First public release

.gitignore

+*~
+*.bak
+*.o
+jpeg2c/image.c
+jpeg2c/jpegtranslater

JPEG-Decoder/ColorConversion.c

+#include "decoding.h"
+#include <stdbool.h>
+#include <stdint.h>
+#include "image.h"
+
+
+// Pixel: 0x00BBGGRR
+void CreateRGBPixels(
+        token_t Y[8*8]      /*in*/, 
+        token_t Cr[8*8]     /*in*/, 
+        token_t Cb[8*8]     /*in*/,
+        token_t Pixels[8*8] /*out*/
+        )
+{
+    int16_t R, G, B;    // While conversion, negative values and 9bit values are possible
+    for(uint8_t i=0; i<8*8; i++)
+    {
+        // Source: https://en.wikipedia.org/wiki/YCbCr
+        R = Y[i]                             + 1.402f   * (Cr[i]-128.0f);
+        G = Y[i] - 0.34414f * (Cb[i]-128.0f) - 0.71414f * (Cr[i]-128.0f);
+        B = Y[i] + 1.772f   * (Cb[i]-128.0f);
+
+        // Check boundaries
+        if(R < 0)
+            R = 0;
+        else if(R > 255)
+            R = 255;
+        if(G < 0)
+            G = 0;
+        else if(G > 255)
+            G = 255;
+        if(B < 0)
+            B = 0;
+        else if(B > 255)
+            B = 255;
+
+        // Create Pixel
+        Pixels[i] = (token_t)B << 16 | G << 8 | R;
+    }
+}
+
+void ColorConversion(
+        token_t Y[8*8]      /*in*/, 
+        token_t Cr[8*8]     /*in*/, 
+        token_t Cb[8*8]     /*in*/,
+        token_t R[8*8]      /*out*/, 
+        token_t G[8*8]      /*out*/, 
+        token_t B[8*8]      /*out*/
+        )
+{
+
+    for(int i=0; i<8*8; i++)
+    {
+        // Source: https://en.wikipedia.org/wiki/YCbCr
+        R[i] = Y[i]                             + 1.402f   * (Cr[i]-128.0f);
+        G[i] = Y[i] - 0.34414f * (Cb[i]-128.0f) - 0.71414f * (Cr[i]-128.0f);
+        B[i] = Y[i] + 1.772f   * (Cb[i]-128.0f);
+
+        if(R[i] < 0)
+            R[i] = 0;
+        else if(R[i] > 255)
+            R[i] = 255;
+        if(G[i] < 0)
+            G[i] = 0;
+        else if(G[i] > 255)
+            G[i] = 255;
+        if(B[i] < 0)
+            B[i] = 0;
+        else if(B[i] > 255)
+            B[i] = 255;
+    }
+}
+
+
+void ConvertRGB24to16(
+        token_t Pixels24[8*8] /*in*/, 
+        token_t Pixels16[8*8] /*out*/
+        )
+{
+    for(uint8_t i=0; i<8*8; i++)
+    {
+        int16_t r,g,b; // The conversion algorithm can temporary create 9bit values
+
+        // Separate R,G,B from pixel
+        r = (Pixels24[i]      ) & 0x000000FF;
+        g = (Pixels24[i] >>  8) & 0x000000FF;
+        b = (Pixels24[i] >> 16) & 0x000000FF;
+
+        // lazy rounding
+        r += 0x04;
+        g += 0x02;
+        b += 0x04;
+        if(r > 255) r = 255;
+        if(g > 255) g = 255;
+        if(b > 255) b = 255;
+
+        // Reduce color bit width
+        r = (r >> 3) & 0x1F; //RRRRRRRR >> 3 ->  RRRRR (5)
+        g = (g >> 2) & 0x3F; //GGGGGGGG >> 2 -> GGGGGG (6)
+        b = (b >> 3) & 0x1F; //BBBBBBBB >> 3 ->  BBBBB (5)
+
+        Pixels16[i] = (r << 11) | (g << 5) | (b << 0);
+    }
+}
+
+
+// vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
+

JPEG-Decoder/IDCT.c

+#include "decoding.h"
+#include <math.h>
+#include <stdbool.h>
+#ifdef DEBUG
+#include <stdio.h>
+#endif
+#include <stdint.h>
+#include "image.h"
+
+
+#ifndef M_PI
+#define M_PI 3.1415926f
+#endif
+
+void IDCT(token_t source[8*8], token_t destination[8*8])
+{
+    for(int dsty=0; dsty<8; dsty++)
+    {
+        for(int dstx=0; dstx<8; dstx++)
+        {
+            float sum;
+            sum = 0.0f;
+            for(int srcy=0; srcy<8; srcy++)
+            {
+                for(int srcx=0; srcx<8; srcx++)
+                {
+                    float cosx, cosy;
+                    // Source: https://www.w3.org/Graphics/JPEG/itu-t81.pdf
+                    cosx = cosf( ( M_PI * (2.0f * dstx + 1.0f) * srcx ) / 16.0f);
+                    cosy = cosf( ( M_PI * (2.0f * dsty + 1.0f) * srcy ) / 16.0f);
+
+                    float cx, cy;
+                    if(srcx == 0)
+                        cx = 1.0f / sqrtf(2.0f);
+                    else
+                        cx = 1.0f;
+
+                    if(srcy == 0)
+                        cy = 1.0f / sqrtf(2.0f);
+                    else
+                        cy = 1.0f;
+
+                    sum += source[srcy*8+srcx] * cx * cy * cosx * cosy;
+                }
+            }
+            
+            // Level shift as told in F.1.1.3: https://www.w3.org/Graphics/JPEG/itu-t81.pdf
+            destination[dsty*8+dstx] = roundf(0.25f * sum + 128.0f);
+
+
+            // Seen at https://github.com/matja/jpegdecoder/blob/master/jpegdecoder.c#L272
+            if(destination[dsty*8+dstx] < 0)
+                destination[dsty*8+dstx] = 0;
+            else if(destination[dsty*8+dstx] > 255)
+                destination[dsty*8+dstx] = 255;
+        }
+    }
+
+#ifdef DEBUG
+    extern int dez2str(char* dst, long src);
+    extern void Print(const char *string);
+    Print("\e[1;34mSlow-Matrix:\e[0;36m\n");
+    for(int y=0; y<8; y++)
+    {
+        Print("\t");
+        for(int x=0; x<8; x++)
+        {
+            char data[20];
+            dez2str(data, destination[y*8+x]);
+            Print(data);
+            Print("\t");
+        }
+        Print("\n");
+    }
+#endif
+}
+
+
+void FastIDCT(token_t source[8*8], token_t destination[8*8])
+{
+    // Source:
+    //  Author: Robert Danielsen
+    //  Modified: T.W., 11-Nov-1996, Adopted from Momusys VM
+    //  Modified by Ralf Stemmer (ralf.stemmer@uol.de)
+    //  Modifications:
+    //      - Using float instead of double
+    //      - Adding offset of 128 to the result
+    //  Link: https://github.com/usamaaftab80/multi-p2p/blob/5c46a17192e6483df1e560337fc0a50bdd7cc0b2/vic264/codec/h263/idctenc.c#L312
+
+    int   j1, i, j;
+    float b[8], b1[8], dd[8][8];
+    float f0 = 0.7071068f;
+    float f1 = 0.4903926f;
+    float f2 = 0.4619398f;
+    float f3 = 0.4157348f;
+    float f4 = 0.3535534f;
+    float f5 = 0.2777851f;
+    float f6 = 0.1913417f;
+    float f7 = 0.0975452f;
+    float e, f, g, h;
+
+    /* Horizontal */
+
+    /* Descan coefficients first */
+
+    for (i = 0; i < 8; i++)
+    {
+        for (j = 0; j < 8; j++)
+        {
+            b[j] = (float)source[8 * i + j];
+        }
+        e = b[1] * f7 - b[7] * f1;
+        h = b[7] * f7 + b[1] * f1;
+        f = b[5] * f3 - b[3] * f5;
+        g = b[3] * f3 + b[5] * f5;
+
+        b1[0] = (b[0] + b[4]) * f4;
+        b1[1] = (b[0] - b[4]) * f4;
+        b1[2] = b[2] * f6 - b[6] * f2;
+        b1[3] = b[6] * f6 + b[2] * f2;
+        b[4]  = e + f;
+        b1[5] = e - f;
+        b1[6] = h - g;
+        b[7]  = h + g;
+
+        b[5] = (b1[6] - b1[5]) * f0;
+        b[6] = (b1[6] + b1[5]) * f0;
+        b[0] = b1[0] + b1[3];
+        b[1] = b1[1] + b1[2];
+        b[2] = b1[1] - b1[2];
+        b[3] = b1[0] - b1[3];
+
+        for (j = 0; j < 4; j++)
+        {
+            j1 = 7 - j;
+            dd[i][j] = b[j] + b[j1];
+            dd[i][j1] = b[j] - b[j1];
+        }
+    }
+
+        /* Vertical */
+
+    for (i = 0; i < 8; i++)
+    {
+        for (j = 0; j < 8; j++)
+        {
+            b[j] = dd[j][i];
+        }
+        e = b[1] * f7 - b[7] * f1;
+        h = b[7] * f7 + b[1] * f1;
+        f = b[5] * f3 - b[3] * f5;
+        g = b[3] * f3 + b[5] * f5;
+
+        b1[0] = (b[0] + b[4]) * f4;
+        b1[1] = (b[0] - b[4]) * f4;
+        b1[2] = b[2] * f6 - b[6] * f2;
+        b1[3] = b[6] * f6 + b[2] * f2;
+        b[4] = e + f;
+        b1[5] = e - f;
+        b1[6] = h - g;
+        b[7] = h + g;
+
+        b[5] = (b1[6] - b1[5]) * f0;
+        b[6] = (b1[6] + b1[5]) * f0;
+        b[0] =  b1[0] + b1[3];
+        b[1] =  b1[1] + b1[2];
+        b[2] =  b1[1] - b1[2];
+        b[3] =  b1[0] - b1[3];
+
+        for (j = 0; j < 4; j++)
+        {
+            j1 = 7 - j;
+            dd[j][i]  = b[j] + b[j1];
+            dd[j1][i] = b[j] - b[j1];
+        }
+    }
+
+    for (i = 0; i < 8; i++)
+    {
+        for (j = 0; j < 8; j++)
+        {
+#define MNINT(a) ((a) < 0 ? (int)(a - 0.5f) : (int)(a + 0.5f))
+            destination[i*8+j]  = (token_t)(MNINT(dd[i][j]) + 128.0f);
+        }
+    }
+#ifdef DEBUG
+    extern int dez2str(char* dst, long src);
+    extern void Print(const char *string);
+    Print("\e[1;34mFast-Matrix:\e[0;36m\n");
+    for(int y=0; y<8; y++)
+    {
+        Print("\t");
+        for(int x=0; x<8; x++)
+        {
+            char data[20];
+            dez2str(data, destination[y*8+x]);
+            Print(data);
+            Print("\t");
+        }
+        Print("\n");
+    }
+#endif
+}
+
+// vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
+

JPEG-Decoder/decoding.c

+#include "decoding.h"
+#include "image.h"
+#include <stdint.h>
+#include <stdbool.h>
+
+uint8_t GetNextBitFromImage(bool reset)
+{
+    static int byteindex = 0;
+    static int bitindex  = 0;
+
+    if(reset)
+    {
+        byteindex = 0;
+        bitindex  = 0;
+        return 0xFF;
+    }
+
+    uint8_t bit;
+    bit  = Image_data[byteindex] >> (7-bitindex);
+    bit &= 0x01;    // be aware of arithmetic shifting
+
+    if(bitindex >= 7)
+    {
+        bitindex = 0;
+        byteindex++;
+    }
+    else
+    {
+        bitindex++;
+    }
+
+    return bit;
+}
+
+// vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
+

JPEG-Decoder/decoding.h

+#ifndef JPEGDECODING
+#define JPEGDECODING
+
+/*
+ * CHANGELOG
+ * 25.10.19 - Comments reviewed for publication
+ * 24.05.19 - Interface of InverQuantization changed to avoid a configuration-depending branching behavior
+ * 13.05.19 - BlockInfo parameter of GetEncodedImageBlock is optional and can be NULL
+ *          - Detailed comments added to this file
+ *          - Cleaning up header file
+ */
+#include <stdint.h>
+
+#ifndef LIBSDF_H
+typedef int token_t;    // Better include sdf.h to get token_t definition
+#endif
+enum component_t {COMP_Y=0, COMP_Cb=1, COMP_Cr=2};
+enum blockinfoindex_t {BII_IMG_WIDTH=0, BII_IMG_HEIGHT=1, BII_CURRENTBLOCK=2, BII_MAXBLOCKS=3};
+
+// Actors
+/*
+ * File: huffman.c
+ * Features:
+ *      Dependent X-Time: Yes, per Iteration (Image Input Data)
+ *      Floatingpoint:    No
+ *      Mult./Div.:       No
+ */
+void GetEncodedImageBlock(
+        token_t DCOffset[3]   /*in/out*/,
+        token_t Y[8*8]        /*out*/,
+        token_t Cr[8*8]       /*out*/,
+        token_t Cb[8*8]       /*out*/,
+        token_t BlockInfo[4]  /*out [optional]*/); // 0: ImgW, 1: ImgH, 2: Block, 3: MaxBlocks
+
+/*
+ * File: quantization.c
+ * Features:
+ *      Dependent X-Time: Yes, per Instance (quantization table)
+ *                        Yes, per Iteration (QuantizedCoefficients get rounded
+ *      Floatingpoint:    No
+ *      Mult./Div.:       Yes (64 multiplications)
+ */
+void InverseQuantization(
+        const uint8_t quantizationtable[8*8],   /*config*/
+        token_t QuantizedCoefficients[8*8] /*in*/,
+        token_t DCTCoefficients[8*8]       /*out*/);
+
+/*
+ * File: IDCT.c
+ * Features:
+ *      Dependent X-Time: Yes, per Iteration (rounding)
+ *      Floatingpoint:    Yes (thousands of times incl sqrtf and cosf)
+ *      Mult./Div.:       Yes (thousands of multiplications and dividations)
+ */
+void IDCT(
+        token_t source[8*8]      /*in*/,
+        token_t destination[8*8] /*out*/);
+
+/*
+ * File: IDCT.c
+ * Features:
+ *      Dependent X-Time: No
+ *      Floatingpoint:    Yes (Lots of *,+,-)
+ *      Mult./Div.:       No
+ */
+void FastIDCT(
+        token_t source[8*8]      /*in*/,
+        token_t destination[8*8] /*out*/);
+
+/*
+ * File: ColorConversion.c
+ * Features:
+ *      Dependent X-Time: Yes, per Iteration (rounding)
+ *      Floatingpoint:    Yes (~100 +,-,·,/)
+ *      Mult./Div.:       No (Only float)
+ */
+void CreateRGBPixels(
+        token_t Y[8*8]      /*in*/, 
+        token_t Cr[8*8]     /*in*/, 
+        token_t Cb[8*8]     /*in*/,
+        token_t Pixels[8*8] /*out*/
+        );
+/*
+ * File: ColorConversion.c
+ * Features:
+ *      Dependent X-Time: Yes, per Iteration (rounding)
+ *      Floatingpoint:    Yes (~100 +,-,·,/)
+ *      Mult./Div.:       No (Only float)
+ */
+void ColorConversion(
+        token_t Y[8*8]      /*in*/, 
+        token_t Cr[8*8]     /*in*/, 
+        token_t Cb[8*8]     /*in*/,
+        token_t R[8*8]      /*out*/, 
+        token_t G[8*8]      /*out*/, 
+        token_t B[8*8]      /*out*/
+        );
+/*
+ * File: ColorConversion.c
+ * Features:
+ *      Dependent X-Time: Yes, per Iteration (rounding)
+ *      Floatingpoint:    No
+ *      Mult./Div.:       No
+ */
+void ConvertRGB24to16(
+        token_t Pixels24[8*8] /*in*/, 
+        token_t Pixels16[8*8] /*out*/
+        );
+
+
+#endif
+
+// vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
+

JPEG-Decoder/huffman.c

+#include "decoding.h"
+#include <stdbool.h>
+#ifdef DEBUG
+#include <stdio.h>
+#endif
+#include <stdint.h>
+#include "image.h"
+
+// Internals
+
+// Does not care about Image_size.
+// To start from the beginning, call with reset=true - the returned value is then invalid!
+uint8_t GetNextBitFromImage(bool reset);
+
+// Huffman decoding
+void GetEncodedImageBlockComponent(enum component_t component, token_t dcoffset, token_t matrix[8*8]);
+uint8_t GetHuffmanDecodedValueFromImage(int tablesize, const uint16_t *codes, const uint8_t *values, const uint16_t *masks);
+signed int DCCodeToInteger(uint16_t dccode, uint8_t dclength);
+
+
+
+void GetEncodedImageBlock(token_t DCOffsets[3], token_t Y[8*8], token_t Cr[8*8], token_t Cb[8*8],
+        token_t BlockInfo[4])
+{
+    // ">> 3" = "/ 8"
+    const uint16_t  numofblocks = (Image_xdimension >> 3) * (Image_ydimension >> 3);
+    static uint16_t blockcount  = 0;
+
+    // When this is the first block, …
+    if(blockcount == 0)
+    {
+        GetNextBitFromImage(true);   // … reset decoder
+        DCOffsets[COMP_Y ] = 0;
+        DCOffsets[COMP_Cb] = 0;
+        DCOffsets[COMP_Cr] = 0;
+    }
+
+    // For Y, Cr, Cb
+    GetEncodedImageBlockComponent(COMP_Y,  DCOffsets[COMP_Y ], Y);
+    GetEncodedImageBlockComponent(COMP_Cb, DCOffsets[COMP_Cb], Cb);
+    GetEncodedImageBlockComponent(COMP_Cr, DCOffsets[COMP_Cr], Cr);
+    DCOffsets[COMP_Y ] = Y[0];
+    DCOffsets[COMP_Cb] = Cb[0];
+    DCOffsets[COMP_Cr] = Cr[0];
+
+    // Output additional information
+    if(BlockInfo != NULL)
+    {
+        BlockInfo[0] = Image_xdimension;
+        BlockInfo[1] = Image_ydimension;
+        BlockInfo[2] = blockcount;
+        BlockInfo[3] = numofblocks;
+    }
+
+    // Update internal state for next block
+    blockcount++;
+    if(blockcount >= numofblocks)
+        blockcount = 0;
+}
+
+
+void GetEncodedImageBlockComponent(enum component_t component, token_t dcoffset, token_t matrix[8*8])
+{
+    int             DCHT_size;
+    const uint16_t *DCHT_codes;
+    const uint8_t  *DCHT_values;
+    const uint16_t *DCHT_masks;
+    int             ACHT_size;
+    const uint16_t *ACHT_codes;
+    const uint8_t  *ACHT_values;
+    const uint16_t *ACHT_masks;
+    
+    switch(component)
+    {
+        case COMP_Y:
+            DCHT_size   = Y_DCHT_size;
+            DCHT_codes  = Y_DCHT_codes;
+            DCHT_values = Y_DCHT_values;
+            DCHT_masks  = Y_DCHT_masks;
+            ACHT_size   = Y_ACHT_size;
+            ACHT_codes  = Y_ACHT_codes;
+            ACHT_values = Y_ACHT_values;
+            ACHT_masks  = Y_ACHT_masks;
+            break;
+
+        case COMP_Cr:
+            DCHT_size   = Cr_DCHT_size;
+            DCHT_codes  = Cr_DCHT_codes;
+            DCHT_values = Cr_DCHT_values;
+            DCHT_masks  = Cr_DCHT_masks;
+            ACHT_size   = Cr_ACHT_size;
+            ACHT_codes  = Cr_ACHT_codes;
+            ACHT_values = Cr_ACHT_values;
+            ACHT_masks  = Cr_ACHT_masks;
+            break;
+
+        case COMP_Cb:
+            DCHT_size   = Cb_DCHT_size;
+            DCHT_codes  = Cb_DCHT_codes;
+            DCHT_values = Cb_DCHT_values;
+            DCHT_masks  = Cb_DCHT_masks;
+            ACHT_size   = Cb_ACHT_size;
+            ACHT_codes  = Cb_ACHT_codes;
+            ACHT_values = Cb_ACHT_values;
+            ACHT_masks  = Cb_ACHT_masks;
+            break;
+    }
+
+    // Decode DC
+    // read code length
+    uint8_t dclength;
+    dclength = GetHuffmanDecodedValueFromImage(
+            DCHT_size, 
+            DCHT_codes,
+            DCHT_values,
+            DCHT_masks
+            );
+
+    // read code word
+    uint16_t dccode = 0;
+    for(int i=0; i<dclength; i++)
+        dccode = (dccode << 1) | (uint16_t)GetNextBitFromImage(false);
+
+    // decode DC value
+    signed int dcvalue;
+    dcvalue = DCCodeToInteger(dccode, dclength);
+
+#ifdef DEBUG
+    printf("\e[1;34mDC length: \e[0;36m0x%02X\n", dclength);
+    printf("\e[1;34mDC code:   \e[0;36m0x%02X\n", dccode);
+    printf("\e[1;34mDC value:  \e[0;36m%d\n",     dcvalue);
+#endif
+
+    matrix[0] = dcoffset + dcvalue; // Difference Encoding!
+
+    // Decode AC values
+    for(int i=1; i<8*8; i++)
+    {
+        uint8_t acrlc;
+        acrlc = GetHuffmanDecodedValueFromImage(
+                ACHT_size, 
+                ACHT_codes,
+                ACHT_values,
+                ACHT_masks
+                );
+
+        if(acrlc == 0x00) // End Of Block - All left values are 0x00
+        {
+            for(; i<8*8; i++)
+                matrix[i] = 0x00;
+            break;
+        }
+        else if(acrlc == 0xF0) // ZRL Code
+        {
+            for(int zeros=0; zeros<16; zeros++, i++)
+                matrix[i] = 0x00;
+            continue;
+        }
+
+        // Decode Run-Length-Code