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"use strict";
const assert = require('assert');
class MBuffer {
constructor() {
this.buffer = null;
this.n = 0;
}
}
const luaZ_buffremove = function(buff, i) {
buff.n -= i;
};
const luaZ_resetbuffer = function(buff) {
buff.n = 0;
buff.buffer = [];
};
class ZIO {
constructor(L, reader, data) {
this.L = L; /* Lua state (for reader) */
assert(typeof reader == "function", "ZIO requires a reader");
this.reader = reader; /* reader function */
this.data = data; /* additional data */
this.n = 0; /* bytes still unread */
this.buffer = null;
this.off = 0; /* current position in buffer */
}
zgetc () {
return ((this.n--) > 0) ? this.buffer[this.off++] : luaZ_fill(this);
}
}
const EOZ = -1;
const luaZ_fill = function(z) {
let size;
let buff = z.reader(z.L, z.data);
if (buff === null)
return EOZ;
if (buff instanceof DataView) {
z.buffer = new Uint8Array(buff.buffer, buff.byteOffset, buff.byteLength);
z.off = 0;
size = buff.byteLength - buff.byteOffset;
} else {
assert(typeof buff !== "string", "Should only load binary of array of bytes");
z.buffer = buff;
z.off = 0;
size = buff.length;
}
if (size === 0)
return EOZ;
z.n = size - 1;
return z.buffer[z.off++];
};
/* b should be an array-like that will be set to bytes
* b_offset is the offset at which to start filling */
const luaZ_read = function(z, b, b_offset, n) {
while (n) {
if (z.n === 0) { /* no bytes in buffer? */
if (luaZ_fill(z) === EOZ)
return n; /* no more input; return number of missing bytes */
else {
z.n++; /* luaZ_fill consumed first byte; put it back */
z.off--;
}
}
let m = (n <= z.n) ? n : z.n; /* min. between n and z->n */
for (let i=0; i<m; i++) {
b[b_offset++] = z.buffer[z.off++];
}
z.n -= m;
if (z.n === 0) // remove reference to input so it can get freed
z.buffer = null;
n -= m;
}
return 0;
};
module.exports.EOZ = EOZ;
module.exports.luaZ_buffremove = luaZ_buffremove;
module.exports.luaZ_fill = luaZ_fill;
module.exports.luaZ_read = luaZ_read;
module.exports.luaZ_resetbuffer = luaZ_resetbuffer;
module.exports.MBuffer = MBuffer;
module.exports.ZIO = ZIO;
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