compress_linux.c

Go to the documentation of this file.

 
#ifndef _WIN32
 
    #include <string.h>
 
    #include <arpa/inet.h>
    #include <zlib.h>
 
    #include "compress.h"
 
/* doxygen コメントはヘッダに記載 */
int potr_compress(uint8_t *dst, size_t *dst_len, const uint8_t *src, size_t src_len)
{
    uint32_t orig_len_nbo;
    z_stream z;
    int ret;
 
    if (dst == NULL || dst_len == NULL || src == NULL || src_len == 0)
    {
        return -1;
    }
 
    if (*dst_len < POTR_COMPRESS_HEADER_SIZE + 1U)
    {
        return -1;
    }
 
    /* 先頭 4 バイトに元サイズ (NBO) を書く */
    orig_len_nbo = htonl((uint32_t)src_len);
    memcpy(dst, &orig_len_nbo, POTR_COMPRESS_HEADER_SIZE);
 
    /* raw DEFLATE (windowBits = -15) で圧縮 */
    memset(&z, 0, sizeof(z));
    z.next_in = (Bytef *)(uintptr_t)src;
    z.avail_in = (uInt)src_len;
    z.next_out = dst + POTR_COMPRESS_HEADER_SIZE;
    z.avail_out = (uInt)(*dst_len - POTR_COMPRESS_HEADER_SIZE);
 
    if (deflateInit2(&z, Z_DEFAULT_COMPRESSION, Z_DEFLATED, -15, 8, Z_DEFAULT_STRATEGY) != Z_OK)
    {
        return -1;
    }
 
    ret = deflate(&z, Z_FINISH);
    deflateEnd(&z);
 
    if (ret != Z_STREAM_END)
    {
        return -1;
    }
 
    *dst_len = POTR_COMPRESS_HEADER_SIZE + (size_t)z.total_out;
    return 0;
}
 
/* doxygen コメントはヘッダに記載 */
int potr_decompress(uint8_t *dst, size_t *dst_len, const uint8_t *src, size_t src_len)
{
    uint32_t orig_len_nbo;
    uint32_t orig_len;
    z_stream z;
    int ret;
 
    if (dst == NULL || dst_len == NULL || src == NULL || src_len <= POTR_COMPRESS_HEADER_SIZE)
    {
        return -1;
    }
 
    /* 先頭 4 バイトから元サイズを取得 */
    memcpy(&orig_len_nbo, src, POTR_COMPRESS_HEADER_SIZE);
    orig_len = ntohl(orig_len_nbo);
 
    if (*dst_len < (size_t)orig_len)
    {
        return -1;
    }
 
    /* raw DEFLATE を解凍 */
    memset(&z, 0, sizeof(z));
    z.next_in = (Bytef *)(uintptr_t)(src + POTR_COMPRESS_HEADER_SIZE);
    z.avail_in = (uInt)(src_len - POTR_COMPRESS_HEADER_SIZE);
    z.next_out = (Bytef *)dst;
    z.avail_out = (uInt)*dst_len;
 
    if (inflateInit2(&z, -15) != Z_OK)
    {
        return -1;
    }
 
    ret = inflate(&z, Z_FINISH);
    inflateEnd(&z);
 
    if (ret != Z_STREAM_END)
    {
        return -1;
    }
 
    *dst_len = (size_t)z.total_out;
    return 0;
}
 
#else /* _WIN32 */
    #pragma warning(disable : 4206)
#endif /* _WIN32 */