48 lines
1.3 KiB
Go
48 lines
1.3 KiB
Go
package pdf
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import (
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"fmt"
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"os"
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"regexp"
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"strconv"
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)
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// CountPDFPages counts the number of pages in a PDF file.
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// It reads the PDF and extracts the page count from its internal structure.
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func CountPDFPages(filePath string) (int, error) {
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// Check if file exists
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if _, err := os.Stat(filePath); err != nil {
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return 0, fmt.Errorf("file not found: %w", err)
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}
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// Read the PDF file
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data, err := os.ReadFile(filePath)
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if err != nil {
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return 0, fmt.Errorf("failed to read file: %w", err)
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}
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// Convert to string for regex matching
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content := string(data)
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// Try to find /Type /Pages /Count pattern
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// This is the most reliable indicator of page count in PDF structure
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pageCountRegex := regexp.MustCompile(`/Type\s+/Pages\s+/Kids\s*\[(.*?)\]\s+/Count\s+(\d+)`)
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matches := pageCountRegex.FindStringSubmatch(content)
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if len(matches) >= 3 {
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count, err := strconv.Atoi(matches[2])
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if err == nil && count > 0 {
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return count, nil
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}
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}
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// Fallback: count individual /Type /Page objects
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pageRegex := regexp.MustCompile(`/Type\s+/Page[\s/\(\)]`)
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pageMatches := pageRegex.FindAllString(content, -1)
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if len(pageMatches) > 0 {
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return len(pageMatches), nil
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}
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// If we can't determine page count, return 0 (indicates error or unknown)
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return 0, fmt.Errorf("unable to determine page count")
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}
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