gecko/mozglue/linker/szip.cpp

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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <algorithm>
#include <sys/stat.h>
#include <cstring>
#include <zlib.h>
#include <fcntl.h>
#include <errno.h>
#include "mozilla/Assertions.h"
#include "SeekableZStream.h"
#include "Utils.h"
#include "Logging.h"
static const size_t CHUNK = 16384;
/* Generate a seekable compressed stream. */
int main(int argc, char* argv[])
{
if (argc != 3 || !argv[1] || !argv[2] || (strcmp(argv[1], argv[2]) == 0)) {
log("usage: %s file_to_compress out_file", argv[0]);
return 1;
}
AutoCloseFD origFd = open(argv[1], O_RDONLY);
if (origFd == -1) {
log("Couldn't open %s: %s", argv[1], strerror(errno));
return 1;
}
struct stat st;
int ret = fstat(origFd, &st);
if (ret == -1) {
log("Couldn't seek %s: %s", argv[1], strerror(errno));
return 1;
}
size_t origSize = st.st_size;
log("Size = %lu", origSize);
if (origSize == 0) {
log("Won't compress %s: it's empty", argv[1]);
return 1;
}
/* Mmap the original file */
MappedPtr origBuf;
origBuf.Assign(mmap(NULL, origSize, PROT_READ, MAP_PRIVATE, origFd, 0), origSize);
if (origBuf == MAP_FAILED) {
log("Couldn't mmap %s: %s", argv[1], strerror(errno));
return 1;
}
/* Create the compressed file */
AutoCloseFD outFd = open(argv[2], O_RDWR | O_CREAT | O_TRUNC, 0666);
if (outFd == -1) {
log("Couldn't open %s: %s", argv[2], strerror(errno));
return 1;
}
/* Expected total number of chunks */
size_t nChunks = ((origSize + CHUNK - 1) / CHUNK);
/* The first chunk is going to be stored after the header and the offset
* table */
size_t offset = sizeof(SeekableZStreamHeader) + nChunks * sizeof(uint32_t);
/* Give enough room for the header and the offset table, and map them */
ret = ftruncate(outFd, offset);
MOZ_ASSERT(ret == 0);
MappedPtr headerMap;
headerMap.Assign(mmap(NULL, offset, PROT_READ | PROT_WRITE, MAP_SHARED,
outFd, 0), offset);
if (headerMap == MAP_FAILED) {
log("Couldn't mmap %s: %s", argv[1], strerror(errno));
return 1;
}
SeekableZStreamHeader *header = new (headerMap) SeekableZStreamHeader;
le_uint32 *entry = reinterpret_cast<le_uint32 *>(&header[1]);
/* Initialize header */
header->chunkSize = CHUNK;
header->totalSize = offset;
/* Seek at the end of the output file, where we're going to append
* compressed streams */
lseek(outFd, offset, SEEK_SET);
/* Initialize zlib structure */
z_stream zStream;
memset(&zStream, 0, sizeof(zStream));
/* Compression buffer */
AutoDeleteArray<Bytef> outBuf = new Bytef[CHUNK * 2];
Bytef *origData = static_cast<Bytef*>(origBuf);
size_t avail = 0;
while (origSize) {
avail = std::min(origSize, CHUNK);
/* Compress chunk */
ret = deflateInit(&zStream, 9);
MOZ_ASSERT(ret == Z_OK);
zStream.avail_in = avail;
zStream.next_in = origData;
zStream.avail_out = CHUNK * 2;
zStream.next_out = outBuf;
ret = deflate(&zStream, Z_FINISH);
MOZ_ASSERT(ret == Z_STREAM_END);
ret = deflateEnd(&zStream);
MOZ_ASSERT(ret == Z_OK);
MOZ_ASSERT(zStream.avail_out > 0);
/* Write chunk */
size_t len = write(outFd, outBuf, 2 * CHUNK - zStream.avail_out);
MOZ_ASSERT(len == 2 * CHUNK - zStream.avail_out);
/* Adjust headers */
header->totalSize += len;
*entry++ = offset;
header->nChunks++;
/* Prepare for next iteration */
origSize -= avail;
origData += avail;
offset += len;
}
header->lastChunkSize = avail;
MOZ_ASSERT(header->nChunks == nChunks);
log("Compressed size is %lu", offset);
return 0;
}