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