{"record":{"id":"799a8ca904a869c2","repo":"Yalantis/uCrop","slug":"load-jpeg-error-message-returned-by-libjpeg-s","errorCode":null,"errorMessage":"load_jpeg(): Error message returned by libjpeg: %s.","messagePattern":"load_jpeg\\(\\): Error message returned by libjpeg: (.+?)\\.","errorType":"exception","errorClass":"CImgIOException","httpStatus":null,"severity":"error","filePath":"ucrop/src/main/jni/CImg.h","lineNumber":57040,"sourceCode":"                              cimg_instance);\n      else return load_other(filename);\n#else\n\n#if defined __GNUC__\n      const char *volatile nfilename = filename; // Use 'volatile' to avoid (wrong) g++ warning\n      std::FILE *volatile nfile = file?file:cimg::fopen(nfilename,\"rb\");\n#else\n      const char *nfilename = filename;\n      std::FILE *nfile = file?file:cimg::fopen(nfilename,\"rb\");\n#endif\n\n      struct jpeg_decompress_struct cinfo;\n      struct _cimg_error_mgr jerr;\n      cinfo.err = jpeg_std_error(&jerr.original);\n      jerr.original.error_exit = _cimg_jpeg_error_exit;\n      if (setjmp(jerr.setjmp_buffer)) { // JPEG error\n        if (!file) cimg::fclose(nfile);\n        throw CImgIOException(_cimg_instance\n                             \"load_jpeg(): Error message returned by libjpeg: %s.\",\n                             cimg_instance,jerr.message);\n      }\n\n      jpeg_create_decompress(&cinfo);\n      jpeg_stdio_src(&cinfo,nfile);\n      jpeg_read_header(&cinfo,TRUE);\n      jpeg_start_decompress(&cinfo);\n\n      if (cinfo.output_components!=1 && cinfo.output_components!=3 && cinfo.output_components!=4) {\n        if (!file) {\n          cimg::fclose(nfile);\n          return load_other(nfilename);\n        } else\n          throw CImgIOException(_cimg_instance\n                                \"load_jpeg(): Failed to load JPEG data from file '%s'.\",\n                                cimg_instance,nfilename?nfilename:\"(FILE*)\");\n      }","sourceCodeStart":57022,"sourceCodeEnd":57058,"githubUrl":"https://github.com/Yalantis/uCrop/blob/f788b534b48c144edf786c8cddbf0e029e637804/ucrop/src/main/jni/CImg.h#L57022-L57058","documentation":"CImg installs a custom libjpeg error handler; when libjpeg signals any decode error (corrupt data, unsupported marker, premature EOF) the handler longjmps back and CImg throws CImgIOException containing libjpeg's own message string.","triggerScenarios":"load_jpeg on a truncated or corrupted JPEG; unsupported JPEG variants (e.g. arithmetic coding, progressive with broken scans); wrong format with .jpg extension.","commonSituations":"Incomplete uploads/downloads, resumptions from partially cached assets, images processed by lossy tools, rare JPEG chroma subsampling combinations.","solutions":["Verify/repair the file (e.g. jpegtran -copy none, or re-save in an image editor)","Re-download or re-export the JPEG","Read jerr.message in the exception text to identify the specific libjpeg failure","Fallback-decode with another library (e.g. stb_image, libvips) or convert the file to PNG"],"exampleFix":"// before\nimg.load_jpeg(\"broken.jpg\"); // throws on corrupt data\n// after\ntry { img.load_jpeg(\"broken.jpg\"); }\ncatch (CImgIOException& e) {\n  // e includes libjpeg's message; attempt fallback\n  img.load(\"broken_reexported.png\");\n}","handlingStrategy":"try-catch","validationCode":"unsigned char soi[2]; FILE* f=fopen(path,\"rb\");\nbool isJpeg = f && fread(soi,1,2,f)==2 && soi[0]==0xFF && soi[1]==0xD8;\nif (f) fclose(f);\nif (!isJpeg) throw std::runtime_error(\"not a jpeg\");","typeGuard":null,"tryCatchPattern":"try { img.load_jpeg(path); }\ncatch (CImgIOException& e) {\n  // e.what() contains libjpeg's message for diagnostics\n  img.assign(); // or fallback decode\n}","preventionTips":["Verify file integrity (SOI marker, size) before decoding","Re-download corrupted/truncated JPEGs","Keep libjpeg version current for broader format support","Test decoding of all user-supplied image variants in QA"],"tags":["jpeg","image-loading","libjpeg","corrupt-file","cimg"],"backgroundTag":"http-error-response","analyzedSha":"f788b534b48c144edf786c8cddbf0e029e637804","analyzedAt":"2026-09-08T08:36:04.887Z","contentChangedAt":"2026-09-08T08:36:04.887Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}