--- /dev/null
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file index_encoder.c
+/// \brief Encodes the Index field
+//
+// Author: Lasse Collin
+//
+// This file has been put into the public domain.
+// You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "index_encoder.h"
+#include "index.h"
+#include "check.h"
+
+
+struct lzma_coder_s {
+ enum {
+ SEQ_INDICATOR,
+ SEQ_COUNT,
+ SEQ_UNPADDED,
+ SEQ_UNCOMPRESSED,
+ SEQ_NEXT,
+ SEQ_PADDING,
+ SEQ_CRC32,
+ } sequence;
+
+ /// Index being encoded
+ const lzma_index *index;
+
+ /// Iterator for the Index being encoded
+ lzma_index_iter iter;
+
+ /// Position in integers
+ size_t pos;
+
+ /// CRC32 of the List of Records field
+ uint32_t crc32;
+};
+
+
+static lzma_ret
+index_encode(lzma_coder *coder,
+ const lzma_allocator *allocator lzma_attribute((__unused__)),
+ const uint8_t *restrict in lzma_attribute((__unused__)),
+ size_t *restrict in_pos lzma_attribute((__unused__)),
+ size_t in_size lzma_attribute((__unused__)),
+ uint8_t *restrict out, size_t *restrict out_pos,
+ size_t out_size,
+ lzma_action action lzma_attribute((__unused__)))
+{
+ // Position where to start calculating CRC32. The idea is that we
+ // need to call lzma_crc32() only once per call to index_encode().
+ const size_t out_start = *out_pos;
+
+ // Return value to use if we return at the end of this function.
+ // We use "goto out" to jump out of the while-switch construct
+ // instead of returning directly, because that way we don't need
+ // to copypaste the lzma_crc32() call to many places.
+ lzma_ret ret = LZMA_OK;
+
+ while (*out_pos < out_size)
+ switch (coder->sequence) {
+ case SEQ_INDICATOR:
+ out[*out_pos] = 0x00;
+ ++*out_pos;
+ coder->sequence = SEQ_COUNT;
+ break;
+
+ case SEQ_COUNT: {
+ const lzma_vli count = lzma_index_block_count(coder->index);
+ ret = lzma_vli_encode(count, &coder->pos,
+ out, out_pos, out_size);
+ if (ret != LZMA_STREAM_END)
+ goto out;
+
+ ret = LZMA_OK;
+ coder->pos = 0;
+ coder->sequence = SEQ_NEXT;
+ break;
+ }
+
+ case SEQ_NEXT:
+ if (lzma_index_iter_next(
+ &coder->iter, LZMA_INDEX_ITER_BLOCK)) {
+ // Get the size of the Index Padding field.
+ coder->pos = lzma_index_padding_size(coder->index);
+ assert(coder->pos <= 3);
+ coder->sequence = SEQ_PADDING;
+ break;
+ }
+
+ coder->sequence = SEQ_UNPADDED;
+
+ // Fall through
+
+ case SEQ_UNPADDED:
+ case SEQ_UNCOMPRESSED: {
+ const lzma_vli size = coder->sequence == SEQ_UNPADDED
+ ? coder->iter.block.unpadded_size
+ : coder->iter.block.uncompressed_size;
+
+ ret = lzma_vli_encode(size, &coder->pos,
+ out, out_pos, out_size);
+ if (ret != LZMA_STREAM_END)
+ goto out;
+
+ ret = LZMA_OK;
+ coder->pos = 0;
+
+ // Advance to SEQ_UNCOMPRESSED or SEQ_NEXT.
+ ++coder->sequence;
+ break;
+ }
+
+ case SEQ_PADDING:
+ if (coder->pos > 0) {
+ --coder->pos;
+ out[(*out_pos)++] = 0x00;
+ break;
+ }
+
+ // Finish the CRC32 calculation.
+ coder->crc32 = lzma_crc32(out + out_start,
+ *out_pos - out_start, coder->crc32);
+
+ coder->sequence = SEQ_CRC32;
+
+ // Fall through
+
+ case SEQ_CRC32:
+ // We don't use the main loop, because we don't want
+ // coder->crc32 to be touched anymore.
+ do {
+ if (*out_pos == out_size)
+ return LZMA_OK;
+
+ out[*out_pos] = (coder->crc32 >> (coder->pos * 8))
+ & 0xFF;
+ ++*out_pos;
+
+ } while (++coder->pos < 4);
+
+ return LZMA_STREAM_END;
+
+ default:
+ assert(0);
+ return LZMA_PROG_ERROR;
+ }
+
+out:
+ // Update the CRC32.
+ coder->crc32 = lzma_crc32(out + out_start,
+ *out_pos - out_start, coder->crc32);
+
+ return ret;
+}
+
+
+static void
+index_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
+{
+ lzma_free(coder, allocator);
+ return;
+}
+
+
+static void
+index_encoder_reset(lzma_coder *coder, const lzma_index *i)
+{
+ lzma_index_iter_init(&coder->iter, i);
+
+ coder->sequence = SEQ_INDICATOR;
+ coder->index = i;
+ coder->pos = 0;
+ coder->crc32 = 0;
+
+ return;
+}
+
+
+extern lzma_ret
+lzma_index_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
+ const lzma_index *i)
+{
+ lzma_next_coder_init(&lzma_index_encoder_init, next, allocator);
+
+ if (i == NULL)
+ return LZMA_PROG_ERROR;
+
+ if (next->coder == NULL) {
+ next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
+ if (next->coder == NULL)
+ return LZMA_MEM_ERROR;
+
+ next->code = &index_encode;
+ next->end = &index_encoder_end;
+ }
+
+ index_encoder_reset(next->coder, i);
+
+ return LZMA_OK;
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_index_encoder(lzma_stream *strm, const lzma_index *i)
+{
+ lzma_next_strm_init(lzma_index_encoder_init, strm, i);
+
+ strm->internal->supported_actions[LZMA_RUN] = true;
+ strm->internal->supported_actions[LZMA_FINISH] = true;
+
+ return LZMA_OK;
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_index_buffer_encode(const lzma_index *i,
+ uint8_t *out, size_t *out_pos, size_t out_size)
+{
+ // Validate the arguments.
+ if (i == NULL || out == NULL || out_pos == NULL || *out_pos > out_size)
+ return LZMA_PROG_ERROR;
+
+ // Don't try to encode if there's not enough output space.
+ if (out_size - *out_pos < lzma_index_size(i))
+ return LZMA_BUF_ERROR;
+
+ // The Index encoder needs just one small data structure so we can
+ // allocate it on stack.
+ lzma_coder coder;
+ index_encoder_reset(&coder, i);
+
+ // Do the actual encoding. This should never fail, but store
+ // the original *out_pos just in case.
+ const size_t out_start = *out_pos;
+ lzma_ret ret = index_encode(&coder, NULL, NULL, NULL, 0,
+ out, out_pos, out_size, LZMA_RUN);
+
+ if (ret == LZMA_STREAM_END) {
+ ret = LZMA_OK;
+ } else {
+ // We should never get here, but just in case, restore the
+ // output position and set the error accordingly if something
+ // goes wrong and debugging isn't enabled.
+ assert(0);
+ *out_pos = out_start;
+ ret = LZMA_PROG_ERROR;
+ }
+
+ return ret;
+}
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