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Address PR comments and minor fixes

dev
Sean Purcell 2017-04-12 10:57:38 -07:00
parent d048fefef7
commit e80f1d74b3
6 changed files with 20 additions and 10 deletions
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8
contrib/seekable_format/examples/Makefile
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@ -23,11 +23,11 @@ default: all
all: seekable_compression seekable_decompression
seekable_compression : seekable_compression.c
$(CC) $(CPPFLAGS) $(CFLAGS) $(SEEKABLE_OBJS) $^ $(LDFLAGS) -o $@
seekable_compression : seekable_compression.c $(SEEKABLE_OBJS)
$(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@
seekable_decompression : seekable_decompression.c
$(CC) $(CPPFLAGS) $(CFLAGS) $(SEEKABLE_OBJS) $^ $(LDFLAGS) -o $@
seekable_decompression : seekable_decompression.c $(SEEKABLE_OBJS)
$(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@
clean:
@rm -f core *.o tmp* result* *.zst \

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contrib/seekable_format/examples/seekable_compression
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15
contrib/seekable_format/zstd_seekable_compression_format.md
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@ -42,13 +42,16 @@ The structure of the seek table frame is as follows:
__`Skippable_Magic_Number`__
Value : 0x184D2A5?, which means any value from 0x184D2A50 to 0x184D2A5F.
All 16 values are valid to identify a skippable frame.
Value : 0x184D2A5E.
This is for compatibility with [Zstandard skippable frames].
Since it is legal for other Zstandard skippable frames to use the same
magic number, it is not recommended for a decoder to recognize frames
solely on this.
__`Frame_Size`__
The total size of the skippable frame, not including the `Skippable_Magic_Number` or `Frame_Size`. This is for compatibility with [Zstandard skippable frames].
The total size of the skippable frame, not including the `Skippable_Magic_Number` or `Frame_Size`.
This is for compatibility with [Zstandard skippable frames].
[Zstandard skippable frames]: https://github.com/facebook/zstd/blob/master/doc/zstd_compression_format.md#skippable-frames
@ -59,6 +62,12 @@ The seek table footer format is as follows:
|------------------|-----------------------|-----------------------|
| 4 bytes | 1 byte | 4 bytes |
__`Seekable_Magic_Number`__
Value : 0x8F92EAB1.
This value must be the last bytes present in the compressed file so that decoders
can efficiently find it and determine if there is an actual seek table present.
__`Number_Of_Chunks`__
The number of stored chunks in the data.

2
contrib/seekable_format/zstdseek_compress.c
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@ -247,7 +247,7 @@ static size_t ZSTD_seekable_writeSeekTable(ZSTD_seekable_CStream* zcs, ZSTD_outB
} \
} while (0)
st_write32(ZSTD_MAGIC_SKIPPABLE_START, 0);
st_write32(ZSTD_MAGIC_SKIPPABLE_START | 0xE, 0);
st_write32(seekTableLen - ZSTD_skippableHeaderSize, 4);
while (zcs->chunkDSize < zcs->chunklog.size) {

4
contrib/seekable_format/zstdseek_decompress.c
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@ -39,7 +39,7 @@ static U32 ZSTD_seekable_offsetToChunk(const seekTable_t* table, U64 pos)
U32 hi = table->tableLen;
while (lo + 1 < hi) {
U32 mid = lo + ((hi - lo) >> 1);
U32 const mid = lo + ((hi - lo) >> 1);
if (table->entries[mid].dOffset <= pos) {
lo = mid;
} else {
@ -139,7 +139,7 @@ size_t ZSTD_seekable_loadSeekTable(ZSTD_seekable_DStream* zds, const void* src,
if (srcSize < frameSize) return frameSize;
if ((MEM_readLE32(base) & 0xFFFFFFF0U) != ZSTD_MAGIC_SKIPPABLE_START) {
if (MEM_readLE32(base) != (ZSTD_MAGIC_SKIPPABLE_START | 0xE)) {
return ERROR(prefix_unknown);
}
if (MEM_readLE32(base+4) + ZSTD_skippableHeaderSize != frameSize) {

1
doc/README.md
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@ -17,3 +17,4 @@ __`zstd_manual.html`__ : Documentation on the functions found in `zstd.h`.
See [http://zstd.net/zstd_manual.html](http://zstd.net/zstd_manual.html) for
the manual released with the latest official `zstd` release.