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mirror of https://github.com/janet-lang/janet synced 2024-11-10 10:49:54 +00:00
janet/value.c
2017-03-08 15:08:46 -05:00

466 lines
15 KiB
C

#include "util.h"
#include "value.h"
#include "ds.h"
#include "vm.h"
#include <stdio.h>
/* Boolean truth definition */
int gst_truthy(GstValue v) {
return v.type != GST_NIL && !(v.type == GST_BOOLEAN && !v.data.boolean);
}
static uint8_t * load_cstring(Gst *vm, const char *string, uint32_t len) {
uint8_t *data = gst_alloc(vm, len + 2 * sizeof(uint32_t));
data += 2 * sizeof(uint32_t);
gst_string_hash(data) = 0;
gst_string_length(data) = len;
gst_memcpy(data, string, len);
return data;
}
GstValue gst_load_cstring(Gst *vm, const char *string) {
GstValue ret;
ret.type = GST_STRING;
ret.data.string = load_cstring(vm, string, strlen(string));
return ret;
}
static uint8_t * number_to_string(Gst *vm, GstNumber x) {
static const uint32_t SIZE = 20;
uint8_t *data = gst_alloc(vm, SIZE + 2 * sizeof(uint32_t));
data += 2 * sizeof(uint32_t);
/* TODO - not depend on stdio */
snprintf((char *) data, SIZE, "%.17g", x);
gst_string_hash(data) = 0;
gst_string_length(data) = strlen((char *) data);
return data;
}
static const char *HEX_CHARACTERS = "0123456789abcdef";
#define HEX(i) (((uint8_t *) HEX_CHARACTERS)[(i)])
/* Returns a string description for a pointer */
static uint8_t *string_description(Gst *vm, const char *title, uint32_t titlelen, void *pointer) {
uint32_t len = 5 + titlelen + sizeof(void *) * 2;
uint32_t i;
uint8_t *data = gst_alloc(vm, len + 2 * sizeof(uint32_t));
uint8_t *c;
union {
uint8_t bytes[sizeof(void *)];
void *p;
} buf;
buf.p = pointer;
data += 2 * sizeof(uint32_t);
c = data;
*c++ = '<';
for (i = 0; i < titlelen; ++i) {
*c++ = ((uint8_t *)title) [i];
}
*c++ = ' ';
*c++ = '0';
*c++ = 'x';
for (i = sizeof(void *); i > 0; --i) {
uint8_t byte = buf.bytes[i - 1];
if (!byte) continue;
*c++ = HEX(byte >> 4);
*c++ = HEX(byte & 0xF);
}
*c++ = '>';
gst_string_hash(data) = 0;
gst_string_length(data) = c - data;
return data;
}
/* Returns a string pointer or NULL if could not allocate memory. */
uint8_t *gst_to_string(Gst *vm, GstValue x) {
switch (x.type) {
case GST_NIL:
return load_cstring(vm, "nil", 3);
case GST_BOOLEAN:
if (x.data.boolean) {
return load_cstring(vm, "true", 4);
} else {
return load_cstring(vm, "false", 5);
}
case GST_NUMBER:
return number_to_string(vm, x.data.number);
case GST_ARRAY:
{
uint32_t i;
GstBuffer *b = gst_buffer(vm, 40);
gst_buffer_push(vm, b, '[');
for (i = 0; i < x.data.array->count; ++i) {
uint8_t *substr = gst_to_string(vm, x.data.array->data[i]);
gst_buffer_append(vm, b, substr, gst_string_length(substr));
if (i < x.data.array->count - 1)
gst_buffer_push(vm, b, ' ');
}
gst_buffer_push(vm, b, ']');
return gst_buffer_to_string(vm, b);
}
case GST_TUPLE:
{
uint32_t i, count;
GstBuffer *b = gst_buffer(vm, 40);
GstValue *tuple = x.data.tuple;
gst_buffer_push(vm, b, '(');
count = gst_tuple_length(tuple);
for (i = 0; i < count; ++i) {
uint8_t *substr = gst_to_string(vm, tuple[i]);
gst_buffer_append(vm, b, substr, gst_string_length(substr));
if (i < count - 1)
gst_buffer_push(vm, b, ' ');
}
gst_buffer_push(vm, b, ')');
return gst_buffer_to_string(vm, b);
}
case GST_OBJECT:
{
uint32_t i, count;
GstBucket *bucket;
GstBuffer *b = gst_buffer(vm, 40);
GstObject *object = x.data.object;
gst_buffer_push(vm, b, '{');
count = 0;
for (i = 0; i < object->capacity; ++i) {
bucket = object->buckets[i];
while (bucket != NULL) {
uint8_t *substr = gst_to_string(vm, bucket->key);
gst_buffer_append(vm, b, substr, gst_string_length(substr));
gst_buffer_push(vm, b, ' ');
substr = gst_to_string(vm, bucket->value);
gst_buffer_append(vm, b, substr, gst_string_length(substr));
count++;
if (count < object->count)
gst_buffer_push(vm, b, ' ');
bucket = bucket->next;
}
}
gst_buffer_push(vm, b, '}');
return gst_buffer_to_string(vm, b);
}
case GST_STRING:
return x.data.string;
case GST_BYTEBUFFER:
return string_description(vm, "buffer", 6, x.data.pointer);
case GST_CFUNCTION:
return string_description(vm, "cfunction", 9, x.data.pointer);
case GST_FUNCTION:
return string_description(vm, "function", 8, x.data.pointer);
case GST_THREAD:
return string_description(vm, "thread", 6, x.data.pointer);
}
return NULL;
}
/* Simple hash function */
static uint32_t djb2(const uint8_t * str) {
const uint8_t * end = str + gst_string_length(str);
uint32_t hash = 5381;
while (str < end)
hash = (hash << 5) + hash + *str++;
return hash;
}
/* Simple hash function to get tuple hash */
static uint32_t tuple_hash(GstValue *tuple) {
uint32_t i;
uint32_t count = gst_tuple_length(tuple);
uint32_t hash = 5387;
for (i = 0; i < count; ++i)
hash = (hash << 5) + hash + gst_hash(tuple[i]);
return hash;
}
/* Check if two values are equal. This is strict equality with no conversion. */
int gst_equals(GstValue x, GstValue y) {
int result = 0;
if (x.type != y.type) {
result = 0;
} else {
switch (x.type) {
case GST_NIL:
result = 1;
break;
case GST_BOOLEAN:
result = (x.data.boolean == y.data.boolean);
break;
case GST_NUMBER:
result = (x.data.number == y.data.number);
break;
/* Assume that when strings are created, equal strings
* are set to the same string */
case GST_STRING:
if (x.data.string == y.data.string) {
result = 1;
break;
}
if (gst_hash(x) != gst_hash(y) ||
gst_string_length(x.data.string) != gst_string_length(y.data.string)) {
result = 0;
break;
}
if (!strncmp((char *) x.data.string, (char *) y.data.string, gst_string_length(x.data.string))) {
result = 1;
break;
}
result = 0;
break;
case GST_TUPLE:
if (x.data.tuple == y.data.tuple) {
result = 1;
break;
}
if (gst_hash(x) != gst_hash(y) ||
gst_tuple_length(x.data.string) != gst_tuple_length(y.data.string)) {
result = 0;
break;
}
result = 1;
{
uint32_t i;
for (i = 0; i < gst_tuple_length(x.data.tuple); ++i) {
if (!gst_equals(x.data.tuple[i], y.data.tuple[i])) {
result = 0;
break;
}
}
}
break;
default:
/* compare pointers */
result = (x.data.array == y.data.array);
break;
}
}
return result;
}
/* Computes a hash value for a function */
uint32_t gst_hash(GstValue x) {
uint32_t hash = 0;
switch (x.type) {
case GST_NIL:
hash = 0;
break;
case GST_BOOLEAN:
hash = x.data.boolean;
break;
case GST_NUMBER:
{
union {
uint32_t hash;
GstNumber number;
} u;
u.number = x.data.number;
hash = u.hash;
}
break;
/* String hashes */
case GST_STRING:
/* Assume 0 is not hashed. */
if (gst_string_hash(x.data.string))
hash = gst_string_hash(x.data.string);
else
hash = gst_string_hash(x.data.string) = djb2(x.data.string);
break;
case GST_TUPLE:
if (gst_tuple_hash(x.data.tuple))
hash = gst_tuple_hash(x.data.tuple);
else
hash = gst_tuple_hash(x.data.tuple) = tuple_hash(x.data.tuple);
break;
default:
/* Cast the pointer */
{
union {
void * pointer;
uint32_t hash;
} u;
u.pointer = x.data.pointer;
hash = u.hash;
}
break;
}
return hash;
}
/* Compares x to y. If they are equal retuns 0. If x is less, returns -1.
* If y is less, returns 1. All types are comparable
* and should have strict ordering. */
int gst_compare(GstValue x, GstValue y) {
if (x.type == y.type) {
switch (x.type) {
case GST_NIL:
return 0;
case GST_BOOLEAN:
if (x.data.boolean == y.data.boolean) {
return 0;
} else {
return x.data.boolean ? 1 : -1;
}
case GST_NUMBER:
/* TODO: define behavior for NaN and infinties. */
if (x.data.number == y.data.number) {
return 0;
} else {
return x.data.number > y.data.number ? 1 : -1;
}
case GST_STRING:
if (x.data.string == y.data.string) {
return 0;
} else {
uint32_t xlen = gst_string_length(x.data.string);
uint32_t ylen = gst_string_length(y.data.string);
uint32_t len = xlen > ylen ? ylen : xlen;
uint32_t i;
for (i = 0; i < len; ++i) {
if (x.data.string[i] == y.data.string[i]) {
continue;
} else if (x.data.string[i] < y.data.string[i]) {
return 1; /* x is less then y */
} else {
return -1; /* y is less than x */
}
}
if (xlen == ylen) {
return 0;
} else {
return xlen < ylen ? -1 : 1;
}
}
/* Lower indices are most significant */
case GST_TUPLE:
{
uint32_t i;
uint32_t xlen = gst_tuple_length(x.data.tuple);
uint32_t ylen = gst_tuple_length(y.data.tuple);
uint32_t count = xlen < ylen ? xlen : ylen;
for (i = 0; i < count; ++i) {
int comp = gst_compare(x.data.tuple[i], y.data.tuple[i]);
if (comp != 0) return comp;
}
if (xlen < ylen)
return -1;
else if (xlen > ylen)
return 1;
return 0;
}
break;
default:
if (x.data.string == y.data.string) {
return 0;
} else {
return x.data.string > y.data.string ? 1 : -1;
}
}
} else if (x.type < y.type) {
return -1;
}
return 1;
}
/* Allow negative indexing to get from end of array like structure */
/* This probably isn't very fast - look at Lua conversion function.
* I would like to keep this standard C for as long as possible, though. */
static int32_t to_index(GstNumber raw, int64_t len) {
int32_t toInt = raw;
if ((GstNumber) toInt == raw) {
/* We were able to convert */
if (toInt < 0 && len > 0) {
/* Index from end */
if (toInt < -len) return -1;
return len + toInt;
} else {
/* Normal indexing */
if (toInt >= len) return -1;
return toInt;
}
} else {
return -1;
}
}
/* Convert a number into a byte. */
static uint8_t to_byte(GstNumber raw) {
if (raw > 255) return 255;
if (raw < 0) return 0;
return (uint8_t) raw;
}
/* Get a value out af an associated data structure.
* Returns possible c error message, and NULL for no error. The
* useful return value is written to out on success */
const char *gst_get(GstValue ds, GstValue key, GstValue *out) {
int32_t index;
GstValue ret;
switch (ds.type) {
case GST_ARRAY:
if (key.type != GST_NUMBER) return "expected numeric key";
index = to_index(key.data.number, ds.data.array->count);
if (index == -1) return "invalid array access";
ret = ds.data.array->data[index];
break;
case GST_TUPLE:
if (key.type != GST_NUMBER) return "expected numeric key";
index = to_index(key.data.number, gst_tuple_length(ds.data.tuple));
if (index < 0) return "invalid tuple access";
ret = ds.data.tuple[index];
break;
case GST_BYTEBUFFER:
if (key.type != GST_NUMBER) return "expected numeric key";
index = to_index(key.data.number, ds.data.buffer->count);
if (index == -1) return "invalid buffer access";
ret.type = GST_NUMBER;
ret.data.number = ds.data.buffer->data[index];
break;
case GST_STRING:
if (key.type != GST_NUMBER) return "expected numeric key";
index = to_index(key.data.number, gst_string_length(ds.data.string));
if (index == -1) return "invalid string access";
ret.type = GST_NUMBER;
ret.data.number = ds.data.string[index];
break;
case GST_OBJECT:
ret = gst_object_get(ds.data.object, key);
break;
default:
return "cannot get";
}
*out = ret;
return NULL;
}
/* Set a value in an associative data structure. Returns possible
* error message, and NULL if no error. */
const char *gst_set(Gst *vm, GstValue ds, GstValue key, GstValue value) {
int32_t index;
switch (ds.type) {
case GST_ARRAY:
if (ds.data.array->flags & GST_IMMUTABLE)
return "cannot set immutable value";
if (key.type != GST_NUMBER) return "expected numeric key";
index = to_index(key.data.number, ds.data.array->count);
if (index == -1) return "invalid array access";
ds.data.array->data[index] = value;
break;
case GST_BYTEBUFFER:
if (ds.data.buffer->flags & GST_IMMUTABLE)
return "cannot set immutable value";
if (key.type != GST_NUMBER) return "expected numeric key";
if (value.type != GST_NUMBER) return "expected numeric value";
index = to_index(key.data.number, ds.data.buffer->count);
if (index == -1) return "invalid buffer access";
ds.data.buffer->data[index] = to_byte(value.data.number);
break;
case GST_OBJECT:
if (ds.data.object->flags & GST_IMMUTABLE)
return "cannot set immutable value";
gst_object_put(vm, ds.data.object, key, value);
break;
default:
return "cannot set";
}
return NULL;
}