/* * * Copyright 2015-2016, Google Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ #include "src/core/transport/chttp2/bin_encoder.h" #include #include "src/core/transport/chttp2/huffsyms.h" #include static const char alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; typedef struct { uint16_t bits; uint8_t length; } b64_huff_sym; static const b64_huff_sym huff_alphabet[64] = {{0x21, 6}, {0x5d, 7}, {0x5e, 7}, {0x5f, 7}, {0x60, 7}, {0x61, 7}, {0x62, 7}, {0x63, 7}, {0x64, 7}, {0x65, 7}, {0x66, 7}, {0x67, 7}, {0x68, 7}, {0x69, 7}, {0x6a, 7}, {0x6b, 7}, {0x6c, 7}, {0x6d, 7}, {0x6e, 7}, {0x6f, 7}, {0x70, 7}, {0x71, 7}, {0x72, 7}, {0xfc, 8}, {0x73, 7}, {0xfd, 8}, {0x3, 5}, {0x23, 6}, {0x4, 5}, {0x24, 6}, {0x5, 5}, {0x25, 6}, {0x26, 6}, {0x27, 6}, {0x6, 5}, {0x74, 7}, {0x75, 7}, {0x28, 6}, {0x29, 6}, {0x2a, 6}, {0x7, 5}, {0x2b, 6}, {0x76, 7}, {0x2c, 6}, {0x8, 5}, {0x9, 5}, {0x2d, 6}, {0x77, 7}, {0x78, 7}, {0x79, 7}, {0x7a, 7}, {0x7b, 7}, {0x0, 5}, {0x1, 5}, {0x2, 5}, {0x19, 6}, {0x1a, 6}, {0x1b, 6}, {0x1c, 6}, {0x1d, 6}, {0x1e, 6}, {0x1f, 6}, {0x7fb, 11}, {0x18, 6}}; static const uint8_t tail_xtra[3] = {0, 2, 3}; gpr_slice grpc_chttp2_base64_encode(gpr_slice input) { size_t input_length = GPR_SLICE_LENGTH(input); size_t input_triplets = input_length / 3; size_t tail_case = input_length % 3; size_t output_length = input_triplets * 4 + tail_xtra[tail_case]; gpr_slice output = gpr_slice_malloc(output_length); uint8_t *in = GPR_SLICE_START_PTR(input); char *out = (char *)GPR_SLICE_START_PTR(output); size_t i; /* encode full triplets */ for (i = 0; i < input_triplets; i++) { out[0] = alphabet[in[0] >> 2]; out[1] = alphabet[((in[0] & 0x3) << 4) | (in[1] >> 4)]; out[2] = alphabet[((in[1] & 0xf) << 2) | (in[2] >> 6)]; out[3] = alphabet[in[2] & 0x3f]; out += 4; in += 3; } /* encode the remaining bytes */ switch (tail_case) { case 0: break; case 1: out[0] = alphabet[in[0] >> 2]; out[1] = alphabet[(in[0] & 0x3) << 4]; out += 2; in += 1; break; case 2: out[0] = alphabet[in[0] >> 2]; out[1] = alphabet[((in[0] & 0x3) << 4) | (in[1] >> 4)]; out[2] = alphabet[(in[1] & 0xf) << 2]; out += 3; in += 2; break; } GPR_ASSERT(out == (char *)GPR_SLICE_END_PTR(output)); GPR_ASSERT(in == GPR_SLICE_END_PTR(input)); return output; } gpr_slice grpc_chttp2_huffman_compress(gpr_slice input) { size_t nbits; uint8_t *in; uint8_t *out; gpr_slice output; uint32_t temp = 0; uint32_t temp_length = 0; nbits = 0; for (in = GPR_SLICE_START_PTR(input); in != GPR_SLICE_END_PTR(input); ++in) { nbits += grpc_chttp2_huffsyms[*in].length; } output = gpr_slice_malloc(nbits / 8 + (nbits % 8 != 0)); out = GPR_SLICE_START_PTR(output); for (in = GPR_SLICE_START_PTR(input); in != GPR_SLICE_END_PTR(input); ++in) { int sym = *in; temp <<= grpc_chttp2_huffsyms[sym].length; temp |= grpc_chttp2_huffsyms[sym].bits; temp_length += grpc_chttp2_huffsyms[sym].length; while (temp_length > 8) { temp_length -= 8; *out++ = (uint8_t)(temp >> temp_length); } } if (temp_length) { /* NB: the following integer arithmetic operation needs to be in its * expanded form due to the "integral promotion" performed (see section * 3.2.1.1 of the C89 draft standard). A cast to the smaller container type * is then required to avoid the compiler warning */ *out++ = (uint8_t)((uint8_t)(temp << (8u - temp_length)) | (uint8_t)(0xffu >> temp_length)); } GPR_ASSERT(out == GPR_SLICE_END_PTR(output)); return output; } typedef struct { uint32_t temp; uint32_t temp_length; uint8_t *out; } huff_out; static void enc_flush_some(huff_out *out) { while (out->temp_length > 8) { out->temp_length -= 8; *out->out++ = (uint8_t)(out->temp >> out->temp_length); } } static void enc_add2(huff_out *out, uint8_t a, uint8_t b) { b64_huff_sym sa = huff_alphabet[a]; b64_huff_sym sb = huff_alphabet[b]; out->temp = (out->temp << (sa.length + sb.length)) | ((uint32_t)sa.bits << sb.length) | sb.bits; out->temp_length += (uint32_t)sa.length + (uint32_t)sb.length; enc_flush_some(out); } static void enc_add1(huff_out *out, uint8_t a) { b64_huff_sym sa = huff_alphabet[a]; out->temp = (out->temp << sa.length) | sa.bits; out->temp_length += sa.length; enc_flush_some(out); } gpr_slice grpc_chttp2_base64_encode_and_huffman_compress(gpr_slice input) { size_t input_length = GPR_SLICE_LENGTH(input); size_t input_triplets = input_length / 3; size_t tail_case = input_length % 3; size_t output_syms = input_triplets * 4 + tail_xtra[tail_case]; size_t max_output_bits = 11 * output_syms; size_t max_output_length = max_output_bits / 8 + (max_output_bits % 8 != 0); gpr_slice output = gpr_slice_malloc(max_output_length); uint8_t *in = GPR_SLICE_START_PTR(input); uint8_t *start_out = GPR_SLICE_START_PTR(output); huff_out out; size_t i; out.temp = 0; out.temp_length = 0; out.out = start_out; /* encode full triplets */ for (i = 0; i < input_triplets; i++) { enc_add2(&out, in[0] >> 2, (uint8_t)((in[0] & 0x3) << 4) | (in[1] >> 4)); enc_add2(&out, (uint8_t)((in[1] & 0xf) << 2) | (in[2] >> 6), (uint8_t)(in[2] & 0x3f)); in += 3; } /* encode the remaining bytes */ switch (tail_case) { case 0: break; case 1: enc_add2(&out, in[0] >> 2, (uint8_t)((in[0] & 0x3) << 4)); in += 1; break; case 2: enc_add2(&out, in[0] >> 2, (uint8_t)((in[0] & 0x3) << 4) | (uint8_t)(in[1] >> 4)); enc_add1(&out, (uint8_t)((in[1] & 0xf) << 2)); in += 2; break; } if (out.temp_length) { /* NB: the following integer arithmetic operation needs to be in its * expanded form due to the "integral promotion" performed (see section * 3.2.1.1 of the C89 draft standard). A cast to the smaller container type * is then required to avoid the compiler warning */ *out.out++ = (uint8_t)((uint8_t)(out.temp << (8u - out.temp_length)) | (uint8_t)(0xffu >> out.temp_length)); } GPR_ASSERT(out.out <= GPR_SLICE_END_PTR(output)); GPR_SLICE_SET_LENGTH(output, out.out - start_out); GPR_ASSERT(in == GPR_SLICE_END_PTR(input)); return output; }