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996
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1 /*
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2 The Sceql specification is not set in stone, so this
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3 interpreter may change in the future. Version 0.1 of the specification
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4 is implemented here.
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5 */
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6
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7 #include <stdio.h>
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8 #include <stdlib.h>
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9 #include <limits.h>
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10
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11 #define NODESIZE 1000
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12 #define LOOPDEPTH 1000
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13
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14 typedef unsigned char byte;
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15
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16 typedef struct byteqnode
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17 {
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18 byte qdata[NODESIZE];
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19 int start; /* the first byte in use in qdata */
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20 int end; /* the last byte in use in qdata */
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21 struct byteqnode *next;
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22 } byteqnode;
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23
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24 typedef struct
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25 {
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26 int len;
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27 byteqnode *head, *tail;
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28 } bytequeue;
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29
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30 void error(char *complaint)
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31 {
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32 fprintf(stderr, "%s\n", complaint);
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33 exit(1);
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34 }
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35
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36 /* create a queue with a zero byte in it */
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37 bytequeue *queue_create(void)
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38 {
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39 bytequeue *myq;
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40 myq = malloc(sizeof (bytequeue));
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41 if (!myq)
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42 error("Out of memory");
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43 myq->len = 1;
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44 myq->head = myq->tail = malloc(sizeof (byteqnode));
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45 if (!myq->head)
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46 error("Out of memory");
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47 myq->tail->next = NULL;
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48 myq->tail->start = myq->tail->end = 0;
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49 myq->tail->qdata[0] = 0;
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50 return myq;
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51 }
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52
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53 /* add a byte onto the back of the queue */
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54 void queue_enqueue(bytequeue *q, byte val)
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55 {
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56 byteqnode *node;
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57 node = q->tail;
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58 node->end++;
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59 if (node->end == NODESIZE)
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60 {
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61 node = q->tail = node->next = malloc(sizeof (byteqnode));
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62 if (!node)
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63 error("Out of memory");
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64 node->next = NULL;
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65 node->start = node->end = 0;
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66 }
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67 node->qdata[node->end] = val;
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68 q->len++;
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69 }
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70
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71 byte queue_peek(bytequeue *q);
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72
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73 /* take a byte from the front of the queue */
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74 byte queue_dequeue(bytequeue *q)
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75 {
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76 byte result;
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77
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78 result = queue_peek(q);
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79
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80 q->head->start++;
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81 if (q->head->start == NODESIZE)
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82 {
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83 byteqnode *node = q->head->next;
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84 free(q->head);
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85 q->head = node;
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86 /* q->head->start should already be 0 */
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87 }
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88 q->len--;
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89 return result;
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90 }
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91
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92 /* peek at a byte from the front of the queue */
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93 byte queue_peek(bytequeue *q)
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94 {
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95 if (q->len == 0)
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96 error("peeking at an empty queue");
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97 return q->head->qdata[q->head->start];
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98 }
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99
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100 /* shove a new byte at the front of the queue replacing what's there */
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101 void queue_shove(bytequeue *q, byte b)
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102 {
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103 if (q->len == 0)
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104 error("shoving into an empty queue");
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105 q->head->qdata[q->head->start] = b;
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106 }
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107
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108 void queue_delete(bytequeue *q)
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109 {
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110 byteqnode *node;
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111 while (q->head)
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112 {
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113 node = q->head->next;
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114 free(q->head);
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115 q->head = node;
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116 }
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117 free(q);
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118 }
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119
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120 #ifdef DEBUGGING
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121 void queue_debug(bytequeue *q)
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122 {
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123 int i;
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124 i = q->len;
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125 if (i > 0)
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126 {
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127 byte b;
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128 b = queue_dequeue(q);
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129 printf("%d", b);
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130 queue_enqueue(q, b);
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131 }
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132 for (i--; i > 0; i--)
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133 {
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134 byte b;
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135 b = queue_dequeue(q);
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136 printf(", %d", b);
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137 queue_enqueue(q, b);
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138 }
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139 putchar('\n');
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140 }
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141 #endif
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142
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143 typedef enum
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144 {
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145 IN_NEXT = 0x01,
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146 IN_DEC = 0x02,
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147 IN_INPUT = 0x03,
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148 IN_OUTPUT = 0x04,
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149 IN_INC = 0x05,
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150 IN_GROW = 0x06,
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151 IN_BEGIN = 0x10,
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152 IN_END = 0x11
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153 #ifdef DEBUGGING
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154 ,IN_DEBUG = 0xff
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155 #endif
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156 } sceql_intype;
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157
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158 typedef struct
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159 {
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160 sceql_intype in;
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161 int r;
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162 } sceql_instruction;
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163
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164 typedef struct
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165 {
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166 sceql_instruction *code;
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167 int len;
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168 } sceql_program;
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169
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170 sceql_intype sceql_getinstruction(FILE *f)
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171 {
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172 static sceql_intype uc2i[UCHAR_MAX + 1] = { IN_BEGIN };
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173 int c;
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174 sceql_intype i;
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175 if (uc2i[0] == IN_BEGIN)
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176 {
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177 uc2i[0] = 0;
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178 for (c = 1; c <= (int) UCHAR_MAX; c++)
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179 {
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180 i = 0;
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181 if (c == '\\')
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182 i = IN_BEGIN;
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183 else if (c == '/')
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184 i = IN_END;
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185 else if (c == '=')
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186 i = IN_NEXT;
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187 else if (c == '-')
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188 i = IN_DEC;
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189 else if (c == '_')
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190 i = IN_INC;
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191 else if (c == '!')
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192 i = IN_GROW;
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193 else if (c == '&')
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194 i = IN_INPUT;
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195 else if (c == '*')
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196 i = IN_OUTPUT;
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197 #ifdef DEBUGGING
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198 else if (c == '`')
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199 i = IN_DEBUG;
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200 #endif
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201 uc2i[c] = i;
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202 }
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203 }
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204 for (;;)
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205 {
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206 c = fgetc(f);
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207 if (c < 0 || c > 255)
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208 return 0;
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209 if ((i = uc2i[c]))
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210 break;
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211 }
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212 return i;
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213 }
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214
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215 void sceql_load(sceql_program *p, FILE *f)
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216 {
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217 sceql_instruction *code;
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218 sceql_intype in;
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219 unsigned long filesize;
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220 int last = 0, depth = 0, begin[LOOPDEPTH];
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221
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222 fseek(f, 0, SEEK_END);
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223 filesize = ftell(f);
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224 if (filesize > INT_MAX)
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225 error("File too long");
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226 fseek(f, 0, SEEK_SET);
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227
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228 code = p->code = malloc(filesize * sizeof (sceql_instruction));
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229 if (!code)
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230 error("Not enough memory");
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231
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232 if (!(in = sceql_getinstruction(f)))
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233 error("Program contains no instructions");
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234 if (in == IN_END)
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235 error("Unbalanced slashes");
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236 if (in == IN_BEGIN)
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237 begin[depth++] = 0;
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238 code[0].in = in;
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239 code[0].r = 1;
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240
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241 while ((in = sceql_getinstruction(f)))
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242 {
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243 if (in == IN_BEGIN)
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244 {
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245 last++;
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246 if (depth < LOOPDEPTH)
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247 begin[depth] = last;
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248 depth++;
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249 }
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250 else if (in == IN_END && depth <= LOOPDEPTH)
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251 {
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252 if (!depth)
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253 error("Unbalanced slashes");
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254 last++;
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255 code[last].r = last - begin[--depth];
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256 code[begin[depth]].r = code[last].r + 1;
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257 }
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258 else if (in == IN_END)
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259 {
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260 int mydepth = depth, start;
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261 for (start = last++; start >= 0; start--)
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262 {
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263 if (code[start].in == IN_BEGIN)
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264 {
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265 if (mydepth == depth)
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266 break;
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267 mydepth--;
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268 }
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269 else if (code[start].in == IN_END)
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270 mydepth++;
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271 }
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272 code[last].r = last - start;
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273 code[start].r = code[last].r + 1;
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274 depth--;
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275 }
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276 else
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277 {
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278 if (in == code[last].in)
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279 {
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280 code[last].r++;
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281 continue;
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282 }
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283 code[++last].r = 1;
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284 }
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285 code[last].in = in;
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286 }
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287 fclose(f);
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288 if (depth)
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289 error("Unbalanced slashes");
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290 p->len = last + 1;
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291 }
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292
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293 void sceql_run(sceql_program *p)
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294 {
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295 bytequeue *q;
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296 sceql_instruction *ip, *end;
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297
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298 ip = p->code;
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299 end = ip + p->len;
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300
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301 q = queue_create();
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302
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303 do
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304 {
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305 register sceql_intype in;
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306 register int r;
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307
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308 in = ip->in;
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309 r = ip->r;
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310
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311 /* run the instruction "in": not just once, but "r" times */
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312
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313 if (in == IN_NEXT)
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314 {
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315 register byte b;
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316 for (; r; r--)
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317 {
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318 b = queue_dequeue(q);
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319 queue_enqueue(q, b);
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320 }
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321 }
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322
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323 /* it just so happens that we can increment or decrement
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324 r times with a one-liner */
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325 else if (in == IN_INC)
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326 queue_shove(q, queue_peek(q) + r);
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327 else if (in == IN_DEC)
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328 queue_shove(q, queue_peek(q) - r);
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329
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330 else if (in == IN_GROW)
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331 {
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332 for (; r; r--)
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333 queue_enqueue(q, 0);
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334 }
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335 else if (in == IN_OUTPUT)
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336 {
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337 register int c;
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338 for (; r; r--)
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339 {
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340 c = queue_dequeue(q);
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341 putchar(c);
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342 queue_enqueue(q, c);
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343 }
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344 }
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345 else if (in == IN_INPUT)
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346 {
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347 register int c;
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348 for (; r; r--)
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349 {
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350 c = getchar();
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351 if (c == EOF)
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352 c = 0;
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353 queue_enqueue(q, c);
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354 }
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355 }
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356 else if (in == IN_BEGIN)
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357 {
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358 register byte b;
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359 if (!(b = queue_peek(q)))
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360 {
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361 ip += r;
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362 continue;
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363 }
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364 }
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365 #ifdef DEBUGGING
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366 else if (in == IN_DEBUG)
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367 queue_debug(q);
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368 #endif
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369 else /* in == IN_END */
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370 {
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371 ip -= r;
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372 continue;
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373 }
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374 ip++;
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375 } while (ip < end);
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376
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377 queue_delete(q);
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378 }
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379
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380 void sceql_freeup(sceql_program *p)
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381 {
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382 free(p->code);
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383 }
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384
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385 void sceql_do(FILE *f)
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386 {
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387 sceql_program prog;
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388 sceql_load(&prog, f);
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389 sceql_run(&prog);
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390 sceql_freeup(&prog);
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391 }
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392
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393 int main(int argc, char *argv[])
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394 {
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395 FILE *codesrc = stdin;
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396 if (argc != 2)
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397 error("usage: sceql [sourcefile.sceql]");
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398 if (!(codesrc = fopen(argv[1], "r")))
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399 {
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400 error("Unable to open file");
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401 }
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402 sceql_do(codesrc);
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403 return 0;
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404 }
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