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Diffstat (limited to 'jpeg/rdtarga.c')
-rw-r--r-- | jpeg/rdtarga.c | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/jpeg/rdtarga.c b/jpeg/rdtarga.c new file mode 100644 index 0000000..4c2cd26 --- /dev/null +++ b/jpeg/rdtarga.c @@ -0,0 +1,500 @@ +/* + * rdtarga.c + * + * Copyright (C) 1991-1996, Thomas G. Lane. + * This file is part of the Independent JPEG Group's software. + * For conditions of distribution and use, see the accompanying README file. + * + * This file contains routines to read input images in Targa format. + * + * These routines may need modification for non-Unix environments or + * specialized applications. As they stand, they assume input from + * an ordinary stdio stream. They further assume that reading begins + * at the start of the file; start_input may need work if the + * user interface has already read some data (e.g., to determine that + * the file is indeed Targa format). + * + * Based on code contributed by Lee Daniel Crocker. + */ + +#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */ + +#ifdef TARGA_SUPPORTED + + +/* Macros to deal with unsigned chars as efficiently as compiler allows */ + +#ifdef HAVE_UNSIGNED_CHAR +typedef unsigned char U_CHAR; +#define UCH(x) ((int) (x)) +#else /* !HAVE_UNSIGNED_CHAR */ +#ifdef CHAR_IS_UNSIGNED +typedef char U_CHAR; +#define UCH(x) ((int) (x)) +#else +typedef char U_CHAR; +#define UCH(x) ((int) (x) & 0xFF) +#endif +#endif /* HAVE_UNSIGNED_CHAR */ + + +#define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len))) + + +/* Private version of data source object */ + +typedef struct _tga_source_struct * tga_source_ptr; + +typedef struct _tga_source_struct { + struct cjpeg_source_struct pub; /* public fields */ + + j_compress_ptr cinfo; /* back link saves passing separate parm */ + + JSAMPARRAY colormap; /* Targa colormap (converted to my format) */ + + jvirt_sarray_ptr whole_image; /* Needed if funny input row order */ + JDIMENSION current_row; /* Current logical row number to read */ + + /* Pointer to routine to extract next Targa pixel from input file */ + JMETHOD(void, read_pixel, (tga_source_ptr sinfo)); + + /* Result of read_pixel is delivered here: */ + U_CHAR tga_pixel[4]; + + int pixel_size; /* Bytes per Targa pixel (1 to 4) */ + + /* State info for reading RLE-coded pixels; both counts must be init to 0 */ + int block_count; /* # of pixels remaining in RLE block */ + int dup_pixel_count; /* # of times to duplicate previous pixel */ + + /* This saves the correct pixel-row-expansion method for preload_image */ + JMETHOD(JDIMENSION, get_pixel_rows, (j_compress_ptr cinfo, + cjpeg_source_ptr sinfo)); +} tga_source_struct; + + +/* For expanding 5-bit pixel values to 8-bit with best rounding */ + +static const UINT8 c5to8bits[32] = { + 0, 8, 16, 25, 33, 41, 49, 58, + 66, 74, 82, 90, 99, 107, 115, 123, + 132, 140, 148, 156, 165, 173, 181, 189, + 197, 206, 214, 222, 230, 239, 247, 255 +}; + + + +LOCAL(int) +read_byte (tga_source_ptr sinfo) +/* Read next byte from Targa file */ +{ + register FILE *infile = sinfo->pub.input_file; + register int c; + + if ((c = getc(infile)) == EOF) + ERREXIT(sinfo->cinfo, JERR_INPUT_EOF); + return c; +} + + +LOCAL(void) +read_colormap (tga_source_ptr sinfo, int cmaplen, int mapentrysize) +/* Read the colormap from a Targa file */ +{ + int i; + + /* Presently only handles 24-bit BGR format */ + if (mapentrysize != 24) + ERREXIT(sinfo->cinfo, JERR_TGA_BADCMAP); + + for (i = 0; i < cmaplen; i++) { + sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo); + sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo); + sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo); + } +} + + +/* + * read_pixel methods: get a single pixel from Targa file into tga_pixel[] + */ + +METHODDEF(void) +read_non_rle_pixel (tga_source_ptr sinfo) +/* Read one Targa pixel from the input file; no RLE expansion */ +{ + register FILE *infile = sinfo->pub.input_file; + register int i; + + for (i = 0; i < sinfo->pixel_size; i++) { + sinfo->tga_pixel[i] = (U_CHAR) getc(infile); + } +} + + +METHODDEF(void) +read_rle_pixel (tga_source_ptr sinfo) +/* Read one Targa pixel from the input file, expanding RLE data as needed */ +{ + register FILE *infile = sinfo->pub.input_file; + register int i; + + /* Duplicate previously read pixel? */ + if (sinfo->dup_pixel_count > 0) { + sinfo->dup_pixel_count--; + return; + } + + /* Time to read RLE block header? */ + if (--sinfo->block_count < 0) { /* decrement pixels remaining in block */ + i = read_byte(sinfo); + if (i & 0x80) { /* Start of duplicate-pixel block? */ + sinfo->dup_pixel_count = i & 0x7F; /* number of dups after this one */ + sinfo->block_count = 0; /* then read new block header */ + } else { + sinfo->block_count = i & 0x7F; /* number of pixels after this one */ + } + } + + /* Read next pixel */ + for (i = 0; i < sinfo->pixel_size; i++) { + sinfo->tga_pixel[i] = (U_CHAR) getc(infile); + } +} + + +/* + * Read one row of pixels. + * + * We provide several different versions depending on input file format. + */ + + +METHODDEF(JDIMENSION) +get_8bit_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) +/* This version is for reading 8-bit grayscale pixels */ +{ + tga_source_ptr source = (tga_source_ptr) sinfo; + register JSAMPROW ptr; + register JDIMENSION col; + + ptr = source->pub.buffer[0]; + for (col = cinfo->image_width; col > 0; col--) { + (*source->read_pixel) (source); /* Load next pixel into tga_pixel */ + *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]); + } + return 1; +} + +METHODDEF(JDIMENSION) +get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) +/* This version is for reading 8-bit colormap indexes */ +{ + tga_source_ptr source = (tga_source_ptr) sinfo; + register int t; + register JSAMPROW ptr; + register JDIMENSION col; + register JSAMPARRAY colormap = source->colormap; + + ptr = source->pub.buffer[0]; + for (col = cinfo->image_width; col > 0; col--) { + (*source->read_pixel) (source); /* Load next pixel into tga_pixel */ + t = UCH(source->tga_pixel[0]); + *ptr++ = colormap[0][t]; + *ptr++ = colormap[1][t]; + *ptr++ = colormap[2][t]; + } + return 1; +} + +METHODDEF(JDIMENSION) +get_16bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) +/* This version is for reading 16-bit pixels */ +{ + tga_source_ptr source = (tga_source_ptr) sinfo; + register int t; + register JSAMPROW ptr; + register JDIMENSION col; + + ptr = source->pub.buffer[0]; + for (col = cinfo->image_width; col > 0; col--) { + (*source->read_pixel) (source); /* Load next pixel into tga_pixel */ + t = UCH(source->tga_pixel[0]); + t += UCH(source->tga_pixel[1]) << 8; + /* We expand 5 bit data to 8 bit sample width. + * The format of the 16-bit (LSB first) input word is + * xRRRRRGGGGGBBBBB + */ + ptr[2] = (JSAMPLE) c5to8bits[t & 0x1F]; + t >>= 5; + ptr[1] = (JSAMPLE) c5to8bits[t & 0x1F]; + t >>= 5; + ptr[0] = (JSAMPLE) c5to8bits[t & 0x1F]; + ptr += 3; + } + return 1; +} + +METHODDEF(JDIMENSION) +get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) +/* This version is for reading 24-bit pixels */ +{ + tga_source_ptr source = (tga_source_ptr) sinfo; + register JSAMPROW ptr; + register JDIMENSION col; + + ptr = source->pub.buffer[0]; + for (col = cinfo->image_width; col > 0; col--) { + (*source->read_pixel) (source); /* Load next pixel into tga_pixel */ + *ptr++ = (JSAMPLE) UCH(source->tga_pixel[2]); /* change BGR to RGB order */ + *ptr++ = (JSAMPLE) UCH(source->tga_pixel[1]); + *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]); + } + return 1; +} + +/* + * Targa also defines a 32-bit pixel format with order B,G,R,A. + * We presently ignore the attribute byte, so the code for reading + * these pixels is identical to the 24-bit routine above. + * This works because the actual pixel length is only known to read_pixel. + */ + +#define get_32bit_row get_24bit_row + + +/* + * This method is for re-reading the input data in standard top-down + * row order. The entire image has already been read into whole_image + * with proper conversion of pixel format, but it's in a funny row order. + */ + +METHODDEF(JDIMENSION) +get_memory_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) +{ + tga_source_ptr source = (tga_source_ptr) sinfo; + JDIMENSION source_row; + + /* Compute row of source that maps to current_row of normal order */ + /* For now, assume image is bottom-up and not interlaced. */ + /* NEEDS WORK to support interlaced images! */ + source_row = cinfo->image_height - source->current_row - 1; + + /* Fetch that row from virtual array */ + source->pub.buffer = (*cinfo->mem->access_virt_sarray) + ((j_common_ptr) cinfo, source->whole_image, + source_row, (JDIMENSION) 1, FALSE); + + source->current_row++; + return 1; +} + + +/* + * This method loads the image into whole_image during the first call on + * get_pixel_rows. The get_pixel_rows pointer is then adjusted to call + * get_memory_row on subsequent calls. + */ + +METHODDEF(JDIMENSION) +preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) +{ + tga_source_ptr source = (tga_source_ptr) sinfo; + JDIMENSION row; + cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress; + + /* Read the data into a virtual array in input-file row order. */ + for (row = 0; row < cinfo->image_height; row++) { + if (progress != NULL) { + progress->pub.pass_counter = (long) row; + progress->pub.pass_limit = (long) cinfo->image_height; + (*progress->pub.progress_monitor) ((j_common_ptr) cinfo); + } + source->pub.buffer = (*cinfo->mem->access_virt_sarray) + ((j_common_ptr) cinfo, source->whole_image, row, (JDIMENSION) 1, TRUE); + (*source->get_pixel_rows) (cinfo, sinfo); + } + if (progress != NULL) + progress->completed_extra_passes++; + + /* Set up to read from the virtual array in unscrambled order */ + source->pub.get_pixel_rows = get_memory_row; + source->current_row = 0; + /* And read the first row */ + return get_memory_row(cinfo, sinfo); +} + + +/* + * Read the file header; return image size and component count. + */ + +METHODDEF(void) +start_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) +{ + tga_source_ptr source = (tga_source_ptr) sinfo; + U_CHAR targaheader[18]; + int idlen, cmaptype, subtype, flags, interlace_type, components; + unsigned int width, height, maplen; + boolean is_bottom_up; + +#define GET_2B(offset) ((unsigned int) UCH(targaheader[offset]) + \ + (((unsigned int) UCH(targaheader[offset+1])) << 8)) + + if (! ReadOK(source->pub.input_file, targaheader, 18)) + ERREXIT(cinfo, JERR_INPUT_EOF); + + /* Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway */ + if (targaheader[16] == 15) + targaheader[16] = 16; + + idlen = UCH(targaheader[0]); + cmaptype = UCH(targaheader[1]); + subtype = UCH(targaheader[2]); + maplen = GET_2B(5); + width = GET_2B(12); + height = GET_2B(14); + source->pixel_size = UCH(targaheader[16]) >> 3; + flags = UCH(targaheader[17]); /* Image Descriptor byte */ + + is_bottom_up = ((flags & 0x20) == 0); /* bit 5 set => top-down */ + interlace_type = flags >> 6; /* bits 6/7 are interlace code */ + + if (cmaptype > 1 || /* cmaptype must be 0 or 1 */ + source->pixel_size < 1 || source->pixel_size > 4 || + (UCH(targaheader[16]) & 7) != 0 || /* bits/pixel must be multiple of 8 */ + interlace_type != 0) /* currently don't allow interlaced image */ + ERREXIT(cinfo, JERR_TGA_BADPARMS); + + if (subtype > 8) { + /* It's an RLE-coded file */ + source->read_pixel = read_rle_pixel; + source->block_count = source->dup_pixel_count = 0; + subtype -= 8; + } else { + /* Non-RLE file */ + source->read_pixel = read_non_rle_pixel; + } + + /* Now should have subtype 1, 2, or 3 */ + components = 3; /* until proven different */ + cinfo->in_color_space = JCS_RGB; + + switch (subtype) { + case 1: /* Colormapped image */ + if (source->pixel_size == 1 && cmaptype == 1) + source->get_pixel_rows = get_8bit_row; + else + ERREXIT(cinfo, JERR_TGA_BADPARMS); + TRACEMS2(cinfo, 1, JTRC_TGA_MAPPED, width, height); + break; + case 2: /* RGB image */ + switch (source->pixel_size) { + case 2: + source->get_pixel_rows = get_16bit_row; + break; + case 3: + source->get_pixel_rows = get_24bit_row; + break; + case 4: + source->get_pixel_rows = get_32bit_row; + break; + default: + ERREXIT(cinfo, JERR_TGA_BADPARMS); + break; + } + TRACEMS2(cinfo, 1, JTRC_TGA, width, height); + break; + case 3: /* Grayscale image */ + components = 1; + cinfo->in_color_space = JCS_GRAYSCALE; + if (source->pixel_size == 1) + source->get_pixel_rows = get_8bit_gray_row; + else + ERREXIT(cinfo, JERR_TGA_BADPARMS); + TRACEMS2(cinfo, 1, JTRC_TGA_GRAY, width, height); + break; + default: + ERREXIT(cinfo, JERR_TGA_BADPARMS); + break; + } + + if (is_bottom_up) { + /* Create a virtual array to buffer the upside-down image. */ + source->whole_image = (*cinfo->mem->request_virt_sarray) + ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE, + (JDIMENSION) width * components, (JDIMENSION) height, (JDIMENSION) 1); + if (cinfo->progress != NULL) { + cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress; + progress->total_extra_passes++; /* count file input as separate pass */ + } + /* source->pub.buffer will point to the virtual array. */ + source->pub.buffer_height = 1; /* in case anyone looks at it */ + source->pub.get_pixel_rows = preload_image; + } else { + /* Don't need a virtual array, but do need a one-row input buffer. */ + source->whole_image = NULL; + source->pub.buffer = (*cinfo->mem->alloc_sarray) + ((j_common_ptr) cinfo, JPOOL_IMAGE, + (JDIMENSION) width * components, (JDIMENSION) 1); + source->pub.buffer_height = 1; + source->pub.get_pixel_rows = source->get_pixel_rows; + } + + while (idlen--) /* Throw away ID field */ + (void) read_byte(source); + + if (maplen > 0) { + if (maplen > 256 || GET_2B(3) != 0) + ERREXIT(cinfo, JERR_TGA_BADCMAP); + /* Allocate space to store the colormap */ + source->colormap = (*cinfo->mem->alloc_sarray) + ((j_common_ptr) cinfo, JPOOL_IMAGE, (JDIMENSION) maplen, (JDIMENSION) 3); + /* and read it from the file */ + read_colormap(source, (int) maplen, UCH(targaheader[7])); + } else { + if (cmaptype) /* but you promised a cmap! */ + ERREXIT(cinfo, JERR_TGA_BADPARMS); + source->colormap = NULL; + } + + cinfo->input_components = components; + cinfo->data_precision = 8; + cinfo->image_width = width; + cinfo->image_height = height; +} + + +/* + * Finish up at the end of the file. + */ + +METHODDEF(void) +finish_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo) +{ + /* no work */ +} + + +/* + * The module selection routine for Targa format input. + */ + +GLOBAL(cjpeg_source_ptr) +jinit_read_targa (j_compress_ptr cinfo) +{ + tga_source_ptr source; + + /* Create module interface object */ + source = (tga_source_ptr) + (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, + SIZEOF(tga_source_struct)); + source->cinfo = cinfo; /* make back link for subroutines */ + /* Fill in method ptrs, except get_pixel_rows which start_input sets */ + source->pub.start_input = start_input_tga; + source->pub.finish_input = finish_input_tga; + + return (cjpeg_source_ptr) source; +} + +#endif /* TARGA_SUPPORTED */ |