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#include "all.h"
#include "str.h"
static void emit_includes(str *out) {
str_append(out, "#include <stdio.h>\n");
str_append(out, "#include <stdlib.h>\n");
str_append(out, "#include <string.h>\n\n");
}
static void emit_runtime(str *out) {
str_append(
out,
"typedef struct {\n"
" unsigned char *data;\n"
" size_t size;\n"
"} tape_t;\n\n"
"static void tape_init(tape_t *t, size_t initial) {\n"
" t->data = calloc(initial, 1);\n"
" t->size = initial;\n"
"}\n\n"
"static void tape_grow_right(tape_t *t, size_t needed) {\n"
" size_t new_size = t->size;\n"
" while (new_size <= needed) new_size *= 2;\n"
" unsigned char *new_data = calloc(new_size, 1);\n"
" memcpy(new_data, t->data, t->size);\n"
" free(t->data);\n"
" t->data = new_data;\n"
" t->size = new_size;\n"
"}\n\n"
"static void tape_grow_left(tape_t *t, size_t add, size_t *ptr) {\n"
" size_t new_size = t->size + add;\n"
" unsigned char *new_data = calloc(new_size, 1);\n"
" memcpy(new_data + add, t->data, t->size);\n"
" free(t->data);\n"
" t->data = new_data;\n"
" t->size = new_size;\n"
" *ptr += add;\n"
"}\n\n"
"static void tape_move_right(tape_t *t, size_t *ptr, size_t amount) {\n"
" *ptr += amount;\n"
" if (*ptr >= t->size)\n"
" tape_grow_right(t, *ptr);\n"
"}\n\n"
"static void tape_move_left(tape_t *t, size_t *ptr, size_t amount) {\n"
" if (amount > *ptr) {\n"
" size_t need = amount - *ptr;\n"
" size_t add = t->size;\n"
" while (add <= need)\n"
" add *= 2;\n"
" tape_grow_left(t, add, ptr);\n"
" }\n"
" *ptr -= amount;\n"
"}\n\n");
}
static void emit_prelude(str *out) {
str_append(out, "int main(void)\n"
"{\n"
" tape_t tape;\n"
" tape_init(&tape, 32);\n"
" size_t ptr = tape.size / 2;\n\n");
}
static void emit_epilogue(str *out) {
str_append(out, " free(tape.data);\n"
" return 0;\n"
"}\n");
}
static void emit_indent(str *out, int indent) {
for (int i = 0; i < indent; i++)
str_append(out, " ");
}
void emit_node(str *out, ast_node_t *node, int indent) {
for (; node; node = node->next) {
switch (node->type) {
case AST_INC:
emit_indent(out, indent);
str_append(out, "tape.data[ptr] += ");
str_appendf(out, "%d;\n", node->val);
break;
case AST_DEC:
emit_indent(out, indent);
str_append(out, "tape.data[ptr] -= ");
str_appendf(out, "%d;\n", node->val);
break;
case AST_PTR_INC:
emit_indent(out, indent);
str_append(out, "tape_move_right(&tape, &ptr, ");
str_appendf(out, "%d", node->val);
str_append(out, ");\n");
break;
case AST_PTR_DEC:
emit_indent(out, indent);
str_append(out, "tape_move_left(&tape, &ptr, ");
str_appendf(out, "%d", node->val);
str_append(out, ");\n");
break;
case AST_OUT:
emit_indent(out, indent);
str_append(out, "putchar((int)tape.data[ptr]);\n");
break;
case AST_IN:
emit_indent(out, indent);
str_append(out,
"{ int ch = getchar();\n"
" tape.data[ptr] = (ch == EOF) ? 0 : (unsigned char)ch; }\n");
break;
case AST_LOOP:
emit_indent(out, indent);
str_append(out, "while (tape.data[ptr]) {\n");
for (int i = 0; i < node->children.len; i++) {
emit_node(out, node->children._data[i], indent + 1);
}
emit_indent(out, indent);
str_append(out, "}\n");
break;
}
}
}
str gen_code(ast_node_t *ast) {
str out = {0};
emit_includes(&out);
emit_runtime(&out);
emit_prelude(&out);
emit_node(&out, ast, 1);
emit_epilogue(&out);
return out;
}
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