/*
 * io-xpm.c: GdkPixBuf I/O for XPM files.
 * Copyright (C) 1999 Mark Crichton
 * Author: Mark Crichton <crichton@gimp.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Cambridge, MA 02139, USA.
 *
 */

#include <config.h>
#include <stdio.h>
#include <string.h>
#include <glib.h>

/* We need gdk.h since we might need to parse X color names */
#include <gdk/gdk.h>

#include "gdk-pixbuf.h"
/*#include "gdk-pixbuf-io.h" */

/* I have must have done something to deserve this.
 * XPM is such a crappy format to handle.
 * This code is an ugly hybred from gdkpixmap.c
 * modified to respect transparent colors.
 * It's still a mess, though.
 */

enum buf_op {
    op_header,
    op_cmap,
    op_body
};

typedef struct {
    gchar *color_string;
    GdkColor color;
    gint transparent;
} _XPMColor;

struct file_handle {
    FILE *infile;
    gchar *buffer;
    guint buffer_size;
};

struct mem_handle {
    gchar **data;
    int offset;
};

static gint
 xpm_seek_string(FILE * infile,
		 const gchar * str,
		 gint skip_comments)
{
    char instr[1024];

    while (!feof(infile)) {
	fscanf(infile, "%1023s", instr);
	if (skip_comments == TRUE && strcmp(instr, "/*") == 0) {
	    fscanf(infile, "%1023s", instr);
	    while (!feof(infile) && strcmp(instr, "*/") != 0)
		fscanf(infile, "%1023s", instr);
	    fscanf(infile, "%1023s", instr);
	}
	if (strcmp(instr, str) == 0)
	    return TRUE;
    }

    return FALSE;
}

static gint
 xpm_seek_char(FILE * infile,
	       gchar c)
{
    gint b, oldb;

    while ((b = getc(infile)) != EOF) {
	if (c != b && b == '/') {
	    b = getc(infile);
	    if (b == EOF)
		return FALSE;
	    else if (b == '*') {	/* we have a comment */
		b = -1;
		do {
		    oldb = b;
		    b = getc(infile);
		    if (b == EOF)
			return FALSE;
		}
		while (!(oldb == '*' && b == '/'));
	    }
	} else if (c == b)
	    return TRUE;
    }
    return FALSE;
}

static gint
 xpm_read_string(FILE * infile,
		 gchar ** buffer,
		 guint * buffer_size)
{
    gint c;
    guint cnt = 0, bufsiz, ret = FALSE;
    gchar *buf;

    buf = *buffer;
    bufsiz = *buffer_size;
    if (buf == NULL) {
	bufsiz = 10 * sizeof(gchar);
	buf = g_new(gchar, bufsiz);
    }
    do
	c = getc(infile);
    while (c != EOF && c != '"');

    if (c != '"')
	goto out;

    while ((c = getc(infile)) != EOF) {
	if (cnt == bufsiz) {
	    guint new_size = bufsiz * 2;
	    if (new_size > bufsiz)
		bufsiz = new_size;
	    else
		goto out;

	    buf = (gchar *) g_realloc(buf, bufsiz);
	    buf[bufsiz - 1] = '\0';
	}
	if (c != '"')
	    buf[cnt++] = c;
	else {
	    buf[cnt] = 0;
	    ret = TRUE;
	    break;
	}
    }

  out:
    buf[bufsiz - 1] = '\0';	/* ensure null termination for errors */
    *buffer = buf;
    *buffer_size = bufsiz;
    return ret;
}

static gchar *
 xpm_skip_whitespaces(gchar * buffer)
{
    gint32 index = 0;

    while (buffer[index] != 0 && (buffer[index] == 0x20 || buffer[index] == 0x09))
	index++;

    return &buffer[index];
}

static gchar *
 xpm_skip_string(gchar * buffer)
{
    gint32 index = 0;

    while (buffer[index] != 0 && buffer[index] != 0x20 && buffer[index] != 0x09)
	index++;

    return &buffer[index];
}

/* Xlib crashed once at a color name lengths around 125 */
#define MAX_COLOR_LEN 120

static gchar *
 xpm_extract_color(gchar * buffer)
{
    gint counter, numnames;
    gchar *ptr = NULL, ch, temp[128];
    gchar color[MAX_COLOR_LEN], *retcol;
    gint space;
    counter = 0;
    while (ptr == NULL) {
	if (buffer[counter] == 'c') {
	    ch = buffer[counter + 1];
	    if (ch == 0x20 || ch == 0x09)
		ptr = &buffer[counter + 1];
	} else if (buffer[counter] == 0)
	    return NULL;

	counter++;
    }
    ptr = xpm_skip_whitespaces(ptr);

    if (ptr[0] == 0)
	return NULL;
    else if (ptr[0] == '#') {
	counter = 1;
	while (ptr[counter] != 0 &&
	       ((ptr[counter] >= '0' && ptr[counter] <= '9') ||
		(ptr[counter] >= 'a' && ptr[counter] <= 'f') ||
		(ptr[counter] >= 'A' && ptr[counter] <= 'F')))
	    counter++;
	retcol = g_new(gchar, counter + 1);
	strncpy(retcol, ptr, counter);

	retcol[counter] = 0;

	return retcol;
    }
    color[0] = 0;
    numnames = 0;

    space = MAX_COLOR_LEN - 1;
    while (space > 0) {
	sscanf(ptr, "%127s", temp);

	if (((gint) ptr[0] == 0) ||
	    (strcmp("s", temp) == 0) || (strcmp("m", temp) == 0) ||
	    (strcmp("g", temp) == 0) || (strcmp("g4", temp) == 0)) {
	    break;
	} else {
	    if (numnames > 0) {
		space -= 1;
		strcat(color, " ");
	    }
	    strncat(color, temp, space);
	    space -= MIN(space, strlen(temp));
	    ptr = xpm_skip_string(ptr);
	    ptr = xpm_skip_whitespaces(ptr);
	    numnames++;
	}
    }

    retcol = g_strdup(color);
    return retcol;
}


/* (almost) direct copy from gdkpixmap.c... loads an XPM from a file */

static gchar *
 file_buffer(enum buf_op op, gpointer handle)
{
    struct file_handle *h = handle;

    switch (op) {
    case op_header:
	if (xpm_seek_string(h->infile, "XPM", FALSE) != TRUE)
	    break;

	if (xpm_seek_char(h->infile, '{') != TRUE)
	    break;
	/* Fall through to the next xpm_seek_char. */

    case op_cmap:
	xpm_seek_char(h->infile, '"');
	fseek(h->infile, -1, SEEK_CUR);
	/* Fall through to the xpm_read_string. */

    case op_body:
	xpm_read_string(h->infile, &h->buffer, &h->buffer_size);
	return h->buffer;
    }
    return NULL;
}

/* This reads from memory */
static gchar *
 mem_buffer(enum buf_op op, gpointer handle)
{
    struct mem_handle *h = handle;
    switch (op) {
    case op_header:
    case op_cmap:
    case op_body:
	if (h->data[h->offset])
	    return h->data[h->offset++];
    }
    return NULL;
}

/* This function does all the work. */

static GdkPixBuf *
 _pixbuf_create_from_xpm(gchar * (*get_buf) (enum buf_op op, gpointer handle),
			 gpointer handle)
{
    gint w, h, n_col, cpp;
    gint cnt, xcnt, ycnt, wbytes, n, ns;
    gint is_trans = FALSE;
    gchar *buffer, *name_buf;
    gchar pixel_str[32];
    GHashTable *color_hash;
    _XPMColor *colors, *color, *fallbackcolor;
    art_u8 *pixels, *pixtmp;
    GdkPixBuf *pixbuf;

    buffer = (*get_buf) (op_header, handle);
    if (!buffer) {
	g_warning("No XPM header found");
	return NULL;
    }
    sscanf(buffer, "%d %d %d %d", &w, &h, &n_col, &cpp);
    if (cpp >= 32) {
	g_warning("XPM has more than 31 chars per pixel.");
	return NULL;
    }
    /* The hash is used for fast lookups of color from chars */
    color_hash = g_hash_table_new(g_str_hash, g_str_equal);

    name_buf = g_new(gchar, n_col * (cpp + 1));
    colors = g_new(_XPMColor, n_col);

    for (cnt = 0; cnt < n_col; cnt++) {
	gchar *color_name;

	buffer = (*get_buf) (op_cmap, handle);
	if (!buffer) {
	    g_warning("Can't load XPM colormap");
	    g_free(name_buf);
	    g_free(colors);
	    return NULL;
	}
	color = &colors[cnt];
	color->color_string = &name_buf[cnt * (cpp + 1)];
	strncpy(color->color_string, buffer, cpp);
	color->color_string[cpp] = 0;
	buffer += strlen(color->color_string);
	color->transparent = FALSE;

	color_name = xpm_extract_color(buffer);

	if ((!color_name) || (g_strcasecmp(color_name, "None") == 0)
	    || (gdk_color_parse(color_name, &color->color) == FALSE)) {
	    color->transparent = TRUE;
	    is_trans = TRUE;
	}
	g_free(color_name);
	g_hash_table_insert(color_hash, color->color_string, color);

	if (cnt == 0)
	    fallbackcolor = color;
    }

    if (is_trans)
	pixels = art_alloc(w * h * 4);
    else
	pixels = art_alloc(w * h * 3);

    if (!pixels) {
	g_warning("XPM: Cannot alloc ArtBuf");
	g_hash_table_destroy(color_hash);
	g_free(colors);
	g_free(name_buf);
	return NULL;
    }
    wbytes = w * cpp;
    pixtmp = pixels;

    for (ycnt = 0; ycnt < h; ycnt++) {
	buffer = (*get_buf) (op_body, handle);
	if ((!buffer) || (strlen(buffer) < wbytes))
	    continue;
	for (n = 0, cnt = 0, xcnt = 0; n < wbytes; n += cpp, xcnt++) {
	    strncpy(pixel_str, &buffer[n], cpp);
	    pixel_str[cpp] = 0;
	    ns = 0;

	    color = g_hash_table_lookup(color_hash, pixel_str);

	    /* Bad XPM...punt */
	    if (!color)
		color = fallbackcolor;

	    pixtmp[0] = color->color.red;
	    pixtmp[1] = color->color.green;
	    pixtmp[2] = color->color.blue;
	    if ((is_trans) && (color->transparent)) {
		pixtmp[3] = 0;
		pixtmp++;
	    } else if (is_trans) {
		pixtmp[3] = 0xFF;
		pixtmp++;
	    }
	    pixtmp += 3;
	}
    }
    /* Ok, now stuff the GdkPixBuf with goodies */

    pixbuf = g_new(GdkPixBuf, 1);

    if (is_trans)
	pixbuf->art_pixbuf = art_pixbuf_new_rgba(pixels, w, h, (w * 4));
    else
	pixbuf->art_pixbuf = art_pixbuf_new_rgb(pixels, w, h, (w * 3));

    /* Ok, I'm anal...shoot me */
    if (!(pixbuf->art_pixbuf))
	return NULL;
    pixbuf->ref_count = 0;
    pixbuf->unref_func = NULL;

    g_hash_table_destroy(color_hash);
    g_free(colors);
    g_free(name_buf);

    return pixbuf;
}

/* Shared library entry point for file loading */
GdkPixBuf *image_load(FILE * f)
{
    GdkPixBuf *pixbuf;
    struct file_handler h;

    g_return_val_if_fail(f != NULL, NULL);

    h = g_new(file_handler, 1);
    h.infile = f;
    pixbuf = _pixbuf_create_from_xpm(file_buffer, &h);
    g_free(h);

    return pixbuf;
}