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DEFINITIONS
This source file includes following definitions.
- freeilbm
- loadchunks
- bodyrow
- scalegun
- scalecmap
- deplane
- load
- save
- formats
/*------------------------------------------------------------------------------
* Reads regular Amiga IFF ILBM files.
*
* Supports IMLIB2_LBM_NOMASK environment variable. If this is set to "1", then
* a transparency mask in an image will be ignored. On the Amiga a mask is often
* applied only when loading a brush rather than a picture, but this loader has
* no way to tell when the user wants this behaviour from the picture alone.
*
* Author: John Bickers <jbickers@ihug.co.nz>
* Since: 2004-08-21
* Version: 2004-08-28
*------------------------------------------------------------------------------*/
#include "loader_common.h"
#define L2RLONG(a) ((((long)((a)[0]) & 0xff) << 24) + (((long)((a)[1]) & 0xff) << 16) + (((long)((a)[2]) & 0xff) << 8) + ((long)((a)[3]) & 0xff))
#define L2RWORD(a) ((((long)((a)[0]) & 0xff) << 8) + ((long)((a)[1]) & 0xff))
typedef struct CHUNK {
long size;
unsigned char *data;
} CHUNK;
typedef struct ILBM {
CHUNK bmhd;
CHUNK camg;
CHUNK cmap;
CHUNK ctbl;
CHUNK sham;
CHUNK body;
int depth;
int mask;
int ham;
int hbrite;
int row;
int offset;
int count;
int rle;
} ILBM;
/*------------------------------------------------------------------------------
* Frees memory allocated as part of an ILBM structure.
*------------------------------------------------------------------------------*/
static void freeilbm(ILBM *ilbm)
{
if (ilbm->bmhd.data) free(ilbm->bmhd.data);
if (ilbm->camg.data) free(ilbm->camg.data);
if (ilbm->cmap.data) free(ilbm->cmap.data);
if (ilbm->ctbl.data) free(ilbm->ctbl.data);
if (ilbm->sham.data) free(ilbm->sham.data);
if (ilbm->body.data) free(ilbm->body.data);
memset(ilbm, 0, sizeof(*ilbm));
}
/*------------------------------------------------------------------------------
* Reads the given chunks out of a file, returns 0 if the file had a problem.
*
* Format FORMsizeILBMtag.size....tag.size....tag.size....
*------------------------------------------------------------------------------*/
static int loadchunks(char *name, ILBM *ilbm, int full)
{
CHUNK *c;
FILE *f;
size_t s;
long formsize, pos, z;
int ok, seek;
char buf[12];
ok = 0;
f = fopen(name, "rb");
if (f) {
s = fread(buf, 1, 12, f);
if (s == 12 && !memcmp(buf, "FORM", 4) && !memcmp(buf + 8, "ILBM", 4)) {
memset(ilbm, 0, sizeof(*ilbm));
formsize = L2RLONG(buf + 4);
while (1) {
pos = ftell(f);
if (pos < 0 || pos >= formsize + 8) break; /* Error or FORM data is finished. */
seek = 1;
s = fread(buf, 1, 8, f);
if (s != 8) break; /* Error or short file. */
z = L2RLONG(buf + 4);
if (z < 0) break; /* Corrupt file. */
c = NULL;
if (!memcmp(buf, "BMHD", 4)) c = &(ilbm->bmhd);
else if (full) {
if (!memcmp(buf, "CAMG", 4)) c = &(ilbm->camg);
else if (!memcmp(buf, "CMAP", 4)) c = &(ilbm->cmap);
else if (!memcmp(buf, "CTBL", 4)) c = &(ilbm->ctbl);
else if (!memcmp(buf, "SHAM", 4)) c = &(ilbm->sham);
else if (!memcmp(buf, "BODY", 4)) c = &(ilbm->body);
}
if (c && !c->data) {
c->size = z;
c->data = malloc(c->size);
if (!c->data) break; /* Out of memory. */
s = fread(c->data, 1, c->size, f);
if (s != c->size) break; /* Error or short file. */
seek = 0;
if (!full) { /* Only BMHD required. */
ok = 1;
break;
}
}
if (pos + 8 + z >= formsize + 8) break; /* This was last chunk. */
if (seek && fseek(f, z, SEEK_CUR) != 0) break;
}
/* File may end strangely, especially if body size is uneven, but it's
* ok if we have the chunks we want. !full check is already done. */
if (ilbm->bmhd.data && ilbm->body.data) ok = 1;
if (!ok) freeilbm(ilbm);
}
fclose(f);
}
return ok;
}
/*------------------------------------------------------------------------------
* Unpacks a row of possibly RLE data at a time.
*
* RLE compression depends on a count byte, followed by data bytes.
*
* 0x80 means skip.
* 0xff to 0x81 means repeat one data byte (256 - count) + 1 times.
* 0x00 to 0x7f means copy count + 1 data bytes.
*
* In theory RLE compression is not supposed to create runs across scanlines.
*------------------------------------------------------------------------------*/
static void bodyrow(unsigned char *p, int z, ILBM *ilbm)
{
int i, x, w;
unsigned char b;
if (ilbm->offset >= ilbm->body.size) {
memset(p, 0, z);
return;
}
if (!ilbm->rle) {
w = ilbm->body.size - ilbm->offset;
if (w > z) w = z;
memcpy(p, ilbm->body.data + ilbm->offset, w);
if (w < z) memset(p + w, 0, z - w);
ilbm->offset += w;
return;
}
for (i = 0; i < z; ) {
b = ilbm->body.data[ilbm->offset++];
while (b == 0x80 && ilbm->offset < ilbm->body.size) b = ilbm->body.data[ilbm->offset++];
if (ilbm->offset >= ilbm->body.size) break;
if (b & 0x80) {
w = (0x100 - b) + 1;
if (w > z - i) w = z - i;
b = ilbm->body.data[ilbm->offset++];
memset(p + i, b, w);
i += w;
}
else {
w = (b & 0x7f) + 1;
if (w > ilbm->body.size - ilbm->offset) w = ilbm->body.size - ilbm->offset;
x = (w <= z - i)? w: z - i;
memcpy(p + i, ilbm->body.data + ilbm->offset, x);
i += x;
ilbm->offset += w;
}
}
if (i < z) memset(p, 0, z - i);
}
/*------------------------------------------------------------------------------
* Shifts a value to produce an 8-bit colour gun, and fills in the lower bits
* from the high bits of the value so that, for example, 4-bit 0x0f scales to
* 0xff, or 1-bit 0x01 scales to 0xff.
*------------------------------------------------------------------------------*/
static unsigned char scalegun(unsigned char v, int sl)
{
int sr;
switch (sl) {
case 1:
case 2:
case 3:
sr = 8 - sl;
return (v << sl) | (v >> sr);
case 4:
return (v << 4) | v;
case 5:
return v * 0x24;
case 6:
return v * 0x55;
case 7:
return v * 0xff;
}
return v;
}
/*------------------------------------------------------------------------------
* Scales the colours in a CMAP chunk if they all look like 4-bit colour, so
* that they use all 8-bits. This is done by copying the high nybble into the
* low nybble, so for example 0xf0 becomes 0xff.
*------------------------------------------------------------------------------*/
static void scalecmap(ILBM *ilbm)
{
int i;
if (!ilbm->cmap.data) return;
for (i = 0; i < ilbm->cmap.size; i++)
if (ilbm->cmap.data[i] & 0x0f) return;
for (i = 0; i < ilbm->cmap.size; i++)
ilbm->cmap.data[i] |= ilbm->cmap.data[i] >> 4;
}
/*------------------------------------------------------------------------------
* Deplanes and converts an array of bitplanes to a single scanline of DATA32
* (unsigned int) values. DATA32 is ARGB.
*------------------------------------------------------------------------------*/
static void deplane(DATA32 *row, int w, ILBM *ilbm, unsigned char *plane[])
{
unsigned long l;
int i, o, x;
unsigned char bit, r, g, b, a, v, h, *pal;
pal = NULL;
if (ilbm->sham.data && ilbm->sham.size >= 2 + (ilbm->row + 1) * 2 * 16)
pal = ilbm->sham.data + 2 + ilbm->row * 2 * 16;
if (ilbm->ctbl.data && ilbm->ctbl.size >= (ilbm->row + 1) * 2 * 16)
pal = ilbm->ctbl.data + ilbm->row * 2 * 16;
if (ilbm->ham) r = g = b = 0;
bit = 0x80;
o = 0;
for (x = 0; x < w; x++) {
l = 0;
for (i = ilbm->depth - 1; i >= 0; i--) {
l = l << 1;
if (plane[i][o] & bit) l = l | 1;
}
a = (ilbm->mask == 0 || (ilbm->mask == 1 && (plane[ilbm->depth][o] & bit)) || ilbm->mask == 2)? 0xff: 0x00;
if (ilbm->depth == 32) {
a = (l >> 24) & 0xff;
b = (l >> 16) & 0xff;
g = (l >> 8) & 0xff;
r = l & 0xff;
}
else if (ilbm->depth == 24) {
b = (l >> 16) & 0xff;
g = (l >> 8) & 0xff;
r = l & 0xff;
}
else if (ilbm->ham) {
v = l & ((1 << (ilbm->depth - 2)) - 1);
h = (l & ~v) >> (ilbm->depth - 2);
if (h == 0x00) {
if (!pal) {
if ((v + 1) * 3 <= ilbm->cmap.size) {
r = ilbm->cmap.data[v * 3];
g = ilbm->cmap.data[v * 3 + 1];
b = ilbm->cmap.data[v * 3 + 2];
}
else r = g = b = 0;
}
else {
r = scalegun(pal[v * 2] & 0x0f, 4);
g = scalegun((pal[v * 2 + 1] & 0xf0) >> 4, 4);
b = scalegun((pal[v * 2 + 1] & 0x0f), 4);
}
}
else if (h == 0x01) b = scalegun(v, 8 - (ilbm->depth - 2));
else if (h == 0x02) r = scalegun(v, 8 - (ilbm->depth - 2));
else g = scalegun(v, 8 - (ilbm->depth - 2));
}
else if (ilbm->hbrite) {
v = l & ((1 << (ilbm->depth - 1)) - 1);
h = (l & ~v) >> (ilbm->depth - 1);
if (!pal) {
if ((v + 1) * 3 <= ilbm->cmap.size) {
r = ilbm->cmap.data[v * 3];
g = ilbm->cmap.data[v * 3 + 1];
b = ilbm->cmap.data[v * 3 + 2];
}
else r = g = b = 0;
}
else {
r = scalegun(pal[v * 2] & 0x0f, 4);
g = scalegun((pal[v * 2 + 1] & 0xf0) >> 4, 4);
b = scalegun((pal[v * 2 + 1] & 0x0f), 4);
}
if (h) {
r = r >> 1;
g = g >> 1;
b = b >> 1;
}
if (ilbm->mask == 2 && v == L2RWORD(ilbm->bmhd.data + 12)) a = 0x00;
}
else if (ilbm->cmap.size == 0 && !pal) {
v = l & ((1 << ilbm->depth) - 1);
r = scalegun(v, ilbm->depth);
g = r;
b = r;
}
else {
v = l & 0xff;
if (!pal) {
if ((v + 1) * 3 <= ilbm->cmap.size) {
r = ilbm->cmap.data[v * 3];
g = ilbm->cmap.data[v * 3 + 1];
b = ilbm->cmap.data[v * 3 + 2];
}
else r = g = b = 0;
}
else {
r = scalegun(pal[v * 2] & 0x0f, 4);
g = scalegun((pal[v * 2 + 1] & 0xf0) >> 4, 4);
b = scalegun((pal[v * 2 + 1] & 0x0f), 4);
}
if (ilbm->mask == 2 && v == L2RWORD(ilbm->bmhd.data + 12)) a = 0x00;
}
row[x] = ((unsigned long)a << 24) | ((unsigned long)r << 16) | ((unsigned long)g << 8) | (unsigned long)b;
bit = bit >> 1;
if (bit == 0) {
o++;
bit = 0x80;
}
}
}
/*------------------------------------------------------------------------------
* Loads an image. If im->loader is non-zero, or immediate_load is non-zero, or
* progress is non-zero, then the file is fully loaded, otherwise only the width
* and height are read.
*
* Imlib2 doesn't support reading comment chunks like ANNO.
*------------------------------------------------------------------------------*/
char load(ImlibImage *im, ImlibProgressFunction progress, char progress_granularity, char immediate_load)
{
char *env;
int cancel, full, i, n, ok, y, z, gran, nexty, prevy;
unsigned char *plane[40];
ILBM ilbm;
/*----------
* Do nothing if the data is already loaded.
*----------*/
if (im->data) return 0;
/*----------
* Load the chunk(s) we're interested in. If full is not true, then we only
* want the image size and format.
*----------*/
full = (im->loader || immediate_load || progress);
ok = loadchunks(im->real_file, &ilbm, full);
if (!ok) return 0;
/*----------
* Use and check header.
*----------*/
ok = 0;
if (ilbm.bmhd.size >= 20) {
ok = 1;
im->w = L2RWORD(ilbm.bmhd.data);
im->h = L2RWORD(ilbm.bmhd.data + 2);
if ((im->w < 1) || (im->h < 1) || (im->w > 8192) || (im->h > 8192))
{
ok = 0;
}
ilbm.depth = ilbm.bmhd.data[8];
if (ilbm.depth < 1 || (ilbm.depth > 8 && ilbm.depth != 24 && ilbm.depth != 32)) ok = 0; /* Only 1 to 8, 24, or 32 planes. */
ilbm.rle = ilbm.bmhd.data[10];
if (ilbm.rle < 0 || ilbm.rle > 1) ok = 0; /* Only NONE or RLE compression. */
ilbm.mask = ilbm.bmhd.data[9];
if (ilbm.mask || ilbm.depth == 32) SET_FLAG(im->flags, F_HAS_ALPHA);
else UNSET_FLAG(im->flags, F_HAS_ALPHA);
env = getenv("IMLIB2_LBM_NOMASK");
if (env && (!strcmp(env, "true") || !strcmp(env, "1") || !strcmp(env, "yes") || !strcmp(env, "on"))) UNSET_FLAG(im->flags, F_HAS_ALPHA);
if (!im->format) im->format = strdup("lbm");
ilbm.ham = 0;
ilbm.hbrite = 0;
if (ilbm.depth <= 8) {
if (ilbm.camg.size == 4) {
if (ilbm.camg.data[2] & 0x08) ilbm.ham = 1;
if (ilbm.camg.data[3] & 0x80) ilbm.hbrite = 1;
}
else { /* Only guess at ham and hbrite if CMAP is present. */
if (ilbm.depth == 6 && full && ilbm.cmap.size >= 3 * 16) ilbm.ham = 1;
if (full && !ilbm.ham && ilbm.depth > 1 && ilbm.cmap.size == 3 * (1 << (ilbm.depth - 1))) ilbm.hbrite = 1;
}
}
}
if (!full || !ok) {
im->w = im->h = 0;
freeilbm(&ilbm);
return ok;
}
/*----------
* The source data is planar. Each plane is an even number of bytes wide. If
* masking type is 1, there is an extra plane that defines the mask. Scanlines
* from each plane are interleaved, from top to bottom. The first plane is the
* 0 bit.
*----------*/
ok = 0;
cancel = 0;
plane[0] = NULL;
im->data = malloc(im->w * im->h * sizeof(DATA32));
n = ilbm.depth;
if (ilbm.mask == 1) n++;
plane[0] = malloc(((im->w + 15) / 16) * 2 * n);
if (im->data && plane[0]) {
for (i = 1; i < n; i++) plane[i] = plane[i - 1] + ((im->w + 15) / 16) * 2;
z = ((im->w + 15) / 16) * 2 * n;
if (progress) {
prevy = 0;
if (progress_granularity <= 0) progress_granularity = 1;
gran = progress_granularity;
nexty = ((im->h * gran) / 100);
}
scalecmap(&ilbm);
for (y = 0; y < im->h; y++) {
bodyrow(plane[0], z, &ilbm);
deplane(im->data + im->w * y, im->w, &ilbm, plane);
ilbm.row++;
if (progress && (y >= nexty || y == im->h - 1)) {
if (!progress(im, (char)((100 * (y + 1)) / im->h), 0, prevy, im->w, y + 1)) {
cancel = 1;
break;
}
prevy = y;
gran += progress_granularity;
nexty = ((im->h * gran) / 100);
}
}
ok = !cancel;
}
/*----------
* We either had a successful decode, the user cancelled, or we couldn't get
* the memory for im->data or plane[0].
*----------*/
if (!ok) {
im->w = im->h = 0;
if (im->data) free(im->data);
im->data = NULL;
}
if (plane[0]) free(plane[0]);
freeilbm(&ilbm);
return (cancel)? 2: ok;
}
/*------------------------------------------------------------------------------
* Perhaps save only in 32-bit format? The IFF ILBM format has pretty much gone
* the way of the Amiga, who saves in this format any more?
*------------------------------------------------------------------------------*/
#if 0
char save(ImlibImage *im, ImlibProgressFunction progress, char progress_granularity)
{
return 0;
}
#endif
/*------------------------------------------------------------------------------
* Identifies the file extensions this loader handles. Standard code from other
* loaders.
*------------------------------------------------------------------------------*/
void formats(ImlibLoader *l)
{
char *list_formats[] = { "iff", "ilbm", "lbm" };
int i;
l->num_formats = sizeof(list_formats) / sizeof(list_formats[0]);
l->formats = malloc(l->num_formats * sizeof(list_formats[0]));
for (i = 0; i < l->num_formats; i++) l->formats[i] = strdup(list_formats[i]);
}