+++ /dev/null
-
-/* gif.c */
-
-#define GIF_C
-
-#include "gif.h"
-#include "image.h"
-
-#define PUSH_PIXEL(p) \
-{ \
- if (pstk_idx == PSTK_SIZE) \
- return GIFIN_ERR_PSO; \
- else \
- pstk[pstk_idx++] = (p); \
-}
-
-/*
- * push a string (denoted by a code) onto the pixel stack
- * (returns the code of the first pixel in the string in ps_rslt)
- */
-
-int ps_rslt; /* return result */
-
-#define GIFIN_PUSH_STRING(code) \
-{ \
- int ps_code; \
- ps_code = code; \
- \
- while (((unsigned int)ps_code) < STAB_SIZE && prefix[ps_code] != NULL_CODE) \
- { \
- PUSH_PIXEL(extnsn[ps_code]); \
- ps_code = prefix[ps_code]; \
- } \
- \
- if (((unsigned int)ps_code) >= STAB_SIZE) \
- return GIFIN_ERR_TAO; \
- PUSH_PIXEL(extnsn[ps_code]); \
- ps_rslt = extnsn[ps_code]; \
- if (((unsigned int)ps_rslt) >= STAB_SIZE) \
- return GIFIN_ERR_TAO; \
-}
-
-/*
- * Look up the ascii message coresponding to
- * the error number.
- */
-static char *get_err_string(int errno)
-{
- int i;
- for (i=0;gif_err_strings[i].err_no != 0;i++)
- {
- if (gif_err_strings[i].err_no == errno)
- return gif_err_strings[i].name;
- }
- return "";
-}
-
-
-static int interlace_start[4] = /* start line for interlacing */
-{
- 0, 4, 2, 1
-};
-
-static int interlace_rate[4] = /* rate at which we accelerate vertically */
-{
- 8, 8, 4, 2
-};
-
-static BYTE file_open = 0; /* status flags */
-static BYTE image_open = 0;
-
-static FILE *ins; /* input stream */
-
-static int root_size; /* root code size */
-static int clr_code; /* clear code */
-static int eoi_code; /* end of information code */
-static int code_size; /* current code size */
-static int code_mask; /* current code mask */
-static int prev_code; /* previous code */
-
-static long work_data; /* working bit buffer */
-static int work_bits; /* working bit count */
-
-static BYTE buf[256]; /* byte buffer */
-static int buf_cnt; /* byte count */
-static int buf_idx; /* buffer index */
-
-static int table_size; /* string table size */
-static int prefix[STAB_SIZE]; /* string table : prefixes */
-static int extnsn[STAB_SIZE]; /* string table : extensions */
-
-static BYTE pstk[PSTK_SIZE]; /* pixel stack */
-static int pstk_idx; /* pixel stack pointer */
-
-
-static int gifin_rast_width; /* raster width */
-static int gifin_rast_height; /* raster height */
-static BYTE gifin_g_cmap_flag; /* global colormap flag */
-static int gifin_g_pixel_bits; /* bits per pixel, global colormap */
-static int gifin_g_ncolors; /* number of colors, global colormap */
-static BYTE gifin_g_cmap[3][256]; /* global colormap */
-static BYTE gifin_g_cmap_sorted; /* global colormap sorted (GIF89a only) */
-static int gifin_bg_color; /* background color index */
-static int gifin_color_bits; /* bits of color resolution */
-static double gifin_aspect; /* pixel aspect ratio (width/height) */
-static int gifin_version; /* gif file version */
-
-static int gifin_img_left; /* image position on raster */
-static int gifin_img_top; /* image position on raster */
-static int gifin_img_width; /* image width */
-static int gifin_img_height; /* image height */
-static BYTE gifin_l_cmap_flag; /* local colormap flag */
-static int gifin_l_pixel_bits; /* bits per pixel, local colormap */
-static int gifin_l_ncolors; /* number of colors, local colormap */
-static BYTE gifin_l_cmap[3][256]; /* local colormap */
-static BYTE gifin_interlace_flag; /* interlace image format flag */
-
-/*
- * open a GIF file, using s as the input stream
- */
-
-static int gifin_open_file(FILE *s)
-{
- int errno;
- /* make sure there isn't already a file open */
- if (file_open)
- return GIFIN_ERR_FAO;
-
- /* remember that we've got this file open */
- file_open = 1;
- ins = s;
-
- /* check GIF signature */
- if (fread(buf, 1, GIF_SIG_LEN, ins) != GIF_SIG_LEN)
- return GIFIN_ERR_EOF;
-
- buf[GIF_SIG_LEN] = '\0';
- if (strcmp((char *) buf, GIF_SIG) == 0)
- gifin_version = GIF87a;
- else if (strcmp((char *) buf, GIF_SIG_89) == 0)
- gifin_version = GIF89a;
- else
- return GIFIN_ERR_BAD_SIG;
-
- /* read screen descriptor */
- if (fread(buf, 1, GIF_SD_SIZE, ins) != GIF_SD_SIZE)
- return GIFIN_ERR_EOF;
-
- /* decode screen descriptor */
- gifin_rast_width = (buf[1] << 8) + buf[0];
- gifin_rast_height = (buf[3] << 8) + buf[2];
- gifin_g_cmap_flag = (buf[4] & 0x80) ? 1 : 0;
- gifin_color_bits = (((int)(buf[4] & 0x70)) >> 4) + 1;
- gifin_g_pixel_bits = (buf[4] & 0x07) + 1;
- gifin_bg_color = buf[5];
- gifin_aspect = 1.0;
-
- if (gifin_version == GIF87a)
- {
- if (buf[4] & 0x08 || buf[6] != 0)
- return GIFIN_ERR_BAD_SD;
- }
- else
- {
- gifin_g_cmap_sorted = ((buf[4] & 0x08) != 0);
- if (buf[6] != 0)
- gifin_aspect = ((double)buf[6] + 15.0) / 64.0;
- }
-
- /* load global colormap */
- if (gifin_g_cmap_flag)
- {
- gifin_g_ncolors = (1 << gifin_g_pixel_bits);
-
- if ((errno = gifin_load_cmap(gifin_g_cmap, gifin_g_ncolors)) != GIFIN_SUCCESS)
- return errno;
- }
- else
- {
- gifin_g_ncolors = 0;
- }
-
- /* done! */
- return GIFIN_SUCCESS;
-}
-
-
-/*
- * open next GIF image in the input stream; returns GIFIN_SUCCESS if
- * successful. if there are no more images, returns GIFIN_DONE. (might
- * also return various GIFIN_ERR codes.)
- */
-
-static int gifin_open_image()
-{
- int i;
- int separator;
- int errno;
-
- /* make sure there's a file open */
- if (!file_open)
- return GIFIN_ERR_NFO;
-
- /* make sure there isn't already an image open */
- if (image_open)
- return GIFIN_ERR_IAO;
-
- /* remember that we've got this image open */
- image_open = 1;
-
- /* skip over any extension blocks */
- do
- {
- separator = fgetc(ins);
- if (separator == GIF_EXTENSION)
- {
- if ((errno = gifin_skip_extension()) != GIFIN_SUCCESS)
- return errno;
- }
- }
- while (separator == GIF_EXTENSION);
-
- /* check for end of file marker */
- if (separator == GIF_TERMINATOR)
- return GIFIN_DONE;
-
- /* make sure we've got an image separator */
- if (separator != GIF_SEPARATOR)
- return GIFIN_ERR_BAD_SEP;
-
- /* read image descriptor */
- if (fread(buf, 1, GIF_ID_SIZE, ins) != GIF_ID_SIZE)
- return GIFIN_ERR_EOF;
-
- /* decode image descriptor */
- gifin_img_left = (buf[1] << 8) + buf[0];
- gifin_img_top = (buf[3] << 8) + buf[2];
- gifin_img_width = (buf[5] << 8) + buf[4];
- gifin_img_height = (buf[7] << 8) + buf[6];
- gifin_l_cmap_flag = (buf[8] & 0x80) ? 1 : 0;
- gifin_interlace_flag = (buf[8] & 0x40) ? 1 : 0;
- gifin_l_pixel_bits = (buf[8] & 0x07) + 1;
-
- /* load local colormap */
- if (gifin_l_cmap_flag)
- {
- gifin_l_ncolors = (1 << gifin_l_pixel_bits);
-
- if ((errno = gifin_load_cmap(gifin_l_cmap, gifin_l_ncolors)) != GIFIN_SUCCESS)
- return errno;
- }
- else
- {
- gifin_l_ncolors = 0;
- }
-
- /* initialize raster data stream decoder */
- root_size = fgetc(ins);
- clr_code = 1 << root_size;
- eoi_code = clr_code + 1;
- code_size = root_size + 1;
- code_mask = (1 << code_size) - 1;
- work_bits = 0;
- work_data = 0;
- buf_cnt = 0;
- buf_idx = 0;
-
- /* initialize string table */
- for (i=0; i<STAB_SIZE; i++)
- {
- prefix[i] = NULL_CODE;
- extnsn[i] = i;
- }
-
- /* initialize pixel stack */
- pstk_idx = 0;
-
- /* done! */
- return GIFIN_SUCCESS;
-}
-
-/*
- * try to read next pixel from the raster, return result in *pel
- */
-
-static int gifin_get_pixel(pel)
- int *pel;
-{
- int code;
- int first;
- int place;
- int errno;
-
- /* decode until there are some pixels on the pixel stack */
- while (pstk_idx == 0)
- {
- /* load bytes until we have enough bits for another code */
- while (work_bits < code_size)
- {
- if (buf_idx == buf_cnt)
- {
- /* read a new data block */
- if ((errno = gifin_read_data_block()) != GIFIN_SUCCESS)
- return errno;
-
- if (buf_cnt == 0)
- return GIFIN_ERR_EOD;
- }
-
- work_data |= ((long) buf[buf_idx++]) << work_bits;
- work_bits += 8;
- }
-
- /* get the next code */
- code = work_data & code_mask;
- work_data >>= code_size;
- work_bits -= code_size;
-
- /* interpret the code */
- if (code == clr_code)
- {
- /* reset decoder stream */
- code_size = root_size + 1;
- code_mask = (1 << code_size) - 1;
- prev_code = NULL_CODE;
- table_size = eoi_code + 1;
- }
- else if (code == eoi_code)
- {
- /* Ooops! no more pixels */
- return GIFIN_ERR_EOF;
- }
- else if (prev_code == NULL_CODE)
- {
- GIFIN_PUSH_STRING(code);
- prev_code = code;
- }
- else
- {
- if (code < table_size)
- {
- GIFIN_PUSH_STRING(code);
- first = ps_rslt;
- }
- else
- {
- place = pstk_idx;
- PUSH_PIXEL(NULL_CODE);
- GIFIN_PUSH_STRING(prev_code);
- first = ps_rslt;
- pstk[place] = first;
- }
-
- if ((errno = gifin_add_string(prev_code, first)) != GIFIN_SUCCESS)
- return errno;
- prev_code = code;
- }
- }
-
- /* pop a pixel off the pixel stack */
- *pel = (int) pstk[--pstk_idx];
-
- /* done! */
- return GIFIN_SUCCESS;
-}
-
-/*
- * close an open GIF file
- */
-
-static int gifin_close_file()
-{
- /* make sure there's a file open */
- if (!file_open)
- return GIFIN_ERR_NFO;
-
- /* mark file (and image) as closed */
- file_open = 0;
- image_open = 0;
-
- /* done! */
- return GIFIN_SUCCESS;
-}
-
-/*
- * load a colormap from the input stream
- */
-
-static int gifin_load_cmap(BYTE cmap[3][256], int ncolors)
-{
- int i;
-
- for (i=0; i<ncolors; i++)
- {
- if (fread(buf, 1, 3, ins) != 3)
- return GIFIN_ERR_EOF;
-
- cmap[GIF_RED][i] = buf[GIF_RED];
- cmap[GIF_GRN][i] = buf[GIF_GRN];
- cmap[GIF_BLU][i] = buf[GIF_BLU];
- }
-
- /* done! */
- return GIFIN_SUCCESS;
-}
-
-/*
- * skip an extension block in the input stream
- */
-
-static int gifin_skip_extension()
-{
- int errno;
-
- /* get the extension function byte */
- fgetc(ins);
-
- /* skip any remaining raster data */
- do
- {
- if ((errno = gifin_read_data_block()) != GIFIN_SUCCESS)
- return errno;
- }
- while (buf_cnt > 0);
-
- /* done! */
- return GIFIN_SUCCESS;
-}
-
-/*
- * read a new data block from the input stream
- */
-
-static int gifin_read_data_block()
-{
- /* read the data block header */
- buf_cnt = fgetc(ins);
-
- /* read the data block body */
- if (fread(buf, 1, buf_cnt, ins) != buf_cnt)
- return GIFIN_ERR_EOF;
-
- buf_idx = 0;
-
- /* done! */
- return GIFIN_SUCCESS;
-}
-
-
-/*
- * add a new string to the string table
- */
-
-static int gifin_add_string(int p, int e)
-{
- prefix[table_size] = p;
- extnsn[table_size] = e;
-
- if ((table_size == code_mask) && (code_size < 12))
- {
- code_size += 1;
- code_mask = (1 << code_size) - 1;
- }
-
- table_size += 1;
- if (table_size > STAB_SIZE)
- return GIFIN_ERR_TAO;
- return GIFIN_SUCCESS;
-}
-
-Image *Read_GIF_to_Image(char *fullname)
-{
- FILE *f;
- Image *image;
- int x, y, pixel, pass, scanlen;
- byte *pixptr, *pixline;
- int errno;
-
- if (!(f = fopen(fullname,"r")))
- {
- perror("gifLoad");
- return(NULL);
- }
-
- if ((gifin_open_file(f) != GIFIN_SUCCESS) || /* read GIF header */
- (gifin_open_image() != GIFIN_SUCCESS)) /* read image header */
- {
- printf("gifin_open_file or gifin_open_image failed!\n");
-
- gifin_close_file();
- fclose(f);
- return(NULL);
- }
-
-
-
- /*
- printf("%s:\n %dx%d %s%s image with %d colors at depth %d\n",
- fullname, gifin_img_width, gifin_img_height,
- (gifin_interlace_flag ? "interlaced " : ""),
- gif_version_name[gifin_version],
- (gifin_l_cmap_flag ? gifin_l_ncolors : gifin_g_ncolors),
- (gifin_l_cmap_flag ? gifin_l_pixel_bits : gifin_g_pixel_bits));
- */
-
-
-
- image = newRGBImage(gifin_img_width, gifin_img_height, (gifin_l_cmap_flag ?
- gifin_l_pixel_bits :
- gifin_g_pixel_bits));
-
- /* if image has a local colormap, override global colormap
- */
-
- if (gifin_l_cmap_flag)
- {
- for (x=0; x<gifin_l_ncolors; x++)
- {
- image->rgb.red[x] = gifin_l_cmap[GIF_RED][x] << 8;
- image->rgb.green[x] = gifin_l_cmap[GIF_GRN][x] << 8;
- image->rgb.blue[x] = gifin_l_cmap[GIF_BLU][x] << 8;
- }
- image->rgb.used = gifin_l_ncolors;
- }
- else
- {
- for (x=0; x<gifin_g_ncolors; x++)
- {
- image->rgb.red[x] = gifin_g_cmap[GIF_RED][x] << 8;
- image->rgb.green[x] = gifin_g_cmap[GIF_GRN][x] << 8;
- image->rgb.blue[x] = gifin_g_cmap[GIF_BLU][x] << 8;
- }
- image->rgb.used = gifin_g_ncolors;
- }
-
- /* interlaced image -- futz with the vertical trace. i wish i knew what
- * kind of drugs the GIF people were on when they decided that they
- * needed to support interlacing.
- */
-
- if (gifin_interlace_flag)
- {
- scanlen = image->height * image->pixlen;
-
- /* interlacing takes four passes to read, each starting at a different
- * vertical point.
- */
-
- for (pass=0; pass<4; pass++)
- {
- y = interlace_start[pass];
- scanlen = image->width * image->pixlen * interlace_rate[pass];
- pixline = image->data + (y * image->width * image->pixlen);
- while (y < gifin_img_height)
- {
- pixptr = pixline;
- for (x=0; x<gifin_img_width; x++)
- {
- if ((errno = gifin_get_pixel(&pixel)) != GIFIN_SUCCESS)
- {
- fprintf(stderr, "gifLoad: %s - Short read within image data, '%s'\n", fullname, get_err_string(errno));
- y = gifin_img_height;
- x = gifin_img_width;
- }
- valToMem(pixel, pixptr, image->pixlen);
- pixptr += image->pixlen;
- }
- y += interlace_rate[pass];
- pixline += scanlen;
- }
- }
- }
- else
- {
- /* not an interlaced image, just read in sequentially
- */
-
- if (image->pixlen == 1) /* the usual case */
- {
- pixptr = image->data;
- for (y=0; y<gifin_img_height; y++)
- for (x=0; x<gifin_img_width; x++)
- {
- if ((errno = gifin_get_pixel(&pixel)) != GIFIN_SUCCESS)
- {
- fprintf(stderr, "gifLoad: %s - Short read within image data, '%s'\n", fullname, get_err_string(errno));
- y = gifin_img_height;
- x = gifin_img_width;
- }
- valToMem(pixel, pixptr, 1);
- pixptr += 1;
- }
- }
- else /* less ususal case */
- {
- pixptr = image->data;
- for (y=0; y<gifin_img_height; y++)
- for (x=0; x<gifin_img_width; x++)
- {
- if ((errno = gifin_get_pixel(&pixel)) != GIFIN_SUCCESS)
- {
- fprintf(stderr, "gifLoad: %s - Short read within image data, '%s'\n", fullname, get_err_string(errno));
- y = gifin_img_height;
- x = gifin_img_width;
- }
- valToMem(pixel, pixptr, image->pixlen);
- pixptr += image->pixlen;
- }
- }
- }
-
- gifin_close_file();
- fclose(f);
-
- return(image);
-}
projects / rocksndiamonds.git / blobdiff