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/* parser.c
* Created: 2023-09-02
* Author: Aryadev Chavali
* Description: Functions for (de)serialising
*/
#include <string.h>
#include "./parser.h"
char *ast_to_str(node_t *ast, size_t size)
{
char *out = calloc(size + 1, 1);
if (!out)
{
print_error(
"[internal]", 0, 0,
"ERROR: Out of Memory (could not allocate buffer in ast_to_str)");
return NULL;
}
for (size_t i = 0; i < size; ++i)
{
switch (ast[i].type)
{
case NEXT:
out[i] = '>';
break;
case PREV:
out[i] = '<';
break;
case INC:
out[i] = '+';
break;
case DEC:
out[i] = '-';
break;
case OUT:
out[i] = '.';
break;
case READ:
out[i] = ',';
break;
case LIN:
out[i] = '[';
break;
case LOUT:
out[i] = ']';
break;
}
}
out[size] = '\0';
return out;
}
struct PResult parse_buffer(buffer_t *buffer)
{
node_t *nodes = NULL;
size_t usable = 0, loops = 0, loop_ends = 0;
// First pass: Compute |nodes|
for (size_t i = 0; i < buffer->size; ++i)
if (usable_character(buffer->data[i]))
{
++usable;
if (buffer->data[i] == '[')
++loops;
else if (buffer->data[i] == ']')
++loop_ends;
}
if (loops != loop_ends)
{
// Look for the point of failure
i64 stack = 0;
for (size_t i = 0, col = 0, row = 0; i < buffer->size; ++i)
{
if (buffer->data[i] == '\n')
{
col = 0;
++row;
continue;
}
else if (buffer->data[i] != ']' && buffer->data[i] != '[')
{
++col;
continue;
}
else if (buffer->data[i] == ']')
{
--stack;
}
else if (buffer->data[i] == '[')
{
++stack;
}
++col;
if (stack < 0)
{
print_error(buffer->name, row, col,
"ERROR: Unbalanced square brackets!");
goto error;
}
}
}
nodes = calloc(usable, sizeof(*nodes));
if (!nodes)
{
print_error(
"[internal]", 0, 0,
"ERROR: Out of Memory (could not allocate buffer in parse_buffer)");
return (struct PResult){0};
}
// Second pass: parse nodes
for (size_t i = 0, col = 0, row = 1, nptr = 0; i < buffer->size; ++i)
{
++col;
if (buffer->data[i] == '\n')
{
++row;
col = 0;
}
else if (usable_character(buffer->data[i]))
{
nodes[nptr].col = col;
nodes[nptr].row = row;
switch (buffer->data[i])
{
case '>':
nodes[nptr].type = NEXT;
break;
case '<':
nodes[nptr].type = PREV;
break;
case '+':
nodes[nptr].type = INC;
break;
case '-':
nodes[nptr].type = DEC;
break;
case '.':
nodes[nptr].type = OUT;
break;
case ',':
nodes[nptr].type = READ;
break;
case '[':
nodes[nptr].type = LIN;
nodes[nptr].loop_ref = -1;
break;
case ']':
nodes[nptr].type = LOUT;
nodes[nptr].loop_ref = -1;
break;
}
++nptr;
}
}
// Third pass: setup loop references
size_t stackptr = 0;
if (loops)
{
node_t *stack[loops];
memset(stack, 0, loops);
for (size_t i = 0; i < usable; ++i)
{
node_t *node = nodes + i;
if (node->type == LIN)
stack[stackptr++] = node;
else if (node->type == LOUT)
{
// Access last IN loop
--stackptr;
node->loop_ref = stack[stackptr] - nodes;
stack[stackptr]->loop_ref = i;
}
}
}
if (stackptr > 0)
{
node_t *node = nodes + usable - 1;
print_error(buffer->name, node->row, node->col,
"ERROR: Unbalanced square brackets!");
goto error;
}
return (struct PResult){nodes, usable, loops};
error:
if (nodes)
free(nodes);
return (struct PResult){0};
}
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