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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 03:10:08 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 03:10:08 +0000 |
commit | 5262a872f308b3b584c97d621992fb3877e392b8 (patch) | |
tree | b956c322376141abeafe639bd72cfecdf16954b5 /src/liblzma/common/vli_encoder.c | |
parent | Initial commit. (diff) | |
download | xz-utils-5262a872f308b3b584c97d621992fb3877e392b8.tar.xz xz-utils-5262a872f308b3b584c97d621992fb3877e392b8.zip |
Adding upstream version 5.6.1+really5.4.5.upstream/5.6.1+really5.4.5
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/liblzma/common/vli_encoder.c')
-rw-r--r-- | src/liblzma/common/vli_encoder.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/src/liblzma/common/vli_encoder.c b/src/liblzma/common/vli_encoder.c new file mode 100644 index 0000000..f864269 --- /dev/null +++ b/src/liblzma/common/vli_encoder.c @@ -0,0 +1,69 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file vli_encoder.c +/// \brief Encodes variable-length integers +// +// Author: Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "common.h" + + +extern LZMA_API(lzma_ret) +lzma_vli_encode(lzma_vli vli, size_t *vli_pos, + uint8_t *restrict out, size_t *restrict out_pos, + size_t out_size) +{ + // If we haven't been given vli_pos, work in single-call mode. + size_t vli_pos_internal = 0; + if (vli_pos == NULL) { + vli_pos = &vli_pos_internal; + + // In single-call mode, we expect that the caller has + // reserved enough output space. + if (*out_pos >= out_size) + return LZMA_PROG_ERROR; + } else { + // This never happens when we are called by liblzma, but + // may happen if called directly from an application. + if (*out_pos >= out_size) + return LZMA_BUF_ERROR; + } + + // Validate the arguments. + if (*vli_pos >= LZMA_VLI_BYTES_MAX || vli > LZMA_VLI_MAX) + return LZMA_PROG_ERROR; + + // Shift vli so that the next bits to encode are the lowest. In + // single-call mode this never changes vli since *vli_pos is zero. + vli >>= *vli_pos * 7; + + // Write the non-last bytes in a loop. + while (vli >= 0x80) { + // We don't need *vli_pos during this function call anymore, + // but update it here so that it is ready if we need to + // return before the whole integer has been decoded. + ++*vli_pos; + assert(*vli_pos < LZMA_VLI_BYTES_MAX); + + // Write the next byte. + out[*out_pos] = (uint8_t)(vli) | 0x80; + vli >>= 7; + + if (++*out_pos == out_size) + return vli_pos == &vli_pos_internal + ? LZMA_PROG_ERROR : LZMA_OK; + } + + // Write the last byte. + out[*out_pos] = (uint8_t)(vli); + ++*out_pos; + ++*vli_pos; + + return vli_pos == &vli_pos_internal ? LZMA_OK : LZMA_STREAM_END; + +} |