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Implement STRFMT and more printf-like format specifiers for string interpolation (#646)
Fixes #570 Fixes #178 Use errors for inapplicable format spec flags instead of -Wstring-format
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Rangi
GitHub
296
src/asm/format.c
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296
src/asm/format.c
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/*
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* This file is part of RGBDS.
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*
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* Copyright (c) 2020, RGBDS contributors.
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*
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* SPDX-License-Identifier: MIT
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*/
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#include <inttypes.h>
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#include <math.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "asm/format.h"
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#include "asm/warning.h"
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struct FormatSpec fmt_NewSpec(void)
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{
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struct FormatSpec fmt = {0};
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return fmt;
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}
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bool fmt_IsEmpty(struct FormatSpec const *fmt)
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{
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return !fmt->state;
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}
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bool fmt_IsValid(struct FormatSpec const *fmt)
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{
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return fmt->valid || fmt->state == FORMAT_DONE;
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}
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bool fmt_IsFinished(struct FormatSpec const *fmt)
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{
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return fmt->state >= FORMAT_DONE;
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}
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void fmt_UseCharacter(struct FormatSpec *fmt, int c)
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{
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if (fmt->state == FORMAT_INVALID)
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return;
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switch (c) {
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/* sign */
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case ' ':
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case '+':
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if (fmt->state > FORMAT_SIGN)
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goto invalid;
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fmt->state = FORMAT_PREFIX;
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fmt->sign = c;
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break;
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/* prefix */
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case '#':
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if (fmt->state > FORMAT_PREFIX)
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goto invalid;
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fmt->state = FORMAT_ALIGN;
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fmt->prefix = true;
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break;
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/* align */
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case '-':
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if (fmt->state > FORMAT_ALIGN)
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goto invalid;
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fmt->state = FORMAT_WIDTH;
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fmt->alignLeft = true;
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break;
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/* pad and width */
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case '0':
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if (fmt->state < FORMAT_WIDTH)
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fmt->padZero = true;
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/* fallthrough */
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case '1':
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case '2':
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case '3':
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case '4':
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case '5':
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case '6':
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case '7':
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case '8':
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case '9':
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if (fmt->state < FORMAT_WIDTH) {
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fmt->state = FORMAT_WIDTH;
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fmt->width = c - '0';
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} else if (fmt->state == FORMAT_WIDTH) {
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fmt->width = fmt->width * 10 + (c - '0');
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} else if (fmt->state == FORMAT_FRAC) {
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fmt->fracWidth = fmt->fracWidth * 10 + (c - '0');
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} else {
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goto invalid;
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}
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break;
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case '.':
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if (fmt->state > FORMAT_WIDTH)
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goto invalid;
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fmt->state = FORMAT_FRAC;
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fmt->hasFrac = true;
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break;
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/* type */
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case 'd':
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case 'u':
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case 'X':
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case 'x':
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case 'b':
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case 'o':
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case 'f':
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case 's':
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if (fmt->state >= FORMAT_DONE)
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goto invalid;
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fmt->state = FORMAT_DONE;
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fmt->valid = true;
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fmt->type = c;
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break;
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default:
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invalid:
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fmt->state = FORMAT_INVALID;
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fmt->valid = false;
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}
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}
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void fmt_FinishCharacters(struct FormatSpec *fmt)
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{
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if (!fmt_IsValid(fmt))
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fmt->state = FORMAT_INVALID;
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}
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void fmt_PrintString(char *buf, size_t bufLen, struct FormatSpec const *fmt, char const *value)
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{
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if (fmt->sign)
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error("Formatting string with sign flag '%c'\n", fmt->sign);
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if (fmt->prefix)
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error("Formatting string with prefix flag '#'\n");
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if (fmt->padZero)
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error("Formatting string with padding flag '0'\n");
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if (fmt->hasFrac)
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error("Formatting string with fractional width\n");
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if (fmt->type != 's')
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error("Formatting string as type '%c'\n", fmt->type);
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size_t len = strlen(value);
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size_t totalLen = fmt->width > len ? fmt->width : len;
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if (totalLen + 1 > bufLen) /* bufLen includes terminator */
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error("Formatted string value too long\n");
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size_t padLen = fmt->width > len ? fmt->width - len : 0;
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if (fmt->alignLeft) {
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strncpy(buf, value, len < bufLen ? len : bufLen);
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for (size_t i = 0; i < totalLen && len + i < bufLen; i++)
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buf[len + i] = ' ';
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} else {
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for (size_t i = 0; i < padLen && i < bufLen; i++)
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buf[i] = ' ';
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if (bufLen > padLen)
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strncpy(buf + padLen, value, bufLen - padLen - 1);
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}
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buf[totalLen] = '\0';
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}
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void fmt_PrintNumber(char *buf, size_t bufLen, struct FormatSpec const *fmt, uint32_t value)
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{
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if (fmt->type != 'X' && fmt->type != 'x' && fmt->type != 'b' && fmt->type != 'o'
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&& fmt->prefix)
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error("Formatting type '%c' with prefix flag '#'\n", fmt->type);
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if (fmt->type != 'f' && fmt->hasFrac)
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error("Formatting type '%c' with fractional width\n", fmt->type);
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if (fmt->type == 's')
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error("Formatting number as type 's'\n");
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char sign = fmt->sign; /* 0 or ' ' or '+' */
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if (fmt->type == 'd' || fmt->type == 'f') {
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int32_t v = value;
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if (v < 0) {
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sign = '-';
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if (v != INT32_MIN)
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value = -v;
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}
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}
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char prefix = !fmt->prefix ? 0
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: fmt->type == 'X' ? '$'
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: fmt->type == 'x' ? '$'
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: fmt->type == 'b' ? '%'
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: fmt->type == 'o' ? '&'
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: 0;
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char valueBuf[262]; /* Max 5 digits + decimal + 255 fraction digits + terminator */
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if (fmt->type == 'b') {
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/* Special case for binary */
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char *ptr = valueBuf;
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do {
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*ptr++ = (value & 1) + '0';
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value >>= 1;
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} while (value);
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*ptr = '\0';
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/* Reverse the digits */
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size_t valueLen = ptr - valueBuf;
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for (size_t i = 0, j = valueLen - 1; i < j; i++, j--) {
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char c = valueBuf[i];
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valueBuf[i] = valueBuf[j];
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valueBuf[j] = c;
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}
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} else if (fmt->type == 'f') {
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/* Special case for fixed-point */
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if (fmt->fracWidth) {
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char spec[16]; /* Max "%" + 5-char PRIu32 + ".%0255.f" + terminator */
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snprintf(spec, sizeof(spec), "%%" PRIu32 ".%%0%d.f", fmt->fracWidth);
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snprintf(valueBuf, sizeof(valueBuf), spec, value >> 16,
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(value % 65536) / 65536.0 * pow(10, fmt->fracWidth) + 0.5);
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} else {
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snprintf(valueBuf, sizeof(valueBuf), "%" PRIu32, value >> 16);
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}
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} else {
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char const *spec = fmt->type == 'd' ? "%" PRId32
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: fmt->type == 'u' ? "%" PRIu32
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: fmt->type == 'X' ? "%" PRIX32
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: fmt->type == 'x' ? "%" PRIx32
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: fmt->type == 'o' ? "%" PRIo32
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: "%" PRId32;
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snprintf(valueBuf, sizeof(valueBuf), spec, value);
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}
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size_t len = strlen(valueBuf);
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size_t numLen = len;
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if (sign)
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numLen++;
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if (prefix)
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numLen++;
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size_t totalLen = fmt->width > numLen ? fmt->width : numLen;
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if (totalLen + 1 > bufLen) /* bufLen includes terminator */
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error("Formatted numeric value too long\n");
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size_t padLen = fmt->width > numLen ? fmt->width - numLen : 0;
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if (fmt->alignLeft) {
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size_t pos = 0;
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if (sign && pos < bufLen)
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buf[pos++] = sign;
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if (prefix && pos < bufLen)
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buf[pos++] = prefix;
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strcpy(buf + pos, valueBuf);
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pos += len;
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for (size_t i = 0; i < totalLen && pos + i < bufLen; i++)
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buf[pos + i] = ' ';
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} else {
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size_t pos = 0;
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if (fmt->padZero) {
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/* sign, then prefix, then zero padding */
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if (sign && pos < bufLen)
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buf[pos++] = sign;
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if (prefix && pos < bufLen)
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buf[pos++] = prefix;
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for (size_t i = 0; i < padLen && pos < bufLen; i++)
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buf[pos++] = '0';
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} else {
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/* space padding, then sign, then prefix */
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for (size_t i = 0; i < padLen && pos < bufLen; i++)
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buf[pos++] = ' ';
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if (sign && pos < bufLen)
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buf[pos++] = sign;
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if (prefix && pos < bufLen)
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buf[pos++] = prefix;
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}
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if (bufLen > pos)
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strcpy(buf + pos, valueBuf);
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}
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buf[totalLen] = '\0';
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}
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