1 files changed, 369 insertions, 0 deletions
diff --git a/src/zstd/contrib/seekable_format/zstdseek_compress.c b/src/zstd/contrib/seekable_format/zstdseek_compress.c
new file mode 100644
index 000000000..5a75714fa
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/zstdseek_compress.c
@@ -0,0 +1,369 @@
+/*
+ * Copyright (c) 2017-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ */
+
+#include <stdlib.h>     /* malloc, free */
+#include <limits.h>     /* UINT_MAX */
+#include <assert.h>
+
+#define XXH_STATIC_LINKING_ONLY
+#define XXH_NAMESPACE ZSTD_
+#include "xxhash.h"
+
+#define ZSTD_STATIC_LINKING_ONLY
+#include "zstd.h"
+#include "zstd_errors.h"
+#include "mem.h"
+#include "zstd_seekable.h"
+
+#define CHECK_Z(f) { size_t const ret = (f); if (ret != 0) return ret; }
+
+#undef ERROR
+#define ERROR(name) ((size_t)-ZSTD_error_##name)
+
+#undef MIN
+#undef MAX
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+typedef struct {
+    U32 cSize;
+    U32 dSize;
+    U32 checksum;
+} framelogEntry_t;
+
+struct ZSTD_frameLog_s {
+    framelogEntry_t* entries;
+    U32 size;
+    U32 capacity;
+
+    int checksumFlag;
+
+    /* for use when streaming out the seek table */
+    U32 seekTablePos;
+    U32 seekTableIndex;
+} framelog_t;
+
+struct ZSTD_seekable_CStream_s {
+    ZSTD_CStream* cstream;
+    ZSTD_frameLog framelog;
+
+    U32 frameCSize;
+    U32 frameDSize;
+
+    XXH64_state_t xxhState;
+
+    U32 maxFrameSize;
+
+    int writingSeekTable;
+};
+
+size_t ZSTD_seekable_frameLog_allocVec(ZSTD_frameLog* fl)
+{
+    /* allocate some initial space */
+    size_t const FRAMELOG_STARTING_CAPACITY = 16;
+    fl->entries = (framelogEntry_t*)malloc(
+            sizeof(framelogEntry_t) * FRAMELOG_STARTING_CAPACITY);
+    if (fl->entries == NULL) return ERROR(memory_allocation);
+    fl->capacity = FRAMELOG_STARTING_CAPACITY;
+
+    return 0;
+}
+
+size_t ZSTD_seekable_frameLog_freeVec(ZSTD_frameLog* fl)
+{
+    if (fl != NULL) free(fl->entries);
+    return 0;
+}
+
+ZSTD_frameLog* ZSTD_seekable_createFrameLog(int checksumFlag)
+{
+    ZSTD_frameLog* fl = malloc(sizeof(ZSTD_frameLog));
+    if (fl == NULL) return NULL;
+
+    if (ZSTD_isError(ZSTD_seekable_frameLog_allocVec(fl))) {
+        free(fl);
+        return NULL;
+    }
+
+    fl->checksumFlag = checksumFlag;
+    fl->seekTablePos = 0;
+    fl->seekTableIndex = 0;
+    fl->size = 0;
+
+    return fl;
+}
+
+size_t ZSTD_seekable_freeFrameLog(ZSTD_frameLog* fl)
+{
+    ZSTD_seekable_frameLog_freeVec(fl);
+    free(fl);
+    return 0;
+}
+
+ZSTD_seekable_CStream* ZSTD_seekable_createCStream()
+{
+    ZSTD_seekable_CStream* zcs = malloc(sizeof(ZSTD_seekable_CStream));
+
+    if (zcs == NULL) return NULL;
+
+    memset(zcs, 0, sizeof(*zcs));
+
+    zcs->cstream = ZSTD_createCStream();
+    if (zcs->cstream == NULL) goto failed1;
+
+    if (ZSTD_isError(ZSTD_seekable_frameLog_allocVec(&zcs->framelog))) goto failed2;
+
+    return zcs;
+
+failed2:
+    ZSTD_freeCStream(zcs->cstream);
+failed1:
+    free(zcs);
+    return NULL;
+}
+
+size_t ZSTD_seekable_freeCStream(ZSTD_seekable_CStream* zcs)
+{
+    if (zcs == NULL) return 0; /* support free on null */
+    ZSTD_freeCStream(zcs->cstream);
+    ZSTD_seekable_frameLog_freeVec(&zcs->framelog);
+    free(zcs);
+
+    return 0;
+}
+
+size_t ZSTD_seekable_initCStream(ZSTD_seekable_CStream* zcs,
+                                 int compressionLevel,
+                                 int checksumFlag,
+                                 unsigned maxFrameSize)
+{
+    zcs->framelog.size = 0;
+    zcs->frameCSize = 0;
+    zcs->frameDSize = 0;
+
+    /* make sure maxFrameSize has a reasonable value */
+    if (maxFrameSize > ZSTD_SEEKABLE_MAX_FRAME_DECOMPRESSED_SIZE) {
+        return ERROR(frameParameter_unsupported);
+    }
+
+    zcs->maxFrameSize = maxFrameSize
+                                ? maxFrameSize
+                                : ZSTD_SEEKABLE_MAX_FRAME_DECOMPRESSED_SIZE;
+
+    zcs->framelog.checksumFlag = checksumFlag;
+    if (zcs->framelog.checksumFlag) {
+        XXH64_reset(&zcs->xxhState, 0);
+    }
+
+    zcs->framelog.seekTablePos = 0;
+    zcs->framelog.seekTableIndex = 0;
+    zcs->writingSeekTable = 0;
+
+    return ZSTD_initCStream(zcs->cstream, compressionLevel);
+}
+
+size_t ZSTD_seekable_logFrame(ZSTD_frameLog* fl,
+                              unsigned compressedSize,
+                              unsigned decompressedSize,
+                              unsigned checksum)
+{
+    if (fl->size == ZSTD_SEEKABLE_MAXFRAMES)
+        return ERROR(frameIndex_tooLarge);
+
+    /* grow the buffer if required */
+    if (fl->size == fl->capacity) {
+        /* exponential size increase for constant amortized runtime */
+        size_t const newCapacity = fl->capacity * 2;
+        framelogEntry_t* const newEntries = realloc(fl->entries,
+                sizeof(framelogEntry_t) * newCapacity);
+
+        if (newEntries == NULL) return ERROR(memory_allocation);
+
+        fl->entries = newEntries;
+        assert(newCapacity <= UINT_MAX);
+        fl->capacity = (U32)newCapacity;
+    }
+
+    fl->entries[fl->size] = (framelogEntry_t){
+            compressedSize, decompressedSize, checksum
+    };
+    fl->size++;
+
+    return 0;
+}
+
+size_t ZSTD_seekable_endFrame(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output)
+{
+    size_t const prevOutPos = output->pos;
+    /* end the frame */
+    size_t ret = ZSTD_endStream(zcs->cstream, output);
+
+    zcs->frameCSize += output->pos - prevOutPos;
+
+    /* need to flush before doing the rest */
+    if (ret) return ret;
+
+    /* frame done */
+
+    /* store the frame data for later */
+    ret = ZSTD_seekable_logFrame(
+            &zcs->framelog, zcs->frameCSize, zcs->frameDSize,
+            zcs->framelog.checksumFlag
+                    ? XXH64_digest(&zcs->xxhState) & 0xFFFFFFFFU
+                    : 0);
+    if (ret) return ret;
+
+    /* reset for the next frame */
+    zcs->frameCSize = 0;
+    zcs->frameDSize = 0;
+
+    ZSTD_resetCStream(zcs->cstream, 0);
+    if (zcs->framelog.checksumFlag)
+        XXH64_reset(&zcs->xxhState, 0);
+
+    return 0;
+}
+
+size_t ZSTD_seekable_compressStream(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
+{
+    const BYTE* const inBase = (const BYTE*) input->src + input->pos;
+    size_t inLen = input->size - input->pos;
+
+    inLen = MIN(inLen, (size_t)(zcs->maxFrameSize - zcs->frameDSize));
+
+    /* if we haven't finished flushing the last frame, don't start writing a new one */
+    if (inLen > 0) {
+        ZSTD_inBuffer inTmp = { inBase, inLen, 0 };
+        size_t const prevOutPos = output->pos;
+
+        size_t const ret = ZSTD_compressStream(zcs->cstream, output, &inTmp);
+
+        if (zcs->framelog.checksumFlag) {
+            XXH64_update(&zcs->xxhState, inBase, inTmp.pos);
+        }
+
+        zcs->frameCSize += output->pos - prevOutPos;
+        zcs->frameDSize += inTmp.pos;
+
+        input->pos += inTmp.pos;
+
+        if (ZSTD_isError(ret)) return ret;
+    }
+
+    if (zcs->maxFrameSize == zcs->frameDSize) {
+        /* log the frame and start over */
+        size_t const ret = ZSTD_seekable_endFrame(zcs, output);
+        if (ZSTD_isError(ret)) return ret;
+
+        /* get the client ready for the next frame */
+        return (size_t)zcs->maxFrameSize;
+    }
+
+    return (size_t)(zcs->maxFrameSize - zcs->frameDSize);
+}
+
+static inline size_t ZSTD_seekable_seekTableSize(const ZSTD_frameLog* fl)
+{
+    size_t const sizePerFrame = 8 + (fl->checksumFlag?4:0);
+    size_t const seekTableLen = ZSTD_SKIPPABLEHEADERSIZE +
+                                sizePerFrame * fl->size +
+                                ZSTD_seekTableFooterSize;
+
+    return seekTableLen;
+}
+
+static inline size_t ZSTD_stwrite32(ZSTD_frameLog* fl,
+                                    ZSTD_outBuffer* output, U32 const value,
+                                    U32 const offset)
+{
+    if (fl->seekTablePos < offset + 4) {
+        BYTE tmp[4]; /* so that we can work with buffers too small to write a whole word to */
+        size_t const lenWrite =
+                MIN(output->size - output->pos, offset + 4 - fl->seekTablePos);
+        MEM_writeLE32(tmp, value);
+        memcpy((BYTE*)output->dst + output->pos,
+               tmp + (fl->seekTablePos - offset), lenWrite);
+        output->pos += lenWrite;
+        fl->seekTablePos += lenWrite;
+
+        if (lenWrite < 4) return ZSTD_seekable_seekTableSize(fl) - fl->seekTablePos;
+    }
+    return 0;
+}
+
+size_t ZSTD_seekable_writeSeekTable(ZSTD_frameLog* fl, ZSTD_outBuffer* output)
+{
+    /* seekTableIndex: the current index in the table and
+     * seekTableSize: the amount of the table written so far
+     *
+     * This function is written this way so that if it has to return early
+     * because of a small buffer, it can keep going where it left off.
+     */
+
+    size_t const sizePerFrame = 8 + (fl->checksumFlag?4:0);
+    size_t const seekTableLen = ZSTD_seekable_seekTableSize(fl);
+
+    CHECK_Z(ZSTD_stwrite32(fl, output, ZSTD_MAGIC_SKIPPABLE_START | 0xE, 0));
+    assert(seekTableLen <= (size_t)UINT_MAX);
+    CHECK_Z(ZSTD_stwrite32(fl, output, (U32)seekTableLen - ZSTD_SKIPPABLEHEADERSIZE, 4));
+
+    while (fl->seekTableIndex < fl->size) {
+        unsigned long long const start = ZSTD_SKIPPABLEHEADERSIZE + sizePerFrame * fl->seekTableIndex;
+        assert(start + 8 <= UINT_MAX);
+        CHECK_Z(ZSTD_stwrite32(fl, output,
+                               fl->entries[fl->seekTableIndex].cSize,
+                               (U32)start + 0));
+
+        CHECK_Z(ZSTD_stwrite32(fl, output,
+                               fl->entries[fl->seekTableIndex].dSize,
+                               (U32)start + 4));
+
+        if (fl->checksumFlag) {
+            CHECK_Z(ZSTD_stwrite32(
+                    fl, output, fl->entries[fl->seekTableIndex].checksum,
+                    (U32)start + 8));
+        }
+
+        fl->seekTableIndex++;
+    }
+
+    assert(seekTableLen <= UINT_MAX);
+    CHECK_Z(ZSTD_stwrite32(fl, output, fl->size,
+                           (U32)seekTableLen - ZSTD_seekTableFooterSize));
+
+    if (output->size - output->pos < 1) return seekTableLen - fl->seekTablePos;
+    if (fl->seekTablePos < seekTableLen - 4) {
+        BYTE sfd = 0;
+        sfd |= (fl->checksumFlag) << 7;
+
+        ((BYTE*)output->dst)[output->pos] = sfd;
+        output->pos++;
+        fl->seekTablePos++;
+    }
+
+    CHECK_Z(ZSTD_stwrite32(fl, output, ZSTD_SEEKABLE_MAGICNUMBER,
+                           (U32)seekTableLen - 4));
+
+    if (fl->seekTablePos != seekTableLen) return ERROR(GENERIC);
+    return 0;
+}
+
+size_t ZSTD_seekable_endStream(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output)
+{
+    if (!zcs->writingSeekTable && zcs->frameDSize) {
+        const size_t endFrame = ZSTD_seekable_endFrame(zcs, output);
+        if (ZSTD_isError(endFrame)) return endFrame;
+        /* return an accurate size hint */
+        if (endFrame) return endFrame + ZSTD_seekable_seekTableSize(&zcs->framelog);
+    }
+
+    zcs->writingSeekTable = 1;
+
+    return ZSTD_seekable_writeSeekTable(&zcs->framelog, output);
+}