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Diffstat (limited to 'image/bmpread.c')
| -rw-r--r-- | image/bmpread.c | 483 |
1 files changed, 483 insertions, 0 deletions
diff --git a/image/bmpread.c b/image/bmpread.c new file mode 100644 index 000000000..15c103ae0 --- /dev/null +++ b/image/bmpread.c @@ -0,0 +1,483 @@ +/* + * This file is part of NetSurf, http://netsurf.sourceforge.net/ + * Licensed under the GNU General Public License, + * http://www.opensource.org/licenses/gpl-license + * Copyright 2006 Richard Wilson <info@tinct.net> + */ + + +#include <assert.h> +#include <stdbool.h> +#include <stdio.h> +#include <string.h> +#include <stdlib.h> +#include "netsurf/image/bmpread.h" +#include "netsurf/image/bitmap.h" +#include "netsurf/utils/log.h" + +#define READ_SHORT(a, o) (a[o]|(a[o+1]<<8)) +#define READ_INT(a, o) (a[o]|(a[o+1]<<8)|(a[o+2]<<16)|(a[o+3]<<24)) + +bmp_result bmp_decode_rgb24(struct bmp_image *bmp, char *data, int bytes); +bmp_result bmp_decode_rgb(struct bmp_image *bmp, char *data, int bytes); +bmp_result bmp_decode_rle(struct bmp_image *bmp, char *data, int bytes, int size); + + +/** + * Analyse a BMP prior to decoding. + * + * This function will scan the data provided and perform simple checks to + * ensure the data is a valid BMP. + * + * This function must be called before bmp_decode() and sets up all the + * relevant values in the bmp structure. + * + * \param bmp the BMP image to analyse + * \return BMP_OK on success + */ +bmp_result bmp_analyse(struct bmp_image *bmp) { + char *data = bmp->bmp_data; + unsigned int header_size; + unsigned int i; + int width, height; + int palette_size; + + /* ensure we aren't already initialised */ + if (bmp->bitmap) + return BMP_OK; + + /* standard 14-byte BMP file header is: + * + * +0 SHORT 'BM' + * +2 INT size of file (in bytes) + * +6 SHORT reserved field (1) + * +8 SHORT reserved field (2) + * +10 INT starting position of image data (in bytes) + */ + if (bmp->buffer_size < 14) + return BMP_INSUFFICIENT_DATA; + if ((data[0] != 'B') || (data[1] != 'M')) + return BMP_DATA_ERROR; + bmp->bitmap_offset = READ_INT(data, 10); + data += 14; + + /* a variety of different bitmap headers can now follow, depending + * on the BMP variant. A full description of the various headers + * can be found at http://www.fileformat.info/format/bmp/ + */ + header_size = READ_INT(data, 0); + if (bmp->buffer_size < (14 + header_size)) + return BMP_INSUFFICIENT_DATA; + if (header_size == 12) { + /* the following header is for os/2 and windows 2.x and consists of: + * + * +0 INT size of this header (in bytes) + * +4 SHORT image width (in pixels) + * +6 SHORT image height (in pixels) + * +8 SHORT number of color planes (always 1) + * +10 SHORT number of bits per pixel + */ + width = READ_SHORT(data, 4); + height = READ_SHORT(data, 6); + if (width < 0) + return BMP_DATA_ERROR; + if (height < 0) { + bmp->reversed = true; + height = -height; + } + bmp->width = width; + bmp->height = height; + if (READ_SHORT(data, 8) != 1) + return BMP_DATA_ERROR; + bmp->bpp = READ_SHORT(data, 10); + bmp->colours = (1 << bmp->bpp); + palette_size = 3; + } else if (header_size < 40) { + return BMP_DATA_ERROR; + } else { + /* the following header is for windows 3.x and onwards. it is a + * minimum of 40 bytes and (as of Windows 95) a maximum of 108 bytes. + * + * +0 INT size of this header (in bytes) + * +4 INT image width (in pixels) + * +8 INT image height (in pixels) + * +12 SHORT number of color planes (always 1) + * +14 SHORT number of bits per pixel + * +16 INT compression methods used + * +20 INT size of bitmap (in bytes) + * +24 INT horizontal resolution (in pixels per meter) + * +28 INT vertical resolution (in pixels per meter) + * +32 INT number of colors in the image + * +36 INT number of important colors + * +40 INT mask identifying bits of red component + * +44 INT mask identifying bits of green component + * +48 INT mask identifying bits of blue component + * +52 INT mask identifying bits of alpha component + * +56 INT color space type + * +60 INT x coordinate of red endpoint + * +64 INT y coordinate of red endpoint + * +68 INT z coordinate of red endpoint + * +72 INT x coordinate of green endpoint + * +76 INT y coordinate of green endpoint + * +80 INT z coordinate of green endpoint + * +84 INT x coordinate of blue endpoint + * +88 INT y coordinate of blue endpoint + * +92 INT z coordinate of blue endpoint + * +96 INT gamma red coordinate scale value + * +100 INT gamma green coordinate scale value + * +104 INT gamma blue coordinate scale value + */ + width = READ_INT(data, 4); + height = READ_INT(data, 8); + if (width < 0) + return BMP_DATA_ERROR; + if (height < 0) { + bmp->reversed = true; + height = -height; + } + bmp->width = width; + bmp->height = height; + if (READ_SHORT(data, 12) != 1) + return BMP_DATA_ERROR; + bmp->bpp = READ_SHORT(data, 14); + bmp->encoding = READ_INT(data, 16); + if (bmp->encoding >= BMP_ENCODING_BITFIELDS) /* unsupported so far */ + return BMP_DATA_ERROR; + bmp->colours = READ_INT(data, 32); + if (bmp->colours == 0) + bmp->colours = (1 << bmp->bpp); + palette_size = 4; + /* we don't understand the rest of the data yet */ + } + data += header_size; + + /* we only have a palette for <16bpp */ + if (bmp->bpp < 16) { + /* we now have a series of palette entries of the format: + * + * +0 BYTE blue + * +1 BYTE green + * +2 BYTE red + * + * if the palette is from an OS/2 or Win2.x file then the entries + * are padded with an extra byte. + */ + if (bmp->buffer_size < (14 + header_size + (4 * bmp->colours))) + return BMP_INSUFFICIENT_DATA; + bmp->colour_table = (unsigned int *) + malloc(bmp->colours * sizeof(int)); + if (!bmp->colour_table) + return BMP_INSUFFICIENT_MEMORY; + for (i = 0; i < bmp->colours; i++) { + bmp->colour_table[i] = (data[2] | (data[1] << 8) | + (data[0] << 16) | (0xff << 24)); + data += palette_size; + } + } + + /* create our bitmap */ + bmp->bitmap = bitmap_create(bmp->width, bmp->height, + BITMAP_NEW | BITMAP_OPAQUE | BITMAP_CLEAR_MEMORY); + if (!bmp->bitmap) { + if (bmp->colour_table) + free(bmp->colour_table); + bmp->colour_table = NULL; + return BMP_INSUFFICIENT_MEMORY; + } + return BMP_OK; +} + + +/** + * Decode a BMP + * + * This function decodes the BMP data such that bmp->bitmap is a valid + * image. The state of bmp->decoded is set to TRUE on exit such that it + * can easily be identified which BMPs are in a fully decoded state. + * + * \param bmp the BMP image to decode + * \return BMP_OK on success + */ +bmp_result bmp_decode(struct bmp_image *bmp) { + char *data; + int bytes; + + assert(bmp->bitmap); + + data = bmp->bmp_data + bmp->bitmap_offset; + bytes = bmp->buffer_size - bmp->bitmap_offset; + + switch (bmp->encoding) { + case BMP_ENCODING_RGB: + if (bmp->bpp >= 24) + return bmp_decode_rgb24(bmp, data, bytes); + else if (bmp->bpp > 8) + return BMP_DATA_ERROR; + else + return bmp_decode_rgb(bmp, data, bytes); + case BMP_ENCODING_RLE8: + return bmp_decode_rle(bmp, data, bytes, 8); + case BMP_ENCODING_RLE4: + return bmp_decode_rle(bmp, data, bytes, 4); + case BMP_ENCODING_BITFIELDS: + /* todo: implement me */ + break; + } + return BMP_DATA_ERROR; +} + + +/** + * Decode BMP data stored in 24bpp colour. + * + * \param bmp the BMP image to decode + * \param data the data to decode + * \param bytes the number of bytes of data available + * \return BMP_OK on success + */ +bmp_result bmp_decode_rgb24(struct bmp_image *bmp, char *data, int bytes) { + char *top, *bottom, *end; + unsigned int *scanline; + unsigned int x, y, swidth, skip; + unsigned int addr; + + swidth = bitmap_get_rowstride(bmp->bitmap); + top = bitmap_get_buffer(bmp->bitmap); + bottom = top + swidth * (bmp->height - 1); + end = data + bytes; + addr = ((unsigned int)data) & 3; + skip = bmp->bpp >> 3; + bmp->decoded = true; + + for (y = 0; y < bmp->height; y++) { + while (addr != (((unsigned int)data) & 3)) + data++; + if ((data + (skip * bmp->width)) > end) + return BMP_INSUFFICIENT_DATA; + if (bmp->reversed) + scanline = (unsigned int *)(top + (y * swidth)); + else + scanline = (unsigned int *)(bottom - (y * swidth)); + for (x = 0; x < bmp->width; x++) { + scanline[x] = data[2] | (data[1] << 8) | (data[0] << 16); + data += skip; + } + } + return BMP_OK; +} + + +/** + * Decode BMP data stored with a palette and in 8bpp colour or less. + * + * \param bmp the BMP image to decode + * \param data the data to decode + * \param bytes the number of bytes of data available + * \return BMP_OK on success + */ +bmp_result bmp_decode_rgb(struct bmp_image *bmp, char *data, int bytes) { + char *top, *bottom, *end; + unsigned int *scanline; + unsigned int addr; + unsigned int x, y, swidth; + int i; + int bit_shifts[8]; + int ppb = 8 / bmp->bpp; + int bit_mask = (1 << bmp->bpp) - 1; + int cur_byte = 0, bit; + + for (i = 0; i < ppb; i++) + bit_shifts[i] = 8 - ((i + 1) * bmp->bpp); + + swidth = bitmap_get_rowstride(bmp->bitmap); + top = bitmap_get_buffer(bmp->bitmap); + bottom = top + swidth * (bmp->height - 1); + end = data + bytes; + addr = ((unsigned int)data) & 3; + bmp->decoded = true; + + for (y = 0; y < bmp->height; y++) { + while (addr != (((unsigned int)data) & 3)) + data++; + bit = 32; + if ((data + (bmp->width / ppb)) > end) + return BMP_INSUFFICIENT_DATA; + if (bmp->reversed) + scanline = (unsigned int *)(top + (y * swidth)); + else + scanline = (unsigned int *)(bottom - (y * swidth)); + for (x = 0; x < bmp->width; x++) { + if (bit >= ppb) { + bit = 0; + cur_byte = *data++; + } + scanline[x] = bmp->colour_table[(cur_byte >> + bit_shifts[bit++]) & bit_mask]; + } + } + return BMP_OK; +} + + +/** + * Decode BMP data stored encoded in either RLE4 or RLE8. + * + * \param bmp the BMP image to decode + * \param data the data to decode + * \param bytes the number of bytes of data available + * \param size the size of the RLE tokens (4 or 8) + * \return BMP_OK on success + */ +bmp_result bmp_decode_rle(struct bmp_image *bmp, char *data, int bytes, int size) { + char *top, *bottom, *end; + unsigned int *scanline; + unsigned int swidth; + int i, length, pixels_left; + unsigned int x = 0, y = 0, last_y = 0; + unsigned int pixel = 0, pixel2; + + swidth = bitmap_get_rowstride(bmp->bitmap); + top = bitmap_get_buffer(bmp->bitmap); + bottom = top + swidth * (bmp->height - 1); + end = data + bytes; + bmp->decoded = true; + + do { + if (data + 2 > end) + return BMP_INSUFFICIENT_DATA; + length = *data++; + if (length == 0) { + length = *data++; + if (length == 0) { + /* 00 - 00 means end of scanline */ + x = 0; + if (last_y == y) { + if (++y > bmp->height) + return BMP_DATA_ERROR; + } + last_y = y; + } else if (length == 1) { + /* 00 - 01 means end of RLE data */ + return BMP_OK; + } else if (length == 2) { + /* 00 - 02 - XX - YY means move cursor */ + if (data + 2 > end) + return BMP_INSUFFICIENT_DATA; + x += *data++; + if (x >= bmp->width) + return BMP_DATA_ERROR; + y += *data++; + if (y >= bmp->height) + return BMP_DATA_ERROR; + } else { + /* 00 - NN means escape pixels */ + if (bmp->reversed) { + pixels_left = (y + 1) * bmp->width - x; + scanline = (unsigned int *)(top + (y * swidth)); + } else { + pixels_left = (bmp->height - y + 1) * bmp->width - x; + scanline = (unsigned int *)(bottom - (y * swidth)); + } + if (length > pixels_left) + length = pixels_left; + if (data + length > end) + return BMP_INSUFFICIENT_DATA; + + /* the following code could be easily optimised by simply + * checking the bounds on entry and using some simply copying + * routines if so */ + if (size == 8) { + for (i = 0; i < length; i++) { + if (x >= bmp->width) { + x = 0; + if (++y > bmp->height) + return BMP_DATA_ERROR; + scanline -= bmp->width; + } + scanline[x++] = bmp->colour_table[(int)*data++]; + } + } else { + for (i = 0; i < length; i++) { + if (x >= bmp->width) { + x = 0; + if (++y > bmp->height) + return BMP_DATA_ERROR; + scanline -= bmp->width; + } + if ((i & 1) == 0) { + pixel = *data++; + scanline[x++] = bmp->colour_table + [pixel >> 4]; + } else { + scanline[x++] = bmp->colour_table + [pixel & 0xf]; + } + } + length = (length + 1) >> 1; + } + if ((length & 1) && (*data++ != 0x00)) + return BMP_DATA_ERROR; + + } + } else { + /* NN means perform RLE for NN pixels */ + if (bmp->reversed) { + pixels_left = (y + 1) * bmp->width - x; + scanline = (unsigned int *)(top + (y * swidth)); + } else { + pixels_left = (bmp->height - y + 1) * bmp->width - x; + scanline = (unsigned int *)(bottom - (y * swidth)); + } + if (length > pixels_left) + length = pixels_left; + + /* the following code could be easily optimised by simply + * checking the bounds on entry and using some simply copying + * routines if so */ + if (size == 8) { + pixel = bmp->colour_table[(int)*data++]; + for (i = 0; i < length; i++) { + if (x >= bmp->width) { + x = 0; + if (++y > bmp->height) + return BMP_DATA_ERROR; + scanline -= bmp->width; + } + scanline[x++] = pixel; + } + } else { + pixel2 = *data++; + pixel = bmp->colour_table[pixel2 >> 4]; + pixel2 = bmp->colour_table[pixel2 & 0xf]; + for (i = 0; i < length; i++) { + if (x >= bmp->width) { + x = 0; + if (++y > bmp->height) + return BMP_DATA_ERROR; + scanline -= bmp->width; + } + if ((i & 1) == 0) + scanline[x++] = pixel; + else + scanline[x++] = pixel2; + } + } + } + } while (data < end); + return BMP_OK; +} + + +/** + * Finalise a BMP prior to destruction. + * + * \param bmp the BMP image to finalise + */ +void bmp_finalise(struct bmp_image *bmp) { + if (bmp->bitmap) + bitmap_destroy(bmp->bitmap); + bmp->bitmap = NULL; + if (bmp->colour_table) + free(bmp->colour_table); + bmp->colour_table = NULL; +} |