1 files changed, 129 insertions, 0 deletions
diff --git a/filter/a85d.c b/filter/a85d.c
new file mode 100644
index 00000000..08c96a1b
--- /dev/null
+++ b/filter/a85d.c
@@ -0,0 +1,129 @@
+#include <fitz.h>
+
+typedef struct fz_a85d_s fz_a85d;
+
+struct fz_a85d_s
+{
+	fz_filter super;
+	unsigned long word;
+	int count;
+};
+
+static inline int iswhite(int a)
+{
+	switch (a) {
+	case '\n': case '\r': case '\t': case ' ':
+	case '\0': case '\f': case '\b': case 0177:
+		return 1;
+	}
+	return 0;
+}
+
+fz_error *
+fz_newa85d(fz_filter **fp, fz_obj *params)
+{
+	FZ_NEWFILTER(fz_a85d, f, a85d);
+	f->word = 0;
+	f->count = 0;
+	return nil;
+}
+
+void
+fz_freea85d(fz_filter *f)
+{
+	fz_free(f);
+}
+
+fz_error *
+fz_processa85d(fz_filter *filter, fz_buffer *in, fz_buffer *out)
+{
+	fz_a85d *f = (fz_a85d*)filter;
+	int c;
+
+	while (1)
+	{
+		if (in->rp == in->wp)
+			return fz_ioneedin;
+
+		c = *in->rp++;
+
+		if (c >= '!' && c <= 'u') {
+			if (f->count == 4) {
+				if (out->wp + 4 > out->ep) {
+					in->rp --;
+					return fz_ioneedout;
+				}
+
+				f->word = f->word * 85 + (c - '!');
+
+				*out->wp++ = (f->word >> 24) & 0xff;
+				*out->wp++ = (f->word >> 16) & 0xff;
+				*out->wp++ = (f->word >> 8) & 0xff;
+				*out->wp++ = (f->word) & 0xff;
+
+				f->word = 0;
+				f->count = 0;
+			}
+			else {
+				f->word = f->word * 85 + (c - '!');
+				f->count ++;
+			}
+		}
+
+		else if (c == 'z' && f->count == 0) {
+			if (out->wp + 4 > out->ep) {
+				in->rp --;
+				return fz_ioneedout;
+			}
+			*out->wp++ = 0;
+			*out->wp++ = 0;
+			*out->wp++ = 0;
+			*out->wp++ = 0;
+		}
+
+		else if (c == '~') {
+			if (in->rp == in->wp) {
+				in->rp --;
+				return fz_ioneedin;
+			}
+
+			c = *in->rp++;
+
+			if (c != '>') {
+				return fz_throw("ioerror: bad eod marker in a85d");
+			}
+
+			if (out->wp + f->count - 1 > out->ep) {
+				in->rp -= 2;
+				return fz_ioneedout;
+			}
+
+			switch (f->count) {
+			case 0:
+				break;
+			case 1:
+				return fz_throw("ioerror: partial final byte in a85d");
+			case 2:
+				f->word = f->word * (85L * 85 * 85) + 0xffffffL;
+				goto o1;
+			case 3:
+				f->word = f->word * (85L * 85) + 0xffffL;
+				goto o2;
+			case 4:
+				f->word = f->word * 85 + 0xffL;
+				*(out->wp+2) = f->word >> 8;
+o2:				*(out->wp+1) = f->word >> 16;
+o1:				*(out->wp+0) = f->word >> 24;
+				out->wp += f->count - 1;
+				break;
+			}
+			out->eof = 1;
+			return fz_iodone;
+		}
+
+		else if (!iswhite(c)) {
+			return fz_throw("ioerror: bad data in a85d: '%c'", c);
+		}
+	}
+}
+