/* $Id$ */ /** @file bmp.cpp Read and write support for bmps. */ #include "stdafx.h" #include "bmp.h" #include "core/bitmath_func.hpp" #include "core/alloc_func.hpp" void BmpInitializeBuffer(BmpBuffer *buffer, FILE *file) { buffer->pos = -1; buffer->file = file; buffer->read = 0; buffer->real_pos = ftell(file); } static inline void AdvanceBuffer(BmpBuffer *buffer) { buffer->read = (int)fread(buffer->data, 1, BMP_BUFFER_SIZE, buffer->file); buffer->pos = 0; } static inline bool EndOfBuffer(BmpBuffer *buffer) { if (buffer->pos == buffer->read || buffer->pos < 0) AdvanceBuffer(buffer); return buffer->pos == buffer->read; } static inline byte ReadByte(BmpBuffer *buffer) { if (buffer->pos == buffer->read || buffer->pos < 0) AdvanceBuffer(buffer); buffer->real_pos++; return buffer->data[buffer->pos++]; } static inline uint16 ReadWord(BmpBuffer *buffer) { uint16 var = ReadByte(buffer); return var | (ReadByte(buffer) << 8); } static inline uint32 ReadDword(BmpBuffer *buffer) { uint32 var = ReadWord(buffer); return var | (ReadWord(buffer) << 16); } static inline void SkipBytes(BmpBuffer *buffer, int bytes) { int i; for (i = 0; i < bytes; i++) ReadByte(buffer); } static inline void SetStreamOffset(BmpBuffer *buffer, int offset) { fseek(buffer->file, offset, SEEK_SET); buffer->pos = -1; buffer->real_pos = offset; AdvanceBuffer(buffer); } /** * Reads a 1 bpp uncompressed bitmap * The bitmap is converted to a 8 bpp bitmap */ static inline bool BmpRead1(BmpBuffer *buffer, BmpInfo *info, BmpData *data) { uint x, y, i; byte pad = GB(4 - info->width / 8, 0, 2); byte *pixel_row; byte b; for (y = info->height; y > 0; y--) { x = 0; pixel_row = &data->bitmap[(y - 1) * info->width]; while (x < info->width) { if (EndOfBuffer(buffer)) return false; // the file is shorter than expected b = ReadByte(buffer); for (i = 8; i > 0; i--) { if (x < info->width) *pixel_row++ = GB(b, i - 1, 1); x++; } } /* Padding for 32 bit align */ SkipBytes(buffer, pad); } return true; } /** * Reads a 4 bpp uncompressed bitmap * The bitmap is converted to a 8 bpp bitmap */ static inline bool BmpRead4(BmpBuffer *buffer, BmpInfo *info, BmpData *data) { uint x, y; byte pad = GB(4 - info->width / 2, 0, 2); byte *pixel_row; byte b; for (y = info->height; y > 0; y--) { x = 0; pixel_row = &data->bitmap[(y - 1) * info->width]; while (x < info->width) { if (EndOfBuffer(buffer)) return false; // the file is shorter than expected b = ReadByte(buffer); *pixel_row++ = GB(b, 4, 4); x++; if (x < info->width) { *pixel_row++ = GB(b, 0, 4); x++; } } /* Padding for 32 bit align */ SkipBytes(buffer, pad); } return true; } /** * Reads a 4-bit RLE compressed bitmap * The bitmap is converted to a 8 bpp bitmap */ static inline bool BmpRead4Rle(BmpBuffer *buffer, BmpInfo *info, BmpData *data) { uint i; uint x = 0; uint y = info->height - 1; byte n, c, b; byte *pixel = &data->bitmap[y * info->width]; while (y != 0 || x < info->width) { if (EndOfBuffer(buffer)) return false; // the file is shorter than expected n = ReadByte(buffer); c = ReadByte(buffer); if (n == 0) { switch (c) { case 0: // end of line x = 0; pixel = &data->bitmap[--y * info->width]; break; case 1: // end of bitmap x = info->width; y = 0; pixel = NULL; break; case 2: // delta x += ReadByte(buffer); i = ReadByte(buffer); if (x >= info->width || (y == 0 && i > 0)) return false; y -= i; pixel = &data->bitmap[y * info->width + x]; break; default: // uncompressed i = 0; while (i++ < c) { if (EndOfBuffer(buffer) || x >= info->width) return false; b = ReadByte(buffer); *pixel++ = GB(b, 4, 4); x++; if (x < info->width && i++ < c) { *pixel++ = GB(b, 0, 4); x++; } } /* Padding for 16 bit align */ SkipBytes(buffer, ((c + 1) / 2) % 2); break; } } else { i = 0; while (i++ < n) { if (EndOfBuffer(buffer) || x >= info->width) return false; *pixel++ = GB(c, 4, 4); x++; if (x < info->width && i++ < n) { *pixel++ = GB(c, 0, 4); x++; } } } } return true; } /** * Reads a 8 bpp bitmap */ static inline bool BmpRead8(BmpBuffer *buffer, BmpInfo *info, BmpData *data) { uint i; uint y; byte pad = GB(4 - info->width, 0, 2); byte *pixel; for (y = info->height; y > 0; y--) { if (EndOfBuffer(buffer)) return false; // the file is shorter than expected pixel = &data->bitmap[(y - 1) * info->width]; for (i = 0; i < info->width; i++) *pixel++ = ReadByte(buffer); /* Padding for 32 bit align */ SkipBytes(buffer, pad); } return true; } /** * Reads a 8-bit RLE compressed bpp bitmap */ static inline bool BmpRead8Rle(BmpBuffer *buffer, BmpInfo *info, BmpData *data) { uint i; uint x = 0; uint y = info->height - 1; byte n, c; byte *pixel = &data->bitmap[y * info->width]; while (y != 0 || x < info->width) { if (EndOfBuffer(buffer)) return false; // the file is shorter than expected n = ReadByte(buffer); c = ReadByte(buffer); if (n == 0) { switch (c) { case 0: // end of line x = 0; pixel = &data->bitmap[--y * info->width]; break; case 1: // end of bitmap x = info->width; y = 0; pixel = NULL; break; case 2: // delta x += ReadByte(buffer); i = ReadByte(buffer); if (x >= info->width || (y == 0 && i > 0)) return false; y -= i; pixel = &data->bitmap[y * info->width + x]; break; default: // uncompressed if ((x += c) > info->width) return false; for (i = 0; i < c; i++) *pixel++ = ReadByte(buffer); /* Padding for 16 bit align */ SkipBytes(buffer, c % 2); break; } } else { for (i = 0; i < n; i++) { if (x >= info->width) return false; *pixel++ = c; x++; } } } return true; } /** * Reads a 24 bpp uncompressed bitmap */ static inline bool BmpRead24(BmpBuffer *buffer, BmpInfo *info, BmpData *data) { uint x, y; byte pad = GB(4 - info->width * 3, 0, 2); byte *pixel_row; for (y = info->height; y > 0; y--) { pixel_row = &data->bitmap[(y - 1) * info->width * 3]; for (x = 0; x < info->width; x++) { if (EndOfBuffer(buffer)) return false; // the file is shorter than expected *(pixel_row + 2) = ReadByte(buffer); // green *(pixel_row + 1) = ReadByte(buffer); // blue *pixel_row = ReadByte(buffer); // red pixel_row += 3; } /* Padding for 32 bit align */ SkipBytes(buffer, pad); } return true; } /* * Reads bitmap headers, and palette (if any) */ bool BmpReadHeader(BmpBuffer *buffer, BmpInfo *info, BmpData *data) { uint32 header_size; assert(info != NULL); /* Reading BMP header */ if (ReadWord(buffer) != 0x4D42) return false; // signature should be 'BM' SkipBytes(buffer, 8); // skip file size and reserved info->offset = ReadDword(buffer); /* Reading info header */ header_size = ReadDword(buffer); if (header_size < 12) return false; // info header should be at least 12 bytes long info->os2_bmp = (header_size == 12); // OS/2 1.x or windows 2.x info header is 12 bytes long if (info->os2_bmp) { info->width = ReadWord(buffer); info->height = ReadWord(buffer); header_size -= 8; } else { info->width = ReadDword(buffer); info->height = ReadDword(buffer); header_size -= 12; } if (ReadWord(buffer) != 1) return false; // BMP can have only 1 plane info->bpp = ReadWord(buffer); if (info->bpp != 1 && info->bpp != 4 && info->bpp != 8 && info->bpp != 24) { /* Only 1 bpp, 4 bpp, 8bpp and 24 bpp bitmaps are supported */ return false; } /* Reads compression method if available in info header*/ if ((header_size -= 4) >= 4) { info->compression = ReadDword(buffer); header_size -= 4; } /* Only 4-bit and 8-bit rle compression is supported */ if (info->compression > 2 || (info->compression > 0 && !(info->bpp == 4 || info->bpp == 8))) return false; if (info->bpp <= 8) { uint i; /* Reads number of colors if available in info header */ if (header_size >= 16) { SkipBytes(buffer, 12); // skip image size and resolution info->palette_size = ReadDword(buffer); // number of colors in palette SkipBytes(buffer, header_size - 16); // skip the end of info header } if (info->palette_size == 0) info->palette_size = 1 << info->bpp; data->palette = CallocT<Colour>(info->palette_size); if (data->palette == NULL) return false; for (i = 0; i < info->palette_size; i++) { data->palette[i].b = ReadByte(buffer); data->palette[i].g = ReadByte(buffer); data->palette[i].r = ReadByte(buffer); if (!info->os2_bmp) SkipBytes(buffer, 1); // unused } } return buffer->real_pos <= info->offset; } /* * Reads the bitmap * 1 bpp and 4 bpp bitmaps are converted to 8 bpp bitmaps */ bool BmpReadBitmap(BmpBuffer *buffer, BmpInfo *info, BmpData *data) { assert(info != NULL && data != NULL); data->bitmap = CallocT<byte>(info->width * info->height * ((info->bpp == 24) ? 3 : 1)); if (data->bitmap == NULL) return false; /* Load image */ SetStreamOffset(buffer, info->offset); switch (info->compression) { case 0: // no compression switch (info->bpp) { case 1: return BmpRead1(buffer, info, data); case 4: return BmpRead4(buffer, info, data); case 8: return BmpRead8(buffer, info, data); case 24: return BmpRead24(buffer, info, data); default: NOT_REACHED(); return false; } case 1: return BmpRead8Rle(buffer, info, data); // 8-bit RLE compression case 2: return BmpRead4Rle(buffer, info, data); // 4-bit RLE compression default: NOT_REACHED(); return false; } } void BmpDestroyData(BmpData *data) { assert(data != NULL); free(data->palette); free(data->bitmap); }