/
imsgi.c
1198 lines (1035 loc) · 29.5 KB
/
imsgi.c
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#include "imsgi.h"
#include <stdlib.h>
#include <errno.h>
#include <string.h>
/* value for imagic */
#define SGI_MAGIC 474
/* values for the storage field */
#define SGI_STORAGE_VERBATIM 0
#define SGI_STORAGE_RLE 1
/* values for the colormap field */
#define SGI_COLORMAP_NORMAL 0
#define SGI_COLORMAP_DITHERED 1
#define SGI_COLORMAP_SCREEN 2
#define SGI_COLORMAP_COLORMAP 3
/* we add that little bit to avoid rounding issues */
#define SampleFTo16(num) ((int)((num) * 65535.0 + 0.01))
typedef struct {
unsigned short imagic;
unsigned char storagetype;
unsigned char BPC;
unsigned short dimensions;
unsigned short xsize, ysize, zsize;
unsigned int pixmin, pixmax;
char name[80];
unsigned int colormap;
} rgb_header;
static i_img *
read_rgb_8_verbatim(i_img *im, io_glue *ig, rgb_header const *hdr);
static i_img *
read_rgb_8_rle(i_img *im, io_glue *ig, rgb_header const *hdr);
static i_img *
read_rgb_16_verbatim(i_img *im, io_glue *ig, rgb_header const *hdr);
static i_img *
read_rgb_16_rle(i_img *im, io_glue *ig, rgb_header const *hdr);
static int
write_sgi_header(i_img *img, io_glue *ig, int *rle, int *bpc2);
static int
write_sgi_8_rle(i_img *img, io_glue *ig);
static int
write_sgi_8_verb(i_img *img, io_glue *ig);
static int
write_sgi_16_rle(i_img *img, io_glue *ig);
static int
write_sgi_16_verb(i_img *img, io_glue *ig);
#define Sample16ToF(num) ((num) / 65535.0)
#define _STRING(x) #x
#define STRING(x) _STRING(x)
/*
=head1 NAME
rgb.c - implements reading and writing sgi image files, uses io layer.
=head1 SYNOPSIS
io_glue *ig = io_new_fd( fd );
i_img *im = i_readrgb_wiol(ig, 0); // disallow partial reads
// or
io_glue *ig = io_new_fd( fd );
return_code = i_writergb_wiol(im, ig);
=head1 DESCRIPTION
imsgi.c implements the basic functions to read and write portable SGI
files. It uses the iolayer and needs either a seekable source or an
entire memory mapped buffer.
=head1 FUNCTION REFERENCE
Some of these functions are internal.
=over
=cut
*/
/*
=item rgb_header_unpack(header, headbuf)
Unpacks the header structure into from buffer and stores
in the header structure.
header - header structure
headbuf - buffer to unpack from
=cut
*/
static
void
rgb_header_unpack(rgb_header *header, const unsigned char *headbuf) {
header->imagic = (headbuf[0]<<8) + headbuf[1];
header->storagetype = headbuf[2];
header->BPC = headbuf[3];
header->dimensions = (headbuf[4]<<8) + headbuf[5];
header->xsize = (headbuf[6]<<8) + headbuf[7];
header->ysize = (headbuf[8]<<8) + headbuf[9];
header->zsize = (headbuf[10]<<8) + headbuf[11];
header->pixmin = (headbuf[12]<<24) + (headbuf[13]<<16)+(headbuf[14]<<8)+headbuf[15];
header->pixmax = (headbuf[16]<<24) + (headbuf[17]<<16)+(headbuf[18]<<8)+headbuf[19];
memcpy(header->name,headbuf+24,80);
header->name[79] = '\0';
header->colormap = (headbuf[104]<<24) + (headbuf[105]<<16)+(headbuf[106]<<8)+headbuf[107];
}
/* don't make this a macro */
static void
store_16(unsigned char *buf, unsigned short value) {
buf[0] = value >> 8;
buf[1] = value & 0xFF;
}
static void
store_32(unsigned char *buf, unsigned long value) {
buf[0] = value >> 24;
buf[1] = (value >> 16) & 0xFF;
buf[2] = (value >> 8) & 0xFF;
buf[3] = value & 0xFF;
}
/*
=item rgb_header_pack(header, headbuf)
Packs header structure into buffer for writing.
header - header structure
headbuf - buffer to pack into
=cut
*/
static
void
rgb_header_pack(const rgb_header *header, unsigned char headbuf[512]) {
memset(headbuf, 0, 512);
store_16(headbuf, header->imagic);
headbuf[2] = header->storagetype;
headbuf[3] = header->BPC;
store_16(headbuf+4, header->dimensions);
store_16(headbuf+6, header->xsize);
store_16(headbuf+8, header->ysize);
store_16(headbuf+10, header->zsize);
store_32(headbuf+12, header->pixmin);
store_32(headbuf+16, header->pixmax);
memccpy(headbuf+24, header->name, '\0', 80);
store_32(headbuf+104, header->colormap);
}
/*
=item i_readsgi_wiol(ig, partial)
Read in an image from the iolayer data source and return the image structure to it.
Returns NULL on error.
ig - io_glue object
length - maximum length to read from data source, before closing it -1
signifies no limit.
=cut
*/
i_img *
i_readsgi_wiol(io_glue *ig, int partial) {
i_img *img = NULL;
int width, height, channels;
rgb_header header;
unsigned char headbuf[512];
mm_log((1,"i_readsgi(ig %p, partial %d)\n", ig, partial));
i_clear_error();
if (ig->readcb(ig, headbuf, 512) != 512) {
i_push_error(errno, "SGI image: could not read header");
return NULL;
}
rgb_header_unpack(&header, headbuf);
if (header.imagic != SGI_MAGIC) {
i_push_error(0, "SGI image: invalid magic number");
return NULL;
}
mm_log((1,"imagic: %d\n", header.imagic));
mm_log((1,"storagetype: %d\n", header.storagetype));
mm_log((1,"BPC: %d\n", header.BPC));
mm_log((1,"dimensions: %d\n", header.dimensions));
mm_log((1,"xsize: %d\n", header.xsize));
mm_log((1,"ysize: %d\n", header.ysize));
mm_log((1,"zsize: %d\n", header.zsize));
mm_log((1,"min: %d\n", header.pixmin));
mm_log((1,"max: %d\n", header.pixmax));
mm_log((1,"name [skipped]\n"));
mm_log((1,"colormap: %d\n", header.colormap));
if (header.colormap != SGI_COLORMAP_NORMAL) {
i_push_errorf(0, "SGI image: invalid value for colormap (%d)", header.colormap);
return NULL;
}
if (header.BPC != 1 && header.BPC != 2) {
i_push_errorf(0, "SGI image: invalid value for BPC (%d)", header.BPC);
return NULL;
}
if (header.storagetype != SGI_STORAGE_VERBATIM
&& header.storagetype != SGI_STORAGE_RLE) {
i_push_error(0, "SGI image: invalid storage type field");
return NULL;
}
if (header.pixmin >= header.pixmax) {
i_push_error(0, "SGI image: invalid pixmin >= pixmax");
return NULL;
}
width = header.xsize;
height = header.ysize;
channels = header.zsize;
switch (header.dimensions) {
case 1:
channels = 1;
height = 1;
break;
case 2:
channels = 1;
break;
case 3:
/* fall through and use all of the dimensions */
break;
default:
i_push_error(0, "SGI image: invalid dimension field");
return NULL;
}
if (!i_int_check_image_file_limits(width, height, channels, header.BPC)) {
mm_log((1, "i_readsgi_wiol: image size exceeds limits\n"));
return NULL;
}
if (header.BPC == 1) {
img = i_img_8_new(width, height, channels);
if (!img)
goto ErrorReturn;
switch (header.storagetype) {
case SGI_STORAGE_VERBATIM:
img = read_rgb_8_verbatim(img, ig, &header);
break;
case SGI_STORAGE_RLE:
img = read_rgb_8_rle(img, ig, &header);
break;
default:
goto ErrorReturn;
}
}
else {
img = i_img_16_new(width, height, channels);
if (!img)
goto ErrorReturn;
switch (header.storagetype) {
case SGI_STORAGE_VERBATIM:
img = read_rgb_16_verbatim(img, ig, &header);
break;
case SGI_STORAGE_RLE:
img = read_rgb_16_rle(img, ig, &header);
break;
default:
goto ErrorReturn;
}
}
if (!img)
goto ErrorReturn;
if (*header.name)
i_tags_set(&img->tags, "i_comment", header.name, -1);
i_tags_setn(&img->tags, "sgi_pixmin", header.pixmin);
i_tags_setn(&img->tags, "sgi_pixmax", header.pixmax);
i_tags_setn(&img->tags, "sgi_bpc", header.BPC);
i_tags_setn(&img->tags, "sgi_rle", header.storagetype == SGI_STORAGE_RLE);
i_tags_set(&img->tags, "i_format", "sgi", -1);
return img;
ErrorReturn:
if (img) i_img_destroy(img);
return NULL;
}
/*
=item i_writergb_wiol(img, ig)
Writes an image in targa format. Returns 0 on error.
img - image to store
ig - io_glue object
=cut
*/
int
i_writesgi_wiol(io_glue *ig, i_img *img) {
int rle;
int bpc2;
i_clear_error();
if (!write_sgi_header(img, ig, &rle, &bpc2))
return 0;
mm_log((1, "format rle %d bpc2 %d\n", rle, bpc2));
if (bpc2) {
if (rle)
return write_sgi_16_rle(img, ig);
else
return write_sgi_16_verb(img, ig);
}
else {
if (rle)
return write_sgi_8_rle(img, ig);
else
return write_sgi_8_verb(img, ig);
}
}
static i_img *
read_rgb_8_verbatim(i_img *img, io_glue *ig, rgb_header const *header) {
i_color *linebuf;
unsigned char *databuf;
int c, y;
int savemask;
i_img_dim width = i_img_get_width(img);
i_img_dim height = i_img_get_height(img);
int channels = i_img_getchannels(img);
int pixmin = header->pixmin;
int pixmax = header->pixmax;
int outmax = pixmax - pixmin;
linebuf = mymalloc(width * sizeof(i_color)); /* checked 31Jul07 TonyC */
databuf = mymalloc(width); /* checked 31Jul07 TonyC */
savemask = i_img_getmask(img);
for(c = 0; c < channels; c++) {
i_img_setmask(img, 1<<c);
for(y = 0; y < height; y++) {
int x;
if (ig->readcb(ig, databuf, width) != width) {
i_push_error(0, "SGI image: cannot read image data");
i_img_destroy(img);
myfree(linebuf);
myfree(databuf);
return NULL;
}
if (pixmin == 0 && pixmax == 255) {
for(x = 0; x < img->xsize; x++)
linebuf[x].channel[c] = databuf[x];
}
else {
for(x = 0; x < img->xsize; x++) {
int sample = databuf[x];
if (sample < pixmin)
sample = 0;
else if (sample > pixmax)
sample = outmax;
else
sample -= pixmin;
linebuf[x].channel[c] = sample * 255 / outmax;
}
}
i_plin(img, 0, width, height-1-y, linebuf);
}
}
i_img_setmask(img, savemask);
myfree(linebuf);
myfree(databuf);
return img;
}
static int
read_rle_tables(io_glue *ig, i_img *img,
unsigned long **pstart_tab, unsigned long **plength_tab,
unsigned long *pmax_length) {
i_img_dim height = i_img_get_height(img);
int channels = i_img_getchannels(img);
unsigned char *databuf;
unsigned long *start_tab, *length_tab;
unsigned long max_length = 0;
int i;
size_t databuf_size = (size_t)height * channels * 4;
size_t tab_size = (size_t)height * channels * sizeof(unsigned long);
/* assumption: that the lengths are in bytes rather than in pixels */
if (databuf_size / height / channels != 4
|| tab_size / height / channels != sizeof(unsigned long)) {
i_push_error(0, "SGI image: integer overflow calculating allocation size");
return 0;
}
databuf = mymalloc(height * channels * 4); /* checked 31Jul07 TonyC */
start_tab = mymalloc(height*channels*sizeof(unsigned long));
length_tab = mymalloc(height*channels*sizeof(unsigned long));
/* Read offset table */
if (ig->readcb(ig, databuf, height * channels * 4) != height * channels * 4) {
i_push_error(0, "SGI image: short read reading RLE start table");
goto ErrorReturn;
}
for(i = 0; i < height * channels; i++)
start_tab[i] = (databuf[i*4] << 24) | (databuf[i*4+1] << 16) |
(databuf[i*4+2] << 8) | (databuf[i*4+3]);
/* Read length table */
if (ig->readcb(ig, databuf, height*channels*4) != height*channels*4) {
i_push_error(0, "SGI image: short read reading RLE length table");
goto ErrorReturn;
}
for(i=0; i < height * channels; i++) {
length_tab[i] = (databuf[i*4] << 24) + (databuf[i*4+1] << 16)+
(databuf[i*4+2] << 8) + (databuf[i*4+3]);
if (length_tab[i] > max_length)
max_length = length_tab[i];
}
mm_log((3, "Offset/length table:\n"));
for(i=0; i < height * channels; i++)
mm_log((3, "%d: %d/%d\n", i, start_tab[i], length_tab[i]));
*pstart_tab = start_tab;
*plength_tab = length_tab;
*pmax_length = max_length;
myfree(databuf);
return 1;
ErrorReturn:
myfree(databuf);
myfree(start_tab);
myfree(length_tab);
return 0;
}
static i_img *
read_rgb_8_rle(i_img *img, io_glue *ig, rgb_header const *header) {
i_color *linebuf = NULL;
unsigned char *databuf = NULL;
unsigned long *start_tab, *length_tab;
unsigned long max_length;
i_img_dim width = i_img_get_width(img);
i_img_dim height = i_img_get_height(img);
int channels = i_img_getchannels(img);
i_img_dim y;
int c;
int pixmin = header->pixmin;
int pixmax = header->pixmax;
int outmax = pixmax - pixmin;
if (!read_rle_tables(ig, img,
&start_tab, &length_tab, &max_length)) {
i_img_destroy(img);
return NULL;
}
mm_log((1, "maxlen for an rle buffer: %d\n", max_length));
if (max_length > (img->xsize + 1) * 2) {
i_push_errorf(0, "SGI image: ridiculous RLE line length %lu", max_length);
goto ErrorReturn;
}
linebuf = mymalloc(width*sizeof(i_color)); /* checked 31Jul07 TonyC */
databuf = mymalloc(max_length); /* checked 31Jul07 TonyC */
for(y = 0; y < img->ysize; y++) {
for(c = 0; c < channels; c++) {
int ci = height * c + y;
int datalen = length_tab[ci];
unsigned char *inp;
i_color *outp;
int data_left = datalen;
int pixels_left = width;
i_sample_t sample;
if (ig->seekcb(ig, start_tab[ci], SEEK_SET) != start_tab[ci]) {
i_push_error(0, "SGI image: cannot seek to RLE data");
goto ErrorReturn;
}
if (ig->readcb(ig, databuf, datalen) != datalen) {
i_push_error(0, "SGI image: cannot read RLE data");
goto ErrorReturn;
}
inp = databuf;
outp = linebuf;
while (data_left) {
int code = *inp++;
int count = code & 0x7f;
--data_left;
if (count == 0)
break;
if (code & 0x80) {
/* literal run */
/* sanity checks */
if (count > pixels_left) {
i_push_error(0, "SGI image: literal run overflows scanline");
goto ErrorReturn;
}
if (count > data_left) {
i_push_error(0, "SGI image: literal run consumes more data than available");
goto ErrorReturn;
}
/* copy the run */
pixels_left -= count;
data_left -= count;
if (pixmin == 0 && pixmax == 255) {
while (count-- > 0) {
outp->channel[c] = *inp++;
++outp;
}
}
else {
while (count-- > 0) {
int sample = *inp++;
if (sample < pixmin)
sample = 0;
else if (sample > pixmax)
sample = outmax;
else
sample -= pixmin;
outp->channel[c] = sample * 255 / outmax;
++outp;
}
}
}
else {
/* RLE run */
if (count > pixels_left) {
i_push_error(0, "SGI image: RLE run overflows scanline");
mm_log((2, "RLE run overflows scanline (y %d chan %d offset %ld len %ld)\n", y, c, start_tab[ci], length_tab[ci]));
goto ErrorReturn;
}
if (data_left < 1) {
i_push_error(0, "SGI image: RLE run has no data for pixel");
goto ErrorReturn;
}
sample = *inp++;
if (pixmin != 0 || pixmax != 255) {
if (sample < pixmin)
sample = 0;
else if (sample > pixmax)
sample = outmax;
else
sample -= pixmin;
sample = sample * 255 / outmax;
}
--data_left;
pixels_left -= count;
while (count-- > 0) {
outp->channel[c] = sample;
++outp;
}
}
}
/* must have a full scanline */
if (pixels_left) {
i_push_error(0, "SGI image: incomplete RLE scanline");
goto ErrorReturn;
}
/* must have used all of the data */
if (data_left) {
i_push_errorf(0, "SGI image: unused RLE data");
goto ErrorReturn;
}
}
i_plin(img, 0, width, height-1-y, linebuf);
}
myfree(linebuf);
myfree(databuf);
myfree(start_tab);
myfree(length_tab);
return img;
ErrorReturn:
if (linebuf)
myfree(linebuf);
if (databuf)
myfree(databuf);
myfree(start_tab);
myfree(length_tab);
i_img_destroy(img);
return NULL;
}
static i_img *
read_rgb_16_verbatim(i_img *img, io_glue *ig, rgb_header const *header) {
i_fcolor *linebuf;
unsigned char *databuf;
int c, y;
int savemask;
i_img_dim width = i_img_get_width(img);
i_img_dim height = i_img_get_height(img);
int channels = i_img_getchannels(img);
int pixmin = header->pixmin;
int pixmax = header->pixmax;
int outmax = pixmax - pixmin;
linebuf = mymalloc(width * sizeof(i_fcolor)); /* checked 31Jul07 TonyC */
databuf = mymalloc(width * 2); /* checked 31Jul07 TonyC */
savemask = i_img_getmask(img);
for(c = 0; c < channels; c++) {
i_img_setmask(img, 1<<c);
for(y = 0; y < height; y++) {
int x;
if (ig->readcb(ig, databuf, width*2) != width*2) {
i_push_error(0, "SGI image: cannot read image data");
i_img_destroy(img);
myfree(linebuf);
myfree(databuf);
return NULL;
}
if (pixmin == 0 && pixmax == 65535) {
for(x = 0; x < img->xsize; x++)
linebuf[x].channel[c] = (databuf[x*2] * 256 + databuf[x*2+1]) / 65535.0;
}
else {
for(x = 0; x < img->xsize; x++) {
int sample = databuf[x*2] * 256 + databuf[x*2+1];
if (sample < pixmin)
sample = 0;
else if (sample > pixmax)
sample = outmax;
else
sample -= pixmin;
linebuf[x].channel[c] = (double)sample / outmax;
}
}
i_plinf(img, 0, width, height-1-y, linebuf);
}
}
i_img_setmask(img, savemask);
myfree(linebuf);
myfree(databuf);
return img;
}
static i_img *
read_rgb_16_rle(i_img *img, io_glue *ig, rgb_header const *header) {
i_fcolor *linebuf = NULL;
unsigned char *databuf = NULL;
unsigned long *start_tab, *length_tab;
unsigned long max_length;
i_img_dim width = i_img_get_width(img);
i_img_dim height = i_img_get_height(img);
int channels = i_img_getchannels(img);
i_img_dim y;
int c;
int pixmin = header->pixmin;
int pixmax = header->pixmax;
int outmax = pixmax - pixmin;
if (!read_rle_tables(ig, img,
&start_tab, &length_tab, &max_length)) {
i_img_destroy(img);
return NULL;
}
mm_log((1, "maxlen for an rle buffer: %lu\n", max_length));
if (max_length > (img->xsize * 2 + 1) * 2) {
i_push_errorf(0, "SGI image: ridiculous RLE line length %lu", max_length);
goto ErrorReturn;
}
linebuf = mymalloc(width*sizeof(i_fcolor)); /* checked 31Jul07 TonyC */
databuf = mymalloc(max_length); /* checked 31Jul07 TonyC */
for(y = 0; y < img->ysize; y++) {
for(c = 0; c < channels; c++) {
int ci = height * c + y;
int datalen = length_tab[ci];
unsigned char *inp;
i_fcolor *outp;
int data_left = datalen;
int pixels_left = width;
int sample;
if (datalen & 1) {
i_push_error(0, "SGI image: invalid RLE length value for BPC=2");
goto ErrorReturn;
}
if (ig->seekcb(ig, start_tab[ci], SEEK_SET) != start_tab[ci]) {
i_push_error(0, "SGI image: cannot seek to RLE data");
goto ErrorReturn;
}
if (ig->readcb(ig, databuf, datalen) != datalen) {
i_push_error(0, "SGI image: cannot read RLE data");
goto ErrorReturn;
}
inp = databuf;
outp = linebuf;
while (data_left > 0) {
int code = inp[0] * 256 + inp[1];
int count = code & 0x7f;
inp += 2;
data_left -= 2;
if (count == 0)
break;
if (code & 0x80) {
/* literal run */
/* sanity checks */
if (count > pixels_left) {
i_push_error(0, "SGI image: literal run overflows scanline");
goto ErrorReturn;
}
if (count > data_left) {
i_push_error(0, "SGI image: literal run consumes more data than available");
goto ErrorReturn;
}
/* copy the run */
pixels_left -= count;
data_left -= count * 2;
if (pixmin == 0 && pixmax == 65535) {
while (count-- > 0) {
outp->channel[c] = (inp[0] * 256 + inp[1]) / 65535.0;
inp += 2;
++outp;
}
}
else {
while (count-- > 0) {
int sample = inp[0] * 256 + inp[1];
if (sample < pixmin)
sample = 0;
else if (sample > pixmax)
sample = outmax;
else
sample -= pixmin;
outp->channel[c] = (double)sample / outmax;
++outp;
inp += 2;
}
}
}
else {
double fsample;
/* RLE run */
if (count > pixels_left) {
i_push_error(0, "SGI image: RLE run overflows scanline");
goto ErrorReturn;
}
if (data_left < 2) {
i_push_error(0, "SGI image: RLE run has no data for pixel");
goto ErrorReturn;
}
sample = inp[0] * 256 + inp[1];
inp += 2;
data_left -= 2;
if (pixmin != 0 || pixmax != 65535) {
if (sample < pixmin)
sample = 0;
else if (sample > pixmax)
sample = outmax;
else
sample -= pixmin;
fsample = (double)sample / outmax;
}
else {
fsample = (double)sample / 65535.0;
}
pixels_left -= count;
while (count-- > 0) {
outp->channel[c] = fsample;
++outp;
}
}
}
/* must have a full scanline */
if (pixels_left) {
i_push_error(0, "SGI image: incomplete RLE scanline");
goto ErrorReturn;
}
/* must have used all of the data */
if (data_left) {
i_push_errorf(0, "SGI image: unused RLE data");
goto ErrorReturn;
}
}
i_plinf(img, 0, width, height-1-y, linebuf);
}
myfree(linebuf);
myfree(databuf);
myfree(start_tab);
myfree(length_tab);
return img;
ErrorReturn:
if (linebuf)
myfree(linebuf);
if (databuf)
myfree(databuf);
myfree(start_tab);
myfree(length_tab);
i_img_destroy(img);
return NULL;
}
static int
write_sgi_header(i_img *img, io_glue *ig, int *rle, int *bpc2) {
rgb_header header;
unsigned char headbuf[512] = { 0 };
header.imagic = SGI_MAGIC;
if (!i_tags_get_int(&img->tags, "sgi_rle", 0, rle))
*rle = 0;
header.storagetype = *rle ? SGI_STORAGE_RLE : SGI_STORAGE_VERBATIM;
header.pixmin = 0;
header.colormap = SGI_COLORMAP_NORMAL;
*bpc2 = img->bits > 8;
if (*bpc2) {
header.BPC = 2;
header.pixmax = 65535;
}
else {
header.BPC = 1;
header.pixmax = 255;
}
if (img->channels == 1) {
header.dimensions = 2;
}
else {
header.dimensions = 3;
}
header.xsize = img->xsize;
header.ysize = img->ysize;
header.zsize = img->channels;
memset(header.name, 0, sizeof(header.name));
i_tags_get_string(&img->tags, "i_comment", 0,
header.name, sizeof(header.name));
rgb_header_pack(&header, headbuf);
if (i_io_write(ig, headbuf, sizeof(headbuf)) != sizeof(headbuf)) {
i_push_error(0, "SGI image: cannot write header");
return 0;
}
return 1;
}
static int
write_sgi_8_verb(i_img *img, io_glue *ig) {
i_sample_t *linebuf;
i_img_dim width = img->xsize;
int c;
i_img_dim y;
linebuf = mymalloc(width); /* checked 31Jul07 TonyC */
for (c = 0; c < img->channels; ++c) {
for (y = img->ysize - 1; y >= 0; --y) {
i_gsamp(img, 0, width, y, linebuf, &c, 1);
if (ig->writecb(ig, linebuf, width) != width) {
i_push_error(errno, "SGI image: error writing image data");
myfree(linebuf);
return 0;
}
}
}
myfree(linebuf);
return 1;
}
static int
write_sgi_8_rle(i_img *img, io_glue *ig) {
i_sample_t *linebuf;
unsigned char *comp_buf;
i_img_dim width = img->xsize;
int c;
i_img_dim y;
unsigned char *offsets;
unsigned char *lengths;
int offset_pos = 0;
size_t offsets_size = (size_t)4 * img->ysize * img->channels * 2;
unsigned long start_offset = 512 + offsets_size;
unsigned long current_offset = start_offset;
int in_left;
unsigned char *outp;
i_sample_t *inp;
size_t comp_size;
if (offsets_size / 2 / 4 / img->channels != img->ysize) {
i_push_error(0, "SGI image: integer overflow calculating allocation size");
return 0;
}
linebuf = mymalloc(width); /* checked 31Jul07 TonyC */
comp_buf = mymalloc((width + 1) * 2); /* checked 31Jul07 TonyC */
offsets = mymalloc(offsets_size);
memset(offsets, 0, offsets_size);
if (i_io_write(ig, offsets, offsets_size) != offsets_size) {
i_push_error(errno, "SGI image: error writing offsets/lengths");
goto Error;
}
lengths = offsets + img->ysize * img->channels * 4;
for (c = 0; c < img->channels; ++c) {
for (y = img->ysize - 1; y >= 0; --y) {
i_gsamp(img, 0, width, y, linebuf, &c, 1);
in_left = width;
outp = comp_buf;
inp = linebuf;
while (in_left) {
unsigned char *run_start = inp;
/* first try for an RLE run */
int run_length = 1;
while (in_left - run_length >= 2 && inp[0] == inp[1] && run_length < 127) {
++run_length;
++inp;
}
if (in_left - run_length == 1 && inp[0] == inp[1] && run_length < 127) {
++run_length;
++inp;
}
if (run_length > 2) {
*outp++ = run_length;
*outp++ = inp[0];
inp++;
in_left -= run_length;
}
else {
inp = run_start;
/* scan for a literal run */
run_length = 1;
run_start = inp;
while (in_left - run_length > 1 && (inp[0] != inp[1] || inp[1] != inp[2]) && run_length < 127) {
++run_length;
++inp;
}
++inp;
/* fill out the run if 2 or less samples left and there's space */
if (in_left - run_length <= 2
&& in_left <= 127) {
run_length = in_left;
}
in_left -= run_length;
*outp++ = run_length | 0x80;
while (run_length--) {
*outp++ = *run_start++;
}
}
}
*outp++ = 0;