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Functions | |
| bool | getJPEGSize (const char *filename, int &width, int &height) |
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Definition at line 65 of file jpegSize.cpp. References first_marker(), height, infile, M_EOI, M_SOF0, M_SOF1, M_SOF10, M_SOF11, M_SOF13, M_SOF14, M_SOF15, M_SOF2, M_SOF3, M_SOF5, M_SOF6, M_SOF7, M_SOF9, M_SOS, next_marker(), process_SOFn(), READ_BINARY, skip_variable(), and width. Referenced by getImageSize(), and isJpeg(). 00066 {
00067 //open file
00068 if ((infile = fopen(filename, READ_BINARY)) == NULL)
00069 return false;
00070
00071 //this is scan_JPEG_header (int verbose)
00072 //Parse the marker stream until SOFn is seen;
00073 int marker;
00074
00075 //Expect SOI at start of file
00076 if (!first_marker(&marker))
00077 {
00078 fclose(infile);
00079 return false;
00080 }
00081
00082 /* Scan miscellaneous markers until we reach SOFn. */
00083 for (;;)
00084 {
00085 if(!next_marker(&marker))
00086 {
00087 fclose(infile);
00088 return false;
00089 }
00090
00091 switch (marker)
00092 {
00093 /* Note that marker codes 0xC4, 0xC8, 0xCC are not, and must not be,
00094 * treated as SOFn. C4 in particular is actually DHT.
00095 */
00096 case M_SOF0: /* Baseline */
00097 case M_SOF1: /* Extended sequential, Huffman */
00098 case M_SOF2: /* Progressive, Huffman */
00099 case M_SOF3: /* Lossless, Huffman */
00100 case M_SOF5: /* Differential sequential, Huffman */
00101 case M_SOF6: /* Differential progressive, Huffman */
00102 case M_SOF7: /* Differential lossless, Huffman */
00103 case M_SOF9: /* Extended sequential, arithmetic */
00104 case M_SOF10: /* Progressive, arithmetic */
00105 case M_SOF11: /* Lossless, arithmetic */
00106 case M_SOF13: /* Differential sequential, arithmetic */
00107 case M_SOF14: /* Differential progressive, arithmetic */
00108 case M_SOF15: /* Differential lossless, arithmetic */
00109 if(!process_SOFn(width, height))
00110 {
00111 fclose(infile);
00112 return false;
00113 }
00114 else
00115 {
00116 fclose(infile);
00117 return true;
00118 }
00119 case M_SOS: /* stop before hitting compressed data */
00120 {
00121 fclose(infile);
00122 return false;
00123 }
00124 case M_EOI: /* in case it's a tables-only JPEG stream */
00125 {
00126 fclose(infile);
00127 return false;
00128 }
00129 default: /* Anything else just gets skipped */
00130 skip_variable(); /* we assume it has a parameter count... */
00131 break;
00132 }
00133 } /* end loop */
00134
00135
00136 //cout << "ERROR!\n";
00137 return false;
00138
00139 }
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1.3.9.1