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authorMarkus F.X.J. Oberhumer <markus@oberhumer.com>2012-08-13 17:24:24 +0200
committerMarkus F.X.J. Oberhumer <markus@oberhumer.com>2013-02-20 19:36:00 +0100
commitb6bec26cea948148a9420e7a0ac337f925de49e7 (patch)
tree79d76d19696b717e9cf032fee48dbc9fc13e066e /lib/lzo/lzo1x_decompress_safe.c
parent19f949f52599ba7c3f67a5897ac6be14bfcb1200 (diff)
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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>
Diffstat (limited to 'lib/lzo/lzo1x_decompress_safe.c')
-rw-r--r--lib/lzo/lzo1x_decompress_safe.c255
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