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authorYann Collet <cyan@fb.com>2022-08-02 14:47:37 (GMT)
committerYann Collet <cyan@fb.com>2022-08-03 00:57:26 (GMT)
commitccd92cb43ba6e6565752edc87a78dcdcf3180317 (patch)
tree1d74e66eb5b01c3a9be8c45e71fcf7c3a7b98985 /lib
parent63e9a622493edfbd9fd05c96f043e74016609836 (diff)
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simplify read_variable_length()
single sumtype return value
Diffstat (limited to 'lib')
-rw-r--r--lib/lz4.c50
1 files changed, 24 insertions, 26 deletions
diff --git a/lib/lz4.c b/lib/lz4.c
index 2aeb051..de0194f 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -1865,33 +1865,29 @@ LZ4_decompress_unsafe_generic(
* @initial_check - check ip >= ipmax before start of loop. Returns initial_error if so.
* @error (output) - error code. Must be set to 0 before call.
**/
-typedef enum { loop_error = -2, initial_error = -1, ok = 0 } variable_length_error;
typedef size_t Rvl_t;
+static const Rvl_t rvl_error = (Rvl_t)(-1);
LZ4_FORCE_INLINE Rvl_t
-read_variable_length(const BYTE**ip, const BYTE* ilimit,
- int initial_check,
- variable_length_error* error)
+read_variable_length(const BYTE** ip, const BYTE* ilimit,
+ int initial_check)
{
Rvl_t s, length = 0;
assert(ip != NULL);
assert(*ip != NULL);
assert(ilimit != NULL);
- if (initial_check && unlikely((*ip) >= ilimit)) { /* overflow detection */
- *error = initial_error;
- return length;
+ if (initial_check && unlikely((*ip) >= ilimit)) { /* read limit reached */
+ return rvl_error;
}
do {
s = **ip;
(*ip)++;
length += s;
- if (unlikely((*ip) >= ilimit)) { /* overflow detection */
- *error = loop_error;
- return length;
+ if (unlikely((*ip) > ilimit)) { /* read limit reached */
+ return rvl_error;
}
/* accumulator overflow detection (32-bit mode only) */
if ((sizeof(length)<8) && unlikely(length > ((Rvl_t)(-1)/2)) ) {
- *error = loop_error;
- return length;
+ return rvl_error;
}
} while (s==255);
@@ -1973,9 +1969,9 @@ LZ4_decompress_generic(
/* decode literal length */
if (length == RUN_MASK) {
- variable_length_error error = ok;
- length += read_variable_length(&ip, iend-RUN_MASK, 1, &error);
- if (error == initial_error) { goto _output_error; }
+ size_t const addl = read_variable_length(&ip, iend-RUN_MASK, 1);
+ if (addl == rvl_error) { goto _output_error; }
+ length += addl;
if (unlikely((uptrval)(op)+length<(uptrval)(op))) { goto _output_error; } /* overflow detection */
if (unlikely((uptrval)(ip)+length<(uptrval)(ip))) { goto _output_error; } /* overflow detection */
@@ -2004,12 +2000,12 @@ LZ4_decompress_generic(
length = token & ML_MASK;
if (length == ML_MASK) {
- variable_length_error error = ok;
- if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) { goto _output_error; } /* Error : offset outside buffers */
- length += read_variable_length(&ip, iend - LASTLITERALS + 1, 0, &error);
- if (error != ok) { goto _output_error; }
- if (unlikely((uptrval)(op)+length<(uptrval)op)) { goto _output_error; } /* overflow detection */
+ size_t const addl = read_variable_length(&ip, iend - LASTLITERALS + 1, 0);
+ if (addl == rvl_error) { goto _output_error; }
+ length += addl;
length += MINMATCH;
+ if (unlikely((uptrval)(op)+length<(uptrval)op)) { goto _output_error; } /* overflow detection */
+ if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) { goto _output_error; } /* Error : offset outside buffers */
if (op + length >= oend - FASTLOOP_SAFE_DISTANCE) {
goto safe_match_copy;
}
@@ -2036,6 +2032,7 @@ LZ4_decompress_generic(
if (checkOffset && (unlikely(match + dictSize < lowPrefix))) { goto _output_error; } /* Error : offset outside buffers */
/* match starting within external dictionary */
if ((dict==usingExtDict) && (match < lowPrefix)) {
+ assert(dictEnd != NULL);
if (unlikely(op+length > oend-LASTLITERALS)) {
if (partialDecoding) {
DEBUGLOG(7, "partialDecoding: dictionary match, close to dstEnd");
@@ -2129,9 +2126,9 @@ LZ4_decompress_generic(
/* decode literal length */
if (length == RUN_MASK) {
- variable_length_error error = ok;
- length += read_variable_length(&ip, iend-RUN_MASK, 1, &error);
- if (error == initial_error) { goto _output_error; }
+ size_t const addl = read_variable_length(&ip, iend-RUN_MASK, 1);
+ if (addl == rvl_error) { goto _output_error; }
+ length += addl;
if (unlikely((uptrval)(op)+length<(uptrval)(op))) { goto _output_error; } /* overflow detection */
if (unlikely((uptrval)(ip)+length<(uptrval)(ip))) { goto _output_error; } /* overflow detection */
}
@@ -2207,9 +2204,9 @@ LZ4_decompress_generic(
_copy_match:
if (length == ML_MASK) {
- variable_length_error error = ok;
- length += read_variable_length(&ip, iend - LASTLITERALS + 1, 0, &error);
- if (error != ok) goto _output_error;
+ size_t const addl = read_variable_length(&ip, iend - LASTLITERALS + 1, 0);
+ if (addl == rvl_error) { goto _output_error; }
+ length += addl;
if (unlikely((uptrval)(op)+length<(uptrval)op)) goto _output_error; /* overflow detection */
}
length += MINMATCH;
@@ -2220,6 +2217,7 @@ LZ4_decompress_generic(
if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) goto _output_error; /* Error : offset outside buffers */
/* match starting within external dictionary */
if ((dict==usingExtDict) && (match < lowPrefix)) {
+ assert(dictEnd != NULL);
if (unlikely(op+length > oend-LASTLITERALS)) {
if (partialDecoding) length = MIN(length, (size_t)(oend-op));
else goto _output_error; /* doesn't respect parsing restriction */