1];
+
+ z1 = tmp0 + tmp3;
+ z2 = tmp1 + tmp2;
+ z3 = tmp0 + tmp2;
+ z4 = tmp1 + tmp3;
+ z5 = MULTIPLY16(z3 + z4, FIX_1_175875602); /* sqrt(2) * c3 */
+
+ tmp0 = MULTIPLY16(tmp0, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
+ tmp1 = MULTIPLY16(tmp1, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
+ tmp2 = MULTIPLY16(tmp2, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
+ tmp3 = MULTIPLY16(tmp3, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
+ z1 = MULTIPLY16(z1, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
+ z2 = MULTIPLY16(z2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
+ z3 = MULTIPLY16(z3, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
+ z4 = MULTIPLY16(z4, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
+
+ z3 += z5;
+ z4 += z5;
+
+ tmp0 += z1 + z3;
+ tmp1 += z2 + z4;
+ tmp2 += z2 + z3;
+ tmp3 += z1 + z4;
+
+ /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
+
+ outptr[0] = range_limit((int) DESCALE(tmp10 + tmp3,
+ CONST_BITS+PASS1_BITS+3));
+ outptr[7] = range_limit((int) DESCALE(tmp10 - tmp3,
+ CONST_BITS+PASS1_BITS+3));
+ outptr[1] = range_limit((int) DESCALE(tmp11 + tmp2,
+ CONST_BITS+PASS1_BITS+3));
+ outptr[6] = range_limit((int) DESCALE(tmp11 - tmp2,
+ CONST_BITS+PASS1_BITS+3));
+ outptr[2] = range_limit((int) DESCALE(tmp12 + tmp1,
+ CONST_BITS+PASS1_BITS+3));
+ outptr[5] = range_limit((int) DESCALE(tmp12 - tmp1,
+ CONST_BITS+PASS1_BITS+3));
+ outptr[3] = range_limit((int) DESCALE(tmp13 + tmp0,
+ CONST_BITS+PASS1_BITS+3));
+ outptr[4] = range_limit((int) DESCALE(tmp13 - tmp0,
+ CONST_BITS+PASS1_BITS+3));
+
+ wsptr += 8; /* advance pointer to next row */
+ }
+}
+
+
+
+/* JPEG decoder implementation */
+
+/* Preprocess the JPEG JFIF file */
+int process_markers(unsigned char* p_src, long size, struct jpeg* p_jpeg)
+{
+ unsigned char* p_bytes = p_src;
+ int marker_size; /* variable length of marker segment */
+ int i, j, n;
+ int ret = 0; /* returned flags */
+
+ p_jpeg->p_entropy_end = p_src + size;
+
+ while (p_src < p_bytes + size)
+ {
+ if (*p_src++ != 0xFF) /* no marker? */
+ {
+ p_src--; /* it's image data, put it back */
+ p_jpeg->p_entropy_data = p_src;
+ break; /* exit marker processing */
+ }
+
+ switch (*p_src++)
+ {
+ case 0xFF: /* Fill byte */
+ ret |= FILL_FF;
+ case 0x00: /* Zero stuffed byte - entropy data */
+ p_src--; /* put it back */
+ continue;
+
+ case 0xC0: /* SOF Huff - Baseline DCT */
+ {
+ ret |= SOF0;
+ marker_size = *p_src++ << 8; /* Highbyte */
+ marker_size |= *p_src++; /* Lowbyte */
+ n = *p_src++; /* sample precision (= 8 or 12) */
+ if (n != 8)
+ {
+ return(-1); /* Unsupported sample precision */
+ }
+ p_jpeg->y_size = *p_src++ << 8; /* Highbyte */
+ p_jpeg->y_size |= *p_src++; /* Lowbyte */
+ p_jpeg->x_size = *p_src++ << 8; /* Highbyte */
+ p_jpeg->x_size |= *p_src++; /* Lowbyte */
+
+ n = (marker_size-2-6)/3;
+ if (*p_src++ != n || (n != 1 && n != 3))
+ {
+ return(-2); /* Unsupported SOF0 component specification */
+ }
+ for (i=0; i<n; i++)
+ {
+ p_jpeg->frameheader[i].ID = *p_src++; /* Component info */
+ p_jpeg->frameheader[i].horizontal_sampling = *p_src >> 4;
+ p_jpeg->frameheader[i].vertical_sampling = *p_src++ & 0x0F;
+ p_jpeg->frameheader[i].quanttable_select = *p_src++;
+ if (p_jpeg->frameheader[i].horizontal_sampling > 2
+ || p_jpeg->frameheader[i].vertical_sampling > 2)
+ return -3; /* Unsupported SOF0 subsampling */
+ }
+ p_jpeg->blocks = n;
+ }
+ break;
+
+ case 0xC1: /* SOF Huff - Extended sequential DCT*/
+ case 0xC2: /* SOF Huff - Progressive DCT*/
+ case 0xC3: /* SOF Huff - Spatial (sequential) lossless*/
+ case 0xC5: /* SOF Huff - Differential sequential DCT*/
+ case 0xC6: /* SOF Huff - Differential progressive DCT*/
+ case 0xC7: /* SOF Huff - Differential spatial*/
+ case 0xC8: /* SOF Arith - Reserved for JPEG extensions*/
+ case 0xC9: /* SOF Arith - Extended sequential DCT*/
+ case 0xCA: /* SOF Arith - Progressive DCT*/
+ case 0xCB: /* SOF Arith - Spatial (sequential) lossless*/
+ case 0xCD: /* SOF Arith - Differential sequential DCT*/
+ case 0xCE: /* SOF Arith - Differential progressive DCT*/
+ case 0xCF: /* SOF Arith - Differential spatial*/
+ {
+ return (-4); /* other DCT model than baseline not implemented */
+ }
+
+ case 0xC4: /* Define Huffman Table(s) */
+ {
+ unsigned char* p_temp;
+
+ ret |= DHT;
+ marker_size = *p_src++ << 8; /* Highbyte */
+ marker_size |= *p_src++; /* Lowbyte */
+
+ p_temp = p_src;
+ while (p_src < p_temp+marker_size-2-17) /* another table */
+ {
+ int sum = 0;
+ i = *p_src & 0x0F; /* table index */
+ if (i > 1)
+ {
+ return (-5); /* Huffman table index out of range */
+ }
+ else if (*p_src++ & 0xF0) /* AC table */
+ {
+ for (j=0; j<16; j++)
+ {
+ sum += *p_src;
+ p_jpeg->hufftable[i].huffmancodes_ac[j] = *p_src++;
+ }
+ if(16 + sum > AC_LEN)
+ return -10; /* longer than allowed */
+
+ for (; j < 16 + sum; j++)
+ p_jpeg->hufftable[i].huffmancodes_ac[j] = *p_src++;
+ }
+ else /* DC table */
+ {
+ for (j=0; j<16; j++)
+ {
+ sum += *p_src;
+ p_jpeg->hufftable[i].huffmancodes_dc[j] = *p_src++;
+ }
+ if(16 + sum > DC_LEN)
+ return -11; /* longer than allowed */
+
+ for (; j < 16 + sum; j++)
+ p_jpeg->hufftable[i].huffmancodes_dc[j] = *p_src++;
+ }
+ } /* while */
+ p_src = p_temp+marker_size - 2; /* skip possible residue */
+ }
+ break;
+
+ case 0xCC: /* Define Arithmetic coding conditioning(s) */
+ return(-6); /* Arithmetic coding not supported */
+
+ case 0xD8: /* Start of Image */
+ case 0xD9: /* End of Image */
+ case 0x01: /* for temp private use arith code */
+ break; /* skip parameterless marker */
+
+
+ case 0xDA: /* Start of Scan */
+ {
+ ret |= SOS;
+ marker_size = *p_src++ << 8; /* Highbyte */
+ marker_size |= *p_src++; /* Lowbyte */
+
+ n = (marker_size-2-1-3)/2;
+ if (*p_src++ != n || (n != 1 && n != 3))
+ {
+ return (-7); /* Unsupported SOS component specification */
+ }
+ for (i=0; i<n; i++)
+ {
+ p_jpeg->scanheader[i].ID = *p_src++;
+ p_jpeg->scanheader[i].DC_select = *p_src >> 4;
+ p_jpeg->scanheader[i].AC_select = *p_src++ & 0x0F;
+ }
+ p_src += 3; /* skip spectral information */
+ }
+ break;
+
+ case 0xDB: /* Define quantization Table(s) */
+ {
+ ret |= DQT;
+ marker_size = *p_src++ << 8; /* Highbyte */
+ marker_size |= *p_src++; /* Lowbyte */
+ n = (marker_size-2)/(QUANT_TABLE_LENGTH+1); /* # of tables */
+ for (i=0; i<n; i++)
+ {
+ int id = *p_src++; /* ID */
+ if (id >= 4)
+ {
+ return (-8); /* Unsupported quantization table */
+ }
+ /* Read Quantisation table: */
+ for (j=0; j<QUANT_TABLE_LENGTH; j++)
+ p_jpeg->quanttable[id][j] = *p_src++;
+ }
+ }
+ break;
+
+ case 0xDD: /* Define Restart Interval */
+ {
+ marker_size = *p_src++ << 8; /* Highbyte */
+ marker_size |= *p_src++; /* Lowbyte */
+ p_jpeg->restart_interval = *p_src++ << 8; /* Highbyte */
+ p_jpeg->restart_interval |= *p_src++; /* Lowbyte */
+ p_src += marker_size-4; /* skip segment */
+ }
+ break;
+
+ case 0xDC: /* Define Number of Lines */
+ case 0xDE: /* Define Hierarchical progression */
+ case 0xDF: /* Expand Reference Component(s) */
+ case 0xE0: /* Application Field 0*/
+ case 0xE1: /* Application Field 1*/
+ case 0xE2: /* Application Field 2*/
+ case 0xE3: /* Application Field 3*/
+ case 0xE4: /* Application Field 4*/
+ case 0xE5: /* Application Field 5*/
+ case 0xE6: /* Application Field 6*/
+ case 0xE7: /* Application Field 7*/
+ case 0xE8: /* Application Field 8*/
+ case 0xE9: /* Application Field 9*/
+ case 0xEA: /* Application Field 10*/
+ case 0xEB: /* Application Field 11*/
+ case 0xEC: /* Application Field 12*/
+ case 0xED: /* Application Field 13*/
+ case 0xEE: /* Application Field 14*/
+ case 0xEF: /* Application Field 15*/
+ case 0xFE: /* Comment */
+ {
+ marker_size = *p_src++ << 8; /* Highbyte */
+ marker_size |= *p_src++; /* Lowbyte */
+ p_src += marker_size-2; /* skip segment */
+ }
+ break;
+
+ case 0xF0: /* Reserved for JPEG extensions */
+ case 0xF1: /* Reserved for JPEG extensions */
+ case 0xF2: /* Reserved for JPEG extensions */
+ case 0xF3: /* Reserved for JPEG extensions */
+ case 0xF4: /* Reserved for JPEG extensions */
+ case 0xF5: /* Reserved for JPEG extensions */
+ case 0xF6: /* Reserved for JPEG extensions */
+ case 0xF7: /* Reserved for JPEG extensions */
+ case 0xF8: /* Reserved for JPEG extensions */
+ case 0xF9: /* Reserved for JPEG extensions */
+ case 0xFA: /* Reserved for JPEG extensions */
+ case 0xFB: /* Reserved for JPEG extensions */
+ case 0xFC: /* Reserved for JPEG extensions */
+ case 0xFD: /* Reserved for JPEG extensions */
+ case 0x02: /* Reserved */
+ default:
+ return (-9); /* Unknown marker */
+ } /* switch */
+ } /* while */
+
+ return (ret); /* return flags with seen markers */
+}
+
+
+void default_huff_tbl(struct jpeg* p_jpeg)
+{
+ static const struct huffman_table luma_table =
+ {
+ {
+ 0x00,0x01,0x05,0x01,0x01,0x01,0x01,0x01,0x01,0x00,0x00,0x00,0x00,0x00,
+ 0x00,0x00,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B
+ },
+ {
+ 0x00,0x02,0x01,0x03,0x03,0x02,0x04,0x03,0x05,0x05,0x04,0x04,0x00,0x00,0x01,0x7D,
+ 0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12,0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07,
+ 0x22,0x71,0x14,0x32,0x81,0x91,0xA1,0x08,0x23,0x42,0xB1,0xC1,0x15,0x52,0xD1,0xF0,
+ 0x24,0x33,0x62,0x72,0x82,0x09,0x0A,0x16,0x17,0x18,0x19,0x1A,0x25,0x26,0x27,0x28,
+ 0x29,0x2A,0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x43,0x44,0x45,0x46,0x47,0x48,0x49,
+ 0x4A,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0x63,0x64,0x65,0x66,0x67,0x68,0x69,
+ 0x6A,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x83,0x84,0x85,0x86,0x87,0x88,0x89,
+ 0x8A,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9A,0xA2,0xA3,0xA4,0xA5,0xA6,0xA7,
+ 0xA8,0xA9,0xAA,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0xC2,0xC3,0xC4,0xC5,
+ 0xC6,0xC7,0xC8,0xC9,0xCA,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,0xD8,0xD9,0xDA,0xE1,0xE2,
+ 0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,
+ 0xF9,0xFA
+ }
+ };
+
+ static const struct huffman_table chroma_table =
+ {
+ {
+ 0x00,0x03,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x00,0x00,0x00,
+ 0x00,0x00,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B
+ },
+ {
+ 0x00,0x02,0x01,0x02,0x04,0x04,0x03,0x04,0x07,0x05,0x04,0x04,0x00,0x01,0x02,0x77,
+ 0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21,0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71,
+ 0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91,0xA1,0xB1,0xC1,0x09,0x23,0x33,0x52,0xF0,
+ 0x15,0x62,0x72,0xD1,0x0A,0x16,0x24,0x34,0xE1,0x25,0xF1,0x17,0x18,0x19,0x1A,0x26,
+ 0x27,0x28,0x29,0x2A,0x35,0x36,0x37,0x38,0x39,0x3A,0x43,0x44,0x45,0x46,0x47,0x48,
+ 0x49,0x4A,0x53,0x54,0x55,0x56,0x57,0x58,0x59,0x5A,0x63,0x64,0x65,0x66,0x67,0x68,
+ 0x69,0x6A,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7A,0x82,0x83,0x84,0x85,0x86,0x87,
+ 0x88,0x89,0x8A,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9A,0xA2,0xA3,0xA4,0xA5,
+ 0xA6,0xA7,0xA8,0xA9,0xAA,0xB2,0xB3,0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0xC2,0xC3,
+ 0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xD2,0xD3,0xD4,0xD5,0xD6,0xD7,0xD8,0xD9,0xDA,
+ 0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,
+ 0xF9,0xFA
+ }
+ };
+
+ MEMCPY(&p_jpeg->hufftable[0], &luma_table, sizeof(luma_table));
+ MEMCPY(&p_jpeg->hufftable[1], &chroma_table, sizeof(chroma_table));
+
+ return;
+}
+
+/* Compute the derived values for a Huffman table */
+void fix_huff_tbl(int* htbl, struct derived_tbl* dtbl)
+{
+ int p, i, l, si;
+ int lookbits, ctr;
+ char huffsize[257];
+ unsigned int huffcode[257];
+ unsigned int code;
+
+ dtbl->pub = htbl; /* fill in back link */
+
+ /* Figure C.1: make table of Huffman code length for each symbol */
+ /* Note that this is in code-length order. */
+
+ p = 0;
+ for (l = 1; l <= 16; l++)
+ { /* all possible code length */
+ for (i = 1; i <= (int) htbl[l-1]; i++) /* all codes per length */
+ huffsize[p++] = (char) l;
+ }
+ huffsize[p] = 0;
+
+ /* Figure C.2: generate the codes themselves */
+ /* Note that this is in code-length order. */
+
+ code = 0;
+ si = huffsize[0];
+ p = 0;
+ while (huffsize[p])
+ {
+ while (((int) huffsize[p]) == si)
+ {
+ huffcode[p++] = code;
+ code++;
+ }
+ code <<= 1;
+ si++;
+ }
+
+ /* Figure F.15: generate decoding tables for bit-sequential decoding */
+
+ p = 0;
+ for (l = 1; l <= 16; l++)
+ {
+ if (htbl[l-1])
+ {
+ dtbl->valptr[l] = p; /* huffval[] index of 1st symbol of code length l */
+ dtbl->mincode[l] = huffcode[p]; /* minimum code of length l */
+ p += htbl[l-1];
+ dtbl->maxcode[l] = huffcode[p-1]; /* maximum code of length l */
+ }
+ else
+ {
+ dtbl->maxcode[l] = -1; /* -1 if no codes of this length */
+ }
+ }
+ dtbl->maxcode[17] = 0xFFFFFL; /* ensures huff_DECODE terminates */
+
+ /* Compute lookahead tables to speed up decoding.
+ * First we set all the table entries to 0, indicating "too long";
+ * then we iterate through the Huffman codes that are short enough and
+ * fill in all the entries that correspond to bit sequences starting
+ * with that code.
+ */
+
+ MEMSET(dtbl->look_nbits, 0, sizeof(dtbl->look_nbits));
+
+ p = 0;
+ for (l = 1; l <= HUFF_LOOKAHEAD; l++)
+ {
+ for (i = 1; i <= (int) htbl[l-1]; i++, p++)
+ {
+ /* l = current code's length, p = its index in huffcode[] & huffval[]. */
+ /* Generate left-justified code followed by all possible bit sequences */
+ lookbits = huffcode[p] << (HUFF_LOOKAHEAD-l);
+ for (ctr = 1 << (HUFF_LOOKAHEAD-l); ctr > 0; ctr--)
+ {
+ dtbl->look_nbits[lookbits] = l;
+ dtbl->look_sym[lookbits] = htbl[16+p];
+ lookbits++;
+ }
+ }
+ }
+}
+
+
+/* zag[i] is the natural-order position of the i'th element of zigzag order.
+ * If the incoming data is corrupted, decode_mcu could attempt to
+ * reference values beyond the end of the array. To avoid a wild store,
+ * we put some extra zeroes after the real entries.
+ */
+static const int zag[] =
+{
+ 0, 1, 8, 16, 9, 2, 3, 10,
+ 17, 24, 32, 25, 18, 11, 4, 5,
+ 12, 19, 26, 33, 40, 48, 41, 34,
+ 27, 20, 13, 6, 7, 14, 21, 28,
+ 35, 42, 49, 56, 57, 50, 43, 36,
+ 29, 22, 15, 23, 30, 37, 44, 51,
+ 58, 59, 52, 45, 38, 31, 39, 46,
+ 53, 60, 61, 54, 47, 55, 62, 63,
+ 0, 0, 0, 0, 0, 0, 0, 0, /* extra entries in case k>63 below */
+ 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+void build_lut(struct jpeg* p_jpeg)
+{
+ int i;
+ fix_huff_tbl(p_jpeg->hufftable[0].huffmancodes_dc,
+ &p_jpeg->dc_derived_tbls[0]);
+ fix_huff_tbl(p_jpeg->hufftable[0].huffmancodes_ac,
+ &p_jpeg->ac_derived_tbls[0]);
+ fix_huff_tbl(p_jpeg->hufftable[1].huffmancodes_dc,
+ &p_jpeg->dc_derived_tbls[1]);
+ fix_huff_tbl(p_jpeg->hufftable[1].huffmancodes_ac,
+ &p_jpeg->ac_derived_tbls[1]);
+
+ /* build the dequantization tables for the IDCT (De-ZiZagged) */
+ for (i=0; i<64; i++)
+ {
+ p_jpeg->qt_idct[0][zag[i]] = p_jpeg->quanttable[0][i];
+ p_jpeg->qt_idct[1][zag[i]] = p_jpeg->quanttable[1][i];
+ }
+
+ for (i=0; i<4; i++)
+ p_jpeg->store_pos[i] = i; /* default ordering */
+
+ /* assignments for the decoding of blocks */
+ if (p_jpeg->frameheader[0].horizontal_sampling == 2
+ && p_jpeg->frameheader[0].vertical_sampling == 1)
+ { /* 4:2:2 */
+ p_jpeg->blocks = 4;
+ p_jpeg->x_mbl = (p_jpeg->x_size+15) / 16;
+ p_jpeg->x_phys = p_jpeg->x_mbl * 16;
+ p_jpeg->y_mbl = (p_jpeg->y_size+7) / 8;
+ p_jpeg->y_phys = p_jpeg->y_mbl * 8;
+ p_jpeg->mcu_membership[0] = 0; /* Y1=Y2=0, U=1, V=2 */
+ p_jpeg->mcu_membership[1] = 0;
+ p_jpeg->mcu_membership[2] = 1;
+ p_jpeg->mcu_membership[3] = 2;
+ p_jpeg->tab_membership[0] = 0; /* DC, DC, AC, AC */
+ p_jpeg->tab_membership[1] = 0;
+ p_jpeg->tab_membership[2] = 1;
+ p_jpeg->tab_membership[3] = 1;
+ p_jpeg->subsample_x[0] = 1;
+ p_jpeg->subsample_x[1] = 2;
+ p_jpeg->subsample_x[2] = 2;
+ p_jpeg->subsample_y[0] = 1;
+ p_jpeg->subsample_y[1] = 1;
+ p_jpeg->subsample_y[2] = 1;
+ }
+ if (p_jpeg->frameheader[0].horizontal_sampling == 1
+ && p_jpeg->frameheader[0].vertical_sampling == 2)
+ { /* 4:2:2 vertically subsampled */
+ p_jpeg->store_pos[1] = 2; /* block positions are mirrored */
+ p_jpeg->store_pos[2] = 1;
+ p_jpeg->blocks = 4;
+ p_jpeg->x_mbl = (p_jpeg->x_size+7) / 8;
+ p_jpeg->x_phys = p_jpeg->x_mbl * 8;
+ p_jpeg->y_mbl = (p_jpeg->y_size+15) / 16;
+ p_jpeg->y_phys = p_jpeg->y_mbl * 16;
+ p_jpeg->mcu_membership[0] = 0; /* Y1=Y2=0, U=1, V=2 */
+ p_jpeg->mcu_membership[1] = 0;
+ p_jpeg->mcu_membership[2] = 1;
+ p_jpeg->mcu_membership[3] = 2;
+ p_jpeg->tab_membership[0] = 0; /* DC, DC, AC, AC */
+ p_jpeg->tab_membership[1] = 0;
+ p_jpeg->tab_membership[2] = 1;
+ p_jpeg->tab_membership[3] = 1;
+ p_jpeg->subsample_x[0] = 1;
+ p_jpeg->subsample_x[1] = 1;
+ p_jpeg->subsample_x[2] = 1;
+ p_jpeg->subsample_y[0] = 1;
+ p_jpeg->subsample_y[1] = 2;
+ p_jpeg->subsample_y[2] = 2;
+ }
+ else if (p_jpeg->frameheader[0].horizontal_sampling == 2
+ && p_jpeg->frameheader[0].vertical_sampling == 2)
+ { /* 4:2:0 */
+ p_jpeg->blocks = 6;
+ p_jpeg->x_mbl = (p_jpeg->x_size+15) / 16;
+ p_jpeg->x_phys = p_jpeg->x_mbl * 16;
+ p_jpeg->y_mbl = (p_jpeg->y_size+15) / 16;
+ p_jpeg->y_phys = p_jpeg->y_mbl * 16;
+ p_jpeg->mcu_membership[0] = 0;
+ p_jpeg->mcu_membership[1] = 0;
+ p_jpeg->mcu_membership[2] = 0;
+ p_jpeg->mcu_membership[3] = 0;
+ p_jpeg->mcu_membership[4] = 1;
+ p_jpeg->mcu_membership[5] = 2;
+ p_jpeg->tab_membership[0] = 0;
+ p_jpeg->tab_membership[1] = 0;
+ p_jpeg->tab_membership[2] = 0;
+ p_jpeg->tab_membership[3] = 0;
+ p_jpeg->tab_membership[4] = 1;
+ p_jpeg->tab_membership[5] = 1;
+ p_jpeg->subsample_x[0] = 1;
+ p_jpeg->subsample_x[1] = 2;
+ p_jpeg->subsample_x[2] = 2;
+ p_jpeg->subsample_y[0] = 1;
+ p_jpeg->subsample_y[1] = 2;
+ p_jpeg->subsample_y[2] = 2;
+ }
+ else if (p_jpeg->frameheader[0].horizontal_sampling == 1
+ && p_jpeg->frameheader[0].vertical_sampling == 1)
+ { /* 4:4:4 */
+ /* don't overwrite p_jpeg->blocks */
+ p_jpeg->x_mbl = (p_jpeg->x_size+7) / 8;
+ p_jpeg->x_phys = p_jpeg->x_mbl * 8;
+ p_jpeg->y_mbl = (p_jpeg->y_size+7) / 8;
+ p_jpeg->y_phys = p_jpeg->y_mbl * 8;
+ p_jpeg->mcu_membership[0] = 0;
+ p_jpeg->mcu_membership[1] = 1;
+ p_jpeg->mcu_membership[2] = 2;
+ p_jpeg->tab_membership[0] = 0;
+ p_jpeg->tab_membership[1] = 1;
+ p_jpeg->tab_membership[2] = 1;
+ p_jpeg->subsample_x[0] = 1;
+ p_jpeg->subsample_x[1] = 1;
+ p_jpeg->subsample_x[2] = 1;
+ p_jpeg->subsample_y[0] = 1;
+ p_jpeg->subsample_y[1] = 1;
+ p_jpeg->subsample_y[2] = 1;
+ }
+ else
+ {
+ /* error */
+ }
+
+}
+
+
+/*
+* These functions/macros provide the in-line portion of bit fetching.
+* Use check_bit_buffer to ensure there are N bits in get_buffer
+* before using get_bits, peek_bits, or drop_bits.
+* check_bit_buffer(state,n,action);
+* Ensure there are N bits in get_buffer; if suspend, take action.
+* val = get_bits(n);
+* Fetch next N bits.
+* val = peek_bits(n);
+* Fetch next N bits without removing them from the buffer.
+* drop_bits(n);
+* Discard next N bits.
+* The value N should be a simple variable, not an expression, because it
+* is evaluated multiple times.
+*/
+
+INLINE void check_bit_buffer(struct bitstream* pb, int nbits)
+{
+ if (pb->bits_left < nbits)
+ { /* nbits is <= 16, so I can always refill 2 bytes in this case */
+ unsigned char byte;
+
+ byte = *pb->next_input_byte++;
+ if (byte == 0xFF) /* legal marker can be byte stuffing or RSTm */
+ { /* simplification: just skip the (one-byte) marker code */
+ pb->next_input_byte++;
+ }
+ pb->get_buffer = (pb->get_buffer << 8) | byte;
+
+ byte = *pb->next_input_byte++;
+ if (byte == 0xFF) /* legal marker can be byte stuffing or RSTm */
+ { /* simplification: just skip the (one-byte) marker code */
+ pb->next_input_byte++;
+ }
+ pb->get_buffer = (pb->get_buffer << 8) | byte;
+
+ pb->bits_left += 16;
+ }
+}
+
+INLINE int get_bits(struct bitstream* pb, int nbits)
+{
+ return ((int) (pb->get_buffer >> (pb->bits_left -= nbits))) & ((1<<nbits)-1);
+}
+
+INLINE int peek_bits(struct bitstream* pb, int nbits)
+{
+ return ((int) (pb->get_buffer >> (pb->bits_left - nbits))) & ((1<<nbits)-1);
+}
+
+INLINE void drop_bits(struct bitstream* pb, int nbits)
+{
+ pb->bits_left -= nbits;
+}
+
+/* re-synchronize to entropy data (skip restart marker) */
+void search_restart(struct bitstream* pb)
+{
+ pb->next_input_byte--; /* we may have overread it, taking 2 bytes */
+ /* search for a non-byte-padding marker, has to be RSTm or EOS */
+ while (pb->next_input_byte < pb->input_end &&
+ (pb->next_input_byte[-2] != 0xFF || pb->next_input_byte[-1] == 0x00))
+ {
+ pb->next_input_byte++;
+ }
+ pb->bits_left = 0;
+}
+
+/* Figure F.12: extend sign bit. */
+#define HUFF_EXTEND(x,s) ((x) < extend_test[s] ? (x) + extend_offset[s] : (x))
+
+static const int extend_test[16] = /* entry n is 2**(n-1) */
+{
+ 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080,
+ 0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000
+};
+
+static const int extend_offset[16] = /* entry n is (-1 << n) + 1 */
+{
+ 0, ((-1)<<1) + 1, ((-1)<<2) + 1, ((-1)<<3) + 1, ((-1)<<4) + 1,
+ ((-1)<<5) + 1, ((-1)<<6) + 1, ((-1)<<7) + 1, ((-1)<<8) + 1,
+ ((-1)<<9) + 1, ((-1)<<10) + 1, ((-1)<<11) + 1, ((-1)<<12) + 1,
+ ((-1)<<13) + 1, ((-1)<<14) + 1, ((-1)<<15) + 1
+};
+
+/* Decode a single value */
+INLINE int huff_decode_dc(struct bitstream* bs, struct derived_tbl* tbl)
+{
+ int nb, look, s, r;
+
+ check_bit_buffer(bs, HUFF_LOOKAHEAD);
+ look = peek_bits(bs, HUFF_LOOKAHEAD);
+ if ((nb = tbl->look_nbits[look]) != 0)
+ {
+ drop_bits(bs, nb);
+ s = tbl->look_sym[look];
+ check_bit_buffer(bs, s);
+ r = get_bits(bs, s);
+ s = HUFF_EXTEND(r, s);
+ }
+ else
+ { /* slow_DECODE(s, HUFF_LOOKAHEAD+1)) < 0); */
+ long code;
+ nb=HUFF_LOOKAHEAD+1;
+ check_bit_buffer(bs, nb);
+ code = get_bits(bs, nb);
+ while (code > tbl->maxcode[nb])
+ {
+ code <<= 1;
+ check_bit_buffer(bs, 1);
+ code |= get_bits(bs, 1);
+ nb++;
+ }
+ if (nb > 16) /* error in Huffman */
+ {
+ s=0; /* fake a zero, this is most safe */
+ }
+ else
+ {
+ s = tbl->pub[16 + tbl->valptr[nb] + ((int) (code - tbl->mincode[nb])) ];
+ check_bit_buffer(bs, s);
+ r = get_bits(bs, s);
+ s = HUFF_EXTEND(r, s);
+ }
+ } /* end slow decode */
+ return s;
+}
+
+INLINE int huff_decode_ac(struct bitstream* bs, struct derived_tbl* tbl)
+{
+ int nb, look, s;
+
+ check_bit_buffer(bs, HUFF_LOOKAHEAD);
+ look = peek_bits(bs, HUFF_LOOKAHEAD);
+ if ((nb = tbl->look_nbits[look]) != 0)
+ {
+ drop_bits(bs, nb);
+ s = tbl->look_sym[look];
+ }
+ else
+ { /* slow_DECODE(s, HUFF_LOOKAHEAD+1)) < 0); */
+ long code;
+ nb=HUFF_LOOKAHEAD+1;
+ check_bit_buffer(bs, nb);
+ code = get_bits(bs, nb);
+ while (code > tbl->maxcode[nb])
+ {
+ code <<= 1;
+ check_bit_buffer(bs, 1);
+ code |= get_bits(bs, 1);
+ nb++;
+ }
+ if (nb > 16) /* error in Huffman */
+ {
+ s=0; /* fake a zero, this is most safe */
+ }
+ else
+ {
+ s = tbl->pub[16 + tbl->valptr[nb] + ((int) (code - tbl->mincode[nb])) ];
+ }
+ } /* end slow decode */
+ return s;
+}
+
+
+#ifdef HAVE_LCD_COLOR
+
+/* JPEG decoder variant for YUV decoding, into 3 different planes */
+/* Note: it keeps the original color subsampling, even if resized. */
+int jpeg_decode(struct jpeg* p_jpeg, unsigned char* p_pixel[3],
+ int downscale, void (*pf_progress)(int current, int total))
+{
+ struct bitstream bs; /* bitstream "object" */
+ int block[64]; /* decoded DCT coefficients */
+
+ int width, height;
+ int skip_line[3]; /* bytes from one line to the next (skip_line) */
+ int skip_strip[3], skip_mcu[3]; /* bytes to next DCT row / column */
+
+ int i, x, y; /* loop counter */
+
+ unsigned char* p_line[3] = {p_pixel[0], p_pixel[1], p_pixel[2]};
+ unsigned char* p_byte[3]; /* bitmap pointer */
+
+ void (*pf_idct)(unsigned char*, int*, int*, int); /* selected IDCT */
+ int k_need; /* AC coefficients needed up to here */
+ int zero_need; /* init the block with this many zeros */
+
+ int last_dc_val[3] = {0, 0, 0}; /* or 128 for chroma? */
+ int store_offs[4]; /* memory offsets: order of Y11 Y12 Y21 Y22 U V */
+ int restart = p_jpeg->restart_interval; /* MCUs until restart marker */
+
+ /* pick the IDCT we want, determine how to work with coefs */
+ if (downscale == 1)
+ {
+ pf_idct = idct8x8;
+ k_need = 64; /* all */
+ zero_need = 63; /* all */
+ }
+ else if (downscale == 2)
+ {
+ pf_idct = idct4x4;
+ k_need = 25; /* this far in zig-zag to cover 4*4 */
+ zero_need = 27; /* clear this far in linear order */
+ }
+ else if (downscale == 4)
+ {
+ pf_idct = idct2x2;
+ k_need = 5; /* this far in zig-zag to cover 2*2 */
+ zero_need = 9; /* clear this far in linear order */
+ }
+ else if (downscale == 8)
+ {
+ pf_idct = idct1x1;
+ k_need = 0; /* no AC, not needed */
+ zero_need = 0; /* no AC, not needed */
+ }
+ else return -1; /* not supported */
+
+ /* init bitstream, fake a restart to make it start */
+ bs.next_input_byte = p_jpeg->p_entropy_data;
+ bs.bits_left = 0;
+ bs.input_end = p_jpeg->p_entropy_end;
+
+ width = p_jpeg->x_phys / downscale;
+ height = p_jpeg->y_phys / downscale;
+ for (i=0; i<3; i++) /* calculate some strides */
+ {
+ skip_line[i] = width / p_jpeg->subsample_x[i];
+ skip_strip[i] = skip_line[i]
+ * (height / p_jpeg->y_mbl) / p_jpeg->subsample_y[i];
+ skip_mcu[i] = width/p_jpeg->x_mbl / p_jpeg->subsample_x[i];
+ }
+
+ /* prepare offsets about where to store the different blocks */
+ store_offs[p_jpeg->store_pos[0]] = 0;
+ store_offs[p_jpeg->store_pos[1]] = 8 / downscale; /* to the right */
+ store_offs[p_jpeg->store_pos[2]] = width * 8 / downscale; /* below */
+ store_offs[p_jpeg->store_pos[3]] = store_offs[1] + store_offs[2]; /* r+b */
+
+ for(y=0; y<p_jpeg->y_mbl && bs.next_input_byte <= bs.input_end; y++)
+ {
+ for (i=0; i<3; i++) /* scan line init */
+ {
+ p_byte[i] = p_line[i];
+ p_line[i] += skip_strip[i];
+ }
+ for (x=0; x<p_jpeg->x_mbl; x++)
+ {
+ int blkn;
+
+ /* Outer loop handles each block in the MCU */
+ for (blkn = 0; blkn < p_jpeg->blocks; blkn++)
+ { /* Decode a single block's worth of coefficients */
+ int k = 1; /* coefficient index */
+ int s, r; /* huffman values */
+ int ci = p_jpeg->mcu_membership[blkn]; /* component index */
+ int ti = p_jpeg->tab_membership[blkn]; /* table index */
+ struct derived_tbl* dctbl = &p_jpeg->dc_derived_tbls[ti];
+ struct derived_tbl* actbl = &p_jpeg->ac_derived_tbls[ti];
+
+ /* Section F.2.2.1: decode the DC coefficient difference */
+ s = huff_decode_dc(&bs, dctbl);
+
+ last_dc_val[ci] += s;
+ block[0] = last_dc_val[ci]; /* output it (assumes zag[0] = 0) */
+
+ /* coefficient buffer must be cleared */
+ MEMSET(block+1, 0, zero_need*sizeof(block[0]));
+
+ /* Section F.2.2.2: decode the AC coefficients */
+ for (; k < k_need; k++)
+ {
+ s = huff_decode_ac(&bs, actbl);
+ r = s >> 4;
+ s &= 15;
+
+ if (s)
+ {
+ k += r;
+ check_bit_buffer(&bs, s);
+ r = get_bits(&bs, s);
+ block[zag[k]] = HUFF_EXTEND(r, s);
+ }
+ else
+ {
+ if (r != 15)
+ {
+ k = 64;
+ break;
+ }
+ k += r;
+ }
+ } /* for k */
+ /* In this path we just discard the values */
+ for (; k < 64; k++)
+ {
+ s = huff_decode_ac(&bs, actbl);
+ r = s >> 4;
+ s &= 15;
+
+ if (s)
+ {
+ k += r;
+ check_bit_buffer(&bs, s);
+ drop_bits(&bs, s);
+ }
+ else
+ {
+ if (r != 15)
+ break;
+ k += r;
+ }
+ } /* for k */
+
+ if (ci == 0)
+ { /* Y component needs to bother about block store */
+ pf_idct(p_byte[0]+store_offs[blkn], block,
+ p_jpeg->qt_idct[ti], skip_line[0]);
+ }
+ else
+ { /* chroma */
+ pf_idct(p_byte[ci], block, p_jpeg->qt_idct[ti],
+ skip_line[ci]);
+ }
+ } /* for blkn */
+ p_byte[0] += skip_mcu[0]; /* unrolled for (i=0; i<3; i++) loop */
+ p_byte[1] += skip_mcu[1];
+ p_byte[2] += skip_mcu[2];
+ if (p_jpeg->restart_interval && --restart == 0)
+ { /* if a restart marker is due: */
+ restart = p_jpeg->restart_interval; /* count again */
+ search_restart(&bs); /* align the bitstream */
+ last_dc_val[0] = last_dc_val[1] =
+ last_dc_val[2] = 0; /* reset decoder */
+ }
+ } /* for x */
+ if (pf_progress != NULL)
+ pf_progress(y, p_jpeg->y_mbl-1); /* notify about decoding progress */
+ } /* for y */
+
+ return 0; /* success */
+}
+#else /* !HAVE_LCD_COLOR */
+
+/* a JPEG decoder specialized in decoding only the luminance (b&w) */
+int jpeg_decode(struct jpeg* p_jpeg, unsigned char* p_pixel[1], int downscale,
+ void (*pf_progress)(int current, int total))
+{
+ struct bitstream bs; /* bitstream "object" */
+ int block[64]; /* decoded DCT coefficients */
+
+ int width, height;
+ int skip_line; /* bytes from one line to the next (skip_line) */
+ int skip_strip, skip_mcu; /* bytes to next DCT row / column */
+
+ int x, y; /* loop counter */
+
+ unsigned char* p_line = p_pixel[0];
+ unsigned char* p_byte; /* bitmap pointer */
+
+ void (*pf_idct)(unsigned char*, int*, int*, int); /* selected IDCT */
+ int k_need; /* AC coefficients needed up to here */
+ int zero_need; /* init the block with this many zeros */
+
+ int last_dc_val = 0;
+ int store_offs[4]; /* memory offsets: order of Y11 Y12 Y21 Y22 U V */
+ int restart = p_jpeg->restart_interval; /* MCUs until restart marker */
+
+ /* pick the IDCT we want, determine how to work with coefs */
+ if (downscale == 1)
+ {
+ pf_idct = idct8x8;
+ k_need = 64; /* all */
+ zero_need = 63; /* all */
+ }
+ else if (downscale == 2)
+ {
+ pf_idct = idct4x4;
+ k_need = 25; /* this far in zig-zag to cover 4*4 */
+ zero_need = 27; /* clear this far in linear order */
+ }
+ else if (downscale == 4)
+ {
+ pf_idct = idct2x2;
+ k_need = 5; /* this far in zig-zag to cover 2*2 */
+ zero_need = 9; /* clear this far in linear order */
+ }
+ else if (downscale == 8)
+ {
+ pf_idct = idct1x1;
+ k_need = 0; /* no AC, not needed */
+ zero_need = 0; /* no AC, not needed */
+ }
+ else return -1; /* not supported */
+
+ /* init bitstream, fake a restart to make it start */
+ bs.next_input_byte = p_jpeg->p_entropy_data;
+ bs.bits_left = 0;
+ bs.input_end = p_jpeg->p_entropy_end;
+
+ width = p_jpeg->x_phys / downscale;
+ height = p_jpeg->y_phys / downscale;
+ skip_line = width;
+ skip_strip = skip_line * (height / p_jpeg->y_mbl);
+ skip_mcu = (width/p_jpeg->x_mbl);
+
+ /* prepare offsets about where to store the different blocks */
+ store_offs[p_jpeg->store_pos[0]] = 0;
+ store_offs[p_jpeg->store_pos[1]] = 8 / downscale; /* to the right */
+ store_offs[p_jpeg->store_pos[2]] = width * 8 / downscale; /* below */
+ store_offs[p_jpeg->store_pos[3]] = store_offs[1] + store_offs[2]; /* r+b */
+
+ for(y=0; y<p_jpeg->y_mbl && bs.next_input_byte <= bs.input_end; y++)
+ {
+ p_byte = p_line;
+ p_line += skip_strip;
+ for (x=0; x<p_jpeg->x_mbl; x++)
+ {
+ int blkn;
+
+ /* Outer loop handles each block in the MCU */
+ for (blkn = 0; blkn < p_jpeg->blocks; blkn++)
+ { /* Decode a single block's worth of coefficients */
+ int k = 1; /* coefficient index */
+ int s, r; /* huffman values */
+ int ci = p_jpeg->mcu_membership[blkn]; /* component index */
+ int ti = p_jpeg->tab_membership[blkn]; /* table index */
+ struct derived_tbl* dctbl = &p_jpeg->dc_derived_tbls[ti];
+ struct derived_tbl* actbl = &p_jpeg->ac_derived_tbls[ti];
+
+ /* Section F.2.2.1: decode the DC coefficient difference */
+ s = huff_decode_dc(&bs, dctbl);
+
+ if (ci == 0) /* only for Y component */
+ {
+ last_dc_val += s;
+ block[0] = last_dc_val; /* output it (assumes zag[0] = 0) */
+
+ /* coefficient buffer must be cleared */
+ MEMSET(block+1, 0, zero_need*sizeof(block[0]));
+
+ /* Section F.2.2.2: decode the AC coefficients */
+ for (; k < k_need; k++)
+ {
+ s = huff_decode_ac(&bs, actbl);
+ r = s >> 4;
+ s &= 15;
+
+ if (s)
+ {
+ k += r;
+ check_bit_buffer(&bs, s);
+ r = get_bits(&bs, s);
+ block[zag[k]] = HUFF_EXTEND(r, s);
+ }
+ else
+ {
+ if (r != 15)
+ {
+ k = 64;
+ break;
+ }
+ k += r;
+ }
+ } /* for k */
+ }
+ /* In this path we just discard the values */
+ for (; k < 64; k++)
+ {
+ s = huff_decode_ac(&bs, actbl);
+ r = s >> 4;
+ s &= 15;
+
+ if (s)
+ {
+ k += r;
+ check_bit_buffer(&bs, s);
+ drop_bits(&bs, s);
+ }
+ else
+ {
+ if (r != 15)
+ break;
+ k += r;
+ }
+ } /* for k */
+
+ if (ci == 0)
+ { /* only for Y component */
+ pf_idct(p_byte+store_offs[blkn], block, p_jpeg->qt_idct[ti],
+ skip_line);
+ }
+ } /* for blkn */
+ p_byte += skip_mcu;
+ if (p_jpeg->restart_interval && --restart == 0)
+ { /* if a restart marker is due: */
+ restart = p_jpeg->restart_interval; /* count again */
+ search_restart(&bs); /* align the bitstream */
+ last_dc_val = 0; /* reset decoder */
+ }
+ } /* for x */
+ if (pf_progress != NULL)
+ pf_progress(y, p_jpeg->y_mbl-1); /* notify about decoding progress */
+ } /* for y */
+
+ return 0; /* success */
+}
+#endif /* !HAVE_LCD_COLOR */
+
+/**************** end JPEG code ********************/
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-02 07:32:56 +0000