1 /////////////////////////////////////////////////////////////////////////////// 2 // 3 /// \file stream_buffer_encoder.c 4 /// \brief Single-call .xz Stream encoder 5 // 6 // Author: Lasse Collin 7 // 8 // This file has been put into the public domain. 9 // You can do whatever you want with this file. 10 // 11 /////////////////////////////////////////////////////////////////////////////// 12 13 #include "common.h" 14 #include "index.h" 15 16 17 /// Maximum size of Index that has exactly one Record. 18 /// Index Indicator + Number of Records + Record + CRC32 rounded up to 19 /// the next multiple of four. 20 #define INDEX_BOUND ((1 + 1 + 2 * LZMA_VLI_BYTES_MAX + 4 + 3) & ~3) 21 22 /// Stream Header, Stream Footer, and Index 23 #define HEADERS_BOUND (2 * LZMA_STREAM_HEADER_SIZE + INDEX_BOUND) 24 25 26 extern LZMA_API(size_t) 27 lzma_stream_buffer_bound(size_t uncompressed_size) 28 { 29 // Get the maximum possible size of a Block. 30 const size_t block_bound = lzma_block_buffer_bound(uncompressed_size); 31 if (block_bound == 0) 32 return 0; 33 34 // Catch the possible integer overflow and also prevent the size of 35 // the Stream exceeding LZMA_VLI_MAX (theoretically possible on 36 // 64-bit systems). 37 if (my_min(SIZE_MAX, LZMA_VLI_MAX) - block_bound < HEADERS_BOUND) 38 return 0; 39 40 return block_bound + HEADERS_BOUND; 41 } 42 43 44 extern LZMA_API(lzma_ret) 45 lzma_stream_buffer_encode(lzma_filter *filters, lzma_check check, 46 const lzma_allocator *allocator, 47 const uint8_t *in, size_t in_size, 48 uint8_t *out, size_t *out_pos_ptr, size_t out_size) 49 { 50 // Sanity checks 51 if (filters == NULL || (unsigned int)(check) > LZMA_CHECK_ID_MAX 52 || (in == NULL && in_size != 0) || out == NULL 53 || out_pos_ptr == NULL || *out_pos_ptr > out_size) 54 return LZMA_PROG_ERROR; 55 56 if (!lzma_check_is_supported(check)) 57 return LZMA_UNSUPPORTED_CHECK; 58 59 // Note for the paranoids: Index encoder prevents the Stream from 60 // getting too big and still being accepted with LZMA_OK, and Block 61 // encoder catches if the input is too big. So we don't need to 62 // separately check if the buffers are too big. 63 64 // Use a local copy. We update *out_pos_ptr only if everything 65 // succeeds. 66 size_t out_pos = *out_pos_ptr; 67 68 // Check that there's enough space for both Stream Header and 69 // Stream Footer. 70 if (out_size - out_pos <= 2 * LZMA_STREAM_HEADER_SIZE) 71 return LZMA_BUF_ERROR; 72 73 // Reserve space for Stream Footer so we don't need to check for 74 // available space again before encoding Stream Footer. 75 out_size -= LZMA_STREAM_HEADER_SIZE; 76 77 // Encode the Stream Header. 78 lzma_stream_flags stream_flags = { 79 .version = 0, 80 .check = check, 81 }; 82 83 if (lzma_stream_header_encode(&stream_flags, out + out_pos) 84 != LZMA_OK) 85 return LZMA_PROG_ERROR; 86 87 out_pos += LZMA_STREAM_HEADER_SIZE; 88 89 // Encode a Block but only if there is at least one byte of input. 90 lzma_block block = { 91 .version = 0, 92 .check = check, 93 .filters = filters, 94 }; 95 96 if (in_size > 0) 97 return_if_error(lzma_block_buffer_encode(&block, allocator, 98 in, in_size, out, &out_pos, out_size)); 99 100 // Index 101 { 102 // Create an Index. It will have one Record if there was 103 // at least one byte of input to encode. Otherwise the 104 // Index will be empty. 105 lzma_index *i = lzma_index_init(allocator); 106 if (i == NULL) 107 return LZMA_MEM_ERROR; 108 109 lzma_ret ret = LZMA_OK; 110 111 if (in_size > 0) 112 ret = lzma_index_append(i, allocator, 113 lzma_block_unpadded_size(&block), 114 block.uncompressed_size); 115 116 // If adding the Record was successful, encode the Index 117 // and get its size which will be stored into Stream Footer. 118 if (ret == LZMA_OK) { 119 ret = lzma_index_buffer_encode( 120 i, out, &out_pos, out_size); 121 122 stream_flags.backward_size = lzma_index_size(i); 123 } 124 125 lzma_index_end(i, allocator); 126 127 if (ret != LZMA_OK) 128 return ret; 129 } 130 131 // Stream Footer. We have already reserved space for this. 132 if (lzma_stream_footer_encode(&stream_flags, out + out_pos) 133 != LZMA_OK) 134 return LZMA_PROG_ERROR; 135 136 out_pos += LZMA_STREAM_HEADER_SIZE; 137 138 // Everything went fine, make the new output position available 139 // to the application. 140 *out_pos_ptr = out_pos; 141 return LZMA_OK; 142 } 143