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1 /* |
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2 * jcmainct.c |
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3 * |
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4 * Copyright (C) 1994-1996, Thomas G. Lane. |
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5 * This file is part of the Independent JPEG Group's software. |
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6 * For conditions of distribution and use, see the accompanying README file. |
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7 * |
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8 * This file contains the main buffer controller for compression. |
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9 * The main buffer lies between the pre-processor and the JPEG |
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10 * compressor proper; it holds downsampled data in the JPEG colorspace. |
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11 */ |
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12 |
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13 #define JPEG_INTERNALS |
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14 #include "jinclude.h" |
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15 #include "jpeglib.h" |
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16 |
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17 |
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18 /* Note: currently, there is no operating mode in which a full-image buffer |
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19 * is needed at this step. If there were, that mode could not be used with |
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20 * "raw data" input, since this module is bypassed in that case. However, |
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21 * we've left the code here for possible use in special applications. |
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22 */ |
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23 #undef FULL_MAIN_BUFFER_SUPPORTED |
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24 |
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25 |
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26 /* Private buffer controller object */ |
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27 |
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28 typedef struct { |
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29 struct jpeg_c_main_controller pub; /* public fields */ |
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30 |
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31 JDIMENSION cur_iMCU_row; /* number of current iMCU row */ |
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32 JDIMENSION rowgroup_ctr; /* counts row groups received in iMCU row */ |
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33 boolean suspended; /* remember if we suspended output */ |
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34 J_BUF_MODE pass_mode; /* current operating mode */ |
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35 |
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36 /* If using just a strip buffer, this points to the entire set of buffers |
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37 * (we allocate one for each component). In the full-image case, this |
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38 * points to the currently accessible strips of the virtual arrays. |
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39 */ |
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40 JSAMPARRAY buffer[MAX_COMPONENTS]; |
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41 |
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42 #ifdef FULL_MAIN_BUFFER_SUPPORTED |
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43 /* If using full-image storage, this array holds pointers to virtual-array |
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44 * control blocks for each component. Unused if not full-image storage. |
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45 */ |
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46 jvirt_sarray_ptr whole_image[MAX_COMPONENTS]; |
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47 #endif |
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48 } my_main_controller; |
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49 |
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50 typedef my_main_controller * my_main_ptr; |
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51 |
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52 |
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53 /* Forward declarations */ |
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54 METHODDEF(void) process_data_simple_main |
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55 JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf, |
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56 JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail)); |
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57 #ifdef FULL_MAIN_BUFFER_SUPPORTED |
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58 METHODDEF(void) process_data_buffer_main |
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59 JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf, |
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60 JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail)); |
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61 #endif |
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62 |
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63 |
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64 /* |
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65 * Initialize for a processing pass. |
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66 */ |
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67 |
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68 METHODDEF(void) |
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69 start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode) |
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70 { |
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71 my_main_ptr main = (my_main_ptr) cinfo->main; |
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72 |
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73 /* Do nothing in raw-data mode. */ |
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74 if (cinfo->raw_data_in) |
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75 return; |
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76 |
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77 main->cur_iMCU_row = 0; /* initialize counters */ |
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78 main->rowgroup_ctr = 0; |
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79 main->suspended = FALSE; |
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80 main->pass_mode = pass_mode; /* save mode for use by process_data */ |
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81 |
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82 switch (pass_mode) { |
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83 case JBUF_PASS_THRU: |
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84 #ifdef FULL_MAIN_BUFFER_SUPPORTED |
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85 if (main->whole_image[0] != NULL) |
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86 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
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87 #endif |
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88 main->pub.process_data = process_data_simple_main; |
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89 break; |
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90 #ifdef FULL_MAIN_BUFFER_SUPPORTED |
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91 case JBUF_SAVE_SOURCE: |
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92 case JBUF_CRANK_DEST: |
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93 case JBUF_SAVE_AND_PASS: |
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94 if (main->whole_image[0] == NULL) |
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95 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
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96 main->pub.process_data = process_data_buffer_main; |
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97 break; |
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98 #endif |
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99 default: |
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100 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
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101 break; |
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102 } |
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103 } |
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104 |
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105 |
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106 /* |
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107 * Process some data. |
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108 * This routine handles the simple pass-through mode, |
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109 * where we have only a strip buffer. |
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110 */ |
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111 |
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112 METHODDEF(void) |
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113 process_data_simple_main (j_compress_ptr cinfo, |
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114 JSAMPARRAY input_buf, JDIMENSION *in_row_ctr, |
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115 JDIMENSION in_rows_avail) |
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116 { |
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117 my_main_ptr main = (my_main_ptr) cinfo->main; |
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118 |
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119 while (main->cur_iMCU_row < cinfo->total_iMCU_rows) { |
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120 /* Read input data if we haven't filled the main buffer yet */ |
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121 if (main->rowgroup_ctr < DCTSIZE) |
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122 (*cinfo->prep->pre_process_data) (cinfo, |
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123 input_buf, in_row_ctr, in_rows_avail, |
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124 main->buffer, &main->rowgroup_ctr, |
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125 (JDIMENSION) DCTSIZE); |
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126 |
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127 /* If we don't have a full iMCU row buffered, return to application for |
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128 * more data. Note that preprocessor will always pad to fill the iMCU row |
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129 * at the bottom of the image. |
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130 */ |
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131 if (main->rowgroup_ctr != DCTSIZE) |
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132 return; |
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133 |
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134 /* Send the completed row to the compressor */ |
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135 if (! (*cinfo->coef->compress_data) (cinfo, main->buffer)) { |
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136 /* If compressor did not consume the whole row, then we must need to |
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137 * suspend processing and return to the application. In this situation |
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138 * we pretend we didn't yet consume the last input row; otherwise, if |
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139 * it happened to be the last row of the image, the application would |
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140 * think we were done. |
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141 */ |
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142 if (! main->suspended) { |
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143 (*in_row_ctr)--; |
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144 main->suspended = TRUE; |
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145 } |
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146 return; |
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147 } |
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148 /* We did finish the row. Undo our little suspension hack if a previous |
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149 * call suspended; then mark the main buffer empty. |
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150 */ |
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151 if (main->suspended) { |
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152 (*in_row_ctr)++; |
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153 main->suspended = FALSE; |
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154 } |
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155 main->rowgroup_ctr = 0; |
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156 main->cur_iMCU_row++; |
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157 } |
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158 } |
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159 |
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160 |
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161 #ifdef FULL_MAIN_BUFFER_SUPPORTED |
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162 |
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163 /* |
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164 * Process some data. |
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165 * This routine handles all of the modes that use a full-size buffer. |
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166 */ |
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167 |
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168 METHODDEF(void) |
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169 process_data_buffer_main (j_compress_ptr cinfo, |
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170 JSAMPARRAY input_buf, JDIMENSION *in_row_ctr, |
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171 JDIMENSION in_rows_avail) |
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172 { |
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173 my_main_ptr main = (my_main_ptr) cinfo->main; |
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174 int ci; |
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175 jpeg_component_info *compptr; |
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176 boolean writing = (main->pass_mode != JBUF_CRANK_DEST); |
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177 |
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178 while (main->cur_iMCU_row < cinfo->total_iMCU_rows) { |
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179 /* Realign the virtual buffers if at the start of an iMCU row. */ |
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180 if (main->rowgroup_ctr == 0) { |
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181 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
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182 ci++, compptr++) { |
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183 main->buffer[ci] = (*cinfo->mem->access_virt_sarray) |
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184 ((j_common_ptr) cinfo, main->whole_image[ci], |
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185 main->cur_iMCU_row * (compptr->v_samp_factor * DCTSIZE), |
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186 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE), writing); |
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187 } |
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188 /* In a read pass, pretend we just read some source data. */ |
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189 if (! writing) { |
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190 *in_row_ctr += cinfo->max_v_samp_factor * DCTSIZE; |
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191 main->rowgroup_ctr = DCTSIZE; |
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192 } |
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193 } |
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194 |
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195 /* If a write pass, read input data until the current iMCU row is full. */ |
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196 /* Note: preprocessor will pad if necessary to fill the last iMCU row. */ |
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197 if (writing) { |
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198 (*cinfo->prep->pre_process_data) (cinfo, |
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199 input_buf, in_row_ctr, in_rows_avail, |
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200 main->buffer, &main->rowgroup_ctr, |
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201 (JDIMENSION) DCTSIZE); |
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202 /* Return to application if we need more data to fill the iMCU row. */ |
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203 if (main->rowgroup_ctr < DCTSIZE) |
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204 return; |
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205 } |
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206 |
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207 /* Emit data, unless this is a sink-only pass. */ |
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208 if (main->pass_mode != JBUF_SAVE_SOURCE) { |
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209 if (! (*cinfo->coef->compress_data) (cinfo, main->buffer)) { |
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210 /* If compressor did not consume the whole row, then we must need to |
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211 * suspend processing and return to the application. In this situation |
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212 * we pretend we didn't yet consume the last input row; otherwise, if |
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213 * it happened to be the last row of the image, the application would |
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214 * think we were done. |
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215 */ |
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216 if (! main->suspended) { |
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217 (*in_row_ctr)--; |
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218 main->suspended = TRUE; |
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219 } |
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220 return; |
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221 } |
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222 /* We did finish the row. Undo our little suspension hack if a previous |
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223 * call suspended; then mark the main buffer empty. |
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224 */ |
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225 if (main->suspended) { |
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226 (*in_row_ctr)++; |
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227 main->suspended = FALSE; |
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228 } |
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229 } |
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230 |
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231 /* If get here, we are done with this iMCU row. Mark buffer empty. */ |
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232 main->rowgroup_ctr = 0; |
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233 main->cur_iMCU_row++; |
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234 } |
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235 } |
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236 |
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237 #endif /* FULL_MAIN_BUFFER_SUPPORTED */ |
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238 |
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239 |
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240 /* |
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241 * Initialize main buffer controller. |
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242 */ |
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243 |
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244 GLOBAL(void) |
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245 jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer) |
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246 { |
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247 my_main_ptr main; |
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248 int ci; |
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249 jpeg_component_info *compptr; |
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250 |
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251 main = (my_main_ptr) |
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252 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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253 SIZEOF(my_main_controller)); |
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254 cinfo->main = (struct jpeg_c_main_controller *) main; |
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255 main->pub.start_pass = start_pass_main; |
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256 |
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257 /* We don't need to create a buffer in raw-data mode. */ |
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258 if (cinfo->raw_data_in) |
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259 return; |
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260 |
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261 /* Create the buffer. It holds downsampled data, so each component |
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262 * may be of a different size. |
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263 */ |
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264 if (need_full_buffer) { |
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265 #ifdef FULL_MAIN_BUFFER_SUPPORTED |
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266 /* Allocate a full-image virtual array for each component */ |
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267 /* Note we pad the bottom to a multiple of the iMCU height */ |
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268 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
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269 ci++, compptr++) { |
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270 main->whole_image[ci] = (*cinfo->mem->request_virt_sarray) |
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271 ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE, |
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272 compptr->width_in_blocks * DCTSIZE, |
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273 (JDIMENSION) jround_up((long) compptr->height_in_blocks, |
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274 (long) compptr->v_samp_factor) * DCTSIZE, |
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275 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE)); |
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276 } |
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277 #else |
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278 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
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279 #endif |
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280 } else { |
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281 #ifdef FULL_MAIN_BUFFER_SUPPORTED |
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282 main->whole_image[0] = NULL; /* flag for no virtual arrays */ |
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283 #endif |
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284 /* Allocate a strip buffer for each component */ |
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285 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
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286 ci++, compptr++) { |
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287 main->buffer[ci] = (*cinfo->mem->alloc_sarray) |
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288 ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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289 compptr->width_in_blocks * DCTSIZE, |
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290 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE)); |
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291 } |
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292 } |
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293 } |