msarett | e16b04a | 2015-04-15 07:32:19 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2015 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
| 8 | #include "SkCodecPriv.h" |
mtklein | 525e90a | 2015-06-18 09:58:57 -0700 | [diff] [blame] | 9 | #include "SkJpegUtility_codec.h" |
msarett | e16b04a | 2015-04-15 07:32:19 -0700 | [diff] [blame] | 10 | |
| 11 | /* |
| 12 | * Initialize the source manager |
| 13 | */ |
| 14 | static void sk_init_source(j_decompress_ptr dinfo) { |
| 15 | skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src; |
| 16 | src->next_input_byte = (const JOCTET*) src->fBuffer; |
| 17 | src->bytes_in_buffer = 0; |
| 18 | } |
| 19 | |
| 20 | /* |
| 21 | * Fill the input buffer from the stream |
| 22 | */ |
| 23 | static boolean sk_fill_input_buffer(j_decompress_ptr dinfo) { |
| 24 | skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src; |
| 25 | size_t bytes = src->fStream->read(src->fBuffer, skjpeg_source_mgr::kBufferSize); |
mtklein | 525e90a | 2015-06-18 09:58:57 -0700 | [diff] [blame] | 26 | |
msarett | e16b04a | 2015-04-15 07:32:19 -0700 | [diff] [blame] | 27 | // libjpeg is still happy with a less than full read, as long as the result is non-zero |
| 28 | if (bytes == 0) { |
| 29 | return false; |
| 30 | } |
| 31 | |
| 32 | src->next_input_byte = (const JOCTET*) src->fBuffer; |
| 33 | src->bytes_in_buffer = bytes; |
| 34 | return true; |
| 35 | } |
| 36 | |
| 37 | /* |
| 38 | * Skip a certain number of bytes in the stream |
| 39 | */ |
| 40 | static void sk_skip_input_data(j_decompress_ptr dinfo, long numBytes) { |
| 41 | skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src; |
| 42 | size_t bytes = (size_t) numBytes; |
| 43 | |
| 44 | if (bytes > src->bytes_in_buffer) { |
| 45 | size_t bytesToSkip = bytes - src->bytes_in_buffer; |
| 46 | if (bytesToSkip != src->fStream->skip(bytesToSkip)) { |
| 47 | SkCodecPrintf("Failure to skip.\n"); |
| 48 | dinfo->err->error_exit((j_common_ptr) dinfo); |
| 49 | return; |
| 50 | } |
| 51 | |
| 52 | src->next_input_byte = (const JOCTET*) src->fBuffer; |
| 53 | src->bytes_in_buffer = 0; |
| 54 | } else { |
| 55 | src->next_input_byte += numBytes; |
| 56 | src->bytes_in_buffer -= numBytes; |
| 57 | } |
| 58 | } |
| 59 | |
| 60 | /* |
| 61 | * We do not need to do anything to terminate our stream |
| 62 | */ |
| 63 | static void sk_term_source(j_decompress_ptr dinfo) |
| 64 | {} |
| 65 | |
| 66 | /* |
| 67 | * Constructor for the source manager that we provide to libjpeg |
| 68 | * We provide skia implementations of all of the stream processing functions required by libjpeg |
| 69 | */ |
| 70 | skjpeg_source_mgr::skjpeg_source_mgr(SkStream* stream) |
| 71 | : fStream(stream) |
| 72 | { |
| 73 | init_source = sk_init_source; |
| 74 | fill_input_buffer = sk_fill_input_buffer; |
| 75 | skip_input_data = sk_skip_input_data; |
msarett | aa2a7de | 2015-07-01 13:11:08 -0700 | [diff] [blame^] | 76 | resync_to_restart = jpeg_resync_to_restart; |
msarett | e16b04a | 2015-04-15 07:32:19 -0700 | [diff] [blame] | 77 | term_source = sk_term_source; |
| 78 | } |
| 79 | |
| 80 | /* |
| 81 | * Call longjmp to continue execution on an error |
| 82 | */ |
| 83 | void skjpeg_err_exit(j_common_ptr dinfo) { |
| 84 | // Simply return to Skia client code |
| 85 | // JpegDecoderMgr will take care of freeing memory |
| 86 | skjpeg_error_mgr* error = (skjpeg_error_mgr*) dinfo->err; |
| 87 | (*error->output_message) (dinfo); |
| 88 | longjmp(error->fJmpBuf, 1); |
| 89 | } |