/* * rdtarga.c * * Copyright (C) 1991-1995, 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[] */ LOCAL 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); } } LOCAL 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 int 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: printf(" is 32bpp!"); return 1; // no 32bpp support // 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; return 0; } /* * 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 */