git ssb

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#include <values.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 <unistd.h>
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#include "lupng.h"
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#include "pngspark.h"
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static const size_t initial_size = 8;
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uint32_t parse_color(const char *color_str)
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{
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	if (!color_str) return 0;
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	if (color_str[0] == '#') color_str++;
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	uint32_t color = strtol(color_str, NULL, 16);
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	return 0xff000000 |
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		((color >> 16) | (color & 0x00ff00) | (color & 0xff) << 16);
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}
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int pngspark_init(struct pngspark *ps, size_t height, const char *color,
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		double scaling)
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{
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	ps->size = initial_size;
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	ps->num_values = 0;
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	ps->values = malloc(initial_size * sizeof(double));
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	if (!ps->values) return 1;
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	ps->color = parse_color(color);
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	ps->height = height;
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	ps->max_value = 0;
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	ps->min_value = DBL_MAX;
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	ps->scaling = scaling;
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	return 0;
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}
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int pngspark_append(struct pngspark *ps, double value)
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{
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	size_t i = ps->num_values++;
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	if (i >= ps->size) {
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		ps->values = realloc(ps->values, sizeof(double) * (ps->size <<= 1));
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		if (!ps->values) return 1;
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	}
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	ps->values[i] = value;
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	if (value > ps->max_value)
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		ps->max_value = value;
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	if (value < ps->min_value)
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		ps->min_value = value;
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	return 0;
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}
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static size_t write_fd(const void *ptr, size_t size, size_t count,
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		void *userPtr)
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{
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	return fwrite(ptr, size, count, (FILE *)userPtr);
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}
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int pngspark_write(struct pngspark *ps, FILE *file)
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{
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	size_t height = ps->height;
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	size_t width = ps->num_values;
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	LuImage *img = luImageCreate(ps->num_values, ps->height, 4, 8);
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	if (!img) return 1;
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	double *values = ps->values;
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	uint32_t *pixels = (uint32_t *)img->data;
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	ps->min_value *= ps->scaling;
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	double height_scale = (double)height / (ps->max_value - ps->min_value);
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	for (size_t x = 0; x < width; x++) {
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		size_t value = height - ((values[x] - ps->min_value) * height_scale);
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		for (size_t y = 0; y < value; y++)
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			pixels[x + width * y] = 0;
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		for (size_t y = value; y < height; y++)
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			pixels[x + width * y] = ps->color;
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	}
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	int ret = luPngWrite(write_fd, file, img);
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	luImageRelease(img);
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	return ret;
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}
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int pngspark_end(struct pngspark *ps)
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{
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	free(ps->values);
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	return 0;
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}
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