1 // Copyright (c) 2010 The Chromium OS Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include <stdint.h> 6 #include <string.h> 7 8 #include "bmpblk_header.h" 9 #include "bmpblk_font.h" 10 #include "image_types.h" 11 12 /* BMP header, used to validate image requirements 13 * See http://en.wikipedia.org/wiki/BMP_file_format 14 */ 15 typedef struct { 16 uint8_t CharB; // must be 'B' 17 uint8_t CharM; // must be 'M' 18 uint32_t Size; 19 uint16_t Reserved[2]; 20 uint32_t ImageOffset; 21 uint32_t HeaderSize; 22 uint32_t PixelWidth; 23 uint32_t PixelHeight; 24 uint16_t Planes; // Must be 1 for x86 25 uint16_t BitPerPixel; // 1, 4, 8, or 24 for x86 26 uint32_t CompressionType; // 0 (none) for x86, 1 (RLE) for arm 27 uint32_t ImageSize; 28 uint32_t XPixelsPerMeter; 29 uint32_t YPixelsPerMeter; 30 uint32_t NumberOfColors; 31 uint32_t ImportantColors; 32 } __attribute__((packed)) BMP_IMAGE_HEADER; 33 34 35 ImageFormat identify_image_type(const void *buf, uint32_t bufsize, 36 ImageInfo *info) { 37 38 if (info) 39 info->format = FORMAT_INVALID; 40 41 if (bufsize < sizeof(BMP_IMAGE_HEADER) && 42 bufsize < sizeof(FontArrayHeader)) { 43 return FORMAT_INVALID; 44 } 45 46 const BMP_IMAGE_HEADER *bhdr = buf; 47 if (bhdr->CharB == 'B' && bhdr->CharM == 'M' && 48 bhdr->Planes == 1 && 49 (bhdr->CompressionType == 0 || bhdr->CompressionType == 1) && 50 (bhdr->BitPerPixel == 1 || bhdr->BitPerPixel == 4 || 51 bhdr->BitPerPixel == 8 || bhdr->BitPerPixel == 24)) { 52 if (info) { 53 info->format = FORMAT_BMP; 54 info->width = bhdr->PixelWidth; 55 info->height = bhdr->PixelHeight; 56 } 57 return FORMAT_BMP; 58 } 59 60 const FontArrayHeader *fhdr = buf; 61 if (0 == memcmp(&fhdr->signature, FONT_SIGNATURE, FONT_SIGNATURE_SIZE) && 62 fhdr->num_entries > 0) { 63 if (info) 64 info->format = FORMAT_FONT; 65 return FORMAT_FONT; 66 } 67 68 return FORMAT_INVALID; 69 } 70 71 72
