/* libFLAC - Free Lossless Audio Codec library
- * Copyright (C) 2000,2001,2002,2003,2004,2005,2006,2007 Josh Coalson
+ * Copyright (C) 2000,2001,2002,2003,2004,2005,2006,2007,2008,2009 Josh Coalson
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
# include <config.h>
#endif
-#if defined _MSC_VER || defined __MINGW32__
-#include <io.h> /* for _setmode() */
-#include <fcntl.h> /* for _O_BINARY */
-#endif
-#if defined __CYGWIN__ || defined __EMX__
-#include <io.h> /* for setmode(), O_BINARY */
-#include <fcntl.h> /* for _O_BINARY */
-#endif
#include <stdio.h>
#include <stdlib.h> /* for malloc() */
#include <string.h> /* for memset/memcpy() */
#include <sys/stat.h> /* for stat() */
#include <sys/types.h> /* for off_t */
-#if defined _MSC_VER || defined __BORLANDC__ || defined __MINGW32__
-#if _MSC_VER <= 1600 || defined __BORLANDC__ /* @@@ [2G limit] */
-#define fseeko fseek
-#define ftello ftell
-#endif
-#endif
+#include "share/compat.h"
#include "FLAC/assert.h"
+#include "share/alloc.h"
#include "protected/stream_decoder.h"
#include "private/bitreader.h"
#include "private/bitmath.h"
#include "private/lpc.h"
#include "private/md5.h"
#include "private/memory.h"
-
-#ifdef max
-#undef max
-#endif
-#define max(a,b) ((a)>(b)?(a):(b))
-
-/* adjust for compilers that can't understand using LLU suffix for uint64_t literals */
-#ifdef _MSC_VER
-#define FLAC__U64L(x) x
-#else
-#define FLAC__U64L(x) x##LLU
-#endif
+#include "private/macros.h"
/* technically this should be in an "export.c" but this is convenient enough */
-FLAC_API int FLAC_API_SUPPORTS_OGG_FLAC =
-#if FLAC__HAS_OGG
- 1
+#ifdef FLAC_API_SUPPORTS_OGG_FLAC
+FLAC_API int FLAC_API_SUPPORTS_OGG_FLAC = FLAC__HAS_OGG ;
#else
- 0
+FLAC_API int FLAC_API_SUPPORTS_OGG_FLAC = 0 ;
#endif
-;
/***********************************************************************
FLAC__StreamMetadata seek_table;
FLAC__bool metadata_filter[128]; /* MAGIC number 128 == total number of metadata block types == 1 << 7 */
FLAC__byte *metadata_filter_ids;
- unsigned metadata_filter_ids_count, metadata_filter_ids_capacity; /* units for both are IDs, not bytes */
+ size_t metadata_filter_ids_count, metadata_filter_ids_capacity; /* units for both are IDs, not bytes */
FLAC__Frame frame;
FLAC__bool cached; /* true if there is a byte in lookahead */
FLAC__CPUInfo cpuinfo;
FLAC__ASSERT(sizeof(int) >= 4); /* we want to die right away if this is not true */
- decoder = (FLAC__StreamDecoder*)calloc(1, sizeof(FLAC__StreamDecoder));
+ decoder = calloc(1, sizeof(FLAC__StreamDecoder));
if(decoder == 0) {
return 0;
}
- decoder->protected_ = (FLAC__StreamDecoderProtected*)calloc(1, sizeof(FLAC__StreamDecoderProtected));
+ decoder->protected_ = calloc(1, sizeof(FLAC__StreamDecoderProtected));
if(decoder->protected_ == 0) {
free(decoder);
return 0;
}
- decoder->private_ = (FLAC__StreamDecoderPrivate*)calloc(1, sizeof(FLAC__StreamDecoderPrivate));
+ decoder->private_ = calloc(1, sizeof(FLAC__StreamDecoderPrivate));
if(decoder->private_ == 0) {
free(decoder->protected_);
free(decoder);
}
decoder->private_->metadata_filter_ids_capacity = 16;
- if(0 == (decoder->private_->metadata_filter_ids = (FLAC__byte*)malloc((FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8) * decoder->private_->metadata_filter_ids_capacity))) {
+ if(0 == (decoder->private_->metadata_filter_ids = malloc((FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8) * decoder->private_->metadata_filter_ids_capacity))) {
FLAC__bitreader_delete(decoder->private_->input);
free(decoder->private_);
free(decoder->protected_);
{
unsigned i;
- FLAC__ASSERT(0 != decoder);
+ if (decoder == NULL)
+ return ;
+
FLAC__ASSERT(0 != decoder->protected_);
FLAC__ASSERT(0 != decoder->private_);
FLAC__ASSERT(0 != decoder->private_->input);
#ifdef FLAC__CPU_IA32
FLAC__ASSERT(decoder->private_->cpuinfo.type == FLAC__CPUINFO_TYPE_IA32);
#ifdef FLAC__HAS_NASM
+#if 1 /*@@@@@@ OPT: not clearly faster, needs more testing */
if(decoder->private_->cpuinfo.data.ia32.bswap)
decoder->private_->local_bitreader_read_rice_signed_block = FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap;
+#endif
if(decoder->private_->cpuinfo.data.ia32.mmx) {
decoder->private_->local_lpc_restore_signal = FLAC__lpc_restore_signal_asm_ia32;
decoder->private_->local_lpc_restore_signal_16bit = FLAC__lpc_restore_signal_asm_ia32_mmx;
if(0 == write_callback || 0 == error_callback)
return decoder->protected_->state = FLAC__STREAM_DECODER_INIT_STATUS_INVALID_CALLBACKS;
- file = filename? fopen(filename, "rb") : stdin;
+ file = filename? flac_fopen(filename, "rb") : stdin;
if(0 == file)
return FLAC__STREAM_DECODER_INIT_STATUS_ERROR_OPENING_FILE;
FLAC__ASSERT(0 != decoder->private_->metadata_filter_ids);
if(decoder->private_->metadata_filter_ids_count == decoder->private_->metadata_filter_ids_capacity) {
- if(0 == (decoder->private_->metadata_filter_ids = (FLAC__byte*)realloc(decoder->private_->metadata_filter_ids, decoder->private_->metadata_filter_ids_capacity * 2))) {
+ if(0 == (decoder->private_->metadata_filter_ids = safe_realloc_mul_2op_(decoder->private_->metadata_filter_ids, decoder->private_->metadata_filter_ids_capacity, /*times*/2))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
FLAC__ASSERT(0 != decoder->private_->metadata_filter_ids);
if(decoder->private_->metadata_filter_ids_count == decoder->private_->metadata_filter_ids_capacity) {
- if(0 == (decoder->private_->metadata_filter_ids = (FLAC__byte*)realloc(decoder->private_->metadata_filter_ids, decoder->private_->metadata_filter_ids_capacity * 2))) {
+ if(0 == (decoder->private_->metadata_filter_ids = safe_realloc_mul_2op_(decoder->private_->metadata_filter_ids, decoder->private_->metadata_filter_ids_capacity, /*times*/2))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
*/
#if defined _MSC_VER || defined __MINGW32__
_setmode(_fileno(stdin), _O_BINARY);
-#elif defined __CYGWIN__ || defined __EMX__
+#elif defined __CYGWIN__
/* almost certainly not needed for any modern Cygwin, but let's be safe... */
setmode(_fileno(stdin), _O_BINARY);
+#elif defined __EMX__
+ setmode(fileno(stdin), O_BINARY);
#endif
return stdin;
* (at negative indices) for alignment purposes; we use 4
* to keep the data well-aligned.
*/
- tmp = (FLAC__int32*)malloc(sizeof(FLAC__int32)*(size+4));
+ tmp = safe_malloc_muladd2_(sizeof(FLAC__int32), /*times (*/size, /*+*/4/*)*/);
if(tmp == 0) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
FLAC__bool has_id_filtered_(FLAC__StreamDecoder *decoder, FLAC__byte *id)
{
- unsigned i;
+ size_t i;
FLAC__ASSERT(0 != decoder);
FLAC__ASSERT(0 != decoder->private_);
decoder->private_->lookahead = (FLAC__byte)x;
decoder->private_->cached = true;
}
- else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
+ else if(x >> 1 == 0x7c) { /* MAGIC NUMBER for the last 6 sync bits and reserved 7th bit */
decoder->private_->header_warmup[1] = (FLAC__byte)x;
decoder->protected_->state = FLAC__STREAM_DECODER_READ_FRAME;
return true;
if(!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, block.data.application.id, FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8))
return false; /* read_callback_ sets the state for us */
+ if(real_length < FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8) { /* underflow check */
+ decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;/*@@@@@@ maybe wrong error? need to resync?*/
+ return false;
+ }
+
real_length -= FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8;
if(decoder->private_->metadata_filter_ids_count > 0 && has_id_filtered_(decoder, block.data.application.id))
case FLAC__METADATA_TYPE_APPLICATION:
/* remember, we read the ID already */
if(real_length > 0) {
- if(0 == (block.data.application.data = (FLAC__byte*)malloc(real_length))) {
+ if(0 == (block.data.application.data = malloc(real_length))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
break;
default:
if(real_length > 0) {
- if(0 == (block.data.unknown.data = (FLAC__byte*)malloc(real_length))) {
+ if(0 == (block.data.unknown.data = malloc(real_length))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
if(!decoder->private_->is_seeking && decoder->private_->metadata_callback)
decoder->private_->metadata_callback(decoder, &block, decoder->private_->client_data);
- /* now we have to free any malloc'ed data in the block */
+ /* now we have to free any malloc()ed data in the block */
switch(type) {
case FLAC__METADATA_TYPE_PADDING:
break;
decoder->private_->seek_table.data.seek_table.num_points = length / FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;
/* use realloc since we may pass through here several times (e.g. after seeking) */
- if(0 == (decoder->private_->seek_table.data.seek_table.points = (FLAC__StreamMetadata_SeekPoint*)realloc(decoder->private_->seek_table.data.seek_table.points, decoder->private_->seek_table.data.seek_table.num_points * sizeof(FLAC__StreamMetadata_SeekPoint)))) {
+ if(0 == (decoder->private_->seek_table.data.seek_table.points = safe_realloc_mul_2op_(decoder->private_->seek_table.data.seek_table.points, decoder->private_->seek_table.data.seek_table.num_points, /*times*/sizeof(FLAC__StreamMetadata_SeekPoint)))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
if(!FLAC__bitreader_read_uint32_little_endian(decoder->private_->input, &obj->vendor_string.length))
return false; /* read_callback_ sets the state for us */
if(obj->vendor_string.length > 0) {
- if(0 == (obj->vendor_string.entry = (FLAC__byte*)malloc(obj->vendor_string.length+1))) {
+ if(0 == (obj->vendor_string.entry = safe_malloc_add_2op_(obj->vendor_string.length, /*+*/1))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
/* read comments */
if(obj->num_comments > 0) {
- if(0 == (obj->comments = (FLAC__StreamMetadata_VorbisComment_Entry*)malloc(obj->num_comments * sizeof(FLAC__StreamMetadata_VorbisComment_Entry)))) {
+ if(0 == (obj->comments = safe_malloc_mul_2op_p(obj->num_comments, /*times*/sizeof(FLAC__StreamMetadata_VorbisComment_Entry)))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
if(!FLAC__bitreader_read_uint32_little_endian(decoder->private_->input, &obj->comments[i].length))
return false; /* read_callback_ sets the state for us */
if(obj->comments[i].length > 0) {
- if(0 == (obj->comments[i].entry = (FLAC__byte*)malloc(obj->comments[i].length+1))) {
+ if(0 == (obj->comments[i].entry = safe_malloc_add_2op_(obj->comments[i].length, /*+*/1))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
obj->num_tracks = x;
if(obj->num_tracks > 0) {
- if(0 == (obj->tracks = (FLAC__StreamMetadata_CueSheet_Track*)calloc(obj->num_tracks, sizeof(FLAC__StreamMetadata_CueSheet_Track)))) {
+ if(0 == (obj->tracks = safe_calloc_(obj->num_tracks, sizeof(FLAC__StreamMetadata_CueSheet_Track)))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
track->num_indices = (FLAC__byte)x;
if(track->num_indices > 0) {
- if(0 == (track->indices = (FLAC__StreamMetadata_CueSheet_Index*)calloc(track->num_indices, sizeof(FLAC__StreamMetadata_CueSheet_Index)))) {
+ if(0 == (track->indices = safe_calloc_(track->num_indices, sizeof(FLAC__StreamMetadata_CueSheet_Index)))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
/* read MIME type */
if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN))
return false; /* read_callback_ sets the state for us */
- if(0 == (obj->mime_type = (char*)malloc(x+1))) {
+ if(0 == (obj->mime_type = safe_malloc_add_2op_(x, /*+*/1))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
/* read description */
if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN))
return false; /* read_callback_ sets the state for us */
- if(0 == (obj->description = (FLAC__byte*)malloc(x+1))) {
+ if(0 == (obj->description = safe_malloc_add_2op_(x, /*+*/1))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
/* read data */
if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &(obj->data_length), FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN))
return false; /* read_callback_ sets the state for us */
- if(0 == (obj->data = (FLAC__byte*)malloc(obj->data_length))) {
+ if(0 == (obj->data = safe_malloc_(obj->data_length))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
decoder->private_->lookahead = (FLAC__byte)x;
decoder->private_->cached = true;
}
- else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
+ else if(x >> 1 == 0x7c) { /* MAGIC NUMBER for the last 6 sync bits and reserved 7th bit */
decoder->private_->header_warmup[1] = (FLAC__byte)x;
decoder->protected_->state = FLAC__STREAM_DECODER_READ_FRAME;
return true;
}
if(!read_zero_padding_(decoder))
return false;
+ if(decoder->protected_->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC) /* means bad sync or got corruption (i.e. "zero bits" were not all zeroes) */
+ return true;
/*
* Read the frame CRC-16 from the footer and check
decoder->private_->output[0][i] = (mid + side) >> 1;
decoder->private_->output[1][i] = (mid - side) >> 1;
#else
- //@@@@@@ OPT: try without 'side' temp variable
+ /* OPT: without 'side' temp variable */
mid = (decoder->private_->output[0][i] << 1) | (decoder->private_->output[1][i] & 1); /* i.e. if 'side' is odd... */
decoder->private_->output[0][i] = (mid + decoder->private_->output[1][i]) >> 1;
decoder->private_->output[1][i] = (mid - decoder->private_->output[1][i]) >> 1;
}
}
- if(!FLAC__format_entropy_coding_method_partitioned_rice_contents_ensure_size(partitioned_rice_contents, max(6, partition_order))) {
+ if(!FLAC__format_entropy_coding_method_partitioned_rice_contents_ensure_size(partitioned_rice_contents, flac_max(6u, partition_order))) {
decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
return false;
}
upper_bound = stream_length;
upper_bound_sample = total_samples > 0 ? total_samples : target_sample /*estimate it*/;
- /*@@@@@@ add step to validate seek table before using? encoding to pipe leaves some flac files with incomplete seektables which screw us up */
- /*@@@@@@ ignore seekpoints where frame_samples = 0 or if point is >= total_samples and total_samples is known (or just alter seek_table in read_metadata_seektable_()) */
-
/*
* Now we refine the bounds if we have a seektable with
* suitable points. Note that according to the spec they
* must be ordered by ascending sample number.
+ *
+ * Note: to protect against invalid seek tables we will ignore points
+ * that have frame_samples==0 or sample_number>=total_samples
*/
if(seek_table) {
+ FLAC__uint64 new_lower_bound = lower_bound;
+ FLAC__uint64 new_upper_bound = upper_bound;
+ FLAC__uint64 new_lower_bound_sample = lower_bound_sample;
+ FLAC__uint64 new_upper_bound_sample = upper_bound_sample;
+
/* find the closest seek point <= target_sample, if it exists */
for(i = (int)seek_table->num_points - 1; i >= 0; i--) {
- if(seek_table->points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER && seek_table->points[i].sample_number <= target_sample)
+ if(
+ seek_table->points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER &&
+ seek_table->points[i].frame_samples > 0 && /* defense against bad seekpoints */
+ (total_samples <= 0 || seek_table->points[i].sample_number < total_samples) && /* defense against bad seekpoints */
+ seek_table->points[i].sample_number <= target_sample
+ )
break;
}
if(i >= 0) { /* i.e. we found a suitable seek point... */
- lower_bound = first_frame_offset + seek_table->points[i].stream_offset;
- lower_bound_sample = seek_table->points[i].sample_number;
+ new_lower_bound = first_frame_offset + seek_table->points[i].stream_offset;
+ new_lower_bound_sample = seek_table->points[i].sample_number;
}
/* find the closest seek point > target_sample, if it exists */
for(i = 0; i < (int)seek_table->num_points; i++) {
- if(seek_table->points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER && seek_table->points[i].sample_number > target_sample)
+ if(
+ seek_table->points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER &&
+ seek_table->points[i].frame_samples > 0 && /* defense against bad seekpoints */
+ (total_samples <= 0 || seek_table->points[i].sample_number < total_samples) && /* defense against bad seekpoints */
+ seek_table->points[i].sample_number > target_sample
+ )
break;
}
if(i < (int)seek_table->num_points) { /* i.e. we found a suitable seek point... */
- upper_bound = first_frame_offset + seek_table->points[i].stream_offset;
- upper_bound_sample = seek_table->points[i].sample_number;
+ new_upper_bound = first_frame_offset + seek_table->points[i].stream_offset;
+ new_upper_bound_sample = seek_table->points[i].sample_number;
+ }
+ /* final protection against unsorted seek tables; keep original values if bogus */
+ if(new_upper_bound >= new_lower_bound) {
+ lower_bound = new_lower_bound;
+ upper_bound = new_upper_bound;
+ lower_bound_sample = new_lower_bound_sample;
+ upper_bound_sample = new_upper_bound_sample;
}
}
}
/* our last move backwards wasn't big enough, try again */
approx_bytes_per_frame = approx_bytes_per_frame? approx_bytes_per_frame * 2 : 16;
- continue;
+ continue;
}
/* allow one seek over upper bound, so we can get a correct upper_bound_sample for streams with unknown total_samples */
first_seek = false;
-
+
/* make sure we are not seeking in corrupted stream */
if (this_frame_sample < lower_bound_sample) {
decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
{
FLAC__uint64 left_pos = 0, right_pos = stream_length;
FLAC__uint64 left_sample = 0, right_sample = FLAC__stream_decoder_get_total_samples(decoder);
- FLAC__uint64 this_frame_sample = 0; /* only initialized to avoid compiler warning */
+ FLAC__uint64 this_frame_sample = (FLAC__uint64)0 - 1;
FLAC__uint64 pos = 0; /* only initialized to avoid compiler warning */
FLAC__bool did_a_seek;
unsigned iteration = 0;
- /* In the first iterations, we will calculate the target byte position
+ /* In the first iterations, we will calculate the target byte position
* by the distance from the target sample to left_sample and
* right_sample (let's call it "proportional search"). After that, we
* will switch to binary search.
/* @@@ TODO: might want to limit pos to some distance
* before EOF, to make sure we land before the last frame,
* thereby getting a this_frame_sample and so having a better
- * estimate. @@@@@@DELETE:this would also mostly (or totally if we could
- * be sure to land before the last frame) avoid the
- * end-of-stream case we have to check later.
+ * estimate.
*/
}
}
}
/* our write callback will change the state when it gets to the target frame */
- else if(!decoder->private_->is_seeking/*@@@@@@ && decoder->protected_->state != FLAC__STREAM_DECODER_END_OF_STREAM*/) {
+ else if(!decoder->private_->is_seeking) {
break;
}
else {
if(decoder->private_->file == stdin)
return FLAC__STREAM_DECODER_SEEK_STATUS_UNSUPPORTED;
- else if(fseeko(decoder->private_->file, (off_t)absolute_byte_offset, SEEK_SET) < 0)
+ else if(fseeko(decoder->private_->file, (FLAC__off_t)absolute_byte_offset, SEEK_SET) < 0)
return FLAC__STREAM_DECODER_SEEK_STATUS_ERROR;
else
return FLAC__STREAM_DECODER_SEEK_STATUS_OK;
FLAC__StreamDecoderTellStatus file_tell_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 *absolute_byte_offset, void *client_data)
{
- off_t pos;
+ FLAC__off_t pos;
(void)client_data;
if(decoder->private_->file == stdin)
FLAC__StreamDecoderLengthStatus file_length_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 *stream_length, void *client_data)
{
- struct stat filestats;
+ struct flac_stat_s filestats;
(void)client_data;
if(decoder->private_->file == stdin)
return FLAC__STREAM_DECODER_LENGTH_STATUS_UNSUPPORTED;
- else if(fstat(fileno(decoder->private_->file), &filestats) != 0)
+ else if(flac_fstat(fileno(decoder->private_->file), &filestats) != 0)
return FLAC__STREAM_DECODER_LENGTH_STATUS_ERROR;
else {
*stream_length = (FLAC__uint64)filestats.st_size;
projects / platform / upstream / flac.git / blobdiff