lib/lzo: Rename lzo1x_decompress.c to lzo1x_decompress_safe.c

Rename the source file to match the function name and thereby
also make room for a possible future even slightly faster
"non-safe" decompressor version.

Signed-off-by: Markus F.X.J. Oberhumer <markus@oberhumer.com>

1 files changed, 255 insertions, 0 deletions

diff --git a/lib/lzo/lzo1x_decompress_safe.c b/lib/lzo/lzo1x_decompress_safe.c
new file mode 100644
index 000000000000..f2fd09850223
--- /dev/null
+++ b/lib/lzo/lzo1x_decompress_safe.c
@@ -0,0 +1,255 @@
+/*
+ *  LZO1X Decompressor from MiniLZO
+ *
+ *  Copyright (C) 1996-2005 Markus F.X.J. Oberhumer <markus@oberhumer.com>
+ *
+ *  The full LZO package can be found at:
+ *  http://www.oberhumer.com/opensource/lzo/
+ *
+ *  Changed for kernel use by:
+ *  Nitin Gupta <nitingupta910@gmail.com>
+ *  Richard Purdie <rpurdie@openedhand.com>
+ */
+
+#ifndef STATIC
+#include <linux/module.h>
+#include <linux/kernel.h>
+#endif
+
+#include <asm/unaligned.h>
+#include <linux/lzo.h>
+#include "lzodefs.h"
+
+#define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x))
+#define HAVE_OP(x, op_end, op) ((size_t)(op_end - op) < (x))
+#define HAVE_LB(m_pos, out, op) (m_pos < out || m_pos >= op)
+
+#define COPY4(dst, src)	\
+		put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst))
+
+int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
+			unsigned char *out, size_t *out_len)
+{
+	const unsigned char * const ip_end = in + in_len;
+	unsigned char * const op_end = out + *out_len;
+	const unsigned char *ip = in, *m_pos;
+	unsigned char *op = out;
+	size_t t;
+
+	*out_len = 0;
+
+	if (*ip > 17) {
+		t = *ip++ - 17;
+		if (t < 4)
+			goto match_next;
+		if (HAVE_OP(t, op_end, op))
+			goto output_overrun;
+		if (HAVE_IP(t + 1, ip_end, ip))
+			goto input_overrun;
+		do {
+			*op++ = *ip++;
+		} while (--t > 0);
+		goto first_literal_run;
+	}
+
+	while ((ip < ip_end)) {
+		t = *ip++;
+		if (t >= 16)
+			goto match;
+		if (t == 0) {
+			if (HAVE_IP(1, ip_end, ip))
+				goto input_overrun;
+			while (*ip == 0) {
+				t += 255;
+				ip++;
+				if (HAVE_IP(1, ip_end, ip))
+					goto input_overrun;
+			}
+			t += 15 + *ip++;
+		}
+		if (HAVE_OP(t + 3, op_end, op))
+			goto output_overrun;
+		if (HAVE_IP(t + 4, ip_end, ip))
+			goto input_overrun;
+
+		COPY4(op, ip);
+		op += 4;
+		ip += 4;
+		if (--t > 0) {
+			if (t >= 4) {
+				do {
+					COPY4(op, ip);
+					op += 4;
+					ip += 4;
+					t -= 4;
+				} while (t >= 4);
+				if (t > 0) {
+					do {
+						*op++ = *ip++;
+					} while (--t > 0);
+				}
+			} else {
+				do {
+					*op++ = *ip++;
+				} while (--t > 0);
+			}
+		}
+
+first_literal_run:
+		t = *ip++;
+		if (t >= 16)
+			goto match;
+		m_pos = op - (1 + M2_MAX_OFFSET);
+		m_pos -= t >> 2;
+		m_pos -= *ip++ << 2;
+
+		if (HAVE_LB(m_pos, out, op))
+			goto lookbehind_overrun;
+
+		if (HAVE_OP(3, op_end, op))
+			goto output_overrun;
+		*op++ = *m_pos++;
+		*op++ = *m_pos++;
+		*op++ = *m_pos;
+
+		goto match_done;
+
+		do {
+match:
+			if (t >= 64) {
+				m_pos = op - 1;
+				m_pos -= (t >> 2) & 7;
+				m_pos -= *ip++ << 3;
+				t = (t >> 5) - 1;
+				if (HAVE_LB(m_pos, out, op))
+					goto lookbehind_overrun;
+				if (HAVE_OP(t + 3 - 1, op_end, op))
+					goto output_overrun;
+				goto copy_match;
+			} else if (t >= 32) {
+				t &= 31;
+				if (t == 0) {
+					if (HAVE_IP(1, ip_end, ip))
+						goto input_overrun;
+					while (*ip == 0) {
+						t += 255;
+						ip++;
+						if (HAVE_IP(1, ip_end, ip))
+							goto input_overrun;
+					}
+					t += 31 + *ip++;
+				}
+				m_pos = op - 1;
+				m_pos -= get_unaligned_le16(ip) >> 2;
+				ip += 2;
+			} else if (t >= 16) {
+				m_pos = op;
+				m_pos -= (t & 8) << 11;
+
+				t &= 7;
+				if (t == 0) {
+					if (HAVE_IP(1, ip_end, ip))
+						goto input_overrun;
+					while (*ip == 0) {
+						t += 255;
+						ip++;
+						if (HAVE_IP(1, ip_end, ip))
+							goto input_overrun;
+					}
+					t += 7 + *ip++;
+				}
+				m_pos -= get_unaligned_le16(ip) >> 2;
+				ip += 2;
+				if (m_pos == op)
+					goto eof_found;
+				m_pos -= 0x4000;
+			} else {
+				m_pos = op - 1;
+				m_pos -= t >> 2;
+				m_pos -= *ip++ << 2;
+
+				if (HAVE_LB(m_pos, out, op))
+					goto lookbehind_overrun;
+				if (HAVE_OP(2, op_end, op))
+					goto output_overrun;
+
+				*op++ = *m_pos++;
+				*op++ = *m_pos;
+				goto match_done;
+			}
+
+			if (HAVE_LB(m_pos, out, op))
+				goto lookbehind_overrun;
+			if (HAVE_OP(t + 3 - 1, op_end, op))
+				goto output_overrun;
+
+			if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
+				COPY4(op, m_pos);
+				op += 4;
+				m_pos += 4;
+				t -= 4 - (3 - 1);
+				do {
+					COPY4(op, m_pos);
+					op += 4;
+					m_pos += 4;
+					t -= 4;
+				} while (t >= 4);
+				if (t > 0)
+					do {
+						*op++ = *m_pos++;
+					} while (--t > 0);
+			} else {
+copy_match:
+				*op++ = *m_pos++;
+				*op++ = *m_pos++;
+				do {
+					*op++ = *m_pos++;
+				} while (--t > 0);
+			}
+match_done:
+			t = ip[-2] & 3;
+			if (t == 0)
+				break;
+match_next:
+			if (HAVE_OP(t, op_end, op))
+				goto output_overrun;
+			if (HAVE_IP(t + 1, ip_end, ip))
+				goto input_overrun;
+
+			*op++ = *ip++;
+			if (t > 1) {
+				*op++ = *ip++;
+				if (t > 2)
+					*op++ = *ip++;
+			}
+
+			t = *ip++;
+		} while (ip < ip_end);
+	}
+
+	*out_len = op - out;
+	return LZO_E_EOF_NOT_FOUND;
+
+eof_found:
+	*out_len = op - out;
+	return (ip == ip_end ? LZO_E_OK :
+		(ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
+input_overrun:
+	*out_len = op - out;
+	return LZO_E_INPUT_OVERRUN;
+
+output_overrun:
+	*out_len = op - out;
+	return LZO_E_OUTPUT_OVERRUN;
+
+lookbehind_overrun:
+	*out_len = op - out;
+	return LZO_E_LOOKBEHIND_OVERRUN;
+}
+#ifndef STATIC
+EXPORT_SYMBOL_GPL(lzo1x_decompress_safe);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZO1X Decompressor");
+
+#endif