// NanoJPEG -- KeyJ's Tiny Baseline JPEG Decoder // version 1.3.5 (2016-11-14) // Copyright (c) 2009-2016 Martin J. Fiedler <martin.fiedler@gmx.net> // published under the terms of the MIT license // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to // deal in the Software without restriction, including without limitation the // rights to use, copy, modify, merge, publish, distribute, sublicense, and/or // sell copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER // DEALINGS IN THE SOFTWARE. /////////////////////////////////////////////////////////////////////////////// // DOCUMENTATION SECTION // // read this if you want to know what this is all about // /////////////////////////////////////////////////////////////////////////////// // INTRODUCTION // ============ // // This is a minimal decoder for baseline JPEG images. It accepts memory dumps // of JPEG files as input and generates either 8-bit grayscale or packed 24-bit // RGB images as output. It does not parse JFIF or Exif headers; all JPEG files // are assumed to be either grayscale or YCbCr. CMYK or other color spaces are // not supported. All YCbCr subsampling schemes with power-of-two ratios are // supported, as are restart intervals. Progressive or lossless JPEG is not // supported. // Summed up, NanoJPEG should be able to decode all images from digital cameras // and most common forms of other non-progressive JPEG images. // The decoder is not optimized for speed, it's optimized for simplicity and // small code. Image quality should be at a reasonable level. A bicubic chroma // upsampling filter ensures that subsampled YCbCr images are rendered in // decent quality. The decoder is not meant to deal with broken JPEG files in // a graceful manner; if anything is wrong with the bitstream, decoding will // simply fail. // The code should work with every modern C compiler without problems and // should not emit any warnings. It uses only (at least) 32-bit integer // arithmetic and is supposed to be endianness independent and 64-bit clean. // However, it is not thread-safe. // COMPILE-TIME CONFIGURATION // ========================== // // The following aspects of NanoJPEG can be controlled with preprocessor // defines: // // _NJ_EXAMPLE_PROGRAM = Compile a main() function with an example // program. // _NJ_INCLUDE_HEADER_ONLY = Don't compile anything, just act as a header // file for NanoJPEG. Example: // #define _NJ_INCLUDE_HEADER_ONLY // #include "nanojpeg.c" // int main(void) { // njInit(); // // your code here // njDone(); // } // NJ_USE_LIBC=1 = Use the malloc(), free(), memset() and memcpy() // functions from the standard C library (default). // NJ_USE_LIBC=0 = Don't use the standard C library. In this mode, // external functions njAlloc(), njFreeMem(), // njFillMem() and njCopyMem() need to be defined // and implemented somewhere. // NJ_USE_WIN32=0 = Normal mode (default). // NJ_USE_WIN32=1 = If compiling with MSVC for Win32 and // NJ_USE_LIBC=0, NanoJPEG will use its own // implementations of the required C library // functions (default if compiling with MSVC and // NJ_USE_LIBC=0). // NJ_CHROMA_FILTER=1 = Use the bicubic chroma upsampling filter // (default). // NJ_CHROMA_FILTER=0 = Use simple pixel repetition for chroma upsampling // (bad quality, but faster and less code). // API // === // // For API documentation, read the "header section" below. // EXAMPLE // ======= // // A few pages below, you can find an example program that uses NanoJPEG to // convert JPEG files into PGM or PPM. To compile it, use something like // gcc -O3 -D_NJ_EXAMPLE_PROGRAM -o nanojpeg nanojpeg.c // You may also add -std=c99 -Wall -Wextra -pedantic -Werror, if you want :) // The only thing you might need is -Wno-shift-negative-value, because this // code relies on the target machine using two's complement arithmetic, but // the C standard does not, even though *any* practically useful machine // nowadays uses two's complement. /////////////////////////////////////////////////////////////////////////////// // HEADER SECTION // // copy and pase this into nanojpeg.h if you want // /////////////////////////////////////////////////////////////////////////////// #ifndef _NANOJPEG_H #define _NANOJPEG_H // nj_result_t: Result codes for njDecode(). typedef enum _nj_result { NJ_OK = 0, // no error, decoding successful NJ_NO_JPEG, // not a JPEG file NJ_UNSUPPORTED, // unsupported format NJ_OUT_OF_MEM, // out of memory NJ_INTERNAL_ERR, // internal error NJ_SYNTAX_ERROR, // syntax error __NJ_FINISHED, // used internally, will never be reported } nj_result_t; // njInit: Initialize NanoJPEG. // For safety reasons, this should be called at least one time before using // using any of the other NanoJPEG functions. void njInit(void); // njDecode: Decode a JPEG image. // Decodes a memory dump of a JPEG file into internal buffers. // Parameters: // jpeg = The pointer to the memory dump. // size = The size of the JPEG file. // Return value: The error code in case of failure, or NJ_OK (zero) on success. nj_result_t njDecode(const void* jpeg, const int size); // njGetWidth: Return the width (in pixels) of the most recently decoded // image. If njDecode() failed, the result of njGetWidth() is undefined. int njGetWidth(void); // njGetHeight: Return the height (in pixels) of the most recently decoded // image. If njDecode() failed, the result of njGetHeight() is undefined. int njGetHeight(void); // njIsColor: Return 1 if the most recently decoded image is a color image // (RGB) or 0 if it is a grayscale image. If njDecode() failed, the result // of njGetWidth() is undefined. int njIsColor(void); // njGetImage: Returns the decoded image data. // Returns a pointer to the most recently image. The memory layout it byte- // oriented, top-down, without any padding between lines. Pixels of color // images will be stored as three consecutive bytes for the red, green and // blue channels. This data format is thus compatible with the PGM or PPM // file formats and the OpenGL texture formats GL_LUMINANCE8 or GL_RGB8. // If njDecode() failed, the result of njGetImage() is undefined. unsigned char* njGetImage(void); // njGetImageSize: Returns the size (in bytes) of the image data returned // by njGetImage(). If njDecode() failed, the result of njGetImageSize() is // undefined. int njGetImageSize(void); // njDone: Uninitialize NanoJPEG. // Resets NanoJPEG's internal state and frees all memory that has been // allocated at run-time by NanoJPEG. It is still possible to decode another // image after a njDone() call. void njDone(void); #endif//_NANOJPEG_H /////////////////////////////////////////////////////////////////////////////// // CONFIGURATION SECTION // // adjust the default settings for the NJ_ defines here // /////////////////////////////////////////////////////////////////////////////// #ifndef NJ_USE_LIBC #define NJ_USE_LIBC 1 #endif #ifndef NJ_USE_WIN32 #ifdef _MSC_VER #define NJ_USE_WIN32 (!NJ_USE_LIBC) #else #define NJ_USE_WIN32 0 #endif #endif #ifndef NJ_CHROMA_FILTER #define NJ_CHROMA_FILTER 1 #endif /////////////////////////////////////////////////////////////////////////////// // EXAMPLE PROGRAM // // just define _NJ_EXAMPLE_PROGRAM to compile this (requires NJ_USE_LIBC) // /////////////////////////////////////////////////////////////////////////////// #ifdef _NJ_EXAMPLE_PROGRAM #include <stdio.h> #include <stdlib.h> #include <string.h> int main(int argc, char* argv[]) { int size; char *buf; FILE *f; if (argc < 2) { printf("Usage: %s <input.jpg> [<output.ppm>]\n", argv[0]); return 2; } f = fopen(argv[1], "rb"); if (!f) { printf("Error opening the input file.\n"); return 1; } fseek(f, 0, SEEK_END); size = (int) ftell(f); buf = (char*) malloc(size); fseek(f, 0, SEEK_SET); size = (int) fread(buf, 1, size, f); fclose(f); njInit(); if (njDecode(buf, size)) { free((void*)buf); printf("Error decoding the input file.\n"); return 1; } free((void*)buf); f = fopen((argc > 2) ? argv[2] : (njIsColor() ? "nanojpeg_out.ppm" : "nanojpeg_out.pgm"), "wb"); if (!f) { printf("Error opening the output file.\n"); return 1; } fprintf(f, "P%d\n%d %d\n255\n", njIsColor() ? 6 : 5, njGetWidth(), njGetHeight()); fwrite(njGetImage(), 1, njGetImageSize(), f); fclose(f); njDone(); return 0; } #endif /////////////////////////////////////////////////////////////////////////////// // IMPLEMENTATION SECTION // // you may stop reading here // /////////////////////////////////////////////////////////////////////////////// #ifndef _NJ_INCLUDE_HEADER_ONLY #ifdef _MSC_VER #define NJ_INLINE static __inline #define NJ_FORCE_INLINE static __forceinline #else #define NJ_INLINE static inline #define NJ_FORCE_INLINE static inline #endif #if NJ_USE_LIBC #include <stdlib.h> #include <string.h> #define njAllocMem malloc #define njFreeMem free #define njFillMem memset #define njCopyMem memcpy #elif NJ_USE_WIN32 #include <windows.h> #define njAllocMem(size) ((void*) LocalAlloc(LMEM_FIXED, (SIZE_T)(size))) #define njFreeMem(block) ((void) LocalFree((HLOCAL) block)) NJ_INLINE void njFillMem(void* block, unsigned char value, int count) { __asm { mov edi, block mov al, value mov ecx, count rep stosb } } NJ_INLINE void njCopyMem(void* dest, const void* src, int count) { __asm { mov edi, dest mov esi, src mov ecx, count rep movsb } } #else extern void* njAllocMem(int size); extern void njFreeMem(void* block); extern void njFillMem(void* block, unsigned char byte, int size); extern void njCopyMem(void* dest, const void* src, int size); #endif typedef struct _nj_code { unsigned char bits, code; } nj_vlc_code_t; typedef struct _nj_cmp { int cid; int ssx, ssy; int width, height; int stride; int qtsel; int actabsel, dctabsel; int dcpred; unsigned char *pixels; } nj_component_t; typedef struct _nj_ctx { nj_result_t error; const unsigned char *pos; int size; int length; int width, height; int mbwidth, mbheight; int mbsizex, mbsizey; int ncomp; nj_component_t comp[3]; int qtused, qtavail; unsigned char qtab[4][64]; nj_vlc_code_t vlctab[4][65536]; int buf, bufbits; int block[64]; int rstinterval; unsigned char *rgb; } nj_context_t; static nj_context_t nj; static const char njZZ[64] = { 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 }; NJ_FORCE_INLINE unsigned char njClip(const int x) { return (x < 0) ? 0 : ((x > 0xFF) ? 0xFF : (unsigned char) x); } #define W1 2841 #define W2 2676 #define W3 2408 #define W5 1609 #define W6 1108 #define W7 565 NJ_INLINE void njRowIDCT(int* blk) { int x0, x1, x2, x3, x4, x5, x6, x7, x8; if (!((x1 = blk[4] << 11) | (x2 = blk[6]) | (x3 = blk[2]) | (x4 = blk[1]) | (x5 = blk[7]) | (x6 = blk[5]) | (x7 = blk[3]))) { blk[0] = blk[1] = blk[2] = blk[3] = blk[4] = blk[5] = blk[6] = blk[7] = blk[0] << 3; return; } x0 = (blk[0] << 11) + 128; x8 = W7 * (x4 + x5); x4 = x8 + (W1 - W7) * x4; x5 = x8 - (W1 + W7) * x5; x8 = W3 * (x6 + x7); x6 = x8 - (W3 - W5) * x6; x7 = x8 - (W3 + W5) * x7; x8 = x0 + x1; x0 -= x1; x1 = W6 * (x3 + x2); x2 = x1 - (W2 + W6) * x2; x3 = x1 + (W2 - W6) * x3; x1 = x4 + x6; x4 -= x6; x6 = x5 + x7; x5 -= x7; x7 = x8 + x3; x8 -= x3; x3 = x0 + x2; x0 -= x2; x2 = (181 * (x4 + x5) + 128) >> 8; x4 = (181 * (x4 - x5) + 128) >> 8; blk[0] = (x7 + x1) >> 8; blk[1] = (x3 + x2) >> 8; blk[2] = (x0 + x4) >> 8; blk[3] = (x8 + x6) >> 8; blk[4] = (x8 - x6) >> 8; blk[5] = (x0 - x4) >> 8; blk[6] = (x3 - x2) >> 8; blk[7] = (x7 - x1) >> 8; } NJ_INLINE void njColIDCT(const int* blk, unsigned char *out, int stride) { int x0, x1, x2, x3, x4, x5, x6, x7, x8; if (!((x1 = blk[8*4] << 8) | (x2 = blk[8*6]) | (x3 = blk[8*2]) | (x4 = blk[8*1]) | (x5 = blk[8*7]) | (x6 = blk[8*5]) | (x7 = blk[8*3]))) { x1 = njClip(((blk[0] + 32) >> 6) + 128); for (x0 = 8; x0; --x0) { *out = (unsigned char) x1; out += stride; } return; } x0 = (blk[0] << 8) + 8192; x8 = W7 * (x4 + x5) + 4; x4 = (x8 + (W1 - W7) * x4) >> 3; x5 = (x8 - (W1 + W7) * x5) >> 3; x8 = W3 * (x6 + x7) + 4; x6 = (x8 - (W3 - W5) * x6) >> 3; x7 = (x8 - (W3 + W5) * x7) >> 3; x8 = x0 + x1; x0 -= x1; x1 = W6 * (x3 + x2) + 4; x2 = (x1 - (W2 + W6) * x2) >> 3; x3 = (x1 + (W2 - W6) * x3) >> 3; x1 = x4 + x6; x4 -= x6; x6 = x5 + x7; x5 -= x7; x7 = x8 + x3; x8 -= x3; x3 = x0 + x2; x0 -= x2; x2 = (181 * (x4 + x5) + 128) >> 8; x4 = (181 * (x4 - x5) + 128) >> 8; *out = njClip(((x7 + x1) >> 14) + 128); out += stride; *out = njClip(((x3 + x2) >> 14) + 128); out += stride; *out = njClip(((x0 + x4) >> 14) + 128); out += stride; *out = njClip(((x8 + x6) >> 14) + 128); out += stride; *out = njClip(((x8 - x6) >> 14) + 128); out += stride; *out = njClip(((x0 - x4) >> 14) + 128); out += stride; *out = njClip(((x3 - x2) >> 14) + 128); out += stride; *out = njClip(((x7 - x1) >> 14) + 128); } #define njThrow(e) do { nj.error = e; return; } while (0) #define njCheckError() do { if (nj.error) return; } while (0) static int njShowBits(int bits) { unsigned char newbyte; if (!bits) return 0; while (nj.bufbits < bits) { if (nj.size <= 0) { nj.buf = (nj.buf << 8) | 0xFF; nj.bufbits += 8; continue; } newbyte = *nj.pos++; nj.size--; nj.bufbits += 8; nj.buf = (nj.buf << 8) | newbyte; if (newbyte == 0xFF) { if (nj.size) { unsigned char marker = *nj.pos++; nj.size--; switch (marker) { case 0x00: case 0xFF: break; case 0xD9: nj.size = 0; break; default: if ((marker & 0xF8) != 0xD0) nj.error = NJ_SYNTAX_ERROR; else { nj.buf = (nj.buf << 8) | marker; nj.bufbits += 8; } } } else nj.error = NJ_SYNTAX_ERROR; } } return (nj.buf >> (nj.bufbits - bits)) & ((1 << bits) - 1); } NJ_INLINE void njSkipBits(int bits) { if (nj.bufbits < bits) (void) njShowBits(bits); nj.bufbits -= bits; } NJ_INLINE int njGetBits(int bits) { int res = njShowBits(bits); njSkipBits(bits); return res; } NJ_INLINE void njByteAlign(void) { nj.bufbits &= 0xF8; } static void njSkip(int count) { nj.pos += count; nj.size -= count; nj.length -= count; if (nj.size < 0) nj.error = NJ_SYNTAX_ERROR; } NJ_INLINE unsigned short njDecode16(const unsigned char *pos) { return (pos[0] << 8) | pos[1]; } static void njDecodeLength(void) { if (nj.size < 2) njThrow(NJ_SYNTAX_ERROR); nj.length = njDecode16(nj.pos); if (nj.length > nj.size) njThrow(NJ_SYNTAX_ERROR); njSkip(2); } NJ_INLINE void njSkipMarker(void) { njDecodeLength(); njSkip(nj.length); } NJ_INLINE void njDecodeSOF(void) { int i, ssxmax = 0, ssymax = 0; nj_component_t* c; njDecodeLength(); njCheckError(); if (nj.length < 9) njThrow(NJ_SYNTAX_ERROR); if (nj.pos[0] != 8) njThrow(NJ_UNSUPPORTED); nj.height = njDecode16(nj.pos+1); nj.width = njDecode16(nj.pos+3); if (!nj.width || !nj.height) njThrow(NJ_SYNTAX_ERROR); nj.ncomp = nj.pos[5]; njSkip(6); switch (nj.ncomp) { case 1: case 3: break; default: njThrow(NJ_UNSUPPORTED); } if (nj.length < (nj.ncomp * 3)) njThrow(NJ_SYNTAX_ERROR); for (i = 0, c = nj.comp; i < nj.ncomp; ++i, ++c) { c->cid = nj.pos[0]; if (!(c->ssx = nj.pos[1] >> 4)) njThrow(NJ_SYNTAX_ERROR); if (c->ssx & (c->ssx - 1)) njThrow(NJ_UNSUPPORTED); // non-power of two if (!(c->ssy = nj.pos[1] & 15)) njThrow(NJ_SYNTAX_ERROR); if (c->ssy & (c->ssy - 1)) njThrow(NJ_UNSUPPORTED); // non-power of two if ((c->qtsel = nj.pos[2]) & 0xFC) njThrow(NJ_SYNTAX_ERROR); njSkip(3); nj.qtused |= 1 << c->qtsel; if (c->ssx > ssxmax) ssxmax = c->ssx; if (c->ssy > ssymax) ssymax = c->ssy; } if (nj.ncomp == 1) { c = nj.comp; c->ssx = c->ssy = ssxmax = ssymax = 1; } nj.mbsizex = ssxmax << 3; nj.mbsizey = ssymax << 3; nj.mbwidth = (nj.width + nj.mbsizex - 1) / nj.mbsizex; nj.mbheight = (nj.height + nj.mbsizey - 1) / nj.mbsizey; for (i = 0, c = nj.comp; i < nj.ncomp; ++i, ++c) { c->width = (nj.width * c->ssx + ssxmax - 1) / ssxmax; c->height = (nj.height * c->ssy + ssymax - 1) / ssymax; c->stride = nj.mbwidth * c->ssx << 3; if (((c->width < 3) && (c->ssx != ssxmax)) || ((c->height < 3) && (c->ssy != ssymax))) njThrow(NJ_UNSUPPORTED); if (!(c->pixels = (unsigned char*) njAllocMem(c->stride * nj.mbheight * c->ssy << 3))) njThrow(NJ_OUT_OF_MEM); } if (nj.ncomp == 3) { nj.rgb = (unsigned char*) njAllocMem(nj.width * nj.height * nj.ncomp); if (!nj.rgb) njThrow(NJ_OUT_OF_MEM); } njSkip(nj.length); } NJ_INLINE void njDecodeDHT(void) { int codelen, currcnt, remain, spread, i, j; nj_vlc_code_t *vlc; static unsigned char counts[16]; njDecodeLength(); njCheckError(); while (nj.length >= 17) { i = nj.pos[0]; if (i & 0xEC) njThrow(NJ_SYNTAX_ERROR); if (i & 0x02) njThrow(NJ_UNSUPPORTED); i = (i | (i >> 3)) & 3; // combined DC/AC + tableid value for (codelen = 1; codelen <= 16; ++codelen) counts[codelen - 1] = nj.pos[codelen]; njSkip(17); vlc = &nj.vlctab[i][0]; remain = spread = 65536; for (codelen = 1; codelen <= 16; ++codelen) { spread >>= 1; currcnt = counts[codelen - 1]; if (!currcnt) continue; if (nj.length < currcnt) njThrow(NJ_SYNTAX_ERROR); remain -= currcnt << (16 - codelen); if (remain < 0) njThrow(NJ_SYNTAX_ERROR); for (i = 0; i < currcnt; ++i) { register unsigned char code = nj.pos[i]; for (j = spread; j; --j) { vlc->bits = (unsigned char) codelen; vlc->code = code; ++vlc; } } njSkip(currcnt); } while (remain--) { vlc->bits = 0; ++vlc; } } if (nj.length) njThrow(NJ_SYNTAX_ERROR); } NJ_INLINE void njDecodeDQT(void) { int i; unsigned char *t; njDecodeLength(); njCheckError(); while (nj.length >= 65) { i = nj.pos[0]; if (i & 0xFC) njThrow(NJ_SYNTAX_ERROR); nj.qtavail |= 1 << i; t = &nj.qtab[i][0]; for (i = 0; i < 64; ++i) t[i] = nj.pos[i + 1]; njSkip(65); } if (nj.length) njThrow(NJ_SYNTAX_ERROR); } NJ_INLINE void njDecodeDRI(void) { njDecodeLength(); njCheckError(); if (nj.length < 2) njThrow(NJ_SYNTAX_ERROR); nj.rstinterval = njDecode16(nj.pos); njSkip(nj.length); } static int njGetVLC(nj_vlc_code_t* vlc, unsigned char* code) { int value = njShowBits(16); int bits = vlc[value].bits; if (!bits) { nj.error = NJ_SYNTAX_ERROR; return 0; } njSkipBits(bits); value = vlc[value].code; if (code) *code = (unsigned char) value; bits = value & 15; if (!bits) return 0; value = njGetBits(bits); if (value < (1 << (bits - 1))) value += ((-1) << bits) + 1; return value; } NJ_INLINE void njDecodeBlock(nj_component_t* c, unsigned char* out) { unsigned char code = 0; int value, coef = 0; njFillMem(nj.block, 0, sizeof(nj.block)); c->dcpred += njGetVLC(&nj.vlctab[c->dctabsel][0], NULL); nj.block[0] = (c->dcpred) * nj.qtab[c->qtsel][0]; do { value = njGetVLC(&nj.vlctab[c->actabsel][0], &code); if (!code) break; // EOB if (!(code & 0x0F) && (code != 0xF0)) njThrow(NJ_SYNTAX_ERROR); coef += (code >> 4) + 1; if (coef > 63) njThrow(NJ_SYNTAX_ERROR); nj.block[(int) njZZ[coef]] = value * nj.qtab[c->qtsel][coef]; } while (coef < 63); for (coef = 0; coef < 64; coef += 8) njRowIDCT(&nj.block[coef]); for (coef = 0; coef < 8; ++coef) njColIDCT(&nj.block[coef], &out[coef], c->stride); } NJ_INLINE void njDecodeScan(void) { int i, mbx, mby, sbx, sby; int rstcount = nj.rstinterval, nextrst = 0; nj_component_t* c; njDecodeLength(); njCheckError(); if (nj.length < (4 + 2 * nj.ncomp)) njThrow(NJ_SYNTAX_ERROR); if (nj.pos[0] != nj.ncomp) njThrow(NJ_UNSUPPORTED); njSkip(1); for (i = 0, c = nj.comp; i < nj.ncomp; ++i, ++c) { if (nj.pos[0] != c->cid) njThrow(NJ_SYNTAX_ERROR); if (nj.pos[1] & 0xEE) njThrow(NJ_SYNTAX_ERROR); c->dctabsel = nj.pos[1] >> 4; c->actabsel = (nj.pos[1] & 1) | 2; njSkip(2); } if (nj.pos[0] || (nj.pos[1] != 63) || nj.pos[2]) njThrow(NJ_UNSUPPORTED); njSkip(nj.length); for (mbx = mby = 0;;) { for (i = 0, c = nj.comp; i < nj.ncomp; ++i, ++c) for (sby = 0; sby < c->ssy; ++sby) for (sbx = 0; sbx < c->ssx; ++sbx) { njDecodeBlock(c, &c->pixels[((mby * c->ssy + sby) * c->stride + mbx * c->ssx + sbx) << 3]); njCheckError(); } if (++mbx >= nj.mbwidth) { mbx = 0; if (++mby >= nj.mbheight) break; } if (nj.rstinterval && !(--rstcount)) { njByteAlign(); i = njGetBits(16); if (((i & 0xFFF8) != 0xFFD0) || ((i & 7) != nextrst)) njThrow(NJ_SYNTAX_ERROR); nextrst = (nextrst + 1) & 7; rstcount = nj.rstinterval; for (i = 0; i < 3; ++i) nj.comp[i].dcpred = 0; } } nj.error = __NJ_FINISHED; } #if NJ_CHROMA_FILTER #define CF4A (-9) #define CF4B (111) #define CF4C (29) #define CF4D (-3) #define CF3A (28) #define CF3B (109) #define CF3C (-9) #define CF3X (104) #define CF3Y (27) #define CF3Z (-3) #define CF2A (139) #define CF2B (-11) #define CF(x) njClip(((x) + 64) >> 7) NJ_INLINE void njUpsampleH(nj_component_t* c) { const int xmax = c->width - 3; unsigned char *out, *lin, *lout; int x, y; out = (unsigned char*) njAllocMem((c->width * c->height) << 1); if (!out) njThrow(NJ_OUT_OF_MEM); lin = c->pixels; lout = out; for (y = c->height; y; --y) { lout[0] = CF(CF2A * lin[0] + CF2B * lin[1]); lout[1] = CF(CF3X * lin[0] + CF3Y * lin[1] + CF3Z * lin[2]); lout[2] = CF(CF3A * lin[0] + CF3B * lin[1] + CF3C * lin[2]); for (x = 0; x < xmax; ++x) { lout[(x << 1) + 3] = CF(CF4A * lin[x] + CF4B * lin[x + 1] + CF4C * lin[x + 2] + CF4D * lin[x + 3]); lout[(x << 1) + 4] = CF(CF4D * lin[x] + CF4C * lin[x + 1] + CF4B * lin[x + 2] + CF4A * lin[x + 3]); } lin += c->stride; lout += c->width << 1; lout[-3] = CF(CF3A * lin[-1] + CF3B * lin[-2] + CF3C * lin[-3]); lout[-2] = CF(CF3X * lin[-1] + CF3Y * lin[-2] + CF3Z * lin[-3]); lout[-1] = CF(CF2A * lin[-1] + CF2B * lin[-2]); } c->width <<= 1; c->stride = c->width; njFreeMem((void*)c->pixels); c->pixels = out; } NJ_INLINE void njUpsampleV(nj_component_t* c) { const int w = c->width, s1 = c->stride, s2 = s1 + s1; unsigned char *out, *cin, *cout; int x, y; out = (unsigned char*) njAllocMem((c->width * c->height) << 1); if (!out) njThrow(NJ_OUT_OF_MEM); for (x = 0; x < w; ++x) { cin = &c->pixels[x]; cout = &out[x]; *cout = CF(CF2A * cin[0] + CF2B * cin[s1]); cout += w; *cout = CF(CF3X * cin[0] + CF3Y * cin[s1] + CF3Z * cin[s2]); cout += w; *cout = CF(CF3A * cin[0] + CF3B * cin[s1] + CF3C * cin[s2]); cout += w; cin += s1; for (y = c->height - 3; y; --y) { *cout = CF(CF4A * cin[-s1] + CF4B * cin[0] + CF4C * cin[s1] + CF4D * cin[s2]); cout += w; *cout = CF(CF4D * cin[-s1] + CF4C * cin[0] + CF4B * cin[s1] + CF4A * cin[s2]); cout += w; cin += s1; } cin += s1; *cout = CF(CF3A * cin[0] + CF3B * cin[-s1] + CF3C * cin[-s2]); cout += w; *cout = CF(CF3X * cin[0] + CF3Y * cin[-s1] + CF3Z * cin[-s2]); cout += w; *cout = CF(CF2A * cin[0] + CF2B * cin[-s1]); } c->height <<= 1; c->stride = c->width; njFreeMem((void*) c->pixels); c->pixels = out; } #else NJ_INLINE void njUpsample(nj_component_t* c) { int x, y, xshift = 0, yshift = 0; unsigned char *out, *lin, *lout; while (c->width < nj.width) { c->width <<= 1; ++xshift; } while (c->height < nj.height) { c->height <<= 1; ++yshift; } out = (unsigned char*) njAllocMem(c->width * c->height); if (!out) njThrow(NJ_OUT_OF_MEM); lin = c->pixels; lout = out; for (y = 0; y < c->height; ++y) { lin = &c->pixels[(y >> yshift) * c->stride]; for (x = 0; x < c->width; ++x) lout[x] = lin[x >> xshift]; lout += c->width; } c->stride = c->width; njFreeMem((void*) c->pixels); c->pixels = out; } #endif NJ_INLINE void njConvert(void) { int i; nj_component_t* c; for (i = 0, c = nj.comp; i < nj.ncomp; ++i, ++c) { #if NJ_CHROMA_FILTER while ((c->width < nj.width) || (c->height < nj.height)) { if (c->width < nj.width) njUpsampleH(c); njCheckError(); if (c->height < nj.height) njUpsampleV(c); njCheckError(); } #else if ((c->width < nj.width) || (c->height < nj.height)) njUpsample(c); #endif if ((c->width < nj.width) || (c->height < nj.height)) njThrow(NJ_INTERNAL_ERR); } if (nj.ncomp == 3) { // convert to RGB int x, yy; unsigned char *prgb = nj.rgb; const unsigned char *py = nj.comp[0].pixels; const unsigned char *pcb = nj.comp[1].pixels; const unsigned char *pcr = nj.comp[2].pixels; for (yy = nj.height; yy; --yy) { for (x = 0; x < nj.width; ++x) { register int y = py[x] << 8; register int cb = pcb[x] - 128; register int cr = pcr[x] - 128; *prgb++ = njClip((y + 359 * cr + 128) >> 8); *prgb++ = njClip((y - 88 * cb - 183 * cr + 128) >> 8); *prgb++ = njClip((y + 454 * cb + 128) >> 8); } py += nj.comp[0].stride; pcb += nj.comp[1].stride; pcr += nj.comp[2].stride; } } else if (nj.comp[0].width != nj.comp[0].stride) { // grayscale -> only remove stride unsigned char *pin = &nj.comp[0].pixels[nj.comp[0].stride]; unsigned char *pout = &nj.comp[0].pixels[nj.comp[0].width]; int y; for (y = nj.comp[0].height - 1; y; --y) { njCopyMem(pout, pin, nj.comp[0].width); pin += nj.comp[0].stride; pout += nj.comp[0].width; } nj.comp[0].stride = nj.comp[0].width; } } void njInit(void) { njFillMem(&nj, 0, sizeof(nj_context_t)); } void njDone(void) { int i; for (i = 0; i < 3; ++i) if (nj.comp[i].pixels) njFreeMem((void*) nj.comp[i].pixels); if (nj.rgb) njFreeMem((void*) nj.rgb); njInit(); } nj_result_t njDecode(const void* jpeg, const int size) { njDone(); nj.pos = (const unsigned char*) jpeg; nj.size = size & 0x7FFFFFFF; if (nj.size < 2) return NJ_NO_JPEG; if ((nj.pos[0] ^ 0xFF) | (nj.pos[1] ^ 0xD8)) return NJ_NO_JPEG; njSkip(2); while (!nj.error) { if ((nj.size < 2) || (nj.pos[0] != 0xFF)) return NJ_SYNTAX_ERROR; njSkip(2); switch (nj.pos[-1]) { case 0xC0: njDecodeSOF(); break; case 0xC4: njDecodeDHT(); break; case 0xDB: njDecodeDQT(); break; case 0xDD: njDecodeDRI(); break; case 0xDA: njDecodeScan(); break; case 0xFE: njSkipMarker(); break; default: if ((nj.pos[-1] & 0xF0) == 0xE0) njSkipMarker(); else return NJ_UNSUPPORTED; } } if (nj.error != __NJ_FINISHED) return nj.error; nj.error = NJ_OK; njConvert(); return nj.error; } int njGetWidth(void) { return nj.width; } int njGetHeight(void) { return nj.height; } int njIsColor(void) { return (nj.ncomp != 1); } unsigned char* njGetImage(void) { return (nj.ncomp == 1) ? nj.comp[0].pixels : nj.rgb; } int njGetImageSize(void) { return nj.width * nj.height * nj.ncomp; } #endif // _NJ_INCLUDE_HEADER_ONLY