From ccd92cb43ba6e6565752edc87a78dcdcf3180317 Mon Sep 17 00:00:00 2001 From: Yann Collet Date: Tue, 2 Aug 2022 16:47:37 +0200 Subject: simplify read_variable_length() single sumtype return value --- lib/lz4.c | 50 ++++++++++++++++++++++++-------------------------- 1 file changed, 24 insertions(+), 26 deletions(-) diff --git a/lib/lz4.c b/lib/lz4.c index 2aeb051a..de0194fe 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 */ -- cgit v1.2.3