mirror of
https://github.com/wpilibsuite/allwpilib
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239 lines
7.8 KiB
C++
239 lines
7.8 KiB
C++
// Copyright (c) FIRST and other WPILib contributors.
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// Open Source Software; you can modify and/or share it under the terms of
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// the WPILib BSD license file in the root directory of this project.
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#include "JpegUtil.hpp"
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#include <string>
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#include "wpi/util/StringExtras.hpp"
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#include "wpi/util/raw_istream.hpp"
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namespace wpi::cs {
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// DHT data for MJPEG images that don't have it.
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static const unsigned char dhtData[] = {
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0xff, 0xc4, 0x01, 0xa2, 0x00, 0x00, 0x01, 0x05, 0x01, 0x01, 0x01, 0x01,
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0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02,
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0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x01, 0x00, 0x03,
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0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
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0x0a, 0x0b, 0x10, 0x00, 0x02, 0x01, 0x03, 0x03, 0x02, 0x04, 0x03, 0x05,
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0x05, 0x04, 0x04, 0x00, 0x00, 0x01, 0x7d, 0x01, 0x02, 0x03, 0x00, 0x04,
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0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, 0x22,
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0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, 0x23, 0x42, 0xb1, 0xc1, 0x15,
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0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16, 0x17,
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0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x34, 0x35, 0x36,
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0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
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0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66,
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0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a,
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0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95,
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0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8,
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0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2,
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0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5,
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0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
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0xe8, 0xe9, 0xea, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9,
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0xfa, 0x11, 0x00, 0x02, 0x01, 0x02, 0x04, 0x04, 0x03, 0x04, 0x07, 0x05,
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0x04, 0x04, 0x00, 0x01, 0x02, 0x77, 0x00, 0x01, 0x02, 0x03, 0x11, 0x04,
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0x05, 0x21, 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 0x13, 0x22,
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0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33,
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0x52, 0xf0, 0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34, 0xe1, 0x25,
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0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x35, 0x36,
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0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
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0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66,
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0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a,
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0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94,
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0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
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0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba,
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0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
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0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
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0xe8, 0xe9, 0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa};
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bool IsJpeg(std::string_view data) {
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if (data.size() < 11) {
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return false;
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}
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// Check for valid SOI
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auto bytes = reinterpret_cast<const unsigned char*>(data.data());
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if (bytes[0] != 0xff || bytes[1] != 0xd8) {
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return false;
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}
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return true;
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}
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bool GetJpegSize(std::string_view data, int* width, int* height) {
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if (!IsJpeg(data)) {
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return false;
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}
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data = wpi::util::substr(data, 2); // Get to the first block
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for (;;) {
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if (data.size() < 4) {
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return false; // EOF
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}
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auto bytes = reinterpret_cast<const unsigned char*>(data.data());
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if (bytes[0] != 0xff) {
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return false; // not a tag
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}
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if (bytes[1] == 0xd9) {
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return false; // EOI without finding SOF?
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}
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if (bytes[1] == 0xda) {
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return false; // SOS without finding SOF?
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}
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if (bytes[1] == 0xc0) {
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// SOF contains the file size
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if (data.size() < 9) {
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return false;
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}
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*height = bytes[5] * 256 + bytes[6];
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*width = bytes[7] * 256 + bytes[8];
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return true;
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}
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// Go to the next block
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data = wpi::util::substr(data, bytes[2] * 256 + bytes[3] + 2);
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}
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}
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bool JpegNeedsDHT(const char* data, size_t* size, size_t* locSOF) {
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std::string_view sdata(data, *size);
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if (!IsJpeg(sdata)) {
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return false;
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}
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*locSOF = *size;
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// Search until SOS for DHT tag
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sdata = wpi::util::substr(sdata, 2); // Get to the first block
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for (;;) {
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if (sdata.size() < 4) {
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return false; // EOF
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}
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auto bytes = reinterpret_cast<const unsigned char*>(sdata.data());
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if (bytes[0] != 0xff) {
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return false; // not a tag
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}
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if (bytes[1] == 0xda) {
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break; // SOS
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}
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if (bytes[1] == 0xc4) {
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return false; // DHT
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}
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if (bytes[1] == 0xc0) {
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*locSOF = sdata.data() - data; // SOF
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}
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// Go to the next block
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sdata = wpi::util::substr(sdata, bytes[2] * 256 + bytes[3] + 2);
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}
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// Only add DHT if we also found SOF (insertion point)
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if (*locSOF != *size) {
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*size += sizeof(dhtData);
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return true;
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}
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return false;
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}
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std::string_view JpegGetDHT() {
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return {reinterpret_cast<const char*>(dhtData), sizeof(dhtData)};
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}
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static inline void ReadInto(wpi::util::raw_istream& is, std::string& buf,
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size_t len) {
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size_t oldSize = buf.size();
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buf.resize(oldSize + len);
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is.read(&(*buf.begin()) + oldSize, len);
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}
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bool ReadJpeg(wpi::util::raw_istream& is, std::string& buf, int* width,
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int* height) {
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// in case we don't get a SOF
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*width = 0;
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*height = 0;
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// read SOI and first marker
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buf.resize(4);
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is.read(&(*buf.begin()), 4);
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if (is.has_error()) {
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return false;
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}
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// Check for valid SOI
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auto bytes = reinterpret_cast<const unsigned char*>(buf.data());
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if (bytes[0] != 0xff || bytes[1] != 0xd8) {
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return false;
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}
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size_t pos = 2; // point to first marker
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for (;;) {
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bytes = reinterpret_cast<const unsigned char*>(buf.data() + pos);
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if (bytes[0] != 0xff) {
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return false; // not a marker
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}
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unsigned char marker = bytes[1];
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if (marker == 0xd9) {
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return true; // EOI, we're done
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}
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if (marker == 0xda) {
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// SOS: need to keep reading until we reach a normal marker.
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// Byte stuffing ensures we don't get false markers.
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// Have to read a byte at a time as we don't want to overread.
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pos += 2; // point after SOS marker
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bool maybeMarker = false;
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for (;;) {
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ReadInto(is, buf, 1);
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if (is.has_error()) {
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return false;
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}
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bytes = reinterpret_cast<const unsigned char*>(buf.data() + pos);
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if (maybeMarker) {
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if (bytes[0] != 0x00 && bytes[0] != 0xff &&
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(bytes[0] < 0xd0 || bytes[0] > 0xd7)) {
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break;
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}
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maybeMarker = false;
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} else if (bytes[0] == 0xff) {
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maybeMarker = true;
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}
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++pos; // point after byte we finished reading
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}
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--pos; // point back to start of marker
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continue;
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}
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// A normal block. Read the length
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ReadInto(is, buf, 2); // read length
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if (is.has_error()) {
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return false;
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}
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// Point to length
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pos += 2;
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bytes = reinterpret_cast<const unsigned char*>(buf.data() + pos);
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// Read the block and the next marker
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size_t blockLength = bytes[0] * 256 + bytes[1];
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ReadInto(is, buf, blockLength);
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if (is.has_error()) {
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return false;
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}
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bytes = reinterpret_cast<const unsigned char*>(buf.data() + pos);
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// Special block processing
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if (marker == 0xc0) {
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// SOF: contains the file size; make sure we actually read enough bytes
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if (blockLength >= 7) {
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*height = bytes[3] * 256 + bytes[4];
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*width = bytes[5] * 256 + bytes[6];
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}
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}
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// Point to next marker
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pos += blockLength;
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}
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}
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} // namespace wpi::cs
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