125 lines
2.8 KiB
C++
125 lines
2.8 KiB
C++
#include "JpegImage.h"
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namespace Image {
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const static JOCTET EOI_BUFFER[1] = { JPEG_EOI };
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JpegImage::JpegImage()
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{
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}
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void JpegImage::SetImageData(const std::string& data)
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{
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DecompressImage(data.c_str(), data.size());
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}
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unsigned int JpegImage::Width() const
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{
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return m_width;
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}
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unsigned int JpegImage::Height() const
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{
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return m_height;
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}
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unsigned int JpegImage::StrideX() const
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{
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return m_strideX;
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}
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unsigned int JpegImage::StrideY() const
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{
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return m_strideY;
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}
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const std::vector<char>& JpegImage::Data() const
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{
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return m_data;
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}
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void JpegImage::InitSource(j_decompress_ptr pCinfo)
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{
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}
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boolean JpegImage::FillInputBuffer(j_decompress_ptr pCinfo)
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{
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SourceMgrPtr pSrc = reinterpret_cast<SourceMgrPtr>(pCinfo->src);
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pSrc->pub.next_input_byte = EOI_BUFFER;
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pSrc->pub.bytes_in_buffer = 1;
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return TRUE;
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}
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void JpegImage::SkipInputData(j_decompress_ptr pCinfo, long numBytes)
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{
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SourceMgrPtr pSrc = reinterpret_cast<SourceMgrPtr>(pCinfo->src);
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if (pSrc->pub.bytes_in_buffer < static_cast<size_t>(numBytes))
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{
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pSrc->pub.next_input_byte = EOI_BUFFER;
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pSrc->pub.bytes_in_buffer = 1;
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}
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else
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{
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pSrc->pub.next_input_byte += numBytes;
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pSrc->pub.bytes_in_buffer -= numBytes;
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}
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}
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void JpegImage::TermSource(j_decompress_ptr pCinfo)
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{
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}
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void JpegImage::SetSourceMgr(j_decompress_ptr pCinfo, const char* pData, size_t len) const
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{
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SourceMgrPtr pSrc;
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if (pCinfo->src == 0)
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pCinfo->src = (struct jpeg_source_mgr *)(*pCinfo->mem->alloc_small)(reinterpret_cast<j_common_ptr>(pCinfo), JPOOL_PERMANENT, sizeof(SourceMgr));
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pSrc = reinterpret_cast<SourceMgrPtr>(pCinfo->src);
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pSrc->pub.init_source = JpegImage::InitSource;
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pSrc->pub.fill_input_buffer = JpegImage::FillInputBuffer;
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pSrc->pub.skip_input_data = JpegImage::SkipInputData;
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pSrc->pub.resync_to_restart = jpeg_resync_to_restart;
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pSrc->pub.term_source = JpegImage::TermSource;
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pSrc->data = (const JOCTET *)pData;
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pSrc->len = len;
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pSrc->pub.bytes_in_buffer = len;
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pSrc->pub.next_input_byte = pSrc->data;
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}
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void JpegImage::DecompressImage(const char* pData, size_t len)
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{
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struct jpeg_decompress_struct cinfo;
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struct jpeg_error_mgr jerr;
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jerr.trace_level = 0;
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cinfo.err = jpeg_std_error(&jerr);
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jpeg_create_decompress(&cinfo);
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SetSourceMgr(&cinfo, pData, len);
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jpeg_read_header(&cinfo, TRUE);
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jpeg_start_decompress(&cinfo);
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m_width = cinfo.image_width;
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m_height = cinfo.image_height;
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m_strideX = cinfo.num_components;
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m_strideY = m_width * cinfo.num_components;
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m_data.resize(m_height * m_strideY);
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JSAMPROW scanlines[1];
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while (cinfo.output_scanline < cinfo.image_height)
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{
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scanlines[0] = reinterpret_cast<JSAMPROW>(&m_data[cinfo.output_scanline * m_strideY]);
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jpeg_read_scanlines(&cinfo, scanlines, 1);
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}
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jpeg_finish_decompress(&cinfo);
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jpeg_destroy_decompress(&cinfo);
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}
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} // namespace Image
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