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/**************************************************************************/
/* */
/* OCaml */
/* */
/* Xavier Leroy, Collège de France and Inria */
/* David Allsopp, Tarides */
/* */
/* Copyright 2023 Institut National de Recherche en Informatique et */
/* en Automatique. */
/* Copyright 2023 David Allsopp Ltd. */
/* */
/* All rights reserved. This file is distributed under the terms of */
/* the GNU Lesser General Public License version 2.1, with the */
/* special exception on linking described in the file LICENSE. */
/* */
/**************************************************************************/
#define CAML_INTERNALS
#include <stdbool.h>
#include "caml/intext.h"
#include "caml/memory.h"
#include "caml/mlvalues.h"
#ifdef HAS_ZSTD
#include <zstd.h>
/* Compress the output */
static bool caml_zstd_compress(struct caml_output_block **extern_output_first)
{
ZSTD_CCtx * ctx;
ZSTD_inBuffer in;
ZSTD_outBuffer out;
struct caml_output_block * input, * output, * output_head;
int rc;
ctx = ZSTD_createCCtx();
if (ctx == NULL) return false;
input = *extern_output_first;
output_head = caml_stat_alloc_noexc(sizeof(struct caml_output_block));
if (output_head == NULL) goto oom1;
output = output_head;
output->next = NULL;
in.src = input->data; in.size = input->end - input->data; in.pos = 0;
out.dst = output->data; out.size = SIZE_EXTERN_OUTPUT_BLOCK; out.pos = 0;
do {
if (out.pos == out.size) {
output->end = output->data + out.pos;
/* Allocate fresh output block */
struct caml_output_block * next =
caml_stat_alloc_noexc(sizeof(struct caml_output_block));
if (next == NULL) goto oom2;
output->next = next;
output = next;
output->next = NULL;
out.dst = output->data; out.size = SIZE_EXTERN_OUTPUT_BLOCK; out.pos = 0;
}
if (in.pos == in.size && input != NULL) {
/* Move to next input block and free current input block */
struct caml_output_block * next = input->next;
caml_stat_free(input);
input = next;
if (input != NULL) {
in.src = input->data; in.size = input->end - input->data;
} else {
in.src = NULL; in.size = 0;
}
in.pos = 0;
}
rc = ZSTD_compressStream2(ctx, &out, &in,
input == NULL ? ZSTD_e_end : ZSTD_e_continue);
} while (! (input == NULL && rc == 0));
output->end = output->data + out.pos;
*extern_output_first = output_head;
ZSTD_freeCCtx(ctx);
return true;
oom2:
/* The old uncompressed blocks that remain to be freed */
*extern_output_first = input;
/* Free the newly-allocated compressed blocks */
for (output = output_head; output != NULL; ) {
struct caml_output_block * next = output->next;
caml_stat_free(output);
output = next;
}
oom1:
ZSTD_freeCCtx(ctx);
return false;
}
static size_t caml_zstd_decompress(unsigned char * blk,
uintnat uncompressed_data_len,
const unsigned char * intern_src,
uintnat data_len)
{
return ZSTD_decompress(blk, uncompressed_data_len, intern_src, data_len);
}
CAMLprim value caml_zstd_initialize(value vunit)
{
caml_extern_compress_output = caml_zstd_compress;
caml_intern_decompress_input = caml_zstd_decompress;
return Val_true;
}
#else
CAMLprim value caml_zstd_initialize(value vunit)
{
return Val_false;
}
#endif
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