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| -rw-r--r-- | src/Fl_Image_Reader.cxx | 131 | ||||
| -rw-r--r-- | src/Fl_Image_Reader.h | 90 |
2 files changed, 221 insertions, 0 deletions
diff --git a/src/Fl_Image_Reader.cxx b/src/Fl_Image_Reader.cxx new file mode 100644 index 000000000..083efb471 --- /dev/null +++ b/src/Fl_Image_Reader.cxx @@ -0,0 +1,131 @@ +// +// Internal (Image) Reader class for the Fast Light Tool Kit (FLTK). +// +// Copyright 2020 by Bill Spitzak and others. +// +// This library is free software. Distribution and use rights are outlined in +// the file "COPYING" which should have been included with this file. If this +// file is missing or damaged, see the license at: +// +// https://www.fltk.org/COPYING.php +// +// Please report all bugs and problems on the following page: +// +// https://www.fltk.org/str.php +// + + +// +// Include necessary header files... +// + +#include "Fl_Image_Reader.h" + +#include <FL/fl_utf8.h> +#include <stdlib.h> +#include <string.h> + +/* + This internal (undocumented) class reads data chunks from a file or from + memory in LSB-first byte order. + + This class is used in Fl_GIF_Image and Fl_BMP_Image to avoid code + duplication and may be extended to be used in similar cases. Future + options might be to read data in MSB-first byte order or to add more + methods. +*/ + +// Initialize the reader to access the file system, filename is copied +// and stored. +int Fl_Image_Reader::open(const char *filename) { + if (!filename) + return -1; + pName = strdup(filename); + if ( (pFile = fl_fopen(filename, "rb")) == NULL ) { + return -1; + } + pIsFile = 1; + return 0; +} + +// Initialize the reader for memory access, name is copied and stored +int Fl_Image_Reader::open(const char *imagename, const unsigned char *data) { + if (imagename) + pName = strdup(imagename); + if (data) { + pStart = pData = data; + pIsData = 1; + return 0; + } else { + return -1; + } +} + +// Close and destroy the reader +Fl_Image_Reader::~Fl_Image_Reader() { + if (pIsFile && pFile) { + fclose(pFile); + } + if (pName) + ::free(pName); +} + +// Read a single byte from memory or a file +uchar Fl_Image_Reader::read_byte() { + if (pIsFile) { + return getc(pFile); + } else if (pIsData) { + return *pData++; + } else { + return 0; + } +} + +// Read a 16-bit unsigned integer, LSB-first +unsigned short Fl_Image_Reader::read_word() { + unsigned char b0, b1; // Bytes from file + if (pIsFile) { + b0 = (uchar)getc(pFile); + b1 = (uchar)getc(pFile); + return ((b1 << 8) | b0); + } else if (pIsData) { + b0 = *pData++; + b1 = *pData++; + return ((b1 << 8) | b0); + } else { + return 0; + } +} + +// Read a 32-bit unsigned integer, LSB-first +unsigned int Fl_Image_Reader::read_dword() { + unsigned char b0, b1, b2, b3; // Bytes from file + if (pIsFile) { + b0 = (uchar)getc(pFile); + b1 = (uchar)getc(pFile); + b2 = (uchar)getc(pFile); + b3 = (uchar)getc(pFile); + return ((((((b3 << 8) | b2) << 8) | b1) << 8) | b0); + } else if (pIsData) { + b0 = *pData++; + b1 = *pData++; + b2 = *pData++; + b3 = *pData++; + return ((((((b3 << 8) | b2) << 8) | b1) << 8) | b0); + } else { + return 0; + } +} + +// Read a 32-bit signed integer, LSB-first +// int Fl_Image_Reader::read_long() -- implementation in header file + +// Move the current read position to a byte offset from the beginning +// of the file or the original start address in memory +void Fl_Image_Reader::seek(unsigned int n) { + if (pIsFile) { + fseek(pFile, n , SEEK_SET); + } else if (pIsData) { + pData = pStart + n; + } +} diff --git a/src/Fl_Image_Reader.h b/src/Fl_Image_Reader.h new file mode 100644 index 000000000..83d9c366e --- /dev/null +++ b/src/Fl_Image_Reader.h @@ -0,0 +1,90 @@ +// +// Internal (Image) Reader class for the Fast Light Tool Kit (FLTK). +// +// Copyright 2020 by Bill Spitzak and others. +// +// This library is free software. Distribution and use rights are outlined in +// the file "COPYING" which should have been included with this file. If this +// file is missing or damaged, see the license at: +// +// https://www.fltk.org/COPYING.php +// +// Please report all bugs and problems on the following page: +// +// https://www.fltk.org/str.php +// + +/* + This internal (undocumented) class reads data chunks from a file or from + memory in LSB-first byte order. + + This class is used in Fl_GIF_Image and Fl_BMP_Image to avoid code + duplication and may be extended to be used in similar cases. Future + options might be to read data in MSB-first byte order or to add more + methods. +*/ + +#ifndef FL_IMAGE_READER_H +#define FL_IMAGE_READER_H + +#include <stdio.h> + +class Fl_Image_Reader +{ +public: + // Create the reader. + Fl_Image_Reader() : + pIsFile(0), pIsData(0), + pFile(0L), pData(0L), + pStart(0L), + pName(0L) + {} + + // Initialize the reader to access the file system, filename is copied + // and stored. + int open(const char *filename); + + // Initialize the reader for memory access, name is copied and stored + int open(const char *imagename, const unsigned char *data); + + // Close and destroy the reader + ~Fl_Image_Reader(); + + // Read a single byte from memory or a file + unsigned char read_byte(); + + // Read a 16-bit unsigned integer, LSB-first + unsigned short read_word(); + + // Read a 32-bit unsigned integer, LSB-first + unsigned int read_dword(); + + // Read a 32-bit signed integer, LSB-first + int read_long() { + return (int)read_dword(); + }; + + // Move the current read position to a byte offset from the beginning + // of the file or the original start address in memory + void seek(unsigned int n); + + // return the name or filename for this reader + const char *name() { return pName; } + +private: + + // open() sets this if we read from a file + char pIsFile; + // open() sets this if we read from memory + char pIsData; + // a pointer to the opened file + FILE *pFile; + // a pointer to the current byte in memory + const unsigned char *pData; + // a pointer to the start of the image data + const unsigned char *pStart; + // a copy of the name associated with this reader + char *pName; +}; + +#endif // FL_IMAGE_READER_H |